2- Formyl-3-methylpyrazine

Reduction of 2-methoxycarbonylpyrazine in tetrahydrofuran with lithium aluminum hydride at about — 70° gave 2-formylpyrazine (46%), but reduction of 2-chlorocarbonylpyrazine with lithium tri-r-butoxyaluminohydride in tetrahydrofuran gave 2-(pyrazin-2-ylmethoxycarbonyl)pyrazine (55%) and 2-formylpyrazine (20%) (1077), and 2-ethoxycarbonyl-3-methylpyrazine was reduced with lithium aluminum hydride in tetrahydrofuran at — 70° to 2-formyl-3-methylpyrazine (1185). 

Reduction of 2-ethoxycarbonyl-3-methylpyrazine with lithium aluminum hydride in tetrahydrofuran at — 70° gave 2-formyl-3-methoxypyrazine (1185), and reduction of 2-amino-3-methoxycarbonylpyrazine with lithium aluminum hydride in tetrahydrofuran at room temperature (1074) and reflux gave 2-amino-3-hydroxymethylpyrazine (1075). 

The preparation of this ring system involves the use of pyrazine intermediates. The parent heterocycle 3 has been prepared in two different ways from 2-amino-3-methylpyrazine (1). Formylation in a mixture of formic acid and acetic anhydride at 50° gives the formamido derivative 2. This is cyclized by heating with sodium ethoxide at 325° to give... 

Formyl derivatives 12 were obtained on Vilsmeier formylation of the 2-amino-3-methylpyrazines 11 with three molar quantities of phosphoryl chloride Although it seems reasonable to suggest that the reaction proceeds through intermediates such as 2 and 3, attempts to formylate... 

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