Methyl 2-pyrazinecarboxylate hydrolysis

Aminopyrazines are conveniently prepared from carboxamido-pyrazines by application of the Hofmann reaction (see Section V,B). Thus, Camerino and Palamidessi prepared aminopyrazine in 80% yield from carboxamidopyrazine.312 Aminopyrazine may also be prepared from the reaction of pyrazine with sodamide in liquid ammonia,313 and 3-amino-2,5-dimethylpyrazine is the product of amination of 2,5-dimethylpyrazine with sodamide in dimethyl-aniline.311 The ammonolysis of halopyrazines also represents a useful preparative procedure for aminopyrazines (see Section V,C). This reaction proceeds most easily in the case of fluoro compounds for example, fluoropyrazine is converted into aminopyrazine in 70% yield by treatment with concentrated aqueous ammonia at room temperature for 3 days,299 whereas the corresponding reaction with chloropyrazine has been carried out in a sealed tube at 150°.147 Alkaline hydrolysis of 2,4-dihydroxypteridines followed by decarboxylation yields aminopyrazines 315 thus, high-temperature alkaline hydrolysis of 7-methyl-2,4-dihydroxypteridine (7-methyIlumazine) gives, after decarboxylation of the intermediate pyrazinecarboxylic... 

Pyrazinecarbaldehydes can of course be recovered from their derivatives for example, the acetal, methyl 6-amino-5-cyano-3-diethoxymethyl- (249), gave methyl 6-amino-5-cyano-3-formyl-2-pyrazinecarboxylate (250) in 85% yield by selective hydrolysis in dilute hydrochloric acid at 20°C during 12 h 773 likewise, the extranu-clear acetal, 2-(3,3-diethoxypropyl)-3-ethoxycarbonylmethylpyrazine, gave 2-ethoxycarbonylmethyl-3-(2-formylethyl)pyrazine in 92% yield on hydrolysis in aqueous alcoholic hydrochloric acid at 35°C during 2 h.1249... 

---