Most Recent Experiments on Wiki

Experiments currently in progress are published on the UsefulChem wiki, for reasons discussed here. They are organized through a contents page.

Exp 016

Objective:To convert adrenaline to DOPAL using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure: Taken from Robbins (1965).A solution of adrenaline (227.74 mg, 1.243mmol) in 85% phosphoric acid (6 mL) was heated in a 12mL vial to 120C in a glycerol bath then removed from heat and allowed to cool for 30 seconds. The solution was added to distilled water (36 mL) and then saturated with NaCl. An ether extract (15 mL, 15 mL, 10mL), was dried over MgSO4 then evaporated to yield 16A (15.6 mg).

Results
Characterization of 16A
TLC of 3:1 methylenechloride methanol with iodine to stain.
HMR(with integration). HMR extension. NMR 8.5-9.7
solubility: good in methanol, poor in methylene chloride
HMR D2O added making 16B (note: the scale is way off)

Discussion:
A plausible assignment of the major peaks for the HMR of 16A: 9.57(CHO),8.96(phenol), 8.9(phenol), 6.5(aromatic), 6.6(aromatic), 6.7(aromatic), 3.5 (CH2). Peaks at 3.4 and 2.5 are attributed to DMSO-d6. Addition of D2O removes the 2 peaks near 9 ppm, supporting the phenolic assignments, although the scale is off and some degradation (perhaps to the carboxylic acid after several days in DMSO).
Li et al in 1998 report the HMR for the target aldehyde (in DMSO-d6) as: 9.67(t, 1H, CHO), 7.27 (dd, 1H, aromatic), 7.2 (d, 1H, aromatic), 6.9 (d, 1H, aromatic), 3.5 (d, 2H, CH2). The peaks in the 6.9-7.3 ppm range are inconsistent with HMR spectra of 4-alkylcatechols, such as 4-methylcatechol, with the three aromatic hydrogens genrally appearing in the 6.5-6.9 ppm range. Since our spectrum is consistent with the majority of other spectra of similar molecules, we suggest that our assignments are correct and that the peaks reported by Li are erroneous.

Our initial attempts focused on modifying a report of the decomposition of adrenaline in glacial acetic/perchloric acids in order to avoid using perchloric acid as stated here. With limited access to NMR for a few months, we attempted to monitor the progress of the reaction mainly by TLC. Based on reported purification of DOPAL using hexanes/methylene chloride on silica gel, we assumed that it was soluble in methylene chloride. Unfortunately adrenaline free base is not that soluble in chlorinated solvents, making monitoring its disappearance by TLC very difficult. We interpreted the lack of formation of a UV-active spot in a methylene chloride or benzene extract of the acidic solution as an indication that the aldehyde did not form.

Conclusion:
Based mainly on HMR evidence of the crude ether wash, DOPAL can be made and isolated, without chromatography, in 5-10% yield as a major product after a brief (15 min) decomposition of adrenaline in 85% phosphoric acid at 100-120 C.

Log
2006-06-28
1.12:00) Glycerol bath was placed on hot plate (setting 3.5)
2. 12:15) Adrenaline and phosphoric acid solution began to heat in 15mL glass vial in glycerol bath that was initially at 100C. Setup Video
3. 12:30) Solution heated to 120C over 15 minutes while glycerol bath heated to up to 140C. Acid solution was taken off of heat, and cooled for 30 seconds.
4. Acid solution was added to 36mL distilled water and allowed to sit for 1.5 hours.
5. Saturated with NaCl (without filtering).
6. Poured solution without excess NaCl into a separatory funnel. Extracted with 15 mL ethyl ether.
7. Extracted again with 15 mL ethyl ether and then 10mL ethyl ether. Acid portion was saved.
8. Saturated with NaCl, solution poured into 2 mL of 0.05M potassium phosphate monobasic-sodium hydroxide 7.00pH buffer solution.
9. Poured ether into 50mL beaker without excess salt.
10. Added magnesium sulfate to dry and filtered.
11. Vacumed off the solvent in a rotatory vacum.
12. Vacumed off remaining ether for 2 hours using high vac, resulting in 16A (15.6 mg)
13. Attempted to dissolve a small portion of 16A in methylene chloride but it did not dissolve
14. Added a small portion of 16A to methanol and it dissolved turning a champagne color.
15. TLC of 16A in methylene chloride produced no movement
16. TLC of 16A in methanol produced too much movement, Rf close to 1.
17. TLC of 16A in 3:1 methylene chloride/methanol produced good movement - Rf = 0.8
18. All of 16A was dissolved in DMSO-d6 and HMR was taken

2006-7-5
19. HMR was taken of half of 16A with added D2O (16B)

Exp 015

Objective:To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure:Taken from Preparation and Properties of p-Hydroxyphenylacetaldehyde and 3-Methoxy-4-Hydroxyphenylacetaldehyde by Jay H. Robbins Archives of Biochemistry and Biophysics.A solution of adrenaline (217 mg, 1.18 mmol) in 85% phosphoric acid (6 mL) was heated in a 12mL vial to 120C in a glycerol bath then removed from heat and allowed to cool for 30 secondsthen added to water (36 mL) and then saturated with NaCl, followed by extraction with ether (17mL, 10mL, 10mL).

Results
Video of set upTwo stains were done without a TLC run Ninhydrin stain Ansaldehyde stainRun in pure methanol visible with iodine.HNMR was obtained of the product after it was re-dissolved with ether, dried with MgSO4, and vacuumed again to have a net weight of 15mg. There is no carbonyl peak that I can see and the NMR seems scewed. There is an expanded version as well.

Discussion
Based on the published H-NMR of DOPAL alone there does not seem to be any aldehyde formed. However HMR spectra of 4-alkylcatechols, such as 4-methylcatechol, with the three aromatic hydrogens genrally appearing in the 6.5-6.9 ppm range gives reason to believe that the published spectra is incorrect.

Conclusion
The aldehyde was not produced however the reaction will be attempted once more.

