Dimethylthiocarbamate

Tellurium dimethylthiocarbamate in combination with mercaptoben2othia2ole, with or without tetramethylthiuram disulfide, is the fastest known accelerator for butyl mbber. It is used extensively in butyl tubes for buses and similar vehicles and in other butyl appUcations (see Elastomers, synthetic Rubber, natural). 

Tellurium-containing donors, synthesis and manufacture of, 22 212 Tellurium-copper alloys, 24 425-426 Tellurium crystals, 24 405-406 Tellurium decafluoride, 24 419 Tellurium dibromide, 24 420 Tellurium dichloride, 24 419-420 Tellurium diethyldithiocarbamate, 24 411 Tellurium dimethylthiocarbamate, 24 428 Tellurium dioxide, 24 407-408, 409, 411, 420, 428... 

Studies have also been conducted on compounds containing a thio-carbonyl group. Photolysis of dimethylthiocarbamates produces128,129 mixtures of deoxy sugars and alcohols (see Table XVI). As the alcohols can be reconverted into dimethylthiocarbamates, and these re-irradiated, the synthesis and irradiation of these compounds offers a useful pathway to deoxy sugars. A simple mechanism for this reaction, based on the two possible a-cleavages resulting from thiocarbonyl excitation, is shown in Scheme 23. In addition, the possibility has been... 

Scheme 24. — Proposed, Photochemical, Freudenberg Rearrangement of Dimethylthiocarbamates. ...

Dimethylthiocarbamates are known to undergo photochemical cleavage, leading, in the case of monosaccharide derivatives, to deoxy sugars and to free alcohols (see Scheme 12). ... 

Dimethylthiocarbamyl chloride, synthesis of, 51,140 with 2-naphthol to give O-2-naphthyl dimethylthiocarbamate, 51, 139... 

Thiols have also been prepared from alcohols. One method involves treatment with H2S and a catalyst such as A1203,747 but this is limited to primary alcohols. Another method involves treatment with Lawesson s reagent (see 6-11).748 Still another method, involving the use of a fluoropyridinium salt and sodium N,N-dimethylthiocarbamate, can be applied... 

Dithiocarbamate fungicides consist of metal salts of dimethylthiocarbamate and ethylenebis-dithiocarbamate anions, as shown in Figure 17.5. These fungicides are named in accordance with the metal ion present. For example, the manganese salt of dimethyldithiocarbamate is called maneb, and the zinc and sodium salts are zineb and nabam, respectively. The iron salt of ethylenebisdithio-carbamate is called ferbam, and the zinc salt of this ion is called ziram. These salts are chelates (Section 2.3) in which two S atoms from the ethylenebisdithiocarbamate anion are bonded to the same metal ion in a ring structure. 

The Newman-Kuart rearrangement is an example of a high-temperature reaction [34]. With the use of a microreactor, the reaction temperature could be extended up to 200 °C. 0-(2-Nitrophenyl)-N,N-dimethylthiocarbamate was converted to S-(2-nitro-phenyl)-N,N-dimethylcarbamothioate at 170 °C in 14 min at 90% yield. Quantitative conversion with a throughput of 34 g/h was achieved with sulfolane as solvent at the same temperature and reaction time. 

The reaction of the formally dipole-stabilized carboanions with a variety of electrophiles gives 2,3-substituted thiiranes (Scheme 74). Ethyl jV,7V-dimethylthiocarbamate (209) undergoes lithiation to give (210), which readily reacts with benzaldehyde to give the thiirane (212) in 81% yield by way of the i -hydroxy adduct (211). The synthesis of thiirane (214) from n-pentyl-jV,jV-dimethyl-thiocarbamate (213) is shown in Equation (33) <82JOC3855>. 

The 1,3-dimercapto derivative conld be obtained also in a rational way, via the bis(dimethylthiocarbamate) in which the remaining OH gronps were protected against the rearrangement (360 °C, 20-30 min) by methylation . Mercapto derivatives were also prepared from thiacalix[4]arenes (see Section VI. F), while larger calixarenes with SH instead of OH gronps are not yet known. 

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