Sulfur functional groups

4-Dihydro-l,2,3-benzotriazin-4-thiones react with ammonia, amines, hydrazine, and hydroxylamine to yield 4-amino-, 4-hydrazino-, and 4-hydroxylamino-l,2,3-benzotriazines 1984CHEC(3)369 . 

Methyl iodide, in the presence of NaOMe in abs. MeOH at room temperature, transforms 3,4-dihydro-1,2,3-benzotriazin-4-thione into 4-methoxy-l,2,3-benzotriazine 222 (64%) 1986J(P1)1249 . The same reagent at reflux temperature is reported to methylate thiones at sulfur, for example, to generate 4-methylthio-l,2,3-benzotriazine 227 (79%) 1971JHC785 . 4-Benzylthio-, 4-phenacylthio-, and 4-ethoxycarbonylmethylthio-l,2,3-benzotriazines have been prepared similarly 1971JHC785 . 

Lawesson s reagent was found quite suitable to convert 6,7-dimethoxy-3,4-dihydro-l,2,3-benzotriazin-4-one 229 to the corresponding thione 230, which was methylated to 231a. Oxidation of the latter furnished the methylsulfone 231b, which in turn underwent displacement by several 4-substituted piperidines (Equation 89) 1990CPB2179 . 

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The review by Trewhella and Grint points out that a factor import in the ability of organic sulfur to enhance liquefaction is the reductive conversion of sulfur functional groups to H2S (. As the relative concentration of H2S increases, improvements are observed in both liquefaction rates and conversions (25). 

When sulfur functional groups and heteroaromatics are combined, an entirely new field of chemistry emerges. Pharmacological uses have expanded for example, introduction of a sulfur atom into nitrogen hetero-... 

ABSTRACT This chapter provides a comprehensive overview of the sulfur-containing natural products that are non-sulfated and have been isolated from marine organisms. The overview covers the published literature from 1985 to 1999. A total of 482 compounds and 371 references are recorded. These secondary metabolites are organized in sections according to structural classifications by sulfur functional groups and by structural families of compounds. Comments on structural characterization, biogenesis, and biological activity have also been included. 

Reviews which cover heterocyclization of unsaturated sulfur compounds have been published recently.16 Cyclizations of sulfur systems can also be effected by radical chain mechanisms or by reactions in which the sulfur acts as an electrophile. Examples of nucleophilic sulfur functional groups used in heterocyclization reactions are shown in Figure 3. ... 

CLEAVAGE WITH THE INTRODUCHON OF NITROGEN AND SULFUR FUNCTIONAL GROUPS 588... 

Imidazoles activated by sulfur functional groups, reactivity of 87-YGK624. 

Data on the Distribution of Organic Sulfur Functional Groups in Coals... 

The distribution of the organic sulfur functional groups was determined in five coals and treated coals using thermo-kinetic analysis. The data surest that 15-30% of the organic sulfur is sulfidic in all coals. About 30-40% of the organic sulfur in lignite is thiolic and the rest is thiophenic. 

All the organic sulfur functional groups can be reduced to H2S if a sufficiently strong reducing agent is used. 

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