TITLE:
Nitriles in Heterocyclic Synthesis: Synthesis of Pyrido[3’,2’:4,5]Thieno[2,3-d] Pyrimidines Derivative
AUTHORS:
Abdel Haleem Mostafa Hussein, Essam Abdel Raheem Eshak, Fathi Aly Abu-Shanab
KEYWORDS:
Nitriles, Heterocyclic Synthesis
JOURNAL NAME:
Open Access Library Journal,
Vol.2 No.1,
January
29,
2015
ABSTRACT:
6-Amino-3,5-dicyano-4-methylpyridine-2(1H)-thione 1 reacted with a-haloketones to give the Salkylated derivatives 2a-m. Compound 2a-m
undergoes cyclization into thieno[2,3-d] pyridine derivatives 3a-m upon treatment
with ethanolic sodium ethoxide. Saponification of 3a gave the amino acid 4
which afforded 5 when refluxed in Ac2O. Treatment of 5 with NH4OAc/AcOH
gave 6a. Compound 6a also was obtained when 3c was refluxed in Ac2O.
Reaction of 3a with formamide gave 7 and with hydrazine hydrate gave 8. The
thiourea derivative 9 was obtained by reaction of 3a with benzoyl
isothiocyanate. Compound 9 when refluxed in
alcoholic KOH gave 10 and with 98% H2SO4 gave 12.
Acetylation of 3a with Ac2O gave the acetyl derivative 13 which on
treatment with aniline afforded 14. Compound 14 was cyclized with H2SO4 to 15. Finally treatment of compound 5 with aniline in AcOH afforded 6b.