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Kinetic study on the anelation of heterocycles. 3 . Pyrazino[2,3‐ d ]pyrimidine derivatives synthesized by the hinsberg reaction
Author(s) -
Abasolo Maria Inés,
Fernández Beatriz M.,
Magrini Edgardo
Publication year - 1992
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570290536
Subject(s) - chemistry , regioselectivity , yield (engineering) , methylene , pyrimidine , aqueous solution , medicinal chemistry , chloride , organic chemistry , stereochemistry , catalysis , materials science , metallurgy
A kinetic study on the obtainment of pyrazinopyrimidine derivatives (pteridines) was performed. The regioselective synthesis of compounds 6‐methylpyrazino[2,3‐ d ]pyrimidin‐7(8 H )‐one (5a) and 7‐methylpyraz‐ino[2,3‐ d ]pyrimidin‐6(5 H )‐one (5b) , in good yields, was expected by the Hinsberg reaction because the synthesis of both isomers analytically pure was never reported to date. This Hinsberg reaction gave good results to obtain compound 5a , regioselectively and in good yields, either in p H 5 aqueous buffer solution or in methylene chloride, among several organic solvents. However, structural and solvation factors prevented the synthesis of the isomer 5b , which was regioselectively formed in very acid solutions (Ho −0.89), but in very poor yield.