Direct Synthesis of Esters and Amides from Unprotected Hydroxyaromatic and -aliphatic Carboxylic Acids
作者:Alan R. Katritzky、Sanjay K. Singh、Chunming Cai、Sergey Bobrov
DOI:10.1021/jo052293q
日期:2006.4.1
activation of hydroxy-substituted carboxylic acids using benzotriazole chemistry without prior protection of the hydroxy substituents is presented. The N-acylbenzotriazole intermediates 2a−g, 6a−d, and 9a−c have been used for high-yielding synthesis of both aliphatic (3a−l) and aromatic (7a−h, 10a−f) hydroxy carboxamides. High yields of aromatic hydroxy esters 12a−h and 13a−i were obtained using either
Synthesis of Benzoxazines, Quinazolines and 4H-Benzo[e][1,3]thiazine by ANRORC Rearrangements of 1,2,4-Oxadiazoles
作者:Alan Katritzky、Bogdan Draghici、Bahaa El-Gendy
DOI:10.1055/s-0031-1289673
日期:2012.2
1,2,4-Oxadiazoles undergo ANRORC (addition of nucleophile, ring-opening and ring-closure) rearrangements upon reaction with excess of n-butyllithium to give benzoxazines, benzothiazines, and quinazolines in good yields under mild conditions. N,O-heterocycles - rearrangements - benzoxazines - quinazolines - benzothiazines
Synthesis of Aliphatic Hydroxyaryl Ketones or (Hetero)aryl Hydroxyaryl Ketones by Acylation of Organometallic Reagents
作者:Alan Katritzky、Khanh Le、Prabhu Mohapatra
DOI:10.1055/s-2007-990786
日期:2007.10
Diverse hydroxyarenecarboxylic acids afford stable N-(hydroxyaroyl)benzotriazoles that react with heteroaryl, alkyl, and aryl Grignard or lithium reagents to give the corresponding hydroxyaryl ketones in 51-94% yields.
作者:Alan R. Katritzky、Khalid Widyan、Kostyantyn Kirichenko
DOI:10.1021/jo070162e
日期:2007.7.1
A general synthesis of acyl azides from the corresponding N-acyl benzotriazoles is described. The procedure affords acyl azides in good yields and avoids the use of acid activators and NO+ equivalents typically employed to synthesize these compounds from acid chlorides and hydrazides, respectively.