Xi:Irritant;19953-61-8Relevant articles and documents
Hexamethonium bis(tribromide) (HMBTB) a recyclable and high bromine containing reagent
Paul, Bappi,Bhuyan, Bishal,Purkayastha, Debraj D.,Dhar, Siddhartha S.,Patel, Bhisma K.
, p. 5646 - 5650 (2015/09/21)
A recyclable and high bromine containing di-(tribromide) reagent, hexamethonium bis(tribromide) (HMBTB) has been synthesized and utilized for the bromination of various organic substrates. The spent reagent hexamethonium bromide (HMB) can be effectively recycled by regenerating and reusing it without significant loss of activity. The crystalline and stable bis(tribromide) is an effective storehouse of very high percentage of active bromine requiring just half an equivalent of it for complete bromination. Both the Br3- moieties in HMBTB are nearly linear with Br-Br-Br angle of 179.55°.
A new recyclable ditribromide reagent for efficient bromination under solvent free condition
Kavala, Veerababurao,Naik, Sarala,Patel, Bhisma K.
, p. 4267 - 4271 (2007/10/03)
1,2-Dipyridiniumditribromide-ethane (DPTBE) has been synthesized and explored as a new efficient brominating agent. The crystalline ditribromide reagent is stable for months and acts as a safe source of bromine requiring just 0.5 equiv for complete bromination. It has high active bromine content per molecule and shows a remarkable reactivity compared to other tribromide reagents toward various substrates by just grinding the reagent and substrates in a porcelain mortar at room temperature. No organic solvent has been used during any stage of the reaction for substrates giving product as solid. Product can easily be isolated by just washing the highly water soluble 1,2- dipyridiniumdibromide-ethane (DPDBE) from the brominated product. The spent reagent can be recovered, regenerated, and reused without any significant loss.
A convenient halogenation of α,β-unsaturated carbonyl compounds with OXONE and hydrohalic acid (HBr,HCl)
Kim, Kyoung-Mahn,Park, In-Hwan
, p. 2641 - 2644 (2007/10/03)
Mixtures of OXONE and hydrobromic acid or hydrochloric acid afford solutions of bromine or chlorine, respectively, α-Bromo- or α-chloro-α,β-unsaturated carbonyl compounds were prepared by addition of hydrobromic acid or hydrochloric acid to the mixture of
Raman, infrared, and microwave spectra and conformational preferences of meso-Bisoxirane
Kalasinsky,Subramaniam,Su,Cook
, p. 521 - 530 (2007/10/03)
Vibrational infrared and Raman spectra of liquid and solid meso-bisoxirane and infrared spectra of the gaseous phase were recorded. Additionally, microwave rotational spectra from 40 to 18 GHz were recorded. The vibrational spectra demonstrate the presence of two conformations in the fluid phases but only one in the solid state. Infrared and Raman activities and gas-phase band contours indicate that the trans conformer with C(i) molecular symmetry is more stable than the gauche conformer (C1 symmetry). Variable temperature studies of two pairs of Raman lines are consistent with a ΔH value of 0.31 ± 0.10 kcal/mol in the liquid state. Rotational constants (A = 9187.45 ± 0.04, B = 2651.80 ± 0.01, C = 2608.92 ± 0.01 MHz) and the dipole moment (μ(total) = 3.03 D) were determined for the gauche conformer. Model calculations give an acceptable match to the observed rotational constants for an H-C-C'-H' dihedral angle of 60°. The relationship of meso-bisoxirane to other similar three-membered ring compounds is discussed. Published by Elsevier Science B.V.
Nickel mdiated Double Bond formation from vic-Dibromides and Ethyl Magnesium Bromide
Malanga, Corrado,Aronica, Laura A.,Lardicci, Luciano
, p. 9189 - 9192 (2007/10/02)
vic-dibromides are quantitaively converted into alkenes by using a catalityc amount of NidppeCl2 in the presence of two molar equivalents of EtMgBr in THF.Stereochemical aspects of the reaction are given.
