Ethylmorpholine → (N-benzyloxycarbonyl-L-isoleucyl)-N-(4-bromo-2-picolinoylpheny)-glycinamide

Participants

Reaction Conditions

Reaction Steps

3.18 g. of N-benzyloxycarbonyl-L-isoleucine were dissolved in 25 ml. of dry tetrahydrofuran and cooled to -10° C. 1.57 ml. of isobutylchloroformate and 1.52 l ml. of N-ethylmorpholine were added and the resulting solution was stirred at -10° C. for 20 minutes. 4.24 g. of 2-amino-N-(4-bromo-2-picolinoylphenyl)-acetamide dihydrochloride, prepared as described in part (A) (i) of Example 1, were added and the resulting suspension was cooled to -20° C. 3.13 ml. of N-ethylmorpholine in 25 ml. of dimethylformamide were added to the vigorously stirred suspension over a period of 0.5 hour. The resulting mixture was stirred at -20° C. for a further 40 minutes and left at room temperature overnight. The product was worked up in a manner analogous to that described in part (A) (ii) of Example 1. Recrystallisation from ethanol yielded 4.2 g (60%) of (N-benzyloxycarbonyl-L-isoleucyl)-N-(4-bromo-2-picolinoylpheny)-glycinamide of melting point 174°-176° C.

Provenance & Evidence