3-Carbamoyl-2-pyrazinecarboxylic

Ammonium 3-carbamoyl-2-pyrazinecarboxylate (77) gave 3-amino-2-pyrazinecar-boxylic acid (78) (NaOCl, H20, 20 - 80°C, 10 min 67%).1318 Also other examples.598,1008 1119 1125... 

Dimethyl 2,3-pyrazinedicarboximidate (86) gave a mixture of 2,3-pyrazinedicar-boxamide (87) and methyl 3-carbamoyl-2-pyrazinecarboxylate (88) (10 M HC1, 20°C, 8 h 16 and 15%, respectively, after separation).1127... 

Methyl 3-chloroformyl-2-pyrazinecarboxylate (129) gave methyl 3-carbamoyl-2-pyrazinecarboxylate (130) [HN(SiMe3)2, CHC13, 0°C —> reflux, 90 min then residue from evaporation, H20, reflux, 30 min 75%. Note survival of the ester grouping under these conditions].1185 l,4-Piperazinedi(thiocarbonyl) dichloride (131) gave l,4-bis[morpholino(thio-formyl)]piperazine (132) [neat 0(CH2CH2)NH, warmed briefly >95%].350... 

Ethyl 5-bromo-2-pyrazinecarboxylate 2-(2-Ethylbut-1 -enyl)-6-methylpyrazine Ethyl 5-carbamoyl-2-pyrazinecarboxylate Ethyl 5-chloro-2-pyrazinecarboxylate Ethyl 3-cyano-5,6-dimethyl-2-pyrazinecarboximidate Ethyl 3-cyano-5,6-dimethyl-2-pyrazinecarboxylate Ethyl 3,5-diami no-6-chloro-2-pyrazi necarboximidate Ethyl 6-diethylamino-2-pyrazinecarboxylate 2-Ethyl-3,6-diisobutyl-5-methylpyrazine 2-Ethyl-3,6-diisobutylpy razi ne 2-Ethyl-3,6-diisobutylpyrazine 1 -oxide 2-Ethyl-3,6-diisobutylpyrazine 4-oxide 2-Ethyl-3,6-diisopropylpyrazine /V-Ethyl-AyV -dimethyl-3,5-bismethylamino-2,6-pyrazinedicarboxamide Ethyl 3,6-dimethyl-5-oxo-4,5-dihydro-2-pyrazinecarboxylate... 

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. 

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