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Efficient synthesis of benzothieno[3,2-d]-1,2,4-triazolo [1,5-a]pyrimidin-5(1H)-ones via a tandem aza-Wittig/heterocumulene-mediated annulation

✍ Scribed by Sheng-Zhen Xu; Min-Hui Cao; Chang-Shui Chen; Ming-Wu Ding

Publisher
Journal of Heterocyclic Chemistry
Year
2009
Tongue
English
Weight
89 KB
Volume
46
Category
Article
ISSN
0022-152X

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✦ Synopsis

Abstract

magnified image

The carbodiimides 2, obtained from reactions of iminophosphorane 1 with isocyanates, reacted with hydrazine to give selectively 3‐amino‐2‐arylaminobenzothieno[3,2‐d]pyrimidin‐4(3__H__)‐ones 4. Reactions of 4 with triphenylphosphine, hexachloroethane, and Et~3~N produced iminophosphoranes 5. A tandem aza‐Wittig reaction of iminophosphorane 5 with isocyanate, acyl chloride generated benzothieno[3,2‐d]‐1,2,4‐triazolo[1,5‐a]pyrimidin‐5(1__H__)‐ones 7 and 9 in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated. J. Heterocyclic Chem., (2009).

📜 SIMILAR VOLUMES

Efficient synthesis of benzothieno[3,2-d
Efficient synthesis of benzothieno[3,2-d]-imidazo[1,2-a]pyrimidine-2,5-(1H, 3H)-diones via a tandem aza-wittig/heterocumulene-mediated annulation
✍ Sheng-Zhen Xu; Jing Wu; Min-Hui Cao; Ming-Wu Ding 📂 Article 📅 2009 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 102 KB

## Abstract magnified image Carbodiimide **2**, obtained from aza‐Wittig reaction of iminophosphorane **1** with aromaic isocyanate, reacted with α‐amino ester in the presence of catalytic amount of sodium ethoxide to give selectively new tetracyclic benzothieno[3,2‐d]‐imidazo[1,2‐a]pyrimidine‐2,5