title: Regioselective reduction of 3-substituted N-acylpyrazinium salts toward the synthesis of 1,2-dihydropyrazines.
abstract: The regioselective reduction of 3-substituted N-acylpyrazinium salts with n-Bu(3)SnH 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 Δ(5)-2-oxopiperazine.
authors.affiliation: Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina 27707, USA. awilliams@nccu.edu
authors.forename: Alfred L
authors.initials: AL
authors.lastname: Williams
authors.forename: Valentine R
authors.initials: VR
authors.lastname: St Hilaire
authors.forename: Tina
authors.initials: T
authors.lastname: Lee
mesh_terms: D007477:Ions / Q000737:chemistry*; D007536:Isomerism; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry*; D011719:Pyrazines / Q000138:chemical synthesis* / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D007477:Ions; D010879:Piperazines; D011719:Pyrazines; D012492:Salts