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Note | Regular issue | Vol 48, No. 4, 1998, pp.775-778
Published online, 1st January, 1970
DOI: 10.3987/COM-97-8086
A Facile and Convenient Synthesis of 9-Methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-one Potassium

Atsunori Sano* and Masami Ishihara

*Tokyo Research Laboratories, Wako Pure Chemical Ind., Ltd., 1633 Matoba, Kawagoe, Saitama 350-1101, Japan


Two convenient synthetic methods of anti-allergy agent, 9-methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-one potassium (1a), are described. Heating of a mixture of malononitrile (2b), 2-amino-3-picoline (4), ethyl orthoformate, and sodium azide in acetic acid, followed by hydrolysis with hydrochloric acid gave 9-methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-one (1b) which was led to 1a by treatment with potassium hydroxide. The use of ethyl cyanoacetate (2a) instead of 2b afforded ethyl 3-(3-methyl-2-pyridylamino)-2-(1H-tetrazol-5-yl)acrylate (8) which was also led to 1a by treatment with potassium hydroxide.