Dibromination of 5-pyrazolones and 5-hydroxypyrazoles via dibromoisocyanuric acid
作者:Kaung-Min Cheng、Jin Bin Wu、Hui-Chang Lin、Jiann-Jyh Huang、Yu-Ying Huang、Shao-Kai Lin、Tsung-Ping Lin、Fung Fuh Wong
DOI:10.1002/jhet.442
日期:——
A safe and efficient method was developed for the dibromination of pyrazolones and 5‐hydroxypyrazoles by use of dibromoisocyanuricacid (DBI). The reaction gave the corresponding dibrominated pyrazolones in excellent yields (≥91%). J. Heterocyclic Chem., (2010).
Chande, Madhukar S.; Bhandari, Jayesh D.; Joshi, Vishwas R., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1993, vol. 32, # 12, p. 1218 - 1228
作者:Chande, Madhukar S.、Bhandari, Jayesh D.、Joshi, Vishwas R.
DOI:——
日期:——
Efficient di-bromination of 5-pyrazolones and 5-hydroxypyrazoles by N-bromobenzamide
An efficient and convenient method for the bromination of pyrazolones and 5-hydroxypyrazoles was developed by using N-bromobenzamide in THF at room temperature. This new method provided di-bromimated pyrazolones in excellent yields (>= 90%). Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved
Ringtransformationen von Pyrazolinonen �ber Azoolefine - ein neuer Zugang zum 1,2,3-Thiadiazol-System
Elektrophilic attack of thiocyanate/bromine to azoenamine (2 a) yields thiocyanato compound 3 a which cyclizes into 1,2,3-thiadiazolium-salt (5 a) on treatment with perchloric acid. 2-Halo-3-arylazo-propenamides (8) form directly thiadiazolium-salts (11) with KSCN/HOAc. The addition of N- or O-nucleophiles to 11 occurs in the 5-position to form 1,2,3-thiadiazolines (13).
WEBER G.; MANN G.; WILDE M.; HAUPTMANN S., Z. CHEM., 1980, 20, NO 12, 437-438