Synthesi
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 protected]
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
