Formation of Amides and Related Compounds

Many carbamoylpyrazines and related compounds such as IV-hydroxyamides (hydroxamic acids), hydrazides, cyanamides, guanidinocarbonyl-, guanidino-carbamoyl-, and ureidocarbonylpyrazines have been prepared from pyrazinecarboxylic esters. The amides were usually prepared with ammonia in methanol (or other alcohols) but also under other conditions. 

Amides have been prepared from the following esters 2-methoxycarbonyl (NHs/MeOH) (1171, 1278, 1312) [Dalmer and Walter (1333, 1360) report the 

5- methyl [NH3/EtOH/2 (420) 25% NH4OH (1327) and also 6-methyl isomer (1327) and alcoholic ammonia with an ester (138)] 5-methoxycarbonyl-2,3-diphenyl (NHs/EtOH/lOO ) (25) 2,3-dimethoxycarbonyl [NHj/MeOH (397, 1172) methanolic ammonia with an ester (138)] 2,3-dialkoxycarbonyl-5-methyl (NHs/EtOH) (138) 2,3-dimethoxycarbonyl-5,6-dimethyl (NHj/MeOH) (403)  

5- dimethoxycarbonyl [NHa/MeOH (676,1172) ammonium hydroxide in ethanol at room temperature gave a mixture of 2-carbamoyl-5-ethoxycarbonylpyrazine, 

5- dicarbamoylpyrazine, and small amounts of 2,5-dicarboxypyrazine and 2,5-diethoxycarbonylpyrazine (676)] 2,5-diethoxycarbonyl-3,6-dimethyl (NHj/EtOH/ 20°/3days) (287) 2,6-dialkoxycarbonyl (NHs/MeOH) (138) 2,3,5-triethoxy-carbonyl (412) and tetraethoxycarbonyl (NH3/MeOH/20 ) (412) 2-chloro-3-methoxycarbonyl (NH40H/20°) (423, 836) 2-chloro-5-methoxycarbonyl (NH3/ EtOH) (839) 2-bromo-5-ethoxycarbonyl (NH4OH/EtOH/2073 h) (839) 2-chloro- 

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