Log
2006-6-22
16:55] turn on hot plate to heat glycerol
17:10] put phosphoric solution in 10mL vial and then in heated glycerol bath
17:23] solution heated to 120C, taken off of heat and cooled for 30seconds. added to 36mL distilled water.
19:00] Saturated with NaCl(didn't filter)
19:13] Poured solution without excess NaCl into a separatory funnel. Extracted with 17mL anhydrous ether
19:20] Extracted with 10mL anhydrous ether
19:24] Extracted with 10mL ether
19:30] Performed TLC 1:1 methylene chloride hexanes (no movement), pure methylenechloride (no movement), pure methanol (some movement)**Ninhydrin and Ansaldehyde stains give little information.
2006-6-23
rotovaped ether extracts
2006-6-26
vacuumed off remains from rotovap. wt=15mg dry product
would not disolve in methylene chloride but did disolve in methanol
TLC of 1:1 methylene chloride in hexanes showed nothing. Methanol had same movement

Exp 014

The Ugi Rerun of experiment 006
Objective : To accomplish the Ugi Synthesis and cyclization to a diketopiperazine using phenylacetaldehyde, 5-methylfurfurylamine, N-(tert) butoxycarbonyl)L-methionine, and benzylisocyanide using the protocol described here. The target diketopiperazine is not predicted to be active but is a close analog of the product that we wish to make once the catechol aldehyde is obtained.
Procedure:
To a 50 ml Erlenmeyer flask added methanol (20 ml), phenyl acetaldehyde, 623µl , 5-methylfurfurylamine 555µl, benzylisocyanide 608µl, and N-(tert) butoxycarbonyl) L-methionine 1.24604 gms. The mixture was stirred for 15 h, evaporated, refluxed for 45min in 1,2-dichloroethane (27 ml) and trifluoroacetic acid (3 ml) then evaporated again to a dark oil. The crude product was taken up in dichloromethane (30 ml), washed with water, dried over anhydrous MgSO4 and evaporated again. A dark, reddish oil was obtained.

Log
1. 9:00pm (05/30/2006) In a 50ml Erlenmeyer flask, 20ml of methanol placed. To it 623µl of phenyl acetaldehyde, 555µl of 5-methylfurfurylamine, 608µl of benzylisocyanide and
1.24604 gms of N-(tert) butoxycarbonyl) L-methionine was added.
2.The reaction was stirred at room temperature with a teflon coated stir bar on a stir plate for 15 hours (stopped stirring at 12:00 noon (05/31/2006). (Videos of the reaction being stirred)
3.Methanol was evaporated on a rotovap set at 100C, Obtained 3.239gms the crude product.
4. Added 27ml of 1,2-dichloroethane and 3ml of trifluoro acetic acid to the methanol void sample in a pre weighed round bottom flask. Refluxed the contents of the flask for 45 mins (the rheostat settings had to be adjusted because the reaction mixture has stopped refluxing during the process),the boiling points of the solvents are, TFA= 72.4 ° C and 1,2-Dichloroethane = 83 °C
5.The reaction mixture was rotovaped (set at 100C) again after 45mins on reflux.
6.The resultant compound was washed with water (twice, 70mls and 30 mls) and partitioned in methylene chloride (60mls)
7.After separation; the organic layer was dried over anhydrous Magnesium Sulfate, filtered.
8. The obtained crude product was subjected to an NMR analysis.
9.2:30pm (06/01/2006) The crude product was further dried under vacuum until it foamed and settled. The process was continued for a period of one and half hours.(4:00pm)
9. After evaporation under vacuum 3.5174gms of product was obtained.
10. 1.3051 gms of the product was weighed and intorduced on a chromtotron. Intially a 2:1 mix of hexanes and methylene chloride was used (about 400ml), 19 of 20mls portions were acuumulated.
11. Most of the compund stillremained on the rotor disc. The compound was let dry
overnight on the rotor.
Upon Dr. Bradley's suggestion the remaining compound was removed from the rotor using methanol.
12. The compound in methanol was rotovaped and evaporated under low pressure, and introduced back on the chromatotron, however the the eluent used this time was 1:1 hexanes
and methylene chloride (100mls mix) The eluent composition was changed gradually from 1:1 hexanes, methylene chloride to just methylene chloride (100mls), then it was further changed to 0.5% methanol in methylene chloride.

Polarity of the solvent was changed regularly. 0.5% methanol, 1% methanol, 2% methanol, 3% methanol,

4% methanol, 6% methanol, and 8% methanol in methylene chloride.
16 fractions were accumulated.

Exp 013

Objective:
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure:
Adrenaline (215 mg, 1.173 mmol) was added to a 100mL round bottom flask with glacial acetic acid (40mL) and water (4mL). The solution was refluxed 24 hours under nitrogen.

Results:
Took round bottome flask of sample 13E, and evaporated the 40mL of acetic down to 10mL. 2hr video 10hr video 24hr video

TLC results of what remained from vacuum pump show some movement in 1:1 methylene chloride methanol. Also in pure methanol.

Discussion:
Analyzing peaks and waiting for spinning to be fixed. Concentration of any product may have been too little however the number of scans was also insufficient. Next reaction will be more concentrated.

Log:
2006-5-30
9:30) sample taken (13A), solution yellow
10:57) solution boiling with slight reflux, heat raised, solution still yellow, sample taken(13B)
11:20) reflux is insufficient, heat turned up to produce better reflux
14:56) sample taken(13C), reflux is better but slow, no changes in color
20:10) sample taken(13D), solution is still yellow, reflux is decent

2006-5-31
8:15) solution did not change over night, sample taken(13E) reflux was still decent

2006-6-2
Took C13 on Varian 300MHz NMR. Concentration wa approximately 20mg(combination of unreacted adrenaline and any product that formed)/1mL acetic acid

2006-6-9
15:00)Vacuumed off the remaining acetic acid. A dark polymer like solid remained.
16:00)Scrapped a little off and dissolved it in 1-1.5mL methanol.
16:40)TLC in 1:1 methylene chloride hexanes showed nothing.
16:50)TLC Pure methylene chloride showed nothing.
17:00) 1:1 methylene chloride methanol produced some movement.
17:10) Pure methanol produced about the same result as the 1:1 methylene chloride in methanol.

Exp 012

Objective:
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure:
Adrenaline (227 mg, 1.239 mmol) was added to a 100mL round bottom flask that holds a thermometer with concentrated sulfuric acid (80mL) . The solution was held at 70C for 24 hours under nitrogen.

