Thiones properties

Moreover, structure 82 (or 84) should explain why usual thione properties are markedly diminished, though not entirely suppressed, for these compounds. 

COMPARISON OF TYPICAL PHYSICOCHEMICAL PROPERTIES OF A-4-THIAZOLINE-2-THJONE (Ii WITH THOSE OF 2-(METHYLTHIO)THIAZOLE (II) AND 3-METHYL-A-4-TH1AZO-LINE-2-THIONE (UIF... 

Physical properties of A-4-thiazoline-2-one and derivatives have received less attention than those of A-4-thiazoline-2-thiones. For the protomeric equilibrium, data obtained by infrared spectroscopy favors fbrm 51a in chloroform (55, 96, 887) and in the solid state (36. 97. 98) (Scheme 23). The same structural preference is suggested by the ultraviolet spectroscopy studies of Sheinker (98), despite the fact that previous studie.s in methanol (36) suggested the presence of both 51a and... 

Thiazole disulfides are reported to yield quantitatively A-4-thiazoline-2-thiones under treatment with zinc powder in acetic acid (326). The disulfide bond can be broken on heating at 100 to 260°C and (or) by alkali. This property has been used for photographic emulsions (327). The disulfide (136) (R = 4-(D-arabmo-tetrahydroxybutyD can be cleaved readily by aqueous sodium hydroxyde. carbonate, or hydrogen carbonate (149) to give 135 a by-product, 4-(D-arabino-ietrahydroxybutyl) thiazole... 

Metal salts of A-4-thiazoline-2-thione are used in the rubber industry Zn salts (123, 152), Pb and Mg salts (54). Cd salts (151, 324), Cu salts (325), in photographic processes (146). and in analysis (328). Zn, Ni, Co and Cd salts are used as germicides (329). Despite their wide range of application, little is known about their physical and chemical properties. 

Besides being useful precursors to pyrroles pyridine-2-ones -4-ones, -4-thiones. and -4-imines 4-alkylidene-dihydropyridines thiophenes 1,2,4-triazoles thiapyrane-2-thiones, isoquinoline-3-ones isoben-zothiophenes and 4-mercaptoimidazolium hydroxide inner salts, mesoionic thiazoles are potentially useful in the construction of molecules with herbicidic (39). central nerve stimulating, and antiinflammatory properties (40,41). Application in dye synthesis has likewise been reported (42). 

Similar to their 2-hydroxy analogs, these compounds exhibit properties (cf. Chapter VII) that are characteristic of each of the two possible tautomeric forms the thiol (163a) and the thione or 2-thioxo-A-4-thiazoline (163b). 

Naphtho[2,l -h]pyran-1 -one, 2,3-dihydro-dehydrogenation, 3, 724 halogenation, 3, 731 Naphthopyranones synthesis, 3, 805 Naphthopyran-2-ones, dihydrosynthesis, 3, 802 Naphtho[l, 2-h]pyran-2-ones synthesis, 3, 802 Naphtho[2,1 -h]pyran-3-ones synthesis, 3, 803, 856 Naphtho[2,1 -c]pyran-4-ones synthesis, 3, 831 Naphtho[2,3-c]pyran-l-ones synthesis, 3, 831 Naphthopyrans H NMR, 3, 580 IR spectra, 3, 594 synthesis, 3, 743, 748, 750, 763 UV spectra, 3, 598 Naphthopyrans, dihydrosynthesis, 3, 778, 783 Naphtho[l,2-h]pyran-4-thione, styryl-properties, 3, 708... 

Thiazoline-2-thione, 3-amino-pharmacological properties, 6, 328 4-Thiazoline-2-thione, 5-amino-Cook s rearrangement, 6, 290 4-Thiazoline-2-thione, 4-/-butyl-3-methyl-rearrangement, 6, 291 4-Thiazoline-2-thione, 3,4-dialkyl-conformation, 6, 247 4-Thiazoline-2-thione, 4,5-dimethyl-reactions... 

The acidic strength of various quinoxaline derivatives is also listed in Table II. -Methyl groups have an acid-weakening effect and quinoxalin-2-one (2-hydroxyquinoxaline) is, as expected, a weaker acid than quinoxaline-2-thione (2-mercaptoquinoxaline), The marked enhancement of the acidic strength of 5-hydroxyquinoxaline 1-methiodide compared to 5-hydroxyquinoxaline itself, is due to the electron-attracting property of the positively charged nitrogen, ... 

In the synthesis of l,3-dithiolan-2-ones from spirocyclic intermediates, via episulfides, substituted tetrathiacyclododecane and the related pentathiacyclopentadecane were isolated in good yields <96JCS(P1)289>. Preparation and molecular dynamics studies of 2,5,8,17,20,23-hexathia[9.9]-p-cyclophane have been reported <96P4203>. The syntheses and properties of thiocrowned l,3-dithiole-2-thiones and their conversion to tetrathiafiilvenes via treatment with triethylphosphine have been described <96LA551>. 

The synthesis, X-ray structure and solid state NMR of 4,4-dimethyl-l,2-ditellurolane 75 have been reported <98PS(136-8)291>. Chemoselective oxidation of 1,2-dithiole derivatives using dimethyldioxirane to give products such as 76 has been described <00SUL169>. Cycloaddition of dihydroquinoline-fused l,2-dithiole-3-thiones 77 with DMAD gives the spiro 1,3-dithioles 78 <99CHE587>. Dicationic thiatelluroles such as 79 have been prepared <00AG(E)1318>, anti cancer properties have been claimed for the simple dithiolopyrrolones... 

Scheffer et al. also reported hydrogen abstraction of thioketones in the solid state [42]. The nTi" and 7171" excited states differ in the spatial properties of the orbitals involved in abstraction, and it follows that ketones and thiones should exhibit significantly different hydrogen atom abstraction geometries. 

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