Regioselective α-Bromination of Aralkyl Ketones Using N-Bromosuccinimide in the Presence of Montmorillonite K-10 Clay: A Simple and Efficient Method

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

“…There are several approaches for α-bromination of carbonyl compounds using NBS as the brominating agent. − The use of a radical initiator is a common approach for such α-bromination reactions. ,, However, this particular reaction can also be carried out in strongly basic media − or in acidic media . Lewis acids such as Mg(ClO 4 ) 2 can be used as catalysts for similar transformations.…”

Substrate Directed Regioselective Monobromination of Aralkyl Ketones Using N-Bromosuccinimide Catalysed by Active Aluminium Oxide: α-Bromination versus Ring Bromination

“…As evident from the literature [ 26 ], portion wise addition of N -bromosuccinimide caused to control the release of bromonium ion and it provided improved yields of α -brominated product ( 2a ). The same was implemented in the present investigation and N -bromosuccinimide was added portion wise (10 portions).…”

“…Alternative reagents were reported in the literature, for example, cupric bromide [ 5 ], dioxane dibromide [ 6 ], tetra butyl ammonium tribromide [ 7 ], H 2 O 2 -HBr [ 8 ], bromodimethyl sulfoniumbromide [ 9 ], ethylene bis( N -methyl imidazolium) ditribromide [ 10 ], trihaloisocyanuric acids [ 11 ], pyridinium bromochromate [ 12 ], and NH 4 Br-oxone [ 13 ]. In addition, a popular and superior brominating agent such as N -bromosuccinimide [ 14 ] was utilized for α -bromination of carbonyl compounds using a radical initiator such as azobisisobutyronitrile (AIBN) or dibenzoyl peroxide (BPO) [ 15 ] and, later, it has been demonstrated that the reactivity of NBS could be modulated with ionic liquids [ 16 ], photochemical energy [ 17 ]; sonochemical energy [ 18 ], solvent free reaction conditions (SFRC) [ 19 ] and various catalysts such as Mg(ClO 4 ) 2 [ 20 ], NH 4 OAc [ 21 ], amberlyst-15 [ 22 ], silica supported NaHCO 3 [ 23 ], sulfonic acid functionalized silica [ 24 ], FeCl 3 [ 25 ], montmorillonite-K10 [ 26 ], and Silica gel [ 27 ]. NBS also is utilized for ring or nuclear bromination using various catalysts such as H 2 SO 4 -CF 3 CO 2 H [ 28 ], p -toluenesulfonic acid [ 29 ], dibromodimethylhydantoin in aqueous base [ 30 ], amberlyst [ 31 ], and HZSM-5 [ 32 ].…”

Synthesis of novel piperazine-based bis(thiazole)(1,3,4-thiadiazole) hybrids as anti-cancer agents through caspase-dependent apoptosis

“…The hydrazonoyl halides 8a-f, 60,62,63 10a, b, 64,65 and a-bromoketones 14a-d (ref. [66][67][68] were synthesized following the literature procedures. Anticancer evaluations were conducted at the National Cancer Institute, Cairo University, Giza, Egypt.…”