Simple construction of fused and spiro nitrogen/sulfur containing heterocycles by addition of thioamides or thioureas on cycloalkenyl-diazenes: examples of click chemistry

New 1-cycloalkenyl-l-diazenes have been obtained in good yields from cyclic beta-ketoesters and hydrazine derivatives. They furnished new cycloalkyl[d][1,3]thiazolines with thioamides or new spirocycloalkyl-thiazolinones with thioureas. Moreover they gave, with imidazolidine2-thione and tetrahydropyrimidine-2-thione, new and interesting spiro[cycloalkyl-1,2'-imidazo[2,1-b][1,3]thiazole] or spiro[cycloalkyl-1,2'-[1,3]thiazolo[3,2-a]pyrimidine] derivatives, respectively. Cycloalkyl[d][1,3]thiazolines were useful for the further preparation of unknown thia-triaza-tricyclo derivatives. Novel hexahydro-1,3-benzothiazoles have been achieved by reaction of N,N '-dialkylthioureas on N-1-phenyl-2-(1-cyclohexenyl)-1-diazene-1-carboxyamide. The acidic hydrolysis of spirocycloalkyl-thiazolinones produced 2-imino-5-(omega-carboxyalkyl)4-thiazolidinones. (c) 2008 Elsevier Ltd. All rights reserved.