Dithio dithiocarbamate esters

Carbamates are substituted esters of carbamic acid (NH2COOH) with aliphatic or aromatic substituents on the oxygen and nitrogen atoms. Carbamate insecticides have an aryl or oxime N-methylcarbamate structure, and their mode of action is based on the inhibition of the enzyme acethylcholine esterase (1). However, this inhibition is reversible, and recovery from sublethal doses occurs rapidly. Some carbamate fungicides have a dithio, bisdithio, or benzimidazole carbamate basic structure, and dithiocarbamate fungicides inhibit the enzyme aldehyde deshydro-genase (2). The herbicides have an /V-alkylthiocarbamate or A-phenylcarbamate structure and interfere with photosynthetic activity or affect meristematic activity or lipid metabolism (3). Representative structures of carbamate pesticides are shown in Fig. 1. 

Load-carrying requirements are generally less severe for marine than automotive applications, e.g. there are no specialised cam and tappet test requirements. Nevertheless, good load-carrying properties are required particularly for crankcase oils. The requirements are achieved through the use of compounds such as zinc dithio-phosphates, dithiocarbamates, sulphurised fatty esters, disulphides and sulphurised alkenes. 

By reaction of the oxydiphenoxarsine (71) with various mono- and dibasic acids the esters (75) were synthesized <92Z0B1294>. The synthesis of phenoxarsin-lO-yl dithiocarbamates (76) by reaction of (59) with sodium dithiocarbamates (reaction in MeOH/water, 4 h, 25 °C) has been described <95JOM(493)6l>. Also the phenoxarsin-lO-yl carbodithioates (77) have been described <95MI 626-0l>. Some phenoxarsin-lO-yl diorganodithiophosphinates (78) were prepared by reaction of (59) with salts of the corresponding dithio compounds <94JCS(D)2191>. 

Reversible addition-fragmentation chain transfer (RAET polymerization is the third LRP method which has been developed to a relatively mature state since its first demonstration in 1998 [51] (Scheme 13.9). RAET is a specialized case of the degenerative transfer LRP mechanism in which the controlling agent (X) is a thiocarbonylthio molecule (e.g. dithio esters, dithiocarbamates, trithiocarbonates). 

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