Ammonia → (s)-1-n-boc-pipecolamide

Participants

Reaction Conditions

Reaction Steps

2.29 g (10 mmoles) of BOC-HPro-OH are dissolved in 30 ml of ethyl acetate, 1.4 ml (10 mmoles) of triethylamine are added to the solution, the mixture is cooled to -10° C., and then 1.3 ml (10 mmoles) of isobutyl chloroformate are added dropwise. After 15 minutes of stirring gaseous ammonia is introduced into the reaction mixture for 0.5 hours at -10° C., and then the mixture is allowed to stand at 0°-5° C. for 2 hours. The precipitate is filtered off, the filtrate is evaporated, and the oily residue is dissolved in 30 ml of chloroform. This solution is washed twice with 10 ml of n hydrochloric acid, each, twice with 10 ml of n sodium hydrocarbonate solution, each, and then with 10 ml of water, dried over anhydrous sodium sulfate, and evaporated. The oily residue is crystallized from n-hexane to obtain 1.95 g of a crude product. This crude product is recrystallized from a mixture of ethyl acetate and ether to obtain 1.78 g (78%) of BOC-HPro-NH2 ; m.p.: 138°-140° C., Rf2 =0.43, [α]D25 =-24.85° (c=1%, in acetic acid).

Provenance & Evidence