Synthesis of Fused Isolated Azoles and N-Heteroaryl Derivatives Based on 2-Methyl-3,4-dihydrothieno[3,4-d]pyrimidin-5-amine

• Published in: Synthetic communications Vol. 44; no. 18; pp. 2692 - 2714
• Main Authors: El Azab, Islam Helmy, Elkanzi, Nadia Ali Ahmed
• Format: Journal Article
• Language: English
• Published: PHILADELPHIA Taylor & Francis Group 17.09.2014; Taylor & Francis; Taylor & Francis Ltd
• Subjects: 2,4-Diaminothiophene-3-carbonitrile; Chemistry; Chemistry, Organic; Derivatives; fused-isolated azoles; heterocycles; Physical Sciences; Science & Technology; synthesis; thieno[3,4-d]pyrimidines; synthesis; 2; 4-Diaminothiophene-3-carbonitrile; heterocycles; 4-d]pyrimidines; thieno; fused-isolated azoles
• ISSN: 0039-7911; 1532-2432
• DOI: 10.1080/00397911.2014.916301

In this work, we report the synthesis and characterization of new compounds derived from thieno[d]pyrimidines. The formation of isolated and fused thieno[d]pyrimidine derivatives was achieved via reacting 5-amino-(2-methyl)thieno[3,4-d]pyrimidin-4(3H)-one (3) with some selected reagents. The starting compound (2) was prepared in a quantitative yield using a modified procedure by conversion of the cyano group in 1 to the amide via hydrolysis using concentrated H 2 SO 4 . Methylthieno[3,4-d]pyrimidin-5-yl (8, 9, and 18), 3-phenylthieno[3,4-e][1,2,4]triazolo[4,3-c]pyrimidines (11-15) and tetrazolo[1,5-c]thieno[3,4-e]pyrimidine (16) have been synthesized in excellent isolated yield. The interaction of N-acetyl derivative 19 with benzaldehyde and/or some nitroso compounds afforded the chalcones and Schiff's bases derivatives 20 and 26a and c respectively. The latter compounds were used as key intermediates in the synthesis of N-acetylpyrazol-3-yl (21a and 21b), 6-phenylpyrimidine-2-(one)thione (22a and b), pyrazolo-1-carbothioamide (25), and thiazolidinone andβ β-lactam derivatives 28a and 28c and 30a and 30c respectively. The structures of these compounds were established by elemental analysis, infrared (IR), mass spectrometry (MS), and NMR spectral analysis.