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Thietane 2-vinyl

Aromatic organosulfur compounds such as thiophenes, benzothiophenes and dibenzothiophenes are frequently contained in fossil oil and their sulfur atoms are generally difficult to remove in HDS process [106], In the industrial HDS process, Mo/Co/S or Ni/Mo/S heterogeneous catalysts supported on alumina are widely employed. In order to obtain ideas to develop more efficient catalysts as well as to shed some light on their mechanisms at a molecular level, transition metal complex-mediated cleavages of C-S bond are extensively studied. On the other hand, thiiranes and thietanes are frequently employed for preparation of transition metal sulfides, in which their C-S bonds are smoothly cleaved. In this section, the C-S bond cleavages of thiophene derivatives, thiiranes, thietanes, vinylic sulfides, allylic sulfides, thiols and dithioacetals are overviewed. [Pg.150]

Many [2 + 2] photocycloadditions have not been assigned a definitive mechanism, but they serve well as synthetic methods. Thiones add vinyl ethers to give thietanes in very good yields (Section 5.14.4.1.2), and interesting wavelength-stereochemistry relations were found in the photoaddition of 2-adamantanone to dicyanoethylene (Section 5.14.4.1.2). Diheterocyclobutanes can also be prepared by [2 + 2] photocycloadditions (Section 5.13.3.3). [Pg.40]

The addition of sulfenic acids to olefins207 has been successfully applied in the synthesis of thietanoprostanoids, the thietane analogues of prostaglandin245. The general synthetic scheme is presented in equation 83207. The key step is the thermolysis of either erythro- or (7ireo-2-f-butylsulphinyl-3-vinyl-l-ol (209) to give the corresponding alkenesulfenic acids 210, which cyclize spontaneously to a mixture of stereoisomeric thietane oxides. [Pg.445]

The photolysis of various substituted thiete dioxides under similar conditions resulted in the formation of the unsaturated ketones (255)264, most probably via a vinyl sulfene intermediate followed by a loss of sulfur monoxide as shown in equation 96. The same results were obtained in the thermolysis of 6e (R1 = R3 = Ph R2 = R4 = H)231, which further demonstrates that similar mechanisms are operative in thermolyses and pho-tolyses of thietane dioxides and thiete dioxides. [Pg.453]

Simple unsaturated sulfides cannot be used in place of enamines in cycloaddition reactions with sulfines leading to thietane dioxide derivatives. " Alkyl, vinyl, and cycloalkylvinyl sulfides, which carry a C=C double bond, are considerably less nucleophilic than the enamines and thus do not partake in cycloadditions to sulfene. But when the more electrophilic methylsulfonyl sulfene is used in association with an unsaturated sulfide substituted with a strong electron donating alkylamino group, the formation of thietane dioxides 72 is successful. [Pg.216]

The yields of thietanone depend on the number of methyl groups attached to the 1,3-dihaloketones, a relationship attributed to the gem effect. Thus the unsubstituted thietane failed to form. Thietanes have been synthesized by a series of reactions involving addition of thiolacetic acid to a vinyl ketone, reduction with LiAlH4, substitution of the acyl group by the nitrile function, and subsequent ring closure to a cis-trans mixture of 119 (Eq. 11). [Pg.227]

The block copolymer of ethylene oxide and 3,3-dimethylthietane shows useful properties of complexing halogen and heavy metal salts (79MI51402). Thietanes can be polymerized with methylmagnesium iodide as well as with a variety of electrophiles such as methyl sulfate, trimethyloxonium tetrafluoroborate, triethylaluminum, boron trifluoride and phosphorus trifluoride (67IC1461, 67MI51400). Thietane (210) has been patented as a stabilizer for poly(vinyl chloride) (73USP3767615). [Pg.447]

The reaction of the thio- and selenoaldehyde complexes with vinyl ethers provides metal-coordinated substituted thietanes and selenetanes.224,250-252 The cycloadditions are highly regio- and stereoselective. [Pg.185]

In an extreme case the reactivity difference between the two monomers is positively utilized to obtain block copolymers. For example, Goethals recently polymerized IBVE with CF3S03H in the presence of thietane (a cyclic thioether) [86]. Because the thioether is much less reactive than vinyl ethers, it cannot polymerize and serves as a nucleophilic additive in the first-phase vinyl ether polymerization [64], but once IBVE has been completely polymerized, the cyclic monomer now polymerizes from the living end to form block polymers. [Pg.393]

Sulfoxid (3,3-Dimethyl-l-butinyl)-vinyl- Ell, 715 (S-Oxigenier.) Thietan 4,4-Dimethyl-2-isopropyli-den-3-oxo- E19b, 643 (aus Diazo-thiophen)... [Pg.513]

The photocycloaddition of thiocarbonyl-containing compounds to alkenes provides an easy route to thietanes. 2,4,6-Tri-(t-butyl)thiobenzaldehyde (249) undergoes regiospecific addition to substituted allenes (250) to give the vinyl-thietanes (251). The formation of the ketones (252) by irradiation of the aryl... [Pg.429]

