Efficient synthesis of 2‐substituted thieno[2,3‐d]pyrimidin‐4(3H)‐ones via an iminophosphorane |
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Authors: | Zheng‐Dong Fang Yang‐Gen Hu Ming‐Wu Ding |
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Abstract: | The carbodiimides 4 , obtained from reactions of iminophosphorane 3 with aromatic isocyanates, were reacted with secondary amines to give 2‐dialkylamino‐5‐ethyl‐6‐methyl‐thieno2,3‐d]pyrimidin‐4(3H)‐ones 6 in the presence of catalytic amount of EtONa. Reactions of 4 with phenols or ROH in the presence of the catalytic amount of K2CO3 or RONa gave 2‐aryloxy‐ or 2‐alkoxy‐5‐ethyl‐6‐methyl‐thieno2,3‐d]pyrimidin‐4(3H)‐ones 6 in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:266–270, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20424 |
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