Hydrogen sulfide acylation

Reactions of (benzotriazol-l-yl)carboximidamides and acyl- or arylamino-carbonyl(benzotriazol-l-yl)carboximidamides with hydrogen sulfide give the corresponding thioureas and tV-acylthioureas or tV-carbamoylthioureas, respectively (Scheme 47).128... 

Dimethylbisthiomalonic acid (120), when treated with an acylated enol, produced intermediate 121 thietanediones 122 and 123 then were formed by elimination of thioketone and acetic acid (see Eq. 12). Similarly, cyclobutane-l,l-bisthiolcarboxylic acid gave 123, a previously unknown sulfur analog of malonic anhydride, (Eq. 12). Thermolysis of 120 also results in the formation of the four-membered heterocycles in addition to carbonyl sulfide, hydrogen sulfide, and thiocarbonic acid. ... 

The pyridinium salt formed from the acyl halide and pyridine in the absence of a carboxylic acid is able to diacylate water and hydrogen sulfide at -20° to give simple anhydrides and diacyl sulfides, respectively. ... 

Acylation of Hydrogen Sulfide (Sulfhydrolysis) with Imidates and Orthoesters... 

Carbon disulfide is a valuable synthon (see Chapter 9, p. 147) which can be used for the synthesis of thiocarbonic acid derivatives. Thus, carbon disulfide reacts with ammonium polysulfide or hydrogen sulfide to give trithiocarbonic acid (70) or symmetrical esters (73) after reaction with an alkyl halide. With alkoxides or thiolates, carbon disulfide forms xanthates (77) or S-alkyl trithiocarbonates the latter by further treatment with alkyl, acyl or diazonium halides affords the derivatives (74)-(76) (Scheme 39). 

Intramolecular acylation then yields (LXXXVII) which forms the oxadiazoline-2-thione by elimination of hydrogen sulfide. The conversion of (LXXXVI) into (LXXXII) via (LXXXVII) might be also possible. 

Thiadiazoles are available by a nnmber of convenient general rontes inclnding cycUsation of N,N -diacyl-hydrazines, or 1,3,4-oxadiazoles, with phosphorus sulfides. 2-Amino-l,3,4-thiadiazoles are prepared via acylation of thiosemicarbazides and the parent compound is easily obtained from hydrogen sulfide and dimethylformamide azine. °... 

It can be formed by a decarboxylative acylation of glycine followed by dehydration of the dienolic form of the intermediate compound. The product was isolated by Takken et al. (1976) when pyruvaldehyde and acetaldehyde reacted in closed vial glass systems at 90 °C with hydrogen sulfide and ammonia. It is also present in roasting mixtures of serine and/or threonine and sucrose (Baltes and Bochmann, 1987d). 

---