Nickel Cyano derivatives

Bromo-ll//-pyrido[2,l-b]quinazolin-ll-one and its 8-methyl and 8-isopropyl derivatives (127, R = Br, R1 = H, Me, iPr) were treated with carbon monoxide and nickel carbonyl in wet dimethylformamide in the presence of calcium hydroxyde to yield 2-carboxylic acid derivatives (127, R = COOH, R1 = H, Me, iPr). 2-Bromo-8-isopropyl-ll//-pyrido[2,l-b]-quinazolin-ll-one (127, R = Br, R1 = iPr) was reacted with copper(I) cyanide in iV-methyl-2-pyrrolidone at 180°C for 10 h, then with ferric chloride hexahydrate in diluted hydrochloric acid at 90°C for 30 min to give the 2-cyano derivative (127, R = CN, R1 = iPr) (85CP1189509). 

Thiazolecarboxylic acids, esters or acid chlorides react readily with ammonia or various amines, affording the corresponding carboxamides. Dehydration of the amides with phosphorus pentoxide or phosphoryl chloride occurs readily and gives the corresponding nitriles (Scheme 99). Thiazolecarboxylic acid hydrazides are obtained in a similar way, using hydrazine or substituted hydrazines instead of ammonia or amines. The Raney nickel reduction of cyanothiazoles leads to the corresponding amino compounds, the 4-cyano derivative being the isomer most readily reduced. 

Scheme 6.10 a-Aminations of a-cyano ketones with a preformed nickel catalyst derived from a diamine ligand. 

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