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A New and Facile Synthesis of Novel Pyrazolothienopyrimidines and Imidazopyrazolothienopyrimidines

Research Authors
Remon M. Zaki, Adel M. Kamal El-Dean and Abdullah Y. Abdulrazzaq
Research Abstract

4-Amino-3-methyl-1-phenyl-1H-thieno[2,3-c]pyrazole-5-carboxamide (5), which was synthesized by an
innovative method, was used as a versatile precursor for synthesizing pyrazolothienopyrimidines and
imidazopyrazolothienopyrimidines compounds. Reaction of amino thienopyrazole carboxamide 5 with
triethyl orthoformate afforded thienopyrazolopyrimidine 6. Chlorination of the latter compound, using
phosphorus oxychloride afforded the chloro pyrazolothienopyrimidine 7, which underwent nucleophilic
substitution reactions with various primary and secondary amines to give the alkyl (aryl) amino pyrimidine
compounds 8a-d. On the other hand, the reaction of chloropyrimidine 7 with thiourea afforded the
pyrimidine thione compound 9, which was alkylated with -halogentaed compounds to afford the
S-alkylated derivatives 10a-c. Also, chloroacetylation of the amino carboxamide 5 using chloroacetyl
chloride yielded the chloromethyl pyrazolothienopyrimidine 12, which underwent nucleophilic substitution
reactions with various primary and secondary amines to afford the alkyl (aryl) aminomethyl compounds
13a-f. The latter Compounds underwent Mannich reaction to give imidazopyrimidothienopyrazoles
14a-c. The newly synthesized compounds and their derivatives were fully characterized by elemental
and spectral analysis.

Research Department
Research Journal
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
Research Publisher
NULL
Research Rank
1
Research Vol
Vol.62
Research Website
NULL
Research Year
2015
Research Pages
PP.1121-1127