Results:
Obtained HNMR but sulfuric acid was the main peak. Need C13 NMR but concentration is too low. Spinner on 300MHz NMR is not operating correctly. Sulfuric solution was diluted with 400mL of water. 2 x 150mL was taken out and one separated with methylene chloride and the other with benzene. TLC of the methylene chloride extraction revealed nothing as well as the benzene extraction.
2hr Video 10hr video 24hr video

Discussion:
No further tests have been done. Nothing else to report at this time.

Log:
2006-5-30
9:30) t=0 sample taken, rheostat set at 51, starting temperature is 30C, solution is light brown
10:57) t=1hr 40min sample taken, temp from rheostat=51 is 61C, rheostat increased to 57, hood sash is fully open, solution is brown
11:18) temperature at 68C from rheostat=57, rheostat pushed to 59
12:15) temperature at 75C from rheostat=59, lowered rheostat to 55, solution is dark brown
15:10) temp=64 from rheostat=55, reset the rheostat set between 56-57, very dark solution, sample t=5.5 hrs
20:10) t=10.5hr sample taken, color same, temp=75C and hood sash was lowered and temp decreased to 68C, rheostat set to approx. 56

2006-5-31
8:15) no change in color, sash remained at lowered position all night, rheostat at 56 and temperture at 72C

Exp 011

Objective:
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure:
Adrenaline (302 mg, 1.653 mmol) was added to a 100mL round bottom flask with concentrated sulfuric acid (40mL) and a benzene layer (27mL+10mL). The solution was refluxed 24 hours under nitrogen.

Results:
The start of the reaction clearly showed two layers here.
After 40minutes there seemed to be only one phase. This video may be deceiving because there is a reflection on the round bottom flask giving the appearance of 2 layers.
A TLC of a small benzene/water extraction (benzene layer) after 24 hours showed little signs of anything UV active.

Discussion:
We would expect the catechol aldehyde to partition in the organic phase of a benzene/aqueous sulfuric acid mixture and be UV active when spotted on a TLC plate, but did not observe this even after 24 hours of reflux.
Here is paper on an experiment that used silica sulfuric acid and benzene to make benzene sulfonic acid. Chances are good that is what happened. Possibly the sulfuric acid concentration should be reduced or the concentration of adrenaline which can act like a soap between the benzene and acid layer.

Conclusion:
Refluxing adrenaline in a mixture of benzene/sulfuric acid for 24 h did not produce the desired aldehyde.

Log:
2006-5-24
1700hours The bubbler oil is brown from Exp 010 but the reaction starts and heat has been turned on. Took sample.
1740hours Where is the benzene layer? The volume is the same and there is only a small benzene layer. Took sample.
19:40)before leaving added 10mL more benzene. Sample taken.
2006-5-25
9:40) Volume of solution was the same. No sample taken.
17:20) Heat turned off. Flask and solution were allowed to cool under nitrogen while water continued through the condenser.
18:00) Turned off water and nitrogen and put parafilm over flask.

Exp 010

Objective:
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure:
Adrenaline (303 mg, 1.653 mmol) was added to a 100mL round bottom flask that had a spout for a thermometer then added concentrated sulfuric acid (40mL). The solution was heated to an uncertain temperature with a reflux condensor for 14 hours under nitrogen.

Results:
At some point during the night the stir plate stopped stirring and sulfuric vapors escaped through the the condenser and ended up in the oil for the nitrogen bubbling. As seen in the videos the thermometer did not actual reach the liquid layer and the reading it gave was off of fumes from the sulfuric acid.
Evening video Next morning video.
Reaction was stopped, water was added to solution. Tried to separate with methlyenechloride but the acid solution was an emulsion. A quick TLC revealed no UV absorption.

Discussion:
Unsure if sulfuric would still travel up the condenser if more stirring was provided. Benzene layer may be needed for concentrated sulfuric. The temperature was probably to high which would account for the color change in the bubbling oil.

Conclusion
Make sure thermometer is in contact with the solution next time.

Log
2006-5-22
19:50) Added sulfuric acid, and adrenaline to a 100mL r.b.f. with a spout for a thermometer. (Thermometer did not touch solution) Took sample t=0, left over night.
2006-5-23
9:50) Stirrer stopped during the night and sulfuric escaped through the condensor and out the N2 needle. Heat turned off. Sample taken.

Exp 009

Objective
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure
Adrenaline (112 mg, 0.665 mmol) was added to a 50mL round bottom flask with concentrated sulfuric acid (15mL) and benzene (15mL) and water (2mL). The solution was refluxed for 24 hours under nitrogen.

Results
The bottom layer (sulfuric layer) turned from yellow to brown to black faster than Exp 008. Benzene layer remained colorless.
Spotting the benzene layer showed some UV activity however in 2:1 methylene chloride hexanes there seemed to be a very small movement.
The benzene layer at first gradually disappeared however this was fixed after witnessing the reflux condenser here when taking the first sample.
Start of reflux, sample 23hrs of reflux, not seen in other refluxes.

Discussion
If the aldehyde formed in the benzene layer, which the slight movement on the TLC plate would suggest, in this before and after shot ,then the reaction is working. However the concentration is low and the movement can not be seen well. Any amines, including the adrenaline starting material, should remain in the acidic aqueous phase. The TLC plates were stained with Ninhydrin and it shows that there are no amines in the benzene layer. The samples that were spotted on the TLC plates had very little benzene in them for some reason. They are at the beginning of the reaction so it is assumed that the aldehyde does not form that rapidly. The problem with keeping the benzene layer was fixed by taping the condenser and increasing the nitrogen pressure.

Conclusion
The desired aldehyde may have been produced but there is still too little of it. Next try will be an increase in adrenaline of about 3 times this concentration.

