2-Hydroxy-5-methoxy-3,6-dimethylpyrazine

Acetoxy-3,6-dibenzyl-5-methoxypyrazine gave 3,6-di benzyl-5-methoxy-2(l//) -pyrazinone (29) (K2C03, MeOH—H20, reflux, 30 min > 95%) 312 2,5-diace-toxy-3,6-dimethylpyrazine gave 5-hydroxy-3,6-dimethyl-2(l//)-pyrazinone (30) (KHC03, MeOH, reflux, 50 min 53%).1386... 

Dimethylamino-7V-hydroxy-2-pyrazinecarboxamide 6-Dimethylamino-7V-hydroxy-2-pyrazinecarboxamidine 2-Dimethylamino-5-iodopyrazine 2-Dimethylamino-6-iodopyrazine 2-Dimethylamino-5-iodopyrazine 4-oxide 2-Dimethylamino-3-isobutylpyrazine 2-Dimethylamino-6-isobutylpyrazine 2-Dimethylamino-5-methoxy-3,6-dimethylpyrazine 2-Dimethylaminomethyl-3,6-bismethylthiopyrazine 2-Dimethylamino-6-methyl-5-phenylpyrazine 4-oxide 2-Dimethylamino-3-methylpyrazine 2-Dimethylamino-6-methylpyrazine 2-Dimethylamino-3-methylpyrazine 4-oxide Dimethyl 5-amino-6-oxo-1,6-dihydro-2,3-pyrazinedicarboxylate 2-Dimethylamino-5-phenylpyrazine 2-(3-Dimethylaminopropyl)-6-methylpyrazine... 

V-Hydroxy-6-propylthio-2-pyrazinecarboxamide V-Hydroxy-6-propylthio-2-pyrazinecarboxamidine 2- (3-Hydroxyprop-1 -ynyl)-3,6-diisobutylpyrazine 2- (3-Hydroxyprop-1 -ynyl)-3,6-diisobutylpyrazine 4-oxide 2- (3-Hydroxyprop-1 -ynyl)-3,6-diisopropylpyrazine 2- (3-Hydroxyprop-1 -ynyl)-3,6-diisopropylpyrazine 4-oxide 2- (3-Hydroxyprop-1 -ynyl)-3,6-dimethylpy razi ne 2-(3-Hydroxyprop-1 -y nyl)-3,6-dimethylpyrazine 4-oxide 2-(3-Hydroxyprop-l-ynyl)-3,5-diphenylpyrazine 2-(3-Hydroxyprop-l-ynyl)-3,6-diphenylpyrazine 2-(3-Hydroxyprop-l-ynyl)-5,6-diphenylpyrazine 2-(3-Hydroxyprop-l-ynyl)-5,6-diphenylpyrazine 4-oxide 2-(3-Hydroxyprop-l-ynyl)-6-methoxy-5-(2-methylprop-l-enyl)pyrazine 2- (3-Hydroxyprop-1 -ynyl )-6-methoxypyrazine N-Hydroxy-2-pyrazinecarboxamide Af-Hydroxy-2-pyrazinecarboxamide 4-oxide... 

The first lithiopyrazine derivative was prepared by Hirschberg et al. (1015) from 3-iodo-2,5-dimethylpyrazine and butyllithium in ether subsequent reaction with (a) carbon dioxide gave 3-carboxy-2,5-dimethylpyrazine, and (b) several aromatic aldehydes gave the carbinols (62, R = H, p-methoxy, m-nitro) (1015). Similar reactions were observed when 2-formylpyridine and 2-acetylpyridine (1016) were used as the carbonyl compounds, but with acetaldehyde attempted reactions were unsuccessful (1015). A patent also describes the preparation of many carbinols from 2,5-disubstituted 3-iodopyrazines (164). The lithio reagent derived from 3-iodo-2,5-dimethylpyrazine (with butyllithium in hexane) with 2-nitrobenzaldehyde gave 2,5-dimethyl-3[ 1 -hydroxy-1 (2"-nitrophenyl)methyl] pyrazine (1017). 

Dichloro-3,6-dimethylpyrazine 1,4-dioxide (91) with sodium methoxide at room temperature gave 2,5-dimethoxy-3,6-dimethylpyrazine 1,4-dioxide (92) and a trace of 2-hydroxy-5-methoxy-3,6-dimethylpyrazine 1,4-dioxide (93) (756). Similarly 2,5-dichloro-3,6-dimethylpyrazine 1,4-dioxide (a) with sodium ethoxide gave 2,5-diethoxy-3,6-dimethylpyrazine 1,4-dioxide (756, 842) and 2-hydroxy-5-... 

