Carboxylic acid amid N-subst

Subst. carboxylic acid amides from N. C O —>- NHCOR... 

Electrochemical oxidation of N-subst. carboxylic acid amides 5,6-Dihydro-l,3-oxazinium salts from ethylene derivs. 

N-Subst. from unsubst. carboxylic acid amides... 

Diphenyl phosphoryl azide in dimethylformamide followed by triethylamine added at or below 0° to a soln. of N-carbobenzoxy-L-leucyl-L-leucine and L-valyl-L-phenylalanine methyl ester hydrochloride in the same solvent, stirred several hrs. at the above temp, and overnight at room temp. -> product. Y 87%. - Practically no racemization occurred. F. e., also direct prepn. of urethans from carboxylic acids (cf. Synth. Meth. 17, 393) by a simplified Curtius degradation, s. T. Shioiri, K. Ninomiya, and S. Yamada, Am. Soc. 94, 6203 (1972) Tetrah. Let. 1973, 2343 synthesis of N-subst. carboxylic acid amides and peptides with diethyl phosphoryl cyanide s. Tetrah. Let. 1973, 1595 coupling reagents in peptide synthesis, review, s. Y. S. Klausner and M. Bodansky, Synthesis 1972, 453 review of peptide synthesis s. J. Meienhofer, Chem. Technol. 3, 242 (1973). 

No pyrimidine is formed in the absence of the above catalyst. Also N-subst carboxylic acid amides from esters s. N. Nakamizo, Bull. Chem. Soc. Japan 44, 2006 (1971). 

---