Log
2006-05-04
13:30. Added all components to 50mL round bottom flask
13:55. Took sample t=0 and turned heat on
14:28. Reflux starts
15:28. Sample t=1hr taken
16:28. Sample t=2hr taken
21:10. Sample t=6.5hr taken, benzene layer depleting, 15mL more benzene added
2006-05-05
9:45. Sample 19hr taken
12:00. Sample 21.5hrs taken
13:40. Sample 23 hours taken
14:30. Sample 24 hours taken, heat turned off, solution capped
2006-05-09
TLC done in 1:1 methylene chloride - no change
TLC done in 2:1 methylene chloride - some movement
2006-05-11
Added 20mL of DI water to round botttom flask and put into 125mL separation funnel
Separated out the acid layer and the benzene layer
Added 10mL more water to acid layer and put back into separation funnel
Added 20mL of benzene, separated and added benzene layers
Put acid layer back into separation funnel and added 30mL benzene
Separated, added benzene layers together and set acid layer aside
Rotovaped the combined benzene layers in 100mL round bottome flask ending with some acid layer still present because Magnesium sulfate was not added.
Took round bottome and added benzene approx. 80mL and 10mL of water, separated then added magnesium sulfate to benzene layer and filtered
Took round bottom flask with benzene and rotovaped ending with a little benzene still left over with a yellowish color.
2006-05-12
Took round bottom flask that was rotovaped which still had some benzene and put it on a vacuum pump. Before doing so the weight of a 50mL round bottom flask was taken (33.86g), the contents of the 100mL r.b.f. was added along with 5mL of methylene chloride, the weight was taken again (40.35g). The flask was put on the vacuum pump and the methylenechloride and benzene were evaporated. The final weight was also taken (33.87g) giving an approximate 10mg of product. A Chromatotron will be done.
2006-05-15
A Chromatotron was performed under nitrogen gas. 10mL of methylene chloride was added to the vacuumed sample and spotted first on a TLC plate and then added to the Chromatotron. A TLC plate was done in pure methylene chloride prior to the chromatotron and the same spot ran quickly suggesting that the same compound is present. The solvent used was 2:1 methylene chloride with hexanes. The bands formed and moved quickly under the force of the moving plate. Before first fraction After first fraction

Exp 008

Objective
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is described here.

Procedure
Adrenaline (50.5 mg, 0.283 mmol) was added to a 50mL round bottom flask with 6M sulfuric acid (15mL) and benzene (15mL). The solution was refluxed for 24 hours under nitrogen.

Results
The bottom aqueous layer turned yellowish ,to brown and gradually to black.
The top benzene layer remained colorless.
Spotting the benzene layer at various times on a TLC slide showed no UV activity after evaporation.
The benzene layer gradually disappeared by the end of the 24 hour period.
beginning of reflux video (avi)
End of reflux video (avi)

Discussion
If the aldehyde formed, it would be expected to be extracted into the benzene layer. Any amines, including the adrenaline starting material, should remain in the acidic aqueous phase. Because the aldehyde is aromatic, a spot on a TLC plate should be UV active. Because the benzene layer was not UV active when spotted, it seems that no significant amount of aldehyde was formed.
The loss of the benzene layer may be due to poor reflux condenser-round bottom flask connection.

Conclusion
The desired aldehyde was not produced in refluxing benzene/6M sulfuric acid over 24 hours. A stronger acid concentration might work.

Log
2006-04-24
17:25] First sample taken and heat turned on under N2.
18:05] Reflux starts
19:15] First reflux sample taken 1hr 10mins from start of reflux
20:05] Second reflux sample taken 2 hrs; some yellowish color
2006-04-25
12:20] Third reflux sample taken 18hrs 15mins; light brown color; benzene layer has decreased
15:20] Fourth sample taken 21hrs 15mins; dark color and diminishing benzene layer
16:20] Fifth reflux sample taken 22 hrs 15mins; benzene layer is gone
17:25] Sixth reflux sample taken 23hrs from start of reflux; heat turned off reflux stopped.
2006-04-27
TLC were done in 1:2 methylenechloride and hexanes. There was no UV activity.

Exp 007

Objective
To convert adrenaline to a catechol aldehyde using acid catalysis. How this fits into the synthesis of anti-malarials is explained here.

Procedure
To a 50 mL round bottom flask was added adrenaline (54.2 mg, 0.23 mmol), acetic acid (25 mL), and 6M sulfuric acid (2 mL). The mixture was refluxed for 24 h.

Results
The solution turned yellow after 24 hours.

Discussion and Conclusion
Because the sample was accidentally discarded, students need to adhere to a better sample labeling and storage protocol.

Log
2006-04-04
1. Added adrenaline, acetic acid and 6M sulfuric acid to flask.
2. 14:45 Attached to a reflux condenser and began heating. Took out 1mL sample of starting reaction (sample 7a).
3. 14:56 Solution began refluxing. Reaction changed color from clear to yellow

2006-04-05

Allowed reaction to reflux for 24 hours. Solution turned dark; this may be a result of oxidation as the nitrogen tank emptied overnight.

15:00 Performed an extraction on the reaction on the reaction using methylene chloride [how much] and water [how much]. Added anhydrous magnesium sulfate to organic layer to get rid of any remaining water.

Exp 006

Objective:
To test out the Ugi Synthesis and cyclization to a diketopiperazine using phenylacetaldehyde, 5-methylfurfurylamine, N-(tert) butoxycarbonyl)L-methionine, and benzylisocyanide using the protocol described here. The target diketopiperazine is not predicted to be active but is a close analog of the product that we wish to make once the catechol aldehyde is obtained.
As pointed in one of the comments posted to exp 003, the complete reaction was carried out at a higher concentration for each of the component involved. Also, the reaction mixture was heated to 80C for 30 min in 1,2-dichloroethane and TFA at the uncyclized stage.

Procedure:
To a 50 ml Erlenmeyer flask was added methanol (20 ml), phenyl acetaldehyde (55µl, 0.49 mmol) , 5-methylfurfurylamine (55µl, 0.49 mmol) , benzylisocyanide 60µl, 0.49mmol) and N-tert-butoxycarbonyl L-methionine (124.7 mg, 0.50 mmol). The mixture was stirred for 24 h, evaporated, refluxed for 30 min in 1,2-dichloroethane (9 ml) and trifluoroacetic acid (1 ml) then evaporated again to a dark oil. The crude product was taken up in dichloromethane (5 mL), washed with 5% HCl, dried over anhydrous MgSO4 and evaporated to yield a dark red oil.

