320338-83-8Relevant academic research and scientific papers
The Dimroth rearrangement: Synthesis and interconversion of isomeric triazolothienopyrimidines
Hamed, Atef A.,El-Ashry, El-Sayed H.,Zeid, Ibrahim F.,Badr, Hesham F.
experimental part, p. 334 - 339 (2009/05/30)
Triazolo-thieno[3,2-e]pyrimidines obtained by cyclisation of 4-hydrazino-2-(methylthio)thieno[2,3-d]pyrimidine with formic acid, acetic acid, cyanogen bromide and carbon disulfide, and by oxidation of the derived aldehyde hydrazones, are found to be the triazolo[4,3-c] isomers. These [4,3-c] compounds resist isomerisation in acid, but they undergo Dimroth rearrangement to the [1,5-c] isomers under basic conditions. The crystal structure of one such rearranged product, 5-methoxy-8,9,10,11-tetrahydro[1]benzothieno[3,2-e][1,2,4] triazolo[1,5-c]pyrimidine (13b) was confirmed by X-ray analysis.
Synthesis and reactions of polynuclear heterocycles with new ring systems
Abdel-Fattah,Aly,Gad,Hassan,El-Gazzar
, p. 1 - 27 (2007/10/03)
Condensation of 5,6-dimethyl-2-hydrazino-3,4-dihydrothieno[2,3-d]pyrimidin-4-one (2) with aromatic aldehydes gave the arylhydrazones 3a-c which cyclized into thienotriazolopyrimidin-5- one 4a-c. Reactions of 2 with aliphatic acids afforded the thienotriazolopyrimidin-5-one a,b. Also, reaction of 2 with each of carbon disulfide and nitrous acid afforded 3-mercaptothienotriazolopyrimidin-5-one 7, and tetrazolothienopyrimidin-5-one 8, respectively, the latter compound 8could be reduced to 2-aminothienopyrimidin-4-one 9. On the other hand, 2-hydrazino derivative 2 condensed with α-haloketones yielded 3-substituted-thienopyrimidotriazin-6-one 10a,b with new ring system, and with β-diketones, β-ketoesters to form 2- (1-pyrazolyl) derivatives 13a-c, 14. The 2-pyrazolinone derivative 15 condensed with aromatic aldehydes to afford arylidene derivatives 16a-c. Also, reaction of 2 with ethyl cyanoacetate yielded 2-(pyrazolyl) derivatives 17.
