Copper-catalyzed ortho-acylation of phenols with aryl aldehydes and its application in one-step preparation of xanthones
作者:Jun Hu、Enoch A. Adogla、Yong Ju、Daping Fan、Qian Wang
DOI:10.1039/c2cc36176k
日期:——
In the presence of triphenylphosphine, copper(II) chloride can catalyze an intermolecular ortho-acylation reaction of phenols with aryl aldehydes. The reaction proceeds smoothly with a wide range of starting materials, and furthermore, it can be used to synthesize xanthone derivatives in a single step in high yields.
A highly efficient photocatalyticaerobicoxidation of cyclic sulfamides to synthesize cyclic N-sulfonyl imines with Ir(ppy)2(dtbpy)PF6 as photocatalyst is reported. These environmentally friendly transformations exihibit good to excellent isolated yields and good generality with respect to both five-membered and six-membered cyclic sulfamides.
HNTf<sub>2</sub>-Catalyzed Synthesis of Hydrodibenzofurans by an Epoxidation/Semipinacol Rearrangement Cascade
作者:Ting Hei Matthew Wong、Xingguang Li、Dengke Ma、Jianwei Sun
DOI:10.1021/acs.orglett.0c00300
日期:2020.3.6
is a highly efficient synthesis of hydrodibenzofurans, an important structural unit lacking general access, in particular, with contiguous quaternary stereocenters. In the presence of HNTf2 as the superior catalyst and mCPBA as an oxidant, the readily available styrene substrates underwent a one-pot cascade process comprising epoxidation, semipinacol rearrangement, and hemiketal formation to furnish
Synthesis and antimicrobial study of novel heterocyclic compounds from hydroxybenzophenones
作者:Shaukath A. Khanum、Sheena Shashikanth、S. Umesha、R. Kavitha
DOI:10.1016/j.ejmech.2005.04.005
日期:2005.11
The triazolothiadiazine analogues 6a-e were obtained via a multistep synthesis sequences beginning with the hydroxybenzophenones la-e. Hydroxybenzophenones on reaction with ethyl chloroacetate affords ethyl (2-aroylarytoxy)acetates 2a-e which on treatment with hydrazine hydrate yields 2-(2-aroylaryloxy)acetohydrazides 3a-e. Intramolecular cyclization of 3a-e with carbon disulfide affords 5-(2-aroylaryloxy)methyl-1,3,4-oxadiazole-2-(3H)thiones 4a-e, which on treatment with hydrazine hydrate yields 4-amino-5-(2-aroyl aryloxy)methyl-1,2,4-triazole-3-(2H)thiones 5a-e. Condensation of 5a-e with alpha-halocarbonyl compound results in 3-(2-aroylaryloxy)methyl-6-phenyl-1,2,4-triazolo[3,4-b][1,3,4] thiadiazine 6a-e analogues. The compounds 4a-e, 5a-e and 6a-e were tested against variety of fungal and bacterial strains in comparison to fluconazole and chloramphenicol, respectively. (c) 2005 Elsevier SAS. All rights reserved.
Heterogeneous catalysis by solid superacids. 17. Polymeric perfluorinated resin sulfonic acid (Nafion-H) catalyzed Fries rearrangement of aryl esters
作者:George A. Olah、Massoud Arvanaghi、V. V. Krishnamurthy