Benzyl bromide sulfone

Eight benzimidazoles Animal tissues ACN extn, liq-liq partns, two SPE cleanups 24 Hewlett-Packard RP-18,5 m, with Kontron RP-18 Presat, 25-40 m, guard column O.OIM pentane-sulfonate contg 0.5% TEA, pH 3.5/ACN (50 50) UV 298 nm/ 20-50 ppb/ GC-NPD 39-87% or GC-EI-MS or GC-Pulsed PICI-NICI-MS after derivatization with methyl iodine or pentafluoro- benzyl bromide 358... 

Cesium fluoride has been used to displace halogens, sulfonate groups and nitro groups among others, with fluorine. 1-Bromooctane (1), ethyl bromoacetate (2), benzyl bromide (3) and octyl tosylate (4) have been converted to the respective fluorides 5-7 by treatment with cesium fluoride in the presence of 10% tetraalkylammonium salt (Bu4NBr or Aliquat 336) in the absence of solvent.166... 

Calcium fluoride supported on cesium fluoride gives also a good conversion rate of 95% for benzyl bromide (3) to benzyl fluoride (4). The reaction is, however, carried out in tetramethylene sulfone. 

Alkene synthesis.1 This sulfone can be subjected to successive alkylation in the order shown in equation (I) to give a tetraalkylated derivative, but the fourth alkylation requires elevated temperatures and an activated reagent such as benzyl bromide. The alkylated derivatives on treatment with base undergo a Ramberg-Backlund reaction to give alkenes. 

Benzyl bromide (17.1 g, 0.1 mol) was added to a mixture of solid sodium dithionite (10.44 g, 0.06 mol) and Aliquat 336 (1.2 g, 0.03 mol). The mixture was vigorously shaken for 5 min and then heated in an oil bath for 20 h at 120 °C. Dibenzyl sulfone was removed by filtration through Florisil with 50 mL of methylene chloride. The solvent was evaporated and the crude solid crystallized from a 1 1 mixture of ethanol and toluene to give the pure sulfone as a white solid (7.54 g, 61%), mp 148-149 °C. 

An analogous procedure was carried out with benzyl bromide (17.1 g, 0.1 mol), sodium formaldehyde sulfoxylate dihydrate (10.35 g, 0.06 mol) and sodium carbonate (10.35 g, 0.075 mol) to obtain the pure dibenzyl sulfone (9.35 g, 76% after recrystallization). 

If the electron-withdrawing group is such that self-condensation does not occur then the anion can be generated in the normal manner. Thus, the anion 349 of cyclopropyl phenyl sulfone (348) can be readily prepared by treatment of the parent compound with n-butyllithium at 0°C in THF. The anion has been shown to condense in excellent yield with aldehydes, ketones, methyl iodide and allyl and benzyl bromides to yield 350. The... 

Sulfones. Organozinc species derived from halides as aUyl and benzyl bromides react with sulfonyl chlorides in ether or aqueous media. ... 

Uses. Tetramethylene sulfone has high solvent power for aromatics and has been used extensively by Olah and co-workers for Friedel-Crafts type nitrations and for studies of the mechanism of nitronium tetrafluoroborate nitration of alkyl-benzenes and halobenzenes in homogeneous solution. It is a superior solvent for quaternization of tertiary amines with alkyl halides, since it has a high dielectric constant and does not enter into side reactions observed with nitrobenzene and dimethylformamide. For example in the synthesis of the acridizinium salt (3), Bradsher and Parham effected quaternization of (1) with benzyl bromide in tetramethylene sulfone at room temperature in excellent yield. Several other salts analagous to (2) were obtained in good yield and in crystalline form with use of tetramethylene sulfone, whereas with other solvents the products were colored... 

The reaction of 3-bromo-l-(phenylsulfonyl)prop-l-ene with Grignard reagents derived from allyl bromide, 2-propynyl bromide, bromobenzene, benzyl bromide or l-bromo-3-methylbut-2-ene affords 2-substituted cyclopropyl phenyl sulfones. On the other hand, alkylmagnesium bromides give the corresponding y-substituted allyl derivatives (Table 20, entries 6-8). 

Hart assembled olefin 109 convergently from benzyl bromide 106 by taking advantage of the Ramberg-Backlund reaction.59 As depicted below, the Sn2 displacement of benzyl bromide 106 with thiol 107 led to sulfide 108. Oxidation of 108 to the sulfone, followed by the Myers modification delivered alkene 109, an intermediate for the synthesis of C-aryl glycosides related to chrysomycins. 

Three-membered cyclic sulfones (episulfones) undergo substitution on treatment with base-electrophile mixtures, such as Bu-P4 phosphazene base-benzyl bromide, to give the corresponding alkenes following loss of sulfur dioxide (SO2). The formation of the trisubstituted episulfone was observable but the compound proved unstable to the workup procedure and rapidly decomposed to the alkene as a mixture of stereoisomers [44] (Scheme 5.26). 

Sulfoxide 6 has been prepared by treating l,2 5,6-dianhydro-3,4-0-isopro-pylidene-D-mannitol successively with the appropriate thiol-potassium carbonate, benzyl bromide-sodium hydride, MCPBA then aqueous acetic acid. Substitution of MCPBA by meta-periodic acid led to the formation of sulfone 7. The compounds were tested as potential inhibitors of HIV-1 protease. ... 

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