Thietane is a superior inhibitor of corrosion of iron in 10% hydrochloric acid and its effectiveness is said to be due to partial polymerization on the surface of the iron. Addition of chloride ion reduces the inhibition, possibly by inducing ringopening with the formation of sulfhydryl groups. The cyclic sulfide also has been considered as an odorant for natural gas and its absorption by organic soil and clay have been determined. Stabilization of methylchloroform and trichloroethylene by thietane, 2-methylthietane, 3-hydroxythietane, and two spirothietane derivatives has been claimed. Phosphorus and tin derivatives of 3,3-bis-hydroxy-methylthie-tane are reported to be light stabilizers for poly(vinyl chloride), and the dibutyl-tin derivative is a catalyst for the polymerization of aliphatic isocyanates. Mercury and zinc compounds derived from phenylmercury or phenylzinc hydroxide and 3-... [Pg.438]

Nonphotochemical cycloadditions of hexafluorothioacetone to alkenes (vinyl ethers, vinyl sulfides, " cyclohexene, and dimethyl maleate " ) have been observed, as illustrated for methyl vinyl ether. The formal addition of thiocarbonyl fluoride to tetrafluorethylene to give hexafluorothietane occurs on thermolysis at 600-700° (lO " mm) of a copolymer of the two components. " QO-Dimethyldithiooxalate undergoes a thermal cycloaddition to quadricyclane to give thietane 51a. ... [Pg.453]

Polymerizations via the hydroxyl group of 3,3-bis(hydroxymethyl) thietane have been used to prepare polyurethanes " and polyethers. " Tin derivatives are stabilizers for poly(vinyl chloride) as well as being used in polyurethane formation. Cyclic carbonate derivatives are homo- or copolymerized to high-molecular-weight solids. The methacrylate ester of 3-hydroxythietane has been copolymerized with methyl methacrylate. ... [Pg.474]

A spirothietane sulfone-oxetane is a comonomer in the preparation of polyethers. A polymer obtained from this sulfone in a solution of bis(3,3-chloromethyl) oxetane with phosphorus pentafluoride can be spun to drawable filaments. Thietane sulfone spirocyclic carbonates may be polymerized via the carbonate group to high-molecular-weight solids said to be useful in laminating. Thietane 1,1-dioxide improves the dye receptivity of poly (acrylonitrile), viscose, cellulose acetate, and poly(vinyl chloride). It is also reported to be a stabilizer for nitric acid in oxidizer mixtures for rocket motors. 2-Methylthietane 1,1-dioxide is claimed to be superior to sulfolane (thiolane 1,1-dioxide) in the liquid extraction of aromatic hydrocarbons from mixtures with saturated hydrocarbons. " A number of bis(3,3-alkoxy) thietane 1,1-dioxides have been proposed as intermediates in the preparation of cyanine dyes useful as photographic sensitizers. " ... [Pg.488]

The similarity in the reactivities of free ions and corresponding ion pairs derived from the same cyclic monomer is more intriguing. Whereas ion pair reactivities are about 10 times smaller than corresponding free ion values in the anionic polymerization of vinyl monomers [39], and probably of the same relative proportions in cationic systems, the difference in cationic ring opening polymerizations is considerably less. For polymerization of THF in methylene chloride the factor is only 7, and for polymerization of 3,3-dimethylthietan, 40 in methylene chloride and 1 in nitrobenzene. Because the overall reactivity in cyclic monomer reactions is lower than for olefinic polymerizations, it might be expected that difference between free ion and ion pair reactivities, within one system, would also be less. However, this does not seem to be the whole answer. Plesch [44] has pointed out that in the polymerization of cyclic ethers and thietans (and presumably, therefore, other cyclic monomers)... [Pg.125]

Termination evidently does not occur as readily in anionic polymerization of thietanes as it does in cationic polymerization. Organo-lithium initiated polymerizations of thietanes lead to living polymers, which have been used to prepare ABA block copolymers of dienes and cyclic sulphides [69, 70]. Since the anionic polymerization of thietanes proceeds via a carbanion, thietEines can initiate vinyl polymerization and their polymerization can be initiated by vinyl monomers. Kinetic parameters of such polymerizations have not yet been reported. [Pg.286]

The photolyses of H2Se,118 dimethyl sulphide, dibutyl sulphide, and methyl vinyl sulphide,119 and dimethyl sulphoxide,120 the role of concerted and hot biradical reactions in the photolysis of thietan and thietan-cyclopentadiene mixtures,121 and the photolysis of aromatic sulphur compounds122 have been reported. [Pg.121]


See other pages where Thietane 2-vinyl is mentioned: [Pg.435]    [Pg.437]    [Pg.514]    [Pg.437]    [Pg.72]    [Pg.78]    [Pg.12]    [Pg.762]    [Pg.762]    [Pg.453]    [Pg.473]    [Pg.492]    [Pg.397]    [Pg.437]    [Pg.213]    [Pg.249]    [Pg.291]    [Pg.72]    [Pg.154]    [Pg.103]    [Pg.112]    [Pg.1409]    [Pg.1355]    [Pg.154]    [Pg.75]    [Pg.76]   
See also in sourсe #XX -- [ Pg.486 ]




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