A direct and high yielding route to 2-(5-tetrazolyl) substituted benzopyran-4-ones: Synthesis of pranlukast

Article abstract of DOI:10.1080/00397919708003052

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 ester 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.

Full text of DOI:10.1080/00397919708003052

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Synthetic Communications: An
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A Direct and High Yielding
Route to 2-(5-Tetrazolyl)
Substituted Benzopyran-4-
ones: Synthesis of Pranlukast
a
b
Graham R. Geen , Robert G. Giles , Trevor J.
b
b
b
Grinter , John D. Hayler , Simon L. B. Howie
c
a
,
Graham Johnson , Inderjit S. Mann , Vance J.
b
b
b
Novack , Paul W. Oxley , John K. Quick & Neil
c
Smith
a
SmithKline Beecham Pharmaceuticals, New
Frontiers Science Park, Third Avenue, Harlow, Essex,
CM19 5AW, UK
b
SmithKline Beecham Pharmaceuticals, Old Powder
Mills, Nr. Leigh, Tonbridge, Kent, TN11 9AN, U.K.
c
SmithKline Beecham Pharmaceuticals, Clarendon
Road, Worthing, West Sussex, BN14 8QH, U.K.
Version of record first published: 22 Aug 2006.
To cite this article: 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 (1997): A Direct and High Yielding Route
to 2-(5-Tetrazolyl) Substituted Benzopyran-4-ones: Synthesis of Pranlukast, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 27:6, 1065-1073

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