PROCEDIMIENTO PARA LA PREPARACION DE TIADIAZOLIL-UREAS.

摘要

1,254,468. 1,3,4-Thiadiazole derivatives; fluoroacyl-thiosemicarbazides. AGRIPAT S.A. 23 Dec., 1968 [27 Dec., 1967; 11 Oct, 1968], No. 60940/68. Heading C2C. The invention comprises compounds of the general formula wherein R 1 represents a perfluoroalkyl radical with 1 or 2 carbon atoms, R 2 represents hydrogen or an alkyi radical having. to 4 carbon atoms, R 3 represents hydrogen or an alkyl radical having 1 to 4 carbon atoms with the proviso that at least one of the symbols R 2 and R 3 represents hydrogen, and R 4 represents an alkyl radical having 1 to 4 carbon atoms which is unsubstituted or is substituted by a substituent selected from chlorine, bromine, cyano, alkoxy having 1 to 3 carbon atoms, alkyl thio having 1 to 3 carbon atoms; an alkenyl or alkynyl radical with 3 or 4 carbon atoms, a cycloalkyl radical with 3 to 6 carbon atoms, or. an alkoxy radical having 1 to 3 carbon atoms. The compounds may be prepared from amines of the general formula by (i) reaction with a haloformic acid ester or halothioformic acid s-ester in the presence of an acid-binding agent to form the corresponding carbamate or thiocarbamate which is reacted with an amine of the formula R 3 R 4 NH, (ii) reaction with an isocyanate of the formula R 4 -NCO where R 4 is as defined above except that it may not represent cyanoalkyl, alkenyl, alkynyl or alkoxy, (iii) when R 2 = H, reaction with a compound of the formula R 3 R 4 N-CO-halogen in the presence of an acid-binding: agent, R 3 being C 1-4 alkyl, (iv) reaction with COCl 2 to give the carbamoyl chloride which is then reacted with an amine R 3 R 4 NH. Aminothiadiazoles of the Formula II above are obtained by ring-closure with polyphosphoric acid fluoroacyl -thioaemicarbazides of the formula R 1 CONHNHCSNHR 2 which are themselves obtained by acylation of the appropriate thiosemicarbazide with a fluorocarboxylic acid derivative, e.g. the anhydride. The compounds of the invention display herbi- cidal activity and may be formulated with conventional additives, fertilizers, or other known herbicides.