2-Chloromethyl-3-methoxy-5-methylpyrazine 1-oxide

Chloromethyl-3-methoxy-5-methylpyrazine 1-oxide (28, R = H) gave 2-chloro-6-chloromethyl-5-methoxy-3-methylpyrazine 1-oxide (28, R = Cl) OV-chIorosuccinimide, Me2NCHO, 20°C, 12 h 90%).333 Also other examples.321,599,1460... 

Chloromethyl-3-methoxy-5-methylpyrazine 1-oxide (232) and indole-l( )-yl-magnesium bromide (233) (made in situ) gave 3-(3-methoxy-5-methyl-l-oxi-dopyrazin-2-ylmethyl)indole (234) (Et20—PhMe, 0 — 20°C, 12 h 77%).333 Also other examples.1614... 

Chloromethyl-3-ethoxy-5-methylpyrazine 2-Chloromethyl-3-methoxy-5-methylpyrazine 1-oxide 2-Chloromethyl-3-methylpyrazine... 

Certain a-chloromethylpyrazine A -oxides have been deoxygenated with phosphorus trichloride. Treatment of 2-amino-5-chloromethyl-3-cyanopyrazine 1-oxide (and 2-amino-3-cyano-5-methoxymethylpyrazine 1-oxide) with phosphorus trichloride at room temperature in tetrahydrofuran resulted in smooth deoxygenation to 2-amino-5-chloromethyl-3-cyanopyrazine (and 2-amino-3-cyano-5-methoxy-methylpyrazine) (529), whereas 2-amino-6-chloromethyl-3-cyanopyrazine 1-oxide was best deoxygenated to 3-amino-5-chloromethyl-2-cyanopyrazine by phosphorus trichloride in refluxing tetrahydrofuran (534). The more vigorous conditions necessary for the last reaction may be a reflection of increased steric hindrance at the fV-oxide grouping (529). Use of solvents like chloroform or dioxane led to slow reactions which were accompanied by the formation of numerous unidentified by-products (534). 

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