H-NMR of the crude product in CDCl3:

TLC after extraction using 1:1 5%HCl/DCM

Discussion

The H-NMR of the crude product does not show an aldehyde peak in the 9-10 ppm region, indicating that at least one starting material is consumed. The crude product may contain both cyclized a diketopiperazine and deprotected uncyclized amine but the NMR of the mixture cannot distinguish between these. For a possible mechanism of the Ugi reaction, click here.

Conclusion

This experiment will have to be aborted if the HNMR obtained is to be trusted. It can be seen that the furan peaks at 5.9 ppm are not strong enough to advocate an isolation and purification.

This experiment helped me acquaint with the chromatotron, NMR and refreshed other experimental techniques .
Log

1. 8:38 pm (03/28/2006): In a 50ml Erlenmeyer flask, 20ml of methanol placed. To it 55µl (0.49mmol) of phenyl acetaldehyde, 55µl (0.49mmol) of 5-methylfurfurylamine, 60µl (0.49mmol) of benzylisocyanide and 0.12468 gms (0.50mmol) of N-(tert) butoxycarbonyl) L-methionine was added. An FTIR spectrum was obtained at t=0.
2. The reaction was stirred at room temperature with a teflon coated stir bar on a stir plate.
3. 8:38pm (03/29/2006): Stirring was stopped.
4. 8:45pm (03/29/2006): Methanol was evaporated from the sample using a rotovap (75 C).
5. 10:30pm (03/29/2006) Added 9ml of 1,2-dichloroethane and 1ml of trifluoro acetic acid to the methanol void sample in a round bottom flask. Heated the reaction mixture for about 5 mins before the vapors got intense and had to attach a reflux condenser, the heating was turned off after 30 mins..; the boiling points of the solvents are, TFA= 72.4 ° C and 1,2-DCE = 83 °C
6. 11:10pm (03/29/2006) After 30 mins the solvents were evaporated using a rotovap, at 85C.
7. 11:40pm (03/29/2006) The residue is a dark brown liquid.
8. 12:10am (03/29/2006) A TLC of the product was run in a mixture of 10ml 1,2-dichloroethane and 10ml of hexanes.
9. H-NMR of the crude final product was also obtained. (Varian 300Mz Instrument)
10. 2:30pm (04/02/2006) Extraction: Added 5ml of 5% HCl and 5 ml methylenechloride to the round bottom flask containg the crude product and transferred it to a separatory funnel. Separated the bottom methylenechloride layer from the top aqueous layer. Washed the aquoues acid layer twice with 5mls of methylenechloride and collected the bottom methylenechloride layer each time. Combined the organic layers and dried it over anhydrous magnesium sulfate (MgSO4). Evaporated the dichloromethane using a rotovap and collected the extracted product. A TLC of the product was obtained (Shown above).
11. 11:30 am (05/10/2006) Separation using a Chromatotron : The compound was dissolved in 10 ml of methylene chloride, applied to the rotating plate on the chromatotron.The round bottom flask was rinsed with 1ml of methylene chloride, the residue was poured over the rotating plate of the chromatotron. A mix of 1:1 hexanes and methylene chloride was used initially as the mobile phase. (60mls).
    In the mean time fractions were collected. To speed-up the movement of the compound a more polar solvent mix was used. The composition of the mobile phase was changed from 1:1 hexanes, methylene chloride to 1:1 methylene chloride, methanol (gradually), and finally to methanol.
    
    
    
    

Exp 005

Purpose: To synthesize 3,4-dihydroxyphenylacetaldehyde from adrenaline. How this fits into the synthesis of anti-malarials is explained here. In a prior attempt using glacial acetic acid as the main solvent, monitoring by TLC and IR was problematic. In this attempt benzene will be added and samples drawn from the top benzene layer should be easier to chromatograph and follow by IR. Also since benzene boils near 80C it will be convenient to reflux at a lower temperature.

Procedure: Benzene (12 mL), glacial acetic acid (12mL), 6M sulfuric acid (1.5mL) and adrenaline (51.7 mg, 0.282mmol) are stirred and refluxed in a 50mL flask under nitrogen.

ABORT
Discussion and Conclusion
The video after 60 minutes shows that a small brown layer separates at the bottom of the flask, suggesting that it contains only the aqueous sulfuric acid dissolving the adrenaline. Since the point of adding the benzene was to extract out the resulting aldehyde from the acetic and sulfuric acids, this didn't work. The acetic acid is clearly favoring the benzene layer. The heavy streaks in the TLCs are consistent with this.

Log

2006-03-28

12:15) Mixed chemicals and turned on heating mantle at 80 degrees C. A sample of 1mL, t=0 (5A) was taken and as expected there was some separation. The bottom layer was brownish in color while top layer was clear.

12:46) Sample 5B or t= 30 min was taken. Still under N2, the flask was allowed to cool to take the sample. The solution did not separate in the amount of time lotted in any visible way. Sample does not separate. TLC of 5A(t0) vs 5B (30 min) with methylene chloride (MC) as eluent was put in iodine chamber.

13:15) Sample 5C (t=60 min) was taken. Still no clear separation in the solution, although the solution itself is clear except for the adrenaline which has not dissolved. Video at this time shows that a small brown layer settles at the bottom of the flask when stirring stops.

13:35) Sample 5D (t=80min) was taken. Reflux solution remains the same, samples turn somewhat cloudy in atmosphere. After a while cloudiness dissipates and sample is clear. Pic of TLC 5A (t0) vs 5C (60min) and 5D(80min) (5D plate is on the left and on each plate 5A is on the left).

14:20) TLC of 5A vs 5B, 5C and 5D was made in 1:1 (MC/hexanes) and is similar to pure MC

14:45) Sample 5E taken t=2.5hrs. Refluxed stopped and solution saved. UV lamp is needed. TLC's reveal after several minutes in iodine chamber what would be a moving streak surrounded by the iodine coating. Streaks of 5B-E against 5A are higher.

