A Direct and High Yielding Route to 2-(5-Tetrazolyl) Substituted Benzopyran-4-ones: Synthesis of Pranlukast
作者:Graham R. Geen、Robert G. Giles、Trevor J. Grinter、John D. Hayler、Simon L. B. Howie、Graham Johnson、Inderjit S. Mann、Vance J. Novack、Paul W. Oxley、John K. Quick、Neil Smith
DOI:10.1080/00397919708003052
日期:1997.3
A direct and high yielding route to 2-(5-tetrazolyl)benzopyran-4-ones 1, including pranlukast 1a is described. This involves the Claisen condensation reaction between the relevant hydroxyacetophenone 2 and the ethyl eater of tetrazole-2-carboxylic acid 5 to give the 1,3-diketone 6, which is then cyclised to give the desired benzopyran-4-ones 1.