1,8-Diazabicyclo[5.4.0]undec-7-ene hydrobromide perbromide: a new mild stable brominating agent for aromatic compounds

Silica-supported quinolinium tribromide: a recoverable solid brominating reagent for regioselective monobromination of aromatic amines

“…or poly(N-bromobenzene-1,3-disulfonylamide), 13 1,2-dipyridiniumditribromide-ethane, 14 ethylenebis(Nmethylimidazolium) ditribromide, 15 1-butyl-3-methylpyridinium tribromide, 16 tert-butylhydroperoxide/ HBr, 17 LiBr/(NH 4 ) 2 Ce(NO 3 ) 6 , 18 KBr/NaBO 3 ·4H 2 O, 19 2 -m e t h y l -4 -p o l y ( s t y r y l m e t h y l ) t h i a z o l i u m hydrotribromide, 20 LiBr/(diacetoxyiodo)benzene, 21 alkalimetal bromide/NaIO 4 , 22 bromodimethylsulfonium bromide, 23 HBr/H 2 O 2 , 24 1,8-diazabicyclo [5.4.0]undec-7-ene hydrobromide perbromide, 25 metal bromides/ sodium bismuthate, 26 N-octyl quinolinium tribromide 27 and pyridinium hydrobromide perbromide. 28 However, some methods still suffer from drawbacks of difficult handling, low selectivity, low yield and corrosion.…”

Synthesis, Characterization and Structure of DBU-hydrobromide-perbromide: A Novel Oxidizing Agent for Selective Oxidation of Alcohols to Carbonyl Compounds

“…A literature survey disclosed that there is only one reference cited in the literature dealing with DBU, HBr and Br2 in AcOH as a brominating agent with the proposed structure as DBU-hydrobromide-perbromide on the basis of its 1 H NMR and UV spectral data. 15 We have now exploited a new synthesis of this reagent together with its 3D-structure by X-ray crystallography and examined its oxidation potential for functional group transformations. The suggested mechanism for the preparation of the reagent can be depicted as in Scheme 2.…”

“…1 Organic tribromide salts as mild reagents are good candidates for this selective conversion, because they are not only stable, crystalline solids, and relatively soluble in most organic solvents but also can be handled more conveniently than liquid bromine and can be used successfully for this purpose. Although they are used as brominating agents of aromatic rings, 2 α-bromination of ketones, [3][4][5][6] and ketals, 3,7 electrophilic addition, 3,4,[8][9][10][11][12][13][14] and substitution, 4,13,[15][16][17][18][19] they are also used as catalyst for the oxidation of aromatic aldehydes to carboxylic acids 20 or ω-bromoesters, 21 and dialkyl and alkyl aryl sulfides to sulfoxides, 22 protection of carbonyl, 23 and hydroxyl groups, 24 cleavage of ethers and dithioacetals 25 and conversion of thioamides into amides. 26 They can also be applied in the synthesis of heterocyclic ring systems such as aziridines 27 and benzothiazoles.…”

Synthesis and Crystal Structure Determination of [H2‐cryptand 222](Br3)2: A Unique Tribromide Catalyst for the Catalytic Chemoselective N‐Boc Protection of Amines

“…13 Organic tribromide reagents (OTBs) are preferable as oxidants to molecular bromine, owing to the hazards associated with elemental bromine. Several tribromides have been reported i.e., tetramethylammonium tribromide, 14,15 phenyltrimethylammonium tribromide, 16 cetyltrimethylammonium tribromide, tetrabutylammonium tribromide, 17 1,8-diazabicyclo [5,4,0]-tetrabutylammonium tribromide, 18 pyridine hydrobromide perbromide, 19 hexamethylenetetramine-bromine 20 and DABCO-bromine. 21 Recently some ionic liquid tribromides (IL-Br 3 -) for the preparation of bromoesters from aromatic aldehydes 22 and bromination of aromatic substrates 23 were reported.…”