Mercaptan Catalysis in Thermoneutral Free Radical Exchange

Abstract

The exchange of (CgHgkCH• with (CgHg)2CH2 was studied by decomposition of (CjH5)2CH-N=N-CHfCgHs)» (I) in (C6H5)2C14H2 at 60°and examination of the (CeH5)2CH-CH(CgH5)2 (II) produced for radioactivity. Little or no exchange was observed. Thiophenol, ca. 0.04 mole/1., led to diminished yield of II and 17% exchange, apparently via the reactions (CgH5)2CH• + CgHsSH (CgHg)2CH2 + CgHsS•. Irradiation of diphenyl disulfide in (CgHghCLB led to II. A few experiments with -mercaptotoluene and 2-mercaptomesitylene led to little if any exchange. Thiophenol and I in both benzene and (C6H5)2CH2 led also, in low yield, to compound III, apparently 2,2,3,3-tetraphenylethylenimine, which was also formed by decomposition of I in benzene in the presence of benzophenone azine. Analysis and interpretation of the results are given.

Hang-gliding with Ferrocenes: Unusual Coordination Chemistry of 1,1‘-Bis(mesitylthio)ferrocene

“…The adoption by the bis(mesitylthio)ferrocene ligand of a binucleating rather than a bidentate coordination mode could be either a consequence of the initial formation of the Re 2 (CO) 8 Br 2 dinuclear species followed by displacement of a pair of axial carbonyls and bis(mesitylthio)ferrocene ligand coordination or that the THF complex [{Re(CO) 3 (THF)(µ-Br)} 2 ] 10 is formed with subsequent displacement of the THF molecules. Indeed, no reaction was observed on heating 1 and Re(CO) 5 Br in toluene at 60 °C for 16 h. Alternatively, the steric bulk of the mesityl groups could inhibit the ligand from adopting a chelating geometry, as mononuclear rhenium carbonyl species with ligands such as dppf and 1,1′-bis-(methylthio)ferrocene are well-known. 1 In contrast to the unexpected reaction with Re, a bidentate coordination mode to a single metal center was obtained by treatment of 1 with trans-Pd(PhCN) 2 Cl 2 and trans-Pt(PhCN) 2 Cl 2 but under different conditions (Scheme 1).…”

Reactions of Nucleosides on Polymer Supports. Synthesis of Thymidylylthymidylylthymidine*

“…Benzene was dried by distillation and dioxane was purified according to Fieser (1957). Monomethoxytrityl chloride (mp 119-121 °) (Marvel etal., 1944), dimethoxytrityl chloride (mp 112-114°) (Hogenkamp and Oikawa, 1964), 5'-O-tritylthymidine (mp 159-160°) (Weimann and Khorana, 1962), 5'-O-monomethoxytritylthymidine (mp 102-105°) (Schaller et al, 1963), 5'-O-dimethoxytritylthymidine (mp 124-126°) (Schaller et al, 1963), mesitylenesulfonyl chloride (mp 56°) (Wang and Cohen, 1957), and 2,4,6-triisopropylbenzenesulfonyl chloride (mp 95-96°) (Lohrman and Khorana, 1966) were prepared by procedures described in the literature. Barium /3-cyanoethyl phosphate was converted to the pyridinium salt by ion exchange with Dowex 50 (pyridinium form) by the method of Tener (1961).…”

Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

“…The preparation and properties of the following have been described previously: methyl 4-methylthiobenzoate, 4b (29, 30) using potassium ethyl xanthate (28); 2-methylthio-1,3,5-trimethylbenzene, 6b, from mesitylenethiol (27); mesitylenethiol from mesitylenes~~lfonyl chloride (33)(34)(35).…”