Nuclear Versus Side-Chain Bromination of 4-Methoxy Toluene by an Electrochemical Method

Abstract

The electrochemical bromination of 4-methoxy toluene by two-phase electrolysis yields 3-bromo 4-methoxy toluene at first, which subsequently undergoes side-chain bromination to give 3-bromo 4-methoxy benzyl bromide as a final product in 86% yield. The two-phase electrolysis consists of 25-50% NaBr as aqueous electrolyte and CHCl 3 containing aromatic compound as organic phase. The reaction temperature is maintained at 10-25 C. The probable orientation of bromine atom in an alkyl aromatic compound (nuclear versus side chain) is explained from the experimental result.

Total Synthesis of Novel Skeleton Flavan-Alkaloids

“…NaBH 3 CN, as a reducing agent, has remarkable stability in acidic environments, whose hydrolysis rate is 10 −8 that of sodium borohydride [ 15 ]. A wide range of acids including BF 3 ·OEt 2 , ZnCl 2 , and concentrated HCl, were compared in the reaction and it was found that 10% HCl delivered the best conversion (60% yield) without opening the A ring at the 2 position [ 16 , 17 ]. The TMS protecting groups were also removed in the reaction by hydrolysis.…”

Scalable Green Approach Toward Fragrant Acetates

“…After extraction of the aqueous phase with Et 2 O (10 mL), the separated organic phase was dried over anhydrous Na 2 SO 4 , filtered, and evaporated in vacuo to furnish an oil. An aliquot sample of the crude material was subjected to proton NMR [ 56 ] and GC-MS [ 57 ] analyses to identify the acetate 22 , and the obtained spectra fully corresponded to the reported data. In the alternative experiment, after completion of the reaction, the enzyme was filtered off, the filtrate was diluted with water, and it was extracted with methyl tert-butyl ether (MTBE).…”

A Compilation of Synthetic Strategies to Access the Most Utilized Indoloquinoline Motifs

“…[42] 2-(3-Bromoquinolin-2-yl)aniline 78 could also be converted to the target indoloquinoline using pyridinium hydrochloride under heating conditions (Scheme 18a). [43] Bach and coworkers reported novel method to install amine functional group into a benzene nucleus which could be applied for the preparation of indoloquinoline. The method employed 2-phenylquinoline substrate 79 to react with BocN 3 via rhodium-catalyzed amination providing the corresponding product 80 in excellent yield.…”

“…Final step was the cyclization using Buchwald‐Hartwig conditions to provide indoloquinoline 2 in good yield (Scheme 18a) [42] . 2‐(3‐Bromoquinolin‐2‐yl)aniline 78 could also be converted to the target indoloquinoline using pyridinium hydrochloride under heating conditions (Scheme 18a) [43] . Bach and coworkers reported novel method to install amine functional group into a benzene nucleus which could be applied for the preparation of indoloquinoline.…”