21151-56-4Relevant academic research and scientific papers
Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids
Wang, Zhentao,Zhu, Lin,Yin, Feng,Su, Zhongquan,Li, Zhaodong,Li, Chaozhong
experimental part, p. 4258 - 4263 (2012/04/10)
Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)2OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.
A Time-Resolved EPR Study on Photodecomposition of Dibenzoyl Peroxides in Carbon Tetrachloride
Yamauchi, Seigo,Hirota, Noboru,Takahara, Shigeru,Misawa, Hiroaki,Sawabe, Ken,et al.
, p. 4402 - 4407 (2007/10/02)
We have investigated the photodecomposition of a series of dibenzoyl peroxides in carbon tetrachloride by means of time-resolved EPR spectroscopy.The EPR spectra of the intermediate benzoyloxyl and trichloromethyl radicals were identified and the reaction mechanisms were clarified.It is shown that the decarboxylation takes place mostly from the intermediate benzoyloxyl radicals whose lifetimes are on the order of 1 μs at room temperature.The rate constants for the decarboxylation determined from the transient EPR signals were in good agreement with those obtainedfrom the transient absorption.On the basis of the observed polarization of the EPR signals, it is concluded that the spin states of the intermediate radicals are in thermal equilibrium within 0.5 μs after the laser excitation.In aerated systems additional radicals with larger g values were detected and tentatively assigned as phenylperoxyl radicals.
Decarboxylation Rates of Benzoyloxyl Radicals as Determined by Laser Flash Photolysis. Further Insight into the Mechanism for Photodecomposition of Dibenzoyl Peroxides
Misawa, Hiroaki,Sawabe, Ken,Takahara, Shigeru,Sakuragi, Hirochika,Tokumaru, Katsumi
, p. 357 - 360 (2007/10/02)
Bis(4-methoxybenzoyl), bis(4-chlorobenzoyl), and dibenzoyl peroxide were photolyzed in various solvents by 308-nm laser pulses to determine the rate constants for decarboxylation of the corresponding benzoyloxyl radicals.The activation energies of this pr
benzenes
Menkisoglou-Spyroudi, Ourania,Varvoglis, Anastasios
, p. 795 - 798 (2007/10/02)
The title compounds (3) have been prepared and their chemical properties studied.With iodine they give aryloxymethyl aryloxyacetates (4) through the intermediacy of aryloxyacetyl hypoiodites and α-iodoanisoles.The former are unstable but have been trapped with pyridine to give N-iodopyridinium aryloxyacetates, whereas the latter are stable and react independently with compounds (3) to afford the acetates (4).The termolysis of (3) has been studied and, besides esters (4), aryl aryloxyacetates are also formed.The mechanism of the thermolysis is briefly discussed.
Substituted pyrimidin-2-ones and the salts thereof
-
, (2008/06/13)
Compounds of the general formula: STR1 (wherein X represents a halogen atom or a trifluoromethyl group; R1 and R2 independently represent a hydrogen atom or a lower alkyl group; Z is --O--, --S--, --SO--, --SO2 -- or the group --NR4 -- wherein R4 is as defined for R hereinafter or represents the group COR5 in which R5 represents a hydrogen atom or an optionally substituted aryl, heterocyclic, aralkyl, lower alkyl or lower alkoxy group; R represents a C6-10 carbocyclic aromatic group or a heterocyclic group containing a 5-9 membered unsaturated or aromatic heterocyclic ring which ring contains one or more heteroatoms selected from O, N and S and optionally carries a fused ring which carbocyclic or heterocyclic group may carry one or more C1-4 alkyl or phenyl groups, said groups being optionally substituted; or, where Z represents the group >NR4, the group --ZR may represent a heterocyclic ring optionally carrying a fused ring and/or optionally substituted as defined for R; and R3 represents a hydrogen atom or a lower alkyl, lower alkenyl, lower alkynyl, lower alkanoyl, lower alkenoyl, C7-16 aralkyl or C6-10 arly group or a 5-9 membered unsaturated or aromatic heterocyclic ring); and, where acid or basic groups are present, the salts thereof; are useful in combating abnormal cell proliferation. The compounds of the invention are prepared by inter alia alkylation, ring closure and oxidation.
Synthesis of α-Haloalkyl Aryl Ethers from O,S-Acetals
Benneche, Tore,Undheim, Kjell
, p. 93 - 96 (2007/10/02)
α-Haloalkyl aryl ethers are prepared under mild conditions in high yileds by selective cleavage of O,S-acetals using sulfuryl chloride or bromine.The intermediate O,S-acetal is prepared from the phenol by O-alkylation using a readily accessible α-haloalkyl thioether.
