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Eine neue Aminoazirin‐Reaktion. Bildung von 3,6‐Dihydropyrazin‐2(1 H )‐onen
Author(s) -
Hugener Martin,
Heimgartner Heinz
Publication year - 1989
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19890720123
Subject(s) - chemistry , medicinal chemistry , amide , nucleophile , dipeptide , trifluoromethyl , nucleophilic addition , stereochemistry , organic chemistry , catalysis , peptide , biochemistry , alkyl
A New Aminoazirine Reaction. Formation of 3,6‐Dihydropyrazin‐2(1 H )‐ones The reaction of 3‐(dimethylamino)‐2 H ‐azirines 1 and 2‐(trifluoromethyl)‐1,3‐oxazol‐5(2 H )‐ones 5 in MeCN or THF at 50–80° leads to 5‐(dimethylamino)‐3,6‐dihydropyrazin‐2(1 H )‐ones 6 ( Scheme 3 ). Reaction mechanisms for the formation of 6 are discussed: either the oxazolones 5 react as CH‐acidic heterocycles with 1 ( Scheme 4 ), or the azirines 1 undergo a nucleophilic attack onto the carbonyl group of 5 ( Scheme 6 ). The reaction via intermediate formation of N ‐(trifluoroacetyl)dipeptide amide 8 ( Scheme 5 ) is excluded.