Pyrazinecarboxylic esters hydrolysis

Several reactions of pyrazinecarboxylic esters have been discussed already reduction to N-alkylpiperazines (Section 3.2.2.2), reduction to extranuclear hydrox-ypyrazines (Section 5.2.1), and hydrolysis to pyrazinecarboxylic acids (Section 8.1.1). Other reactions to be expected of carboxylic or carboximidic esters are typified in the following classified examples ... 

Reactions of pyrazinecarbonitriles already discussed include photochemical alkanelysis (Section 3.2.1.3), reduction to aminomethylpyrazines (Section 7.3.1), hydrolysis to pyrazinecarboxylic acids (Section 8.1.1), alcohol addition to afford pyrazinecarboximidic esters (and thence hydrolysis to regular esters) (Section 8.2.1), and conversion into pyrazinecarboxamides or the like (Section 8.4.1). 

Ethyl 5-amino-2-pyrazinecarboxylate (12) gave ethyl 5-oxo-4,5-dihydro-2-pyrazinecarboxylate (13) (NaNO2, H2SO4, 3 -> 45°C, 1 min 80% the use of concentrated H2SO4 ensured minimal hydrolysis of the ester grouping). ... 

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