42589-21-9

Aliphatic and aromatic thiols react smoothly with dialkyl dicyanofumarates in CH2Cl2 at room temperature to give the corresponding disulfides in excellent yields. Aliphatic 1,2-, 1,3-, and 1,4-dithiols afford cyclic disulfides. Analogous reaction courses were observed for selenols, and the required diselenides also formed in nearly quantitative yields. In all of the reactions, dialkyl dicyanosuccinates formed as 1:1 mixtures of diastereoisomers as the only other product. Cysteamine (2-mercaptoethylamine) behaved differently; the Michael addition of the primary amine group led to the complete consumption of the dicyanofumarate, and the formation of the disulfide containing an enamine moiety occurred without the formation of dicyanosuccinate.

Tetrathiomolybdate provides an easy access to β-hydroxy disulfides, β-hydroxy sulfides, and selenides from epoxides in a tandem, multistep process in one pot. This strategy has been utilized effectively in the construction of thiabicylo[3.2.2]nonane derivative 24.

The kinetics of reaction between triarylphosphanes and two newly prepared dioxorhenium(VII) compounds has been evaluated. The compounds are MeReVII(O)2( O,S ) in which O,S represents an alkoxo, thiolato chelating ligand. With MeReO3, ligands derived from 1-mercaptoethanol and 1-mercapto-2-propanol form MeRe(O)2(met), 2, and MeRe(O)2(m2p), 3. These compounds persist in chloroform solution for several hours at room temperature and for 2-3 weeks at -22°C, particularly when water is carefully excluded. They were obtained as red oils with clean 1H NMR spectra, but attempts to obtain pure, crystalline products were not successful because one decomposition pathway shows a kinetic order >1. The fastest reaction occurs between P(p-MeOC6H4)3 and 2; k298 = 215(7) L mol-1 s-1 in chloroform at 25(1)°C. The other rate constants follow a Hammett correlation against 3σ, with ρ = -0.69(7). This study relates to oxygen atom transfer reactions catalyzed by MeReO(mtp)PPh3, 1, in which MeRe(O)2(mtp), 4, is a postulated intermediate that does not build up to a measurable concentration during the catalytic cycle. Compound 2 does not react with MeSTol, but MeS(O)Tol was formed when tert-butyl hydroperoxide was added. This suggests that equilibrium lies to the left in this reaction, 2 + MeSTol + L = MeReO(met)L + MeS(O)Tol, and is drawn to the right by a reaction between MeReO(met)L and the hydroperoxide. Triphenyl arsane does not react with 2, but thermodynamic versus kinetic barriers were not resolved.

The hydrolysis of 2-hydroxypropyl methanethiolsulfonate (HPMTS), an industrial water treatment microbicide, was investigated at 25°C and at three pH values (pH 5, 7, and 9). Radiolabeled (14C) HPMTS at a concentration of 100 mg/L was used to determine rate constants and to identify hydrolytic degradation products. The hydrolysis at all three pHs followed pseudo-first-order kinetics with rate constants of 5.8 × 10-4, 7.6 × 10-2, and 7.3. h-1 at pH 5, 7, and 9, respectively. Two major radiolabeled hydrolytic degradation products were observed at all three pH values and were identified to be bis(2-hydroxyisopropyl) disulfide and bis(2-hydroxypropyl) disulfide by particle beam LC/MS. On the basis of the observed degradation products, a hydrolytic degradation pathway for HPMTS using propylene epoxide as a reactive intermediate was postulated.