Exp 003

Objective:
To test out the Ugi Synthesis and cyclization to a diketopiperazine using phenylacetaldehyde, methyl furfurylamine, N(tert-Butoxycarbonyl)L-methionine, and benzylisocyanide using the protocol described here. The target diketopiperazine is not predicted to be active but is a close analog of the product that we wish to make once the catechol aldehyde is obtained. 2006-02-09

Procedure PartA:
Reagents in MeOHPlaced 50mL methanol in an 125mL Erlenmeyer flask. Added 23 microliters phenylacetaldehyde(0.21mmol), 24 microliters 5-methylfurfurylamine(0.21mmol, 52.66mg N-(tert) butoxycarbonyl)L-methionine (0.21mmol), and 26 microliters of benzylisocyanide (0.21mmol) in that specific order. Solution was flushed with nitrogen and stoppered. The reaction was stirred at room temperature ovenight. Various samples were taken out over time to monitor the reaction via TLC.

Results of PartA
mass spec are inconclusive. See discussion for detailed explanation.

Procedure PartB:
TFA AdditionPippetted out 5mL of reaction solution. Evaporated solvent in vaccuo at 65 degrees Celsius. Prepared solution of 10% TFA in methylene chloride. Added 10mL of TFA solution to products.

Results of PartB
2006-03-10
Mass Spectrum from 2006-02-17 Mass Spectrum of the matrix used in MS MS of 3H MS of 3G MS of 3I

Discussion
Based on the results of the TLC we can postulate that the intermediate diketopiperazine is there, but not the cyclized version. This is evidenced by the TLC plates where we were expecting the final product to have moved faster with the eluent. I believe the product didn't cyclize was because it was not heated in the last step.

Concerning the FAB-MS analysis of this experiment, it does not look like anything useful can be extracted. None of the pure starting materials show M+ peaks, just a lot of matrix peaks. Also, it is unclear that the calibration is correct based on a possible assignment of a strong peak corresponding to a benzyl fragment at 91.6 (off by 0.6 amu) phenylacetaldehyde expect M+ at 120 but don't see that in either spectrum (Mass Spectrum1, Mass Spectrum2) - in both spectra see peak at 91.6 (is this benzyl fragment off by 0.6 amu?) 5-methylfurfurylamine expecting MH+ at 116 but don't see any there or nearby (Mass Spectrum) N-(tert) butoxycarbonyl)L-methionine expecting M+ at 249 - there is a small peak at 251.0 (Mass Spectrum) benzylisocyanide expecting M+ at 117 but nothing nearby (Mass Spectrum) - note that phenyl isocyanide is drawn on this spectrum ConclusionWithout better testing this experiment will have to be done again. NMR and MALD/I is suggested.

LOG
PartA
13:03 Solution was flushed with nitrogen and stoppered. 2mL of starting solution was placed in a 1 dram vial. (sample 3A)
13:50 2mL of the reaction was pippetted out and placed in a 1 dram vial. (sample 3B).
14:15 2mL of the reaction was pippetted out and placed in a 1 dram vial. (sample 3C).
15:05 2mL of the reaction was pippetted out and placed in a 1 dram vial. (sample 3D).
17:05 2mL of the reaction was pippetted out and placed in a 1 dram vial. (sample 3E). Let reaction continue to stir over night.

2006-2-13
Reaction continued to stir over the weekend. 11:00 2mL of reaction was pippetted out and placed in a 1 dram vial (sample 3F) TLC plates of samples 3B, 3C, 3D, and 3E were run against the starting sample (3A) using methanol as the eluent. All of the samples (including 3A) had an Rf value of approximately1.
A TLC was run in 4:1 Hexanes and Dichloromethane with 3A as the standard against the final sample of the Ugi synthesis. The Rf value of the sample is 0.35 while the standard is 0.08. IR graphs were made for the Ugi synthesis at t=o, 50min., 72min, and 120min. 30microliter samples of the Ugi synthesis were evaporated on a KBr pellet. Graphs of the KBr pellets were also made to determine any possible error. It was determined by the t=72min graph that there was an insufficient amount of sample to provide a clear graph and all that was seen was the vibration of the material. The t=120min had a sample of 60microliters which produced a better plot.

2006-02-14 (James)
Submitted a 0.5mL sample of the reaction mixture (now 5 days at room temp) for MS analysis by FAB. The product mass weight was found with very little of the reactants. However the peak of this is small, and there is an overwhelming peak of a mass of 436.7. What this is, is not yet known. The sample that was given was not heated in TFA (trifluoroacetic acid) so we are not yet sure that this is the cyclized diketopiperazine. This is the uncyclized product. Also the 436.7 peak could have something to do with the golden yellow color that we have seen in the samples.

2006-02-16 (James)
11:00. Solutions of the reactants of the mock Ugi synthesis were prepared to perform a TLC vs the 3F sample of the reaction (which was taken two days after the solution was heated) in order to determine if the reactants are still present. Solutions were made as follows in 2mL glass viles: (16A) 30microliters of Phenylacetaldehyde in 1mL MeOH. (16B) 30microliters of Methylfurfurylamine in 1mL MeOH. (16C) 30microliters of Benzylisocyanide in 30mL MeOH 11:45. The results of the TLC in 4:1 hexanes and methylenechloride are as follows: (16A) The Rf value of the standard (3F) was 0.32, while the reactant was 0.23 (16B) The Rf value of 3F was 0.38 while the reactant did not travel at all. (16C) The Rf value of 3F and the reactant was 0.21. They traveled approximately the same distance.
12:15. A solution of the last reactant was made to do a TLC. (16D) 0.0011g of N-(tert-Butoxycarbonyl) in 1mL MeOH.
12:30. Results of the TLC in 4:1 hexanes and methylenechloride are an Rf value of 0.32 for the standard while the reactant did not move.
13:10. The reactant solutions (16A-D) were given over for MS analysis along with a sample of t=0 of the mock Ugi reaction and a sample of the extraction from 13t[2] (See Exp 002). The t=0 solution was was golden yellow as the rest of the samples taken from this reaction.

