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Dithiins, synthesis

Only two examples of the 1,2-dithiine synthesis from biphenyls are known (1996NJC1031), although this transformation is the expected one. Dibenzodithiin 155 was formed in a reaction of 3,3, 4,4, 5,5 -hexamethylbiphenyl 154 with sulfur monochloride at low (0-5 °C) temperature. At room temperature the main product was bis[l,2]dithiine 156. Surprisingly, monodithiine 155 did not convert to bisdithiine 156 after treatment with S2CI2, and this probably implies that the addition of two sulfur monochloride molecules to biphenyl 154 took place simultaneously (Scheme 82). [Pg.206]

Dithiins are also synthesized from conjugated diynes using benzyl thiol reductive debenzylation of intermediate 153 by sodium in liquid ammonia at 70 C gives, after aerial oxidation, the 1,2-dithiin 154 (Scheme 77) <1967AGE698>. Additional examples of 1,2-dithiins synthesis utilizing this approach are provided in CHEC-III . [Pg.727]

Dithiin, 2,4-dimethyl-2,4,6-triphenyl-thiophene synthesis from, 4, 903... [Pg.615]

Dithiin, tetraphenyl-dication salt, 3, 968 half-wave potential, 3, 968 synthesis, 3, 982... [Pg.615]

In the synthesis of l,3-dithiole-2-thione derivatives as intermediates for electropolymerization precursors, the bicyclic 462 was found to be inert to normal cyclization conditions <1999JOC6418>. This is believed to be due to steric hindrance, from the boat conformation of the dithiin ring. Cyclization was achieved, albeit in only moderate yields, by heating with P2S3 to give the thiophene 463a or HBr/AcOH for the furan 463b (Equation 125). [Pg.761]

The present procedure is applicable only to bromomalononitrile various a-halogen active methylene derivatives, (e.g., diethyl chloromalonate, methyl bromoacetoacetate) led predominantly to the formation of ring-contracted styrene derivatives. On the other hand, substituted cycloheptatrienylium salts with bromomalononitrile gave the desired dicyanoheptafulvene derivatives in excellent yields. One notable example is the synthesis of 5- and 7-(dicyanomethylene)-2,3-dihydrocyclohepta-1,4-dithiins.6... [Pg.254]

The synthesis of 1,4-dithiines from arenes and heteroarenes has been known for more than 100 years. The reaction of quinoline and sulfur monochloride gave dithiodiquinoline 152 (R = R = H) (1896JPR340). The structure of such compounds has been correctly identified only recently (1976PJC785, 1997JCR(S)435 Scheme 80). [Pg.205]

As in the case of the 1,2-dioxins, the 1,2-dithiins exist in various states of saturation, oxidation, and benzoannelation (cf. Scheme 1, 17-27) and they have been studied in detail both theoretically and experimentally. Not only were the conformations of the ring and attached substituents investigated, but the valence isomerism of 1,2-dithiin by both NMR and high-level ab initio molecular orbital (MO) calculations and the dithiol/disulfide equilibrium by MP2 calculations were also examined. The latter equilibrium has been applied successfully as a luminescent molecular switch (cf. Section 8.10.2.1). Finally, as a very interesting 1,2-dithiin derivative, the synthesis, structure, and reactivity of the (-l-)-camphor-derived analog 25 and its sulfoxide 26 and sulfone 27 have been reported. Both the synthesis and the antimalarial activity of the 2,3-dioxabicyclo[3.3.1]nonane pharmacophore 28, which contains the 1,2-dioxane moiety, have been reviewed recently <2006BML2991>. [Pg.679]


See other pages where Dithiins, synthesis is mentioned: [Pg.601]    [Pg.614]    [Pg.982]    [Pg.601]    [Pg.614]    [Pg.982]    [Pg.601]    [Pg.614]    [Pg.310]    [Pg.601]    [Pg.614]    [Pg.601]    [Pg.614]    [Pg.982]    [Pg.601]    [Pg.614]    [Pg.982]    [Pg.601]    [Pg.614]    [Pg.310]    [Pg.601]    [Pg.614]    [Pg.605]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.615]    [Pg.1200]    [Pg.120]    [Pg.90]    [Pg.45]    [Pg.864]    [Pg.723]    [Pg.728]    [Pg.838]    [Pg.874]   
See also in sourсe #XX -- [ Pg.535 ]

See also in sourсe #XX -- [ Pg.1421 ]

See also in sourсe #XX -- [ Pg.1421 ]

See also in sourсe #XX -- [ Pg.535 ]

See also in sourсe #XX -- [ Pg.361 , Pg.892 ]

See also in sourсe #XX -- [ Pg.98 , Pg.535 ]




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1.2- Dithiins

1.4- Dithiin

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