The C-X Bond Formation Research Based On Tetramethylthiuram Disulfide

The reaction involving C-X bond(X: heteroatom including O?S?C)catalyzed by metal-free or transition-metal condition is a hot-spot field in the modern organic synthesis,which has attracted more and more attention from organic chemists around the world.On the basis of the explored research progress in the C-O,C-S and C-C bond formation reactions,we investigated the C-X(X = O,S,C)bond formation reactions regarding tetramethylthiuram disulfide(TMTD).O-Aryl N,Ndimethylthiocarbamates derivatives,diphenyl sulfide derivatives and thiobenzamide derivatives are synthesized respectively,which has wide application potentials in medicine,pesticides,natural products and organic intermediates showing biological activities.Therefore,it is significant to explore the synthetic method of these compounds.The details are summarized as follows:1.We have discovered a metal-free catalytic synthetic reaction to generate C-O bond.Taking phenolic compounds and tetramethylthiuram disulfide(TMTD)as the starting material,the type of base,solvent,reaction temperature,dosage of base,mole ratio of substrates and catalysts are selected to achieve the optimal reaction conditions.The results show that when phenolic compounds and TMTD react under NaH in DMF solvent at 80 oC for 12 h,we can get the best yield.A total of 16 O-Aryl N,N-dimethylthiocarbamates were synthesized,the yield of which can reach to 55 %~76 % in the optimum condition.All the product structures are identified by necessary spectra.The method avoided the employment of metal catalysts,which has advantages such as simple operation,starting material cheap and easy to get,broadening the synthetic methods of prepare thiocarbamates compounds.2.We have studied the C-S bond formation reactioncatalyzed by copper.Taking phenyl dimethylcarbamodithioate and arylboronic acidas the starting material,the dosage of catalyst and ligand,the types of ligands,solvents,temperature and mole ratio of substrates are selected to achieve the optimal reaction conditions.The results show that the optimum condition is when arylboronic acid and phenyl dimethylcarbamodithioate react in DMF solvent catalyzed by Cu(OAc)2 at 110 oC for 6 h.A total of 16 phenyl sulfides were synthesized,the yield of which can reach to 63 %~88 % in the optimum condition.All the product structures are identified by necessary spectra.With ligand free,and with the involment of environmentally green copper catalyst,the protocol is easy to handle,and showed good expanding to the substrates,which broadened the phenyl dimethylcarbamodithioate involved C-S bond formation reaction.3.We have studied the C-C bond formation reaction catalyzed by copper.Taking tetramethylthiuram disulfide(TMTD)as the starting material,the dosage of oxidizing agent,solvents,temperature,oxidizing agent and mole ratio of substrates are selected to achieve the optimal reaction conditions.The results show that the optimum condition is when benzaldehyde and TMTD are oxidized by di-tbutyl peroxide(DTBP),catalyzed by CuI in ethyl acetate solvent at 120 oC for 7 h.A total of 16 thiobenzamides were synthesized,the yield of which can reach to 77 %~83 % in the optimum condition.All the product structures are identified by necessary spectra.The protocol is easy to handle,showing economic and environmentally green properties,offering a new approach for the synthesis of thiobenzamide.