- Aromatic Halogenation Using N-Halosuccinimide and PhSSiMe3 or PhSSPh
-
We developed a mild aromatic halogenation reaction using a combination of N-halosuccinimide and PhSSiMe3 or PhSSPh. Less reactive aromatic compounds, such as methyl 4-methoxybenzoate, were brominated with PhSSiMe3 or PhSSPh and N-bromosuccinimide in high yields. No reaction was observed in the absence of PhSSiMe3 or PhSSPh. This method is also applicable to chlorination reactions using N-chlorosuccinimide and PhSSPh.
- Hirose, Yuuka,Yamazaki, Mirai,Nogata, Misa,Nakamura, Akira,Maegawa, Tomohiro
-
p. 7405 - 7410
(2019/06/14)
-
- Bromination of arenes using I2O5-KBr in water
-
An efficient and environmentally benign bromination of various aromatic compounds using aN aqueous I2O5-KBr system at room temperature has been developed in this work. A series of aromatic compounds such as acetophenones, benzaldehydes, benzoic acids, anilines, amides, and aminopyridine have been successfully brominated in excellent regioselectivities and good yields under the typical reaction conditions. The features of KBr as brominating reagent, water as solvent, and mild conditions make this system an attractive synthetic procedure. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Hou, Jieping,Li, Zejiang,Jia, Xiao-Dong,Liu, Zhong-Quan
-
supporting information
p. 181 - 187
(2013/12/04)
-
- Aromatic substitution in ball mills: Formation of aryl chlorides and bromides using potassium peroxomonosulfate and NaX
-
Aryl chlorides and bromides are formed from arenes in a ball mill using KHSO5 and NaX (X = Cl, Br) as oxidant and halogen source, respectively. Investigation of the reaction parameters identified operating frequency, milling time, and the number of milling balls as the main influencing variables, as these determine the amount of energy provided to the reaction system. Assessment of liquid-assisted grinding conditions revealed, that the addition of solvents has no advantageous effect in this special case. Preferably activated arenes are halogenated, whereby bromination afforded higher product yields than chlorination. Most often reactions are regio- and chemoselective, since p-substitution was preferred and concurring side-chain oxidation of alkylated arenes by KHSO5 was not observed. The Royal Society of Chemistry.
- Schmidt, Robert,Stolle, Achim,Ondruschka, Bernd
-
p. 1673 - 1679
(2013/02/22)
-
- Method for brominating organic compounds
-
The present invention relates to processes for the bromination of organic compounds, and to bromination microreactors for carrying out these processes.
- -
-
Page/Page column 5-6
(2008/06/13)
-
- Increasing the selectivity of bromination of aromatic compounds using Br2/SiO2
-
Br2/SiO2 possessed considerable practical advantages over traditional reagents for the bromination of aromatic hydrocarbons, e.g., toluene, o-, m-, and p-xylene, anthracene and phenol. In the presence of SiO2, toluene reacted with bromine instantly. Compounds containing electron-donating substituents showed mainly bromination on the rings. The behavior of o-, m-, and p-xylene showed predominant substitution on the rings. The bromination of phenol to p-bromophenol showed good yield at 81%. Naphthalene was monobrominated to 1-bromonaphthalene with a yield of 84% in 2 has the potential to alter reaction selectivity. It may be able to switch a mechanism from radical to polar, or to influence the regioselectivity of the products formed. In the absence of SiO2, selectivity was lost and a mixture of products by substitution of bromine atom on the ring and on the side chain without any preferability was obtained. The nature of silica gel was important for the success of the reaction. Optimal results were obtained with silica gel dried at 250°C for 1 hr.
- Ghiaci,Asghari
-
p. 1151 - 1152
(2007/10/03)
-
- An experimental estimation of aromaticity relative to that of benzene. The synthesis and NMR properties of a series of highly annelated dimethyldihydropyrenes: Bridged benzannulenes
-
The synthesis of 13 trans-dimethyldihydropyrenes (bridged [14]annulenes) fused to one or more benzene, naphthalene, phenanthrene, phenalene, or quinoxaline rings and 6 cis-dihydropyrene derivatives from benzenoid precursors using either a thiacyclophane route or an electrocyclic addition of a furan to an annulyne followed by deoxygenation is reported. Their 1H NMR spectra are studied in detail to obtain correlations between 3JH,H coupling constants and the internal methyl proton chemical shifts and also between the latter and the more distant external annulene ring proton shifts. These linear correlations are then used to obtain a relationship between the relative aromaticity of benzene and the fused ring in question, such that the aromaticity of the fused ring can be estimated relative to that of a benzene ring simply from a measurement of chemical shift in the fused annulene.
- Mitchell, Reginald H.,Iyer, Vivekanantan S.,Khalifa, Nasr,Mahadevan, Ramanathan,Venugopalan, Santhanagopalan,Weerawarna, Sirimevan Ananda,Zhou, Pengzu
-
p. 1514 - 1532
(2007/10/02)
-
- Ring Halogenations of Polyalkylbenzenes by Ionic Halides and Koser's Reagent
-
Ring chlorinations of polyalkylbenzenes such as mesitylene have been carried out at room temperature with LiCl or NaCl and stoichiometric amounts of Koser's reagent.Solvent range from water to methylene chloride.The procedures were extended to bromination and iodination.
- Bovonsombat, Pakorn,Djuardi, Elsa,Nelis, Edward Mc
-
p. 2841 - 2844
(2007/10/02)
-
- Halogenation Using Quaternary Ammonium Polyhalides. XIV. Aromatic Bromination and Iodination of Arenes by Use of Benzyltrimethylammonium Polyhalides-Zinc Chloride System
-
The reaction of arenes with benzyltrimethylammonium tribromide or benzyltrimethylammonium dichloroiodate in acetic acid in the presence of ZnCl2 at room temperature or at 70 deg C gave brome- or iodo-substituted arenes in good yield, respectively.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Moriwaki, Masayuki,Tanaka, Toshio,Fujisaki, Shizuo,Okamoto, Tsuyoshi
-
p. 439 - 443
(2007/10/02)
-
- Selective Nuclear Halogenation of Polymethylbenzenes with Alumina-Supported Copper(II) Halides
-
The halogenation of polymethylbenzenes with alumina-supported copper(II) halides under heterogeneous conditions in nonpolar solvents gave nuclear-halogenated compounds selectively in high yields; no side-chain-halogenated compounds were formed.
- Kodomari, Mitsuo,Satoh, Hiroaki,Yoshitomi, Suehiko
-
p. 4149 - 4150
(2015/06/25)
-
- SYNTHESIS OF DIATROPIC HIGHLY BENZANNELATED ANNULENES.
-
The first examples of annelated cis-dihydropyrenes, 16, 18, 19, together with a number of highly annelated trans-dihydropyrenes, 2-4 and, 17, are described.All are diatropic and indicate that higher annelation does not remove the delocalisation in a macrocyclic ring.
- Mitchell, Reginald H.,Mahadevan, Ramanathan
-
p. 5131 - 5134
(2007/10/02)
-
