Lawesson's reagent for direct thionation of hydroxamic acids: Substituent effects on LR reactivity
作者:Witold Przychodzeń
DOI:10.1002/hc.20259
日期:——
To explore the generality and scope of direct thionation of hydroxamicacids (HAs), the reaction of various structurally diverse HAs with Lawesson's reagent was investigated. The yield of thiohydroxamic acid (THAs) is poor when HAs possess bulky acyl and/or N-substituents, acidic α-hydrogen atoms, or an N-phenyl ring. THAs yields were correlated with Brown sigma parameter. The relative rates of two
Mechanism of the Reaction of Lawesson’s Reagent withN-Alkylhydroxamic Acids
作者:Witold Przychodzeń
DOI:10.1002/ejoc.200400727
日期:2005.5
The mechanism of the reaction under discussion has been established by investigating the products of the reaction between 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson’sreagent, LR) and N-alkylhydroxamic acids HAs 1. The primary intermediate is an adduct, O-dithiophosphonylated hydroxamic acid 19, which decomposes to yield metathiophosphonate (AnsPOS), a sulfur atom