Synthesis of Some Aryl Thienopyridine, Pyridothienopyrimidine, and Pyridothienotriazolopyrimidine Derivatives
Ali Khader El-Louh1, Shadia Mahmoud Abdallah2* and Emtithal Ahmed El-Sawi2
1Department of Chemistry, Faculty of Science, Al-Azhar University-Gaza, Gaza, Palestine
2 Department of Chemistry, University College of Women for Arts, Science, and Education, Ain Shams University, Cairo-Egypt. email@example.com
Abstract: Synthesis of 2-thioxopyridine-3-carbonitriles 3a-d and their reaction with chloroacetonitrile 4a or chloroacetamide 4b afforded pyridin-2-ylthioacetonitriles 5a-d and pyridin-2-ylthioacetamides 6a-d, respectively, which on cyclization gave the corresponding 3-aminothienopyridine derivatives 7a-d and 8a-d. Reaction of triethyl orthoformate in acetic anhydride gave with 7a-d 3-ethoxymethylenethienopyridine derivatives 9a-d which on their reaction with hydrazine hydrate yielded 3-amino-4-imino-3,4-dihydropyridothienopyrimidine derivatives 10a-d. Reaction of with triethyl orthoformate with 10a-d produced pyridothienotriazolopyrimidine derivatives 11a-d, where Dimroth rearrangement yielded 4-hydrazinopyridothienopyrimidine derivatives 12a-d. On the other hand reaction of 8a-d with triethyl orthoformate in acetic anhydride gave pyridothienopyrimidine-4-one derivatives 13a-d, which on their chlorination produced 4-chloropyridothienopyrimidine derivatives 14a-d, and treatment with hydrazine hydrate authenticated 12a-d. Reaction of compounds 8a-d with nitrous acid afforded 3,4-dihydropyridothienotriazin-4-ones15a,b,d. Compounds 12a-d reacted with benzaldehyde, diethylmalonate, and acetylacetone, to give 4-benzylidinehydrazinopyridopyrimidines 16a-d, ethyl 1,2,4-triazolopyridothienopyrimidin-3-ylacetates 17a-d, and 4-(3,5-dimethylpyrazolo)pyridothienopyrimidines 18a-d, respectively.
[Ali Khader El-Louh, Shadia Mahmoud Abdallah and Emtithal Ahmed El-Sawi. Synthesis of Some Aryl Thienopyridine, Pyridothienopyrimidine, and Pyridothienotriazolopyrimidine Derivatives. Life Sci J 2012;9(1):220-230]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 32
Keywords: Thioxopyridine; carbonitrile; thienopyridine; pyridothienopyrimidine; triazolopyridothienopyrimidine; pyridothienopyrazolopyrimidine Full Text 32