Synthesis and Antiallergy Activity of (1,3,4)Thiadiazolo(3,2-a)-1,2,3-triazolo(4,5-d)pyrimidin-9(3H)-one Derivatives. I.

Microwave Assisted Synthesis of Some Novel Thiadiazolothienopyrimidines

“…Stirring was continued for 3 h. The reaction mixture was poured into ice-water mixture. The precipitate so obtained was filtered, dried and recrystallised from ethanol as a pale yellow amorphous powder (5.35 g, 81%) 3-Amino-2-mercapto- 3,5,6,7,8,9-hexahydro-4H-cyclohepta [4,5] thieno [2,3-d]pyrimidin-4-one (4): Compound 2 (0.329 g, 0.001 mole) in isopropanol (1.0 ml) was heated at 960 W in a domestic microwave oven with hydrazine hydrate (99%) (0.5 g, 0.001 mole), until the evolution, of methyl mercaptan ceased (300 s). After cooling, the solid obtained was filtered, dried and recrystallised from ethanol as white needles (0.165 g, 61%), m.p.…”

“…Here we report a microwave-assisted route for the preparation of 2-(arylaminomethyl)-7,8,9,10tetrahydro-6H,11H-cyclohepta [4,5]thieno [2,3-d] [1,3,4]thiadiazolo[3,2-a]pyrimidin-11-ones (6a-d).…”

One-Pot Synthesis of 5-Acyl-2-amino-1,3,4-thiadiazoles

“…2-Amino-1,3,4-thiadiazoles have been reported to be useful in many different fields and applications, for example, exerting immunotropic activity, 2 as antimicrobials, 3 as antibacterials, 4 as fungicides, 5 showing anti-allergy activity, 6 as dyes, 7 as virus inhibitors, 8 as drugs, and drug intermediates. 9 The entity 5-acyl-2-amino-1,3,4-thiadiazole is considered as a promising building block in organic chemistry with two functional groups, the amine and the preferred methanone.…”

Kost-Sagitullin Rearrangement and Other Isomerization Recyclizations of Pyrimidines. (Review)

“…We mention only that since the time of their investigation these reactions have changed from the unexpected and unusual transformation that they seemed initially into a tool of organic synthesis making it possible to produce new substances often difficult to obtain in other ways. Publications of recent years have shown that in the pyrimidine series the Dimroth rearrangement has become an important method of fine organic synthesis used for the transformation of biologically active and medicinal substances such as nucleosides [49][50][51][52][53][54][55][56][57] and drugs [58][59][60][61][62][63].…”

“…It was shown that 2-cyanomethyl-3-ethoxycarbonyl-5,7-dimethylpyrazolo[1,5-a]pyrimidine(58) is formed together with the 2-methylaminopyridine 27. Similar rearrangement of a pyrimidinium salt to a pyrazolo[1,5-a]pyrimidine derivative was also detected during the action of the hydrazides of certain other carboxylic acids, demonstrating the general nature of this previously undescribed recyclization of 1,2-dialkylpyrimidinium salts.…”