Exp107-15-3.JPG

Objective

To synthesize 1-(5-tert-butyl-2-furyl)methanamine from Furfurylamine and tert-butanol in the presence of a strongly acidic cation exchanger, amberlyst 15 (H). [É. Ya. Lukevits 1986]

Procedure

The synthesis of 1-(5-tert-butyl-2-furyl)methanamine was accomplished by stirring a solution of tert-butanol (5mmol, 370.6mg, 478.19uL), Furfurylamine (5mmol, 485.6 mg, 441.8 uL) and amberlyst 15 (H) dry (11.5 meq; 2.446 g) in CDCl3 (5 mL) for 24h at room temperature.Subsequently, the solvent and resin free chemicals were filtered off. Dichloromethane was then added to the resin. Then the resin bound amine was freed by adding 10% NaOH solution to obtain a pH ~11. The resin was then filtered off and the solution obtained was extracted with dichloromethane, dried over anhydrous MgSO4, concentrated and characterized.

Results

Furfurylamine
H NMR
C NMR
tert-butanol
H NMR
C NMR
107A
H NMR (t = 32min)
H NMR (t = 20h 02min)
107B
H NMR

Discussion

Proton NMR of 107B indicates that the reaction did occur. Peaks corresponding to the t-butyl gourp (1.28ppm) can be correlate to the furan protons (6.16, 6.32ppm). Moreover there appears to be some amount of starting material, amine still present in the product. This is seen clearly looking at the methylene peak at 3. 7ppm (from amine) and the product peaks at 3.85ppm in 107B.

Conclusion

The product was contaminated with the starting amine. Needs further purification. Longer reaction time or refluxing the reaction mixture for a short time may likely help complete the reaction. (Reaction optimization is needed)
Friedel-Crafts alkylation of furfuryl amine can be accomplished under mild conditions using amberlyst resin.

Log

2007-06-08

20:00 Made up a solution of furfurylamine, amberlyst 15 (H) and tert-butanol in CDCl3 to obtain 107A
20:32 Obtained H NMR of 107A (800uL) (t = 32min).

2007-06-09

16:02 Obtained H NMR of 107A (800uL) (t = 20h 02min).
20:00 Stopped stirring the reaction mixture, filtered the solvent off.
20:20 Dichloromethane (~10mL) was then added to the obtained resin bound product.
20:25 In order to release the amine from resin, 10% NaOH (~5mL) was then added it, until a pH 11 was obtained. This solution was stirred for 10min.
20:40 The solution was then filtered off to remove the free resin and two layers (DCM / aqueous layers) were separated using a separatory funnel.
20:55 The product (if any) was further extracted from the aqueous layer with DCM (5mL)
21:05 The combined methylene chloride layer was then dried with anhydrous MgSO4 (~6g)
21:20 The dry methylene chloride layer was set on a high vac (5mm of Hg) to concentrate the product.
21:55 Turned off the vacuum pump.The product has an intense smell of ammonia.

2007-06-10

13:20 It was assumed that the product may still contain traces of methylene chloride, therefore it was set back on the vacuum pump (5mmHg)
14:30 Removed from the vacuum pump...hardly anything remaining in the rb flask...this is 107B (10mg)
14:44 Obtained H NMR of 107B



Reference
1. É. Ya. Lukevits, et.al.; Chemistry of Heterocyclic Compounds; Vol. 22, Iss. 6 pp 678-679.
2. I. Iovel, et.al.; Chemistry of Heterocyclic Compounds; Vol. 31, Iss.2 pp 140-143

Tags

Furfurylamine InChI=1/C5H7NO/c6-4-5-2-1-3-7-5/h1-3H,4,6H2
1-(5-tert-butyl-2-furyl)methanamine InChI=1/C9H15NO/c1-9(2,3)8-5-4-7(6-10)11-8/h4-5H,6,10H2,1-3H3