Vinyl alcohol bromide

The phosphonium salt (82) can be obtained by treatment of the vinyl alcohol (83) with triphenylphosphonium bromide." ... 

The behavior of Cu(II)(aq) is relatively more understood than other metal ions. Haas and Gedanken [74] found only a partial reduction of Cu2+ ions to Cu+ (95%) instead of metallic copper (5.1%) in the presence of cetyltrimethylammonium bromide in an ultrasonic field and thus obtained CuBr particles instead of Cu. Nevertheless, when polymers such as poly(N-vinyl 2-pyrrolidone) or poly(vinyl alcohol) were used, the end product was metallic copper particles, as expected. They have proposed the reduction of Cu2+ ions to copper as the first stage, however, in the second stage Cu reacted with OH radicals or H2O2, formed by sonolysis of water to produce Cu+ and OH- ions as under ... 

Another domino process, designed by Polt and coworkers [16], deals with the consecutive transformation of an in situ-prepared aldehyde to give 3-amino allylic alcohols 7-31 from 3-amino acids. When the 3-amino acid ester derivative 7-29 is sequentially treated with iBu5Al2H and vinyl magnesium bromide, a 3 2 mixture of the allylic alcohol derivatives 7-30 is obtained in 60% yield, which can be hydrolyzed to give 7-31 (Scheme 7.10). 

Photocycloaddition of allene to cyclohexenone (341) gave the (3,y-enone (342), which reacted with vinyl magnesium bromide to produce the tertiary alcohol (343) in 79% yield. When the compound (343) was treated with KH and 18-crown-6 in THF at room temperature for two hours and quenched with aq. NH4C1, the cyclobutene (344) was obtained. The thermal ring opening of the cyclobutene (344) proceeded in toluene in a sealed-tube at 180 °C for twelve hours to give a readily separable 5 1 mixture of the civ-olefin (345), and the trans-olefin (346) respectively in 95 % yield. Moreover, (345) could be converted to a mixture of (346) and (345) in the ratio of 10 1 by irradiation. The compounds (345) and (346) possess the skeleton of the germacranes (347), (348) and (349) 122). 

Valeric acid, see Pentane Vinyl acetate, see Vinyl chloride Vinyl alcohol, see Vinyl acetate Vinyl bromide, see Ethylene dibromide Vinyl chloride, see 1,1-Dichloroethane, 1,2-... 

Alternatively, vinylation can be achieved in useful yields using readily available vinyl magnesium bromide. The allylic tertiary alcohol resulting from this condensation on a ketosugar can be further elaborated by suitable modification of the vinylic group. 

The interfacial properties of an amphiphilic block copolymer have also attracted much attention for potential functions as polymer compatibilizers, adhesives, colloid stabilizers, and so on. However, only a few studies have dealt with the monolayers o well - defined amphiphilic block copolymers formed at the air - water interface. Ikada et al. [124] have studied monolayers of poly(vinyl alcohol)- polystyrene graft and block copolymers at the air - water interface. Bringuier et al. [125] have studied a block copolymer of poly (methyl methacrylate) and poly (vinyl-4-pyridinium bromide) in order to demonstrate the charge effect on the surface monolayer- forming properties. Niwa et al. [126] and Yoshikawa et al. [127] have reported that the poly (styrene-co-oxyethylene) diblock copolymer forms a monolayer at the air - water... 

The high reactivity of compounds containing an episulfonium moiety has been used in an one-carbon ring expansion step [42]. This method is explained at the system shown in Scheme II/8. 1-Vinylcyclopentanol is easily prepared from cyclopentanone (11/50) and vinyl magnesium bromide. The silylation of the alcohols was carried out with re/7-butyldimethylsilyloxytriflate (TBDMSOTf). Using trimethylsilylethers instead of TBDMSO-derivatives side reactions are... 

Condensation of the vinyl alcohol (54) with 2-ethylcyclopentane-l,3-dione je j to the expected product from which B-noroestradiol was ultimately obtained.19 Of particular conformational interest is that the double bond in one of the intermediates (55) was not isomerized by acid to the A9(11)-position despite the fact that the compound is a trans-hydrindane. The compound (56), prepared from m-methoxyphenylethylmagnesium bromide and the corresponding cis-hydrindanedione, undergoes dehydration but not cyclization on treatment with... 

In a synthesis of (+)-pleuromutilin, only a 1 1 mixture of diastereomeric vinylic alcohols (86% yield) was obtained by addition of vinylmagnesium bromide to the precursor ketone. Equilibration of the easily separated undesired alcohol to a 1 1 mixture was achieved by a twofold sulfoxide - sulfenate rearrangement [C6H5SC1, then (EtO)3P in refluxing methanol] raising the overall yield of the desired diastereomer to 70% after two cycles81. 

In a side-chain containing a double-bond 3 to the oxirane, double-bond migration has also been observed. The effects of the solvent and the reagent have been examined in the reaction of vinyl-magnesium bromide and phenyloxirane. Acetylenic oxirane gives a complicated mixture of products with a Grignard reagent, but the Cu halide-catalyzed reaction leads to an allene alcohol (Eq. 

