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Deoxygenative vs. Vicarious Nucleophilic Substitution of Hydrogen in Reactions of 1,2,4‐Triazine 4‐Oxides with α‐Halocarbanions
Author(s) -
Kozhevnikov Dmitry N.,
Rusinov Vladimir L.,
Chupakhin Oleg N.,
Makosza Mieczyslaw,
Rykowski Andrzej,
Wolinska Ewa
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200204)2002:8<1412::aid-ejoc1412>3.0.co;2-9
Subject(s) - chemistry , sulfone , nucleophilic substitution , intramolecular force , medicinal chemistry , carbanion , aryl , nucleophile , triazine , substitution reaction , 1,3,5 triazine , adduct , radical nucleophilic aromatic substitution , ring (chemistry) , nucleophilic aromatic substitution , stereochemistry , polymer chemistry , organic chemistry , catalysis , alkyl
Abstract The 3,6‐diaryl‐1,2,4‐triazine 4‐oxides 1a − e undergo a nucleophilic substitution of hydrogen with the α‐halomethyl aryl sulfones 2, 3 and 7 by two alternative pathways: vicarious nucleophilic substitution (VNS) and/or an intramolecular deoxygenative process. The former pathway is found to dominate in the reaction of 1 with bromomethyl tolyl sulfone ( 7 ) yielding the 5‐tosylmethyl‐1,2,4‐triazine 4‐oxides 6 , while the reaction with the chloromethyl aryl sulfones 2 and 3 leads to the 5‐arylsulfonylchloromethyl‐1,2,4‐triazines 4 and 5 , respectively, as the products of deoxygenative substitution. The reaction of 6‐phenyl‐1,2,4‐triazine 4‐oxide ( 1f ) with the chloromethyl aryl sulfones 2 and 3 proceeds differently. At low temperature (−75 C) the products of the VNS reaction at position 5 ( 6f and 12f) are formed. At room temperature the 7‐chloro‐1‐hydroxy‐3‐phenyl‐7‐(arylsulfonyl)‐1,4,5‐triazahepta‐1,3,6‐trienes 10f and 11f are obtained by addition of the carbanions 2 and 3 in the 3‐position, followed by the ring opening of the resulting σ adduct. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)