1,3,4-Thiadiazole durch Umsetzung von Dithioestern mit Kohlensäurehydraziden

✍ Scribed by Dr. sc. nat. W. Thiel; Prof. Dr. R. Mayer

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 425 KB
• Volume: 332
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/prac.19903320107

✦ Synopsis

1,3,4‐Thiadiazoles by Reaction of Dithiocarboxylic Esters with Carbonic Hydrazides

1,1‐Dithiooxalic esters 1 and heteroaryl dithiocarboxylic esters 2 react with carbonic hydrazides yielding 1,3,4‐thiadiazoles. The 1‐thiooxamoyl semicarbazides 3 or 1‐heteroylthiocarbonyl semicarbazides 4, primarily formed by thioacylation of semicarbazide, where isolated. By cyclocondensation they yield 1,3,4‐thiadiazole‐2(3 H) ones 5, 6, or in the presence of acetic anhydride 3‐acetyl‐1,3,4‐thiadiazol‐2‐ones‐ 7, 8, respectively.

2‐Amino‐ or 2‐methylthio‐1,3,4‐thiadiazoles 11, 12 or 13, 14 are formed by reaction of the dithioesters 1, 2 with thiosemicarbazide or methyl dithiocarbazinate. By this way 1,3,4‐thiadiazoles with heteroaryl‐ or carbamoylresidues in position 5 where synthesized for the first time.