- CRYSTALLINE FORM OF PEMIROLAST
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There is provided a hemihydrate form of the sodium salt of pemirolast.
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Page/Page column 11
(2016/09/26)
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- A facile and convenient synthesis of 9-methyl-3(1H-tetrazol-5-YL)-4H-pyrido[1,2-a]pyrimidin-4-one potassium
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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. 1. The generic name is pemirolast potassium.
- Sano, Atsunori,Ishihara, Masami
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p. 775 - 778
(2007/10/03)
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- A facile and practical synthesis of 9-Methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-one
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A facile and practical synthesis of 9-methyl-3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-one (4), the potassium salt of which is used clinically as an anti-asthma agent, is described. Treatment of a key intermediate (6b), prepared from 2-amino-3-methylpyridine (1) and 2-ethoxymethylene-1,3-propanedinitrile, with sodium azide in N,N-dimethylformamide gave predominantly the cyanotetrazole (7a), while in acetic acid it gave exclusively the iminotetrazole (7b), which was easily converted into 4 by acid hydrolysis. A one-pot process starting from 6b to give 4, avoiding the use of explosive aluminum azide, was established.
- Sano,Ishihara,Yoshihara,Sumino,Nawa
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p. 683 - 685
(2007/10/03)
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- Process for producing 3-tetrazolyl pyrido[1,2-a]pyrimidine derivatives
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3-Tetrazolylpyrido[1,2-a]pyrimidin-4-one derivatives useful as an antiallergy agent are produced by reacting a cyano derivative of pyrido[1,2-a]pyrimidin-4-one compound with (i) hydrazoic acid, followed by hydrolysis, or with (ii) a salt of hydrazoic acid
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- 3-TETRAZOLO-5,6,7,8-SUBSTITUTED PYRIDO[1,2-a]PYRIMIDIN-4-ONES
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A novel series of optionally substituted 3-(1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyrimidin-4-ones is provided for use as inhibitors of allergic reactions. The compounds exhibit antiallergy activity by both oral and parenteral routes of administration
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