Patent ID: 8779194

Claim:
A method for the preparation of a compound of formula IV R—NH—CO—X—R′ (IV) wherein —R is an aliphatic or aromatic organic group, and R′ is an aliphatic organic group and X is NH; S or NR″, wherein R″ is alkyl; or R′ is an aromatic organic group and X is S or O, comprising (a) reacting a compound of formula R—N 3 (II), wherein R is as defined above, with a compound of trivalent phosphorous in the presence of an aqueous solution of hydrogen carbonate ions, in an organic solvent, to obtain an isocyanate of formula III —R—N═C═O— (III) wherein R is as defined above, and (b) reacting the isocyanate of formula III with a compound of formula R′—XH, wherein R′ and X are as defined above, to obtain a compound of formula IV.