PartB
2006-02-17 (Alicia)
Phenylacetaldehyde (Mass Spectrum1, Mass Spectrum2) Methyl furfurylamine (Mass Spectrum) N(tert-Butoxycarbonyl)L-methionine (Mass Spectrum) Benzylisocyanide (Mass Spectrum)
15:02 Solution turned from bright yellow to deep red-brown. Pippetted out approximately 1 mL and placed in a 1dram vial (sample 3G). Allow solution to stir at room temperature for 1 hr. Ran a TLC plate of sample 3G against our original starting solution (3A) using 1:1 methylene chloride/hexane. The starting sample had an rf value of approximately 0.2 while 3G had an rf=0.
16:02 Pippetted 1mL of reaction and placed in a 1 dram vial (sample 3H, t=1hr). Ran TLC plate against sample 3A. Evaporated remaining solution in vaccuo at 65 degrees Celsius and dissolved product in methylene chloride(sample 3I). A 0.5mL sample of 3G, 3H, and 3I will be submitted for MS on Monday.

2006-02-20
Samples were submitted for MS. IR graphs were also mad with sample 3G and 3I.

2006-03-02 (Alicia)Ran TLC of phenalacetaldehyde against samples 3B, 3C, 3D, 3E, 3F, 3G, and 3H. Ran TLC of 5-methylfurfurylamine against samples 3B, 3C, 3D, 3E, 3F, 3G, and 3H. The eluent used for both was 9:1 hexane/methylene chloride. The 5-methylfurfurylamine appeared to run down into the eluent, will re-run TLC. It was determined that these samples were overloaded. Will re-run samples of 3F(right before TFA soln was added) and 3H (after TFA was added).Will upload pictures of the TLC plates as soon as equipment becomes available.

2006-03-08 (Alicia)
Prepared a phenylacetaldehyde/methanol solution by adding 4.6uL phenylacetaldehyde to 10mL of methanol. Ran a TLC plate against samples 3F and 3H using a 6:4 methylene chloride/hexane solution as the eluent. The picture may be somewhat unclear. Prepared a 5-methylfurfurylamine/methanol solution by adding 4.8uL 5-methylfurfurylamine to 10mL of methanol. Ran a TLC plate against samples 3F and 3H using a 6:4 methylene chloride/hexane solution as the eluent. Prepared a N(tert-butoxycarbonyl)L-methionine/methanol solution by adding 5.3mg N(tert-butoxycarbonyl)L-methionine to 5mL methanol. Ran a TLC plate against samples 3F and 3H using a 6:4 methylene chloride/hexane solution as the eluent. Prepared a benzylisocyanide/methanol solution by adding 5.2uL of benzylisocyanide to 10mL of methanol. Ran a TLC plate against samples 3F and 3H using a 6:4 methylene chloride/hexane solution as the eluent. These numbers were chosen to reflect the concentration of the reactants in the original starting solution.

2006-03-09
Made dilute samples of the raw starting materials for TLC. Phenylacetaldehyde (18P), Benzylisocyanide (18B), and Methylfurfurylamine (18M) where made as 30microliters samples in 1 mL methanol while a small amount of crystals was used to make the sample of N-(tertButoxcarbonyl)-L-methionine (18N) in 1mL methanol. The TLC was don in 1:1 hexanes methylenechloride. TLC plates are marked as the samples were named. The spots on the TLC plate from left to right are the sample, after TFA, and before TFA. TLC Pic1 TLC Pic2

2006-03-14 (Alicia)
Based on previous TLC of the reaction it was concluded that we have obtained the linear intermediate. More TFA will be added to the solution and then refluxed. TLC of the reaction will be taken to see if the reaction cyclized. This will be evidenced by a faster moving spot than the linear intermediate. Prepared a 10% TFA/methylene chloride solution. Added 20mL TFA solution to products (3I). Attached flask to a reflux condenser and ran under nitrogen gas. Took sample of the solution (3J). Turned on heat at 12:19.
12:40 Reaction began refluxing.13:09 Took sample of the refluxing reaction (3K). Ran TLC against 3J using 1:1 methylene chloride/hexanes as the eluent.
13:50 Took sample of the refluxing reaction (3L). Ran TLC against 3J using 1:1 methylene chloride/hexanes as the eluent.
14:35 Took sample of the refluxing reaction (3M). Ran TLC against 3J using 1:1 methylene chloride/hexanes.17:00 Took sample of the refluxing reaction(3N). Ran TLC against 3J using 1:1 methylene chloride/hexanes. The TLCs don't appear to have any spots on them. The amount of product that was left in the flask was uncertain which may explain why there aren't any moving spots on the TLC plates. It may be worthwhile to restart this experiment using dichloroethane as the solvent instead of methylene chloride. Aborted.

NEXT
-submit reactants and reaction before and after TFA for usual MS analysis (not FAB)
-update discussion for TLC analysis and future TLC work
-determine if the reaction worked and if not, what happened

Exp 002

Objective: To convert adrenaline to a catechol aldehyde under acid catalysis via refulxing under nitrogen gas in glacial acetic acid and a small amount of sulfuric acid. How this fits into the synthesis of anti-malarials is explained here.
IR of Adrenaline

Procedure:

Prepared a solution of 25.5mg (0.139mmol) adrenaline, 25mL acetic acid, 1.5ml 1M sulfuric acid and placed in a 50mL round bottom flask. Refluxed solution under nitrogen gas. Solution refluxed for approximately 2 hours. Ran TLC plates of the reaction against a standard solution of adrenaline and acetic acid.

Results

TLC plates were run under methylene chloride and under methanol. Those under methanol had rf values of approximately 0.6. Those under methylene chloride had rf values of approximately 0.1.
AldehydeMS
MS Aldehyde in glacial acetic
MS Aldehyde from extraction

Aborted

Discussion: The mass spectrum that was done by FAB shows no M+ peak for the catechol aldehyde as discussed here in the Discussion section. There was probably some oxidation of the reaction in taking the samples. The TLC plates show no signs of the aldehyde forming either. Moving on.

Conclusion: We learned from Exp003 that FAB is too harsh a process to give us the M+ and M+2 peaks that we expects. MALD/I may generate better results. Also because there were no fast moving spot on the TLC, as is expected, the product was probably not formed.

