A Convenient Halogenation of α,β-Unsaturated Carbonyl Compounds withOXONE ^®and Hydrohalic Acid (HBr, HCl)

Abstract

Mixtures of OXONE ® and hydrobromic acid or hydrochloric acid afford solutions of bromine or chlorine, respectively. aBromo-or a-chloro-a,b-unsaturated carbonyl compounds were prepared by addition of hydrobromic acid or hydrochloric acid to the mixture of a,b-unsaturated carbonyl compounds and OXONE ® in CH 2 Cl 2 followed by treatment of Et 3 N in moderate to good yields.

An efficient methodology for the synthesis of 3-styryl coumarins

“…To carry out the synthesis of 3-styryl coumarins the synthesis of 3-bromo-6,7-dimethoxycoumarin 21 (2) was essential which was accomplished with oxone 22 and HBr on reaction with 6,7-dimethoxicoumarin (4) (Scheme 2). Compound 2 was obtained in high yield (96%).…”

Chlorinated Englerins with Selective Inhibition of Renal Cancer Cell Growth

“…Following dichlorination, dehydrohalogenation with Et 3 N yielded 3 in modest yield. 10 While it is not possible to specify the conditions that inadvertently led to dehydrohalogenation, it is likely that molecular chlorine was generated in stored CHCl 3 and reacted with the biosynthetic product englerin A ( 1 ) to form the dichloro products 4 and 5 , which then yielded 3 (Scheme 1). The generation of molecular chlorine by photo-oxidation has long been recognized due to chloroform’s importance in 19 th century anesthesia, with phosgene and hydrochloric acid among the other major products generated.…”

Electrophilic Bromination of Alkenes: Environmental, Health and Safety Aspects of New Alternative Methods

“…[39] The latter was used to convert hydrobromic acid (entry 20), [40,41] which can also be oxidised by using Oxone (2 KHSO 5 ·KHSO 4 ·K 2 SO 4 , entry 21). [42] Oxone is applied directly during the synthesis to convert the alkene into the dibromide (entry 21, [42] entry 22 [43] ), but also to regenerate the reagent, which is a carrying agent (entry 10b), [29] an N-halo compound (entry 23), [44,45] or another N-halo compound, Nbromsuccinimide (NBS, entry 24). [46] Overviews of applications of the oxidants sodium perborate, [50][51][52] CAN, [53][54][55][56] Selectfluor [57,58] and other N-halo reagents, [59] sodium periodate, [60] DIB as a polyvalent iodine compound [61][62][63][64] and Oxone [65,66] can be found in the litera- ture.…”

“…[47] No. 19 [39] 9a [27] 20 [40] 9b [27] 21 [42] [g] 10a [28] 22 [43] [f] 10b [28] [h] 23a [44] 11a [29] 23b [45] 11b [29] 24 [46] [a] poly(vinylpyrrolidone)-bromine complex.…”