Condensation of acyl chloride on sodium cyanate - preparation of acyl isocyanates.pdf

Tetrahedron Vol 44, No. 19, pp 6079 to 6086,1988 Pnnted In Great Bntam. 0040-4020/88 $3 00 + 00 {~, 1988 Pergamon Press pic Abstract CONDENSATION OF ACYL CHLORIDE ON SODIUM CYANATE PREPARATION OF ACYL ISOCYANATES M.-Z. DENG, P. CAUBERE* Universite de Nancy I, Laboratoire de Chimie Organique I, UA CNRS nO 457 B.P. 239, 54560 VANDOEUVRE-les-NANCY Cedex (FRANCE) J.P. SENET, S. LECOLIER S.N.P.E., Centre de Recherches du Bouchet, 91710 VERT-Ie-PETIT (FRANCE) (Received in Belgium 28 June 1988) The catalytic effects of various metal halides and solvents on the reaction of benzoyl chloride with sodium cyanate were studied. It has been found that SnC14, and ZnC12 catalyze the reaction to give the corresponding acyl isocyanates in good yields. The scope of the reaction was studied and a number of aroyl isocyanates and their derivatives were prepared. A few non aromatic isocyanates and their derivatives were also prepared. Acyl ureas and acyl carbamates playa considerable role in phytochemistryl,2,3 as well as in medicinal chemistry4 Interested in the synthesis of a number of such derivatives we were confron- ted with the preparation of acyl isocyanates which are among their best precursors. A number of acyl isocyanate preparations have been reported in the literature s ,6,7 However none of them was completely satisfactory for our purposes. We therefore decided to study the synthe- sis of acyl isocyanates and we wish to report in the present publication the results obtained concer- ning the condensation of acyl halides with sodium cyanate. Condensation of aroyl chlorides on sodium cyanate : influence of the catalysts and solvents Aroyl isocyanates can be prepared by the condensation of aroyl chlorides with sodium cya- nates in general. However, special catalysts and solvents must be used for receiving satisfactory yields. For searching the best conditions the condensation of benzoyl chloride l (I eq.) with sodium isocyanate ~ (1.3 eq.) in an acetonitri