Group 13 sulfides hydrogen sulfide

Hahn. Reasoning from the observation that proteins and other substances which contain sulfhydryl groups produce hydrogen sulfide on addition of sulfur, Heffter denied that a biochemical reduction process took place at all. As a generalization this negation seems definitely unjustified (see pp. 93 and 95). 

The action of aniline on 3-phenyl-5-mercapto-l,2,4-thiadiazole under restrained conditions is reported to remove the mercapto group as hydrogen sulfide, with formation of the corresponding 5-anilino compound.75,200 This replacement, normally difficult in aromatic systems, may be due to the unusual reactivity of the thiol grouping in this particular structural environment. 

As with alcohols, mercaptans must be considered from the aspect of the site of acid-base function we must be concerned with the basic function at the sulfur site and the acid function at the hydrogen site (the thioethers do not have the corresponding acid-function site) but both mercaptans and thioethers can have other sites which must be considered from the aspect of acid-base function, e.g., the phenyl group. That hydrogen sulfide and the mercaptans are not associated is taken to mean that the linkage... 

Compounds with active hydrogen add to the carbonyl group of acetone, often followed by the condensation of another molecule of the addend or loss of water. Hydrogen sulfide forms hexamethyl-l,3,5-trithiane probably through the transitory intermediate thioacetone which readily trimerizes. Hydrogen cyanide forms acetone cyanohydrin [75-86-5] (CH2)2C(OH)CN, which is further processed to methacrylates. Ammonia and hydrogen cyanide give (CH2)2C(NH2)CN [19355-69-2] ix.orn. 6<55i the widely used polymerization initiator, azobisisobutyronitrile [78-67-1] is made (4). 

Reduction of sulfur dioxide to sulfur includes an industrially important group of reactions (227). Hydrogen sulfide reduces sulfur dioxide even at ambient temperature in the presence of water, but in the dry state and in the absence of a catalyst, a temperature of ca 300°C is required. 

The piefeiied route depends upon the avajlabihty of a hydrogen atom in the beta-position to the thiol group. In other words, a-toluenethiol (in toluene) decomposes to give 1,2-diphenylethane and hydrogen sulfide, via the homolytic route, whereas 2-methyl-2-propanethiol decomposes to give 2-methyl-1-propene and hydrogen sulfide. 

Arninobenzoyl-L-glutarnic acid (12) is obtained by condensation of -nitrobenzoyl chloride [122-04-3] (18) with L-glutamic acid [56-86-0] (19) under Schotten-Baumann conditions. This is followed by reduction of the nitro group with either sodium hydrogen sulfide (29) or by electrochemical methods (30). 

At room temperature bismuthine rapidly decomposes into its elements. The rate of decomposition increases markedly at higher temperatures (8). Bismuthine decomposes when bubbled through silver nitrate or alkafl solutions but is unaffected by light, hydrogen sulfide, or 4 sulfuric acid solution. There is no evidence for the formation of BiH, though the phenyl derivative, (C H BU, is known. The existence of BiH would not be anticipated on the basis of the trend found with other Group 15 (V) "onium" ions. 

When an acetylamino group is attached at an ortho position the replacement of chlorine is followed by cyclization. For example, 4-acetylamino-5-chloro-l-phenylpyridazin-6(lH)-one is converted with hydrogen sulfide in DMF to 2-methyl-6-phenylthiazolo[4,5- f]pyridazin-7(6//)-one (116). 

A thioamide of isonicotinic acid has also shown tuberculostatic activity in the clinic. The additional substitution on the pyridine ring precludes its preparation from simple starting materials. Reaction of ethyl methyl ketone with ethyl oxalate leads to the ester-diketone, 12 (shown as its enol). Condensation of this with cyanoacetamide gives the substituted pyridone, 13, which contains both the ethyl and carboxyl groups in the desired position. The nitrile group is then excised by means of decarboxylative hydrolysis. Treatment of the pyridone (14) with phosphorus oxychloride converts that compound (after exposure to ethanol to take the acid chloride to the ester) to the chloro-pyridine, 15. The halogen is then removed by catalytic reduction (16). The ester at the 4 position is converted to the desired functionality by successive conversion to the amide (17), dehydration to the nitrile (18), and finally addition of hydrogen sulfide. There is thus obtained ethionamide (19)... 

Ceftiofur (57) differs from the preceding cephalosporin derivatives in that it ha.s a thioester moiety at C-3. This can be introduced by displacement of the C-3 acetyl group of 7-aminocepha-losporanic acid (40) with hydrogen sulfide and esterification with 2-furylcarboxylic acid to give synthon 5reacted with trimethylsilylated oximinoether derivative 55 (itself obtained from the corresponding acid by reaction with dicyclohexylcarbodiimide and 1-hydroxy-benzotriazole) to produce, after deprotecting, ceftiofur (57) [18]. 

Schwefelwasserstoff, m. hydrogen sulfide, -rest, m. mercapto group, sulfhydryl, SH. -saure, /. hydrosulfuric acid (H2S). -Strom,... 

Group II consists of six different cations, all of which form very insoluble sulfides (Figure A). These compounds are precipitated selectively by adding hydrogen sulfide, a toxic, foul-smelling gas. at a pH of 0.5. At this rather high H+ ion concentration. 0.3 M, the equilibrium... 

Carbon tetrachloride-hydrogen sulfide-water ternary system, 49, 51, 52 Carboniuin ion polymerization, 158 Carboxylic groups initiator, 174 Catalyst clathrates equilibrium, 35 Cell partition function, in calculation of thermodynamic quantities of clathrates, 26... 

The reaction of PAN with hydrogen sulfide was for the first time achieved in DMF solution at 50-70 °C. It has been shown that under these conditions the nitrile groups are partially converted into thioamide groups and polymers corresponding to copolymers of AN with acrylthioamide are formed54 ... 

This fact gives enough reason to suppose that the reaction of hydrogen sulfide addition to nitrile groups starts with the attack of the nucleophilic mercapto anion... 

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