Previous preparations by Scolastico were based on the Strecker synthesis of aminonitrile and lacked steroselectivity [74,75]. More recently, two formal syntheses were reported from the same ketone 71. In Rama Rao s synthesis (Scheme 11.19) [76], 71 was condensed with vinyl magnesium bromide to give the tertiary alcohol 72 as a single isomer. This compound was then transformed into the vinyl epoxide 73 that, under palladium catalysis, reacted with 4-methoxyphenyl isocyanate to produce the oxazohdinone 74 with retention of its configuration. The remainder of the synthesis consisted of heterocycle opening and adjustment of the oxidation level to provide the lactone 75. Excision of two carbons was necessary to form the known aldehyde 76, previously transformed into myriocin [74]. 

Continuing, one carbon homologation of 96 was easily achieved by oxidation of the alcohol to the corresponding ketone and a subsequent enolisation-formylation sequence. The last lacking carbon was introduced by nucleophilic addition on the complex keto-sugar 97 using vinyl magnesium bromide in the presence of cerium salts. The diol 98 was further elaborated into a relay compound already prepared from squalestatin [88]. 

First, in a Grignard reaction, vinyl magnesium bromide is added to the dialdehyde 29 to give the corresponding bis-allyl alcohol, which is oxidized in the second step to form the a,P-unsaturated diketone 30 using Dess-Martin periodinane. 

Fig. 3 Typical chromatograms of mixed sample containing (1) chloride, (2) bromide, (3) nitrate, and (4) sulfate. Anion-ex-change groups (a) H(bpa-ODP) and (b) Cd(bpa-ODP) are from the bpa-ODP, protonated, and complexed with Cd(II), respectively. Bpa-ODP is A,A-bis(2-pyridylmethyl)octadecyl-amine-coated octadecylated poly (vinyl alcohol). Eluent 5 mmol/L benzenesulfonate (pH 5.0). (From Ref. [4].)...

In vinyl compound polymerization of vinyl acetate, alcohol, bromide, chloride, or carbonate, ascorbic acid can be a component of the polymerization mixture (733-749). Activators for the polymerization have been acriflavine (734), other photosensitive dye compounds (737,738), hydrogen peroxides (740,741,742), potassium peroxydisulfate (743), ferrous sulfate, and acyl sulfonyl peroxides (747). Nagabhooshanam and Santappa (748) reported on dye sensitized photopolymerization of vinyl monomers in the presence of ascorbic acid-sodium hydrogen orthophosphate complex. Another combination is vinyl chloride with cyclo-hexanesulfonyl acetyl peroxide with ascorbic acid, iron sulfate, and an alcohol (749). Use of low temperature conditions in emulsion polymerization, with ascorbic acid, is mentioned (750,751). Clarity of color is important and impact-resistant, clear, moldable polyvinyl chloride can be prepared with ascorbic acid as an acid catalyst (752) in the formulation. 

Treatment of aldehyde 128 with vinyl magnesium bromide followed by oxidation of the diastereomeric mixture of alcohols under Swem conditions delivered compound 130 in an overall yield of 17% for the 6 steps. 

Vinylmagnesium bromide, 251 Vinylmagnesium chloride, 221, 572 Vinyl trifluoromethanesulfonates, 533 3-Vinyl-3,5,5-trimethylcyclohexanone, 221 Vinyl triphenylphosphonium bromide, 572 Vitamin A acetate, 16 Vitamin A alcohol, 372 Vitamin B, 2, 82... 

Sensitive extraction-spectrophotometric methods are based on the extractable (into CHCI3, 1,2-diehloroethane, benzene, or toluene) ion-associates of basic dyes and anionic Ag complexes with cyanide [35,36], iodide [37,38], and bromide [39]. In these methods, use has been made of such dyes as Crystal Violet [35,39], Brilliant Green [38,39], Malachite Green [39], Methylene Blue [36], and Nile Blue A [37]. In some of these methods the molar absorptivities are elose to MO [36,39]. A flotation method has been proposed, based on the addition compound [R6G ][Ag(SCN )2] [R6G ][SCN ] which is formed by silver ions (at pH 2-5) in the presence of thiocyanate and Rhodamine 6G (flotation with DIPE, the precipitated compound is washed and dissolved in acetone, e = 1.5-10 ) [40]. The complex Ag(CN)2 , associated with Crystal Violet, has been utilized in another flotation-spectrophotometric method of determining silver [41]. Silver has been determined also in a system comprising thiocyanate and Rhodamine B, as an aqueous pseudo-solution, in the presence of poly(vinyl alcohol) [42]. 

Construction of the acyclic segment 395 was initiated by conversion of (-)-citronellal (392) into bromo aldehyde 393. Formation of the unsaturated aldehyde via the intermediate enamine was followed by reduction to the allylic alcohol 394. Elimination of the vinyl bromide in 394 to the acetylene was followed by the addition of trimethylaluminum to give the terminal vinyl alane. The intermediate alane was then quenched with iodine to furnish the corresponding iodo-vinyl alcohol, which was protected as the THP ether to afford 395. 

If additional a values are measured with great accuracy in the future, a refined relationship may emerge. For example, polypropylene, poly(vinyl alcohol), poly(vinyl fluoride), poly(vinyl chloride) and poly(vinyl bromide) all have equal H,BB1, H,BB2, qSG and qtrans, and therefore the same o according to Equation 12.26. Existing data do not show trends of sufficient statistical significance to justify the introduction of additional parameters to distinguish between them. 

Addition of vinyl magnesium bromide to bicyclic ketone 240 under normant conditions (60AdvOCl) gave the anticipated allyl alcohol 242... 

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