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Regioselective Reduction of 3-Substituted N-Acylpyrazinium Salts toward the Synthesis of 1,2-Dihydropyrazines

Author:
Williams, Alfred L., St. Hilaire, Valentine R., Lee, Tina
Source:
Journal of organic chemistry 2012 v.77 no.8 pp. 4097-4102
ISSN:
1520-6904
Subject:
chemical reactions, chemical structure, organic chemistry, organic compounds, regioselectivity, salts
Abstract:
The regioselective reduction of 3-substituted N-acylpyrazinium salts with n-Bu₃SnH has been developed for the synthesis of 3-substituted 1,2-dihydropyrazines in yields of 56–94%. Substitution of the pyrazinium salts with electron-donating groups favors the formation of the 1,2-isomers as a result of their better stability over the 1,6-isomers. Under mild acidic conditions, 3-methoxy substituted 1,2-dihydropyrazine was easily hydrolyzed in excellent yield to Δ⁵-2-oxopiperazine.
Agid:
5499817