13509-28-9Relevant academic research and scientific papers
Phenolysis and aminolysis of 4-nitrophenyl and 2,4-dinitrophenyl S-methyl thiocarbonates in aqueous ethanol
Castro, Enrique A.,Aliaga, Margarita E.,Cepeda, Marjorie,Santos, Jose G.
experimental part, p. 353 - 358 (2011/11/30)
The reactions of S-methyl O-(4-nitrophenyl) thiocarbonate (1) and S-methyl O-(2,4-dinitrophenyl) thiocarbonate (2) with a series of secondary alicyclic (SA) amines and phenols are subjected to a kinetic investigation. Under nucleophile excess, pseudo-first-order rate coefficients (kobs) are obtained. Plots of kobs against the free nucleophile concentration at constant pH are linear with slopes kN. The Brnsted plots (log kN vs. nucleophile pKa) for the reactions are linear with slope (β) values in the 0.5-0.7 range, in accordance with concerted mechanisms. Comparison of the SA aminolysis of 1 with the same one carried out in water shows that the change of solvent from water to aqueous ethanol destabilizes the zwitterionic tetrahedral intermediate, changing the mechanism from stepwise to concerted. This destabilization is greater than that due to the change from SA amines to quinuclidines. For the phenolysis reactions, the kN values in aqueous ethanol are smaller than those for the same reactions in water. Considering that the nucleophile is an anion, this result is unexpected because the anion should be more stabilized in the more polar solvent. This result is explained by the facts that the phenoxide reactant has a negative charge that is delocalized in the aromatic ring and the transition state is highly polar.
Synthesis of S-aryl/alkyl thiolcarbonates from disulfides and chloroformates in the presence of the Zn/AlCl3 system
Movassagh, Barahman,Tavoosi, Maryam
experimental part, p. 251 - 253 (2009/05/26)
A simple, general, and high yielding method has been developed for the synthesis of S-aryl/alkyl-O-aryl/alkyl thiolcarbonates from various chloroformates and disulfides by reductive cleavage of the S-S bond with a Zn/AlCl3 system in dry acetonitrile at 80°C.
Effect of substitution of oxygen by sulfur in the npnleaving group of a carbonate: Kinetics of the phenolysis and benzenethiolysis of 5-methyl aryl thiocarbonates
Castro, Enrique A.,Aliaga, Margarita,Santos, Jose G.
, p. 533 - 538 (2008/02/06)
The phenolysis and benzenethiolysis of S-methyl 4-nitrophenyl thiocarbonate (1) and S-methyl 2,4-dinitrophenyl thiocarbonate (2) in water are studied kinetically. The Brnsted plots (log kN versus nucleophile basicity) are linear for all reactions. The Bronsted slopes for 1 and 2 are, 0.51 and 0.66 (phenolysis) and 0.55 and 0.70 (benzenethiolysis), respectively. These values suggest a concerted mechanism for these reactions, as found in the corresponding carbonates. Namely, substitution of OMe by SMe in the nonleaving group does not change the mechanism. Copyright 2007 John Wiley & Sons, Ltd.
Solvent-assisted thiocarboxylation of amines and alcohols with carbon monoxide and sulfur under mild conditions
Mizuno, Takumi,Iwai, Toshiyuki,Ishino, Yoshio
, p. 9157 - 9163 (2007/10/03)
DMSO or DMF as a solvent strongly accelerated the thiocarboxylation of amines and alcohols with carbon monoxide and sulfur. Under mild conditions (1 atm, 20°C), this thiocarboxylation of amines assisted by DMSO with carbon monoxide and sulfur has been developed into a practical and convenient synthetic method for S-alkyl thiocarbamates in good to excellent yields, including EPTC, thiobencarb, orbencarb, and molinate (herbicides). DMF also showed the similar solvent effect. NMP slightly decreased the effect for the thiocarboxylation of amines, and the yield of S-alkyl thiocarbamate was lowered in DMAc. Surprisingly, no formation of S-alkyl thiocarbamate was observed at the use of the other solvents, such as THF, hexane, toluene, AcOEt, MeCN, MeOH, and H 2O. The present solvent-assisted thiocarboxylation with carbon monoxide and sulfur could be also applied to a new synthesis of S-alkyl O-alkyl carbonothioates from alcohols under mild conditions (1 atm, 20°C) in DMF using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene).
Benzyl chloroformate (CbzCl) synthesis using carbon monoxide as a carbonyl source
Mizuno, Takumi,Takahashi, Junko,Ogawa, Akiya
, p. 10011 - 10015 (2007/10/03)
A novel non-phosgene synthetic method for benzyl chloroformate (CbzCl) was established. S-Methyl O-benzyl carbonothioates were prepared by the carbonylation of benzyl alcohols with carbon monoxide and sulfur (or carbonyl sulfide) in the presence of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) followed by esterification using methyl iodide in good yields. Then, CbzCl derivatives were successfully synthesized by the chlorination of S-methyl O-benzyl carbonothioates using sulfuryl chloride in excellent yields.
