Synthese of substitutd pyrazolopyrimidines

Abstract

Methods of making substituted pyrazolopyrimidines generally and, more particularly, N-methyl-N-(3-{3-[2-thienylcarbonyl]-pyrazol-[1,5- alpha ]-pyrimidin-7-yl}phenyl)acetamide. Such compounds have utility over a wide range of indications, including treatment of insomnia. In the practice of the present invention, improved techniques which do not require use and / or isolation of the pyrazole intermediate are disclosed, as well as improved techniques for making the reaction intermediates themselves. Such techniques offer significant advantages, including enhanced efficiency, particularly in the context of large scale manufacture.

Description

technical field [0001] The present invention relates to the synthesis of substituted pyrazolopyrimidines which are effective for a wide variety of indications, including the treatment of insomnia. Background of the invention [0002] U.S. Patent No. 4,521,422 to the American Cyanamid Company relates to certain aryl and heteroaryl [7-(aryl and heteroaryl)-pyrazolo(1,5-a)pyrimidines -3-yl]methanone, a class of compounds that are active as anxiolytics, anticonvulsants, sedative-hypnotics and skeletal muscle relaxants. Such compounds can generally be classified as "substituted pyrazolopyrimidines" and have the following structure (I): [0003] [0004] where R 2 , R 3 , R 5 , R 6 and R 7 As defined in US Patent No. 4,521,422 (but in a different numbered scheme for each R group). [0005] Compounds of structure (I) are prepared according to U.S. Patent No. 4,521,422 by combining an appropriately substituted pyrazole (a) with an appropriately substituted 3-dimethylamino-...

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Problems solved by technology

[0018] Although U.S. Patent Nos. 4,521,422 and 4,900,836 teach synthetic techniques for compounds of structure (I), these methods are relatively time-consuming, involve many steps, and are not particularly economical or efficient for large-scale syntheses

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