Methoxypyrazines (31) have been prepared by diazomethane methylation of 2-hydroxy-3-isobutylpyrazine (60, 311, 367), 2-hydroxy-3-isopropylpyrazine (59, 367), 2-hydroxy-3-propyl(ethyl or hexyl)pyrazine (367), 3-hydroxy-2-isobutyl-5(and 6)methylpyrazine and 2-hydroxy-3-isobutyl-5,6-dimethylpyrazine (368), 2,3-dihydroxypyrazine (832), 2-hydroxy-5-methoxy- and 2,5-dihydroxy-3,6-diphenyl-pyrazine (832), 2-hydroxy-6-methoxy(and benzyloxy)pyrazine (832), 2,6-dihydroxy-3,5-diphenylpyrazine (873), 2,3,5-trifluoro-6-hydroxypyrazine (851), 2-chloro-6-hydroxy-3,5-diphenylpyrazine (873), 2-chloro-6-hydroxy-5-methyl-3-phenylpyrazine (873), 2-chloro-6-hydroxy-3-methyl-5-phenylpyrazine (873), 5,6-dichloro-1 -cyclohexyl-34iydroxy-2-oxo-l, 2-dihydropyrazine (853), 2-chloro-5-hydroxy-3-methoxy-6-methoxycarbonylpyrazine (881), 2-(4 -amino-3, 5 -dibromo-phenylsulfonamido)-3Tiydroxy-6-methoxypyrazine (881), 2-amino-3-hydroxy-... 

Dicyano-3,6-dimethylpyrazine shaken with sodium ethoxide at room temperature for 10 hours produced 2-cyano-5-ethoxy-3,6-dimethylpyrazine (288). Bromination of 2-methoxy-3-sulfanilamidopyrazine (39) in methanol led to 5-(4 -amino-3, 5 -dibromobenzenesulfonimido)-6-hydroxy-2,3-dimethoxy-2,3,4,5-tetrahydropyrazine (32) which with 2 N sodium hydroxide gave 3-(4 -amino-3, 5 -dibromobenzenesulfonamido)-2-hydroxy-5 nethoxypyrazine (40) (816). The preparation of 2-amino-3,5-dicyano-6-methoxy(and ethoxy)pyrazine from a-(p-toluenesulfonyloxyiminomalononitrile and malononitrile has been described in Section II.7 (484). 2-Methoxycarbonyl(and cyano)-5-pyridiniopyrazine chloride (41) is reported (conditions not stated) to give 2-carboxy(and carbamoyl)-5-methoxypyrazine (765). 

Crystal structures of 3,5,6-tri-t-butyl-2-hydroxypyrazine (1093) 2,5-dichloro-3-methoxypyrazine (915) and 2,3-dichloro-5-ethylamino-6-methoxypyrazine (916) have been determined. The dipole moment of 2-amino-5-bromo-3-methoxypyrazine (2.94D in benzene) is consistent with the S-cis configuration (52) (749) and the polarographic behavior of 3-hydroxy(and methoxy)-2,5-dimethylpyrazine (and their A(-oxides) at various pH values has been investigated (588). 

Methylation (666, 912) of 2-methoxypyrazine with methyl iodide in dimethyl sulfoxide at room temperature gave 3-methoxy-l-methylpyrazinium iodide with a rate of methylation relative to pyrazine of 1.05 (666). 2-Methoxypyrazine with tetracyanoethylene oxide gave a small yield of 3 ethoxypyrazinium dicyano-methylide (53) (1094). Alkylation of 2-methoxypyrazine with ethyl methyl ketone in the presence of sodium in liquid ammonia to give 2-s-butyl-6-methoxypyrazine (17%) has been described (614). The reactions of 3-hydroxy-2,5-dimethylpyrazine and alkylhalides have been examined (1095). 

Dimethylamino-23-dimethylpyrazine 1-oxide in boiling acetic anhydride gave 2-acetoxymethyl-3-dimethylamino-5-methylpyrazine (793) which was not isolated but saponified directly to 3-dimethylamino-2-hydroxymethyl-5-methylpyrazine (793). 2-Amino-3-cyano-5-methylpyrazine 1,4-dioxide refluxed with (a) acetic anhydride gave 3-acetamido-2-cyano-5-hydroxy-6-methylpyrazine 1-oxide (532) and (6) sodium methoxide gave 3-amino-2-cyano-5-methoxy-6-methylpyrazine 1-oxide (532). 

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