Abstract
The dehydrative cyclization of potassium N-(1-adamantylcarbonyl)dithiocarbazate 4 with sulfuric acid was studied under several conditions. Treatment of compound 4 with sulfuric acid at room temperature yielded a separable mixture of 5-(1-adamantyl)-1,3,4-thiadiazole-2-thiol 5 and 1,2-bis[5-(1-adamantyl)-1,3,4-thiadiazol-2-yl]disulfide 6. The reaction product (5:6) ratio was found to be time and temperature dependent. Thiol 5 was obtained as the sole product on dehydrative cyclization of 4 at 0 degrees C. Meanwhile, disulfide 6 was obtained as the major product (55%) on carrying out the reaction at room temperature for 36h, in addition to thiol 5 as a minor product (16%). The structure of the oxidized thiol 6 was confirmed by H-1 and C-13 NMR, HR-MS, and independent synthesis via oxidation of thiol 5 with dimethylsulfoxide. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]