5-Chloroallyl thiocarbamates

Synthesis. Oxidation of -alkyl or -benzyl IJ,IJ-dialkylthio-carbamates with one equivalent of m-chloroperoxybenzoic acid (MCPBA) in chloroform or methylene chloride at -25° to 25°C yields the corresponding carbamoyl sulfoxide (3) in essentially quantitative yield (3-5). The -chloroallyl thiocarbamate sulfoxides (e.g., 4-7) are obtained in the same manner except that the temperature is maintained between -20°C and 0°C for the oxidation and extraction of the reaction mixture with 5% sodium carbonate aqueous solution (7, 8). 

H Chemical Shift Data (ppm) for -Chloroallyl Thiocarbamates and Thiocarbamate Sulfoxides (2, 8). Solutions in CDCl at 20 -40°C with tetramethylsilane as the internal standard. Proton coupling in Hz ... 

Protons 2-Chloroallyl thiocarbamate U Sulfoxide 4 3-Chloroallyl thiocarbamate Sulfoxide 5 Diallate cis (trans) Sulfoxide ( cis (trans) Triallate Sulfoxide X... 

Chloroallyl) thiocarbamate sulfoxides (. ., 5-2) un-.doubtedly rearrange in an analogous manner but in tbis case tbe sulfenate quickly undergoes an additional 1,2-elimination reaction (7 ). Tbe resulting products are tbe IJ, -dialkylcarbamoyl-sulfenyl chloride (M) and tbe carbonyl compound, aldehydes... 

Carbamylation Reactions. -Alkyl, -benzyl and -chloroallyl thiocarbamates do not readily react with GSH. In contrast, their sulfoxide derivatives ( and 6,) are very effective carbamylating agents for many thiols including GSH (19, ). The GSH conjugates formed vivo via 3 and 6 are quickly cleaved, acetylated and further metabolized as follows (19-21. 23. 24). 

Proherbicides. Thio- and dithiocarbamates probably require metabolic activation prior to exerting their herbicidal effects. Sulfoxide metabolites of the -alkyl thiocarbamates are generally more potent herbicides than the parent compounds ( -5). The herbicidal action of these sulfoxides probably results from their carbamylating action for thiols, although the specific target site or receptor is not defined (23, 24). It is conceivable that the -chloroallyl thiocarbamate herbicides may act in the same way, since their sulfoxides are also potent carbamylating agents... 

Field experiments were conducted to determine the effect of multiple applications of butylate alone or with enzyme inhibitors on the efficacy of butylate. A Dothan loamy sand (fine, loamy, siliceous, thermic Plinthic Paleudults) not previously treated with butylate was used for these studies. Dietholate and the experimental inhibitors, SC-0058 [S-ethyl di(3-chloroallyl)thiocarbamate), SC-0520 (chemistry not disclosed), and SC-7432 (diallylamine) were evaluated for their efficacy as inhibitors of microbial degradation (26). Treatments of butylate were applied at six-week intervals to the same plots for a total of four cycles in 1984. In 1985, the sequence was repeated using only dietholate and SC-0058 for a total of eight cycles. 

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