3-Cyano-9-hydroxy-4/7-pyrido

Reaction of 8-substituted 3-[2-(4-methoxybenzyl)-2//-tetrazol-5-yl]-4//-pyrido[l,2-u]pyrimidin-4-ones with CF3COOH for 2 days at room temperature gave 3-(2//-tetrazol-5-yl) derivatives (OlMIPl). The cyano group of a 3-(8-substituted 2-hydroxy-4-oxo-4//-pyrido[l,2-u]pyrimidin-3-yl)-2-propenenitrile was converted into a 5-tetrazolyl group by treatment with NaN3 in the presence of AICI3 in DMF at 100 °C for 2 days. 

Mild acidic hydrolysis of amino nitrile 369 gave m-4,9a-/7-rra r-9-7/-9-benzyloxy-4-phenyl-3,4,9,9a-tetrahydro-17/,67/-pyrido[2,l-d[l,4]oxazin-l-one <1996TL4001>. (2A)-2-Cyano-l-[(lR)-2-hydroxy-l-phenylethyl]piperidin-6-one, on standing for 20 days in ethanol saturated with HC1 gas, afforded (4/ ,9aA)-4-phenylperhydropyrido[l,2-4[l,4]oxazine-l,6-dione, which was sometimes accompanied by the unstable (26 )-l-[(l/ )-2-hydroxy-l-phenylethyl]-... 

Methylation of 7-hydroxy-8-cyano-5,9-dihydro-ll//-pyrido[2,l-b]-quinazoline-9,ll-dione (45) with etheral diazomethane yielded ring-opened product 46 [84AP(317)824]. 

Reaction of anthranilic acid and 2-chloro-5-cyano-4-hydroxypyridin-6(l//)-one in glacial acetic acid for 18 h gave 8-cyano-7-hydroxy-5,9-dihydro-11 //-pyrido[2,l-6]quinazoline-9,l 1-dione (45). When the reaction was carried out in dimethylformamide under Ullmann conditions, 5-cyano-2-dimethylamino-4-hydroxypyridin-6-one also formed as a by-product... 

Cyclocondensations of benzylidenemalononitrile with pyridinethiones 210 and 211 afforded the amino derivatives of pyrido[2,l-h][l,3]thiazines 212 and 213, respectively (90MI2 92MI6). Reaction of 5-acetyl-3-cyano-6-methyl-4-phenyl-3,4-dihydropyridine-2(lfl)-thione with epichlorohydrin in the presence of potassium hydroxide and sodium methylate gave 7-acetyl-3-hydroxy-6-methyl-8-phenyl-2,3,4,8-tetrahydropyrido[2,l-h][l,3]-thiazine-9-carbonitrile (94KGS139). 

The method can be used to cyclize ethyl 4-(butylamino)-5-cyano-6-formylpyridinc-3-carboxy-late with hydrazine hydrate in acetic acid at room temperature to give pyrido[2,3-c/]pyridazin-5(6//)-one 19 the 5-amino group of the intermediate apparently being exchanged for a hydroxy function in the course of the reaction.61... 

One of the less common leaving groups in aromatic nucleophilic substitution reactions is the cyano group. However, a 4-cyano substituent in pyrido[2,3-t/]pyrimidine can be exchanged for methoxy or hydroxy functions by refluxing in methanolic sodium methoxide or aqueous sodium hydroxide solution.296... 

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