Thiocarbonic acids

Kohlen-schwarz, n. carbon black charcoal black, -schwefelwasserstoffsaure, /, (tri)-thiocarbonic acid (H2CS1). -spat, m. anthraconite whewellite, -spitze,/. carbon point, -staub, m. coal dust charcoal dust, -stick-stoff, m. cyanogen, -stickstoffsaure, /, car-bazotic acid (picric acid), -stoff, m. carbon,... 

Sulfkohlensaure, /. sulfocarbonic acid (tri-thiocarbonic acid) thionocarbonic acid (HOCSOH). 

Thio-germaniumsaure, /. thiogermanic acid, -harnstoff, m. thiourea, -kohlensaure, /. thiocarbonic acid, specif, trithiocarbonic acid. H CSa. 

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. ... 

Carbon disulphide, like the dioxide, is the anhydride (or, more strictly, thioanhydride) of a feeble acid, thiocarbonic acid, H2CS3. Moreover, between carbonic and thiocarbonic acids a number of intermediate acids are capable of existence. They are as follows ... 

An investigation of the freezing curve for the system CS2-H2S has demonstrated the existence of two thiohydrates, CS2.H2S and CS2.6H2S, the former being isomeric with thiocarbonic acid.3... 

Thiolcarbonic Acid, HS.CO.OH, yields carbon oxysulphide, COS, by decomposition its esters yield alcohols or mereaptans when saponified, according to whether the alkyl group is attached to oxygen or to sulphur by this means the constitutions of the thiocarbonic acids are established. 

As carbamic acid and carbamide are related to carbonic acid, so are thioearbamic acid and thiocarbamide related to thiocarbonic acid ... 

Thiocarbonic Acid. Dithiocarbamic Acid, or Thiolthioncarbamic Acid. Thiocarbamide. 

Minkwitz and co-workers have recently obtained the X-ray crystal structure of protonated thiocarbonic acid, protonated (9,5-dimethyl dithiocarbonate, and protonated dimethyl trithiocarbonate. Protonated thiocarbonic acid 354 has C—S bond lengths of 1.683-1.708 A.662 The small differences imply a nonequal distribution of the positive charge over the S atoms. All hydrogen atoms have trans positions and they are... 

The crystal structure of the dithioacetylacetone (sacsacH) complex of cobalt(n), Co(sacsac)2, shows it to be monomeric square planar,164 in marked contrast to the acacH analogue. Pyridine 2-thiol (LH), which can exist as the thione tautomer (31) forms Co(LH)2X2 (X = Cl, Br, or I) complexes these contain the ligand bonded through the sulphur, as evidenced by the presence of a v(N—H) vibration in the i.r. spectra.165 Morpholine 4-thiocarbonic acid (32) also appears to be S-bonded in the CoL2X2 complexes (X = Cl, Br, or I), since the v(C=S) frequency is lowered upon co-ordination.166 The electronic spectra of the CoL2C12 complexes (L = thiourea, A-phenylthiourea, and TViV -diphenylthiourea) have been recorded.167... 

Fig. 1.37. Cyclization-free defunctionalization of the thiocarbonic acid derivative from Figure 1.35.

The carbonates and thiocarbonates may be classified quite simply into the following types, (i) Mixed Esters. In these esters, the carbonic acid or thiocarbonic acid is esterified with both an alcohol and a carbohydrate, (ii) Acid Esters. Here, a metal salt of a half-ester of a carbohydrate has been formed, (iii) Intermolecular Esters. Here, an ester has been formed between one molecule of the acid and two molecules of carbohydrate, (iv) Cyclic or Intramolecular Esters. Here, one molecule of the acid is di-esterified with one molecule of carbohydrate. 

Another interesting and more general methodology to a carbene with only one chiral carbon atom in the backbone was introduced by Hahn et al. [61] (see Figure 5.16). Here, an arylamine is treated with n-BuLi and carbon disulfide to the corresponding thiocarbonic acid amide. Second deprotonation with 5ec-BuLi and subsequent reaction with an asymmetrically substituted Schiff base affords the imidazolidinone that can be reduced with Na/K alloy to the respective carbene. Chirality is introduced via the prochiral N=C bond of the Schiff base and the prodnct is usually a racemate since no chiral discriminator is present in the formative step. 

Reaction 2 has also been used to synthesize polysulfanes of thiocarbonic acids,aUcoxythiocarbonic acids, (alkylthio)thiocarbonic acids, or of aUcoxydithiocarbonic acids (xanthates ) (reactions 6-8 with M = H, Na, K and... 

Figure 2. GC-MS analysis of thiocarbonic acid O, S-dimethyl ester (4) in Scheurebe wine extract (SP II). GC column DB-Wax...

Another application of thiocarbamoyl chlorides (15) and related activated thiocarbonic acid derivatives in thioamide synthesis is found in their reaction with carbanions of highly CH acidic compounds EWG2CH2 to give thioamides EWG2CHCSNR2. ... 

Phenyl carbodithioates are obtained in acceptable yields by an intramolecular thioacylation according to equation (59).The intermediate mixed thiocarboxylic thiocarbonic acid anhydride is not isolated but spontaneously eliminates carbon oxysulfide. 

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). 

Carbon disulfide is a useful synthon for the preparation of thiocarbonic acid derivatives (see Chapter 8, p. 135). Carbon disulfide will react with alkynes (18) under forcing conditions the reaction is facilitated by the presence of electron-... 

Replacement of halogen leads to formation of a C-S bond in many cases when alkyl or aryl halides are allowed to react with thiocarbonic acid derivatives such-as thiocarbamates, thiourea, dithiocarbamates, or xanthates. The importance of this method is due to the fact that the intermediates are readily converted into thiols by hydrolysis ... 

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