2-Hydroxy-5-methoxy-3,6-dimethylpyrazine 1,4-dioxide

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-... 

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). 

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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