2-Amino-5-methyl-1,3,4-thiadiazole was used as a reagent in the synthesis of substituted 5H-benzo[i][1,3,4]thiadiazolo[3,2-a]quinazoline-6,7-diones which diplayed good cytotoxic activities. Also used in the design of new phenothiazine-thiadiazole hybrids for development of antitubercular agents.
1) 0.05 mol of aminothiourea was added to a dry mortar, followed by 0.055 mol of glacial acetic acid, 0.055 mol of silica, and 0.25 mol of phosphorus trichloride, and ground for 10 min at room temperature. The progress of the reaction was monitored by thin layer chromatography (TLC) using a solvent mixture of ethyl acetate and petroleum ether in the ratio of 1:3 by volume as the unfolding agent until the point of raw material aminothiourea disappeared, indicating that the reaction was complete. The crude product was obtained after standing for 30 min.2) The crude product was transferred to a beaker and the pH was adjusted to 8 by adding 5% sodium carbonate solution.The mixture was withdrawn and filtered and the filter cake was dissolved with N,N-dimethylformamide (DMF) to remove silica gel. The filtrate was concentrated under reduced pressure, and after removing the solvent, washed with water and filtered by suction to afford 2-amino-5-methyl-1,3,4-thiadiazole in 95.2% yield.
[1] Patent: CN103880776, 2016, B. Location in patent: Paragraph 0024-0026
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