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Selektive Acylierungen von 3(5)‐Alkyl‐5(3)‐amino‐1 H ‐pyrazolen und eine neue Pyrazolo[5,1‐ c ]‐1,2,4‐triazol‐Synthese
Author(s) -
Kirschke Klaus,
Wolff Erich,
Ramm Matthias,
Lutze Gerhard,
Schulz Burkhard
Publication year - 1994
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199419941014
Subject(s) - chemistry , alkyl , nitrile , acylation , acetylation , stereochemistry , amino acid , medicinal chemistry , organic chemistry , catalysis , biochemistry , gene
Selective Acylations of 3(5)‐Alkyl‐5(3)‐amino‐1 H ‐pyrazoles and a New Pyrazolo[5,1‐ c ]‐1,2,4‐triazole Synthesis ( Z )‐5‐Amino‐1‐[1‐(hydroximino)alkyl]‐1 H ‐pyrazoles 3 have been synthesized by acylation of 3(5)‐alkyl‐5(3)‐amino‐1 H ‐pyrazoles 1 with nitrile oxides. The tosylation of the hydroxyimino group of 3 to ( Z )‐5‐amino‐1‐[1‐( p ‐tosyloximino)alkyl]‐1 H ‐pyrazoles 4 and the subsequent acetylation of the 5‐amino group give ( E )‐ and ( Z )‐5‐acetamido‐1‐[1‐( p ‐tosyloximino)alkyl]‐1 H ‐pyrazoles 5 , which undergo cyclization under basic conditions to pyrazolo[5,1‐ c ]‐1,2,4‐triazoles 6, 7 or 8 .