Log
1. 11:55) Prepared a new solution(Soln1) of 25.5mg (0.14mmol) of adrenaline, 25mL of glacial acetic acid, and 1.5mL of a 1M sulfuric acid solution. Started reflux of new solution in a 50mL round bottom flask, and a 0.5mL sample was taken to use in an NMR tube in a sit in a temperature bath at 60 degrees Celsius flushed with nitrogen gas. Other than this, no sample was taken for a t=0, however at t=0 the solution appeared clear with no visible amounts of undissolved adrenaline.
N.B.: The NMR tube was kept in the temperature bath for an hour and a half, however because a working NMR was not available in a sufficient amount of time, that portion of the experiment has been scraped.
2. 12:55) A 1mL sample was taken from the refluxing of Soln1. (t=1hr) This sample became tan over time as well as the refluxing Soln1.
3. 13:55) A 1mL sample was taken from the refluxing Soln1 which was now very tan. (t=2hr). The Soln1 was taken off reflux and a loosely fitting stopper was placed on the round bottom flask which was then no longer on nitrogen gas atmosphere.
4. 14:10) A small solution of 1.87mg of adrenaline and 1mL of glacial acetic acid was made in a 3mL vile to use as a standard(Std) for TLC against Soln1 samples t=1hr and t=2hr.
5. 14:22) A TLC was done with the Std and t=1hr in both methanol and methylene chloride. The TLC plates were first spotted with thin capillaries however this produced no visible results even in an iodine chamber so the plates were respoted using a melting point capillary tube. The plates were then reintroduced to their respectable methanol and dichloromethane. The Rf values for the plates in dichloromethane were in the vicinity of 0.1 and those in methanol were in the vicinity of 0.6.

2006-02-08
11:00. Prepared a solution of 26.4mg adrenaline and 25mL acetic acid.

11:30. Refluxed under N2 gas. Took a 1mL t=0 sample.

12:30. Took a 1.5mL sample of reaction(13t[1]). Took half a mL of this and extracted with 5mL of water and 0.5mL methylene chloride. Ran two TLC of 13t[1] versus the t=0 sample in 4:1 hexanes methylene chloride in MeOH.

13:30. Took a 1.5mL sample of reaction(13t[2]). Took half a mL of this and extracted with 1mL methylenechloride and 5mL of water. Ran two TLC of
13t[2] versus t=0 in 4:1 hexanes methylene chloride in MeOH.

14:30. Took a 1.5mL sample of reaction(13t[3]). Turned off reflux.

Exp 001

Objective: To convert adrenaline to a catechol aldehyde under acid catalysis in methanol/water. How this fits into the synthesis of anti-malarials is explained here.

2006-01-24

1. Prepared a 50mL stock solution of 0.100g adrenaline, 5mL 1M sulfuric acid and methanol in a flask.
2. 14:47 Placed 1.86mL of adrenaline solution and 2.0mL 1M sulfuric acid in a round bottom flask. A 0.5mL sample of the starting reaction solution was pippetted out (sample A) and placed into a 1 dram vial. Attached the flask to a condenser and into a sand bath and turned the heat on low.

3. 15:17 Pippetted out 0.5mL of the reaction. (sample B)

4. 15:47 Pippetted out 0.5mL of the reaction. (sample C)

5. 16:47 Pippetted out 0.5mL of the reaction. (sample D)

6. 18:47 Pippetted out 0.5mL of the reaction. (sample E)

7. TLC was performed on all samples of the reaction using methanol as the eluent.

sample A Rf= 0.338
sample B Rf= 0.571 The sample began to spread out.
sample C Rf= 0.661 The sample continued to spread out.
sample D Rf= 0.625 The sample is less spread out than previous samples.
sample E Rf= 0.642

Reaction was allowed to run overnight.

2006-01-25

Contents of the reaction flask decomposed. Aborted.

Discussion
Based on this experiment we were able to conclude that no aldelhyde was formed and that the reaction needed to be ran under nitrogen in order to avoid oxidation. In addition there was not enough sample in the reaction flask to produce significant results.

2006-01-26

1. 15:25)Prepared solution 26.6mg (0.148mmol) of Adrenaline, 20mL of Methanol and 5mL of a 1M aqueous sulfuric acid solution. Put solution in a 50mL round bottom flask and attached to a reflux condenser under nitrogen gas and started heating the flask.
Sample was taken at t=15:25 (t=0)
2. 15:55) Sample was taken at t=15:55. It was noted that the sample had started to reflux. (t=0.5)
3. 16:25) Sample was taken at t=16:25 (t=1)
4. 17:25) Sample was taken at t=17:25. The samples were approximately 1mL-2mL. (t=2)

2006-01-27

5) Micropipetted 0.5mL of each sample (A, B, C, and D) and placed them into a new sample vial.
6) Added a small amount of sodium bicarbonate powder to these vials until bubbling ceased.
7) TLC was used to assess production of an aldehyde
8) Using an eluent of 4:1 Hexane:Methylene Chloride
i) None of the samples migrated on the TLC plates (7A, 7B, 7C, & 7D)
9) Using an eluent of pure methylene chloride
i) None of the samples previously spotted on plates 7A, 7B, 7C, or 7D migrated with this eluent
10) Using an eluent of methanol
i) New plate 8A created using dotted sample from t=0 vial and t=0 with sodium bicarbonate vial (left lane t=0, right lane t=0 with sodium bicarbonate)
a) Solvent traveled 6.0cm. Tip of spot: left lane: 3.8cm, right lane: 3.3cm
ii) New plate 8B created using dotted sample from t=0.5 vial and t=0.5 with sodium bicarbonate vial. Set-up same as in (i)
a) Solvent traveled: 5.9cm. Tip of spot: left lane: 4.0cm, right lane: 3.1cm
iii) New plate 9A created using dotted sample from t=1 vial and t=1 with sodium bicarbonate vial. Set-up same as in (i and ii)
a)Solvent traveled: 6.5cm. Tip of spot: left lane: 4.1cm, right lane: 2.0cm
iv) New plate 9B created using dotted sample from t=2 vial and t=2 with sodium bicarbonate vial. Set-up same as in (i, ii, and iii)
a) Solvent traveled: 5.5cm. Tip of spot: left lane: 3.8cm, right lane: 3.3cm

The following picture was taken of plates 8A, 8B, 9A, and 9B.



Aborted.











Conclusion
Adrenaline (5.8 mMolar), sulfuric acid (0.2 M) in 4:1 methanol/water refluxed for 2h in air did not generate DOPAL, based on the absence of a faster moving spot in TLC.