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Synthesis and regiospecificity in methylation of pyrido[1,2‐ a ]pyrazinium‐1‐ and 3‐olates and pyrido[1,2‐ b ]pyridazinium‐2‐ and 4‐olates
Author(s) -
Bátori Sándor,
Messmer András
Publication year - 1990
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.5570270630
Subject(s) - chemistry , reagent , methylation , selectivity , medicinal chemistry , stereochemistry , combinatorial chemistry , organic chemistry , biochemistry , dna , catalysis
New methods have been developed for the synthesis of pyrido[1,2‐ a ]pyrazinium‐1‐ and 3‐olates 5a‐f, 9 and 1‐thiolate 24 as well as of pyrido[1,2‐ b ]pyridazinium‐4‐ and 2‐olates 14, 20 . The methylation of these new compounds was studied by soft and hard methylating agents. Depending on the nature of the reagent used, the pyrido[1,2‐ a ]pyrazinium‐1‐olates 5a‐f gave NMe 22a‐f and/or OMe 23a‐f products, whereas the 3‐olate 9 and both the 4‐ and 2‐pyridazinium‐olates 14, 20 afforded solely OMe compounds 10, 15, 21 . A selectivity rule for methylation is proposed.