Hydrosilylation of 2-(2-Propynyl)-2,3-dihydro-1,2-benzothiazol-3-one 1,1-Dioxide with 1-Alkynyl(dimethyl)- and Bis(1-alkynyl)methylsilanes

Hydrosilylation of 2-(2-propynyl)-2,3-dihydro-1,2-benzothiazol-3-one 1,1-dioxide with 1-alkynyldimethyl- and bis(1-alkynyl)methylsilanes of the general formula Me _n HSi(C=-CR)₃-n (n = 1, 2) in the presence of H₂PtCl₆ (Speier's catalyst) occurs in a nonregioselective but stereoselective fashion, yielding mixtures of the corresponding trans-- and -adducts. The fraction of the latter ranges from 50 to 70%, depending mainly on the substrate nature rather than on the nature of substituent at the triple bond of the reagent.     

Synthesis of methylamides of O-(2-acetamido-2-desoxy-Β-D-glucopyranosyl)-N-acetylserine and O-(2-acetamido-2-desoxy-Β-D-glucopyranosyl)-N-acetylthreonine

Conclusions The oxazoline method was used to synthesize the methylamides of O-(2-acetamido-2-desoxy--D-glucopyranosyl)-N-acetylserine and O-(2-acetamido-2-desoxy--D-glucopyranosyl)-N-acetylthreonine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 697–699, March, 1975.     

Activation and Reaction Volumes for [4+2] and [3+2] Additions Involving Maleic Anhydride

The partial molar volumes of reactants and products of the [3+2] addition of C-(p-nitrophenyl)-N-phenylnitrone to maleic anhydride and of the [4+2] addition of 9,10-dimethylanthracene to the same dienophile were determined, and the reaction volumes were calculated. A new method was suggested for determining the reaction volume. The activation volumes of both reactions were calculated from the dependences of the reaction rates on the external pressure. The volume parameters of the reactions involving the reagents of close size are close. The ratios of the activation volumes to the reaction volumes are unity, which suggests a common concerted mechanism of the reactions. Factors that could be responsible for significant changes in the absolute values of the reaction volume parameters are discussed.     

Addition of mercaptans to acetylenic γ-hydroxy ketones

Conclusions Both the nucleophilic and the free radical addition of n-butyl mercaptan to acetylenic-hydroxy ketones (1,1-disubstituted derivatives of 2-pentyn-1-ol-4-one) lead to the formation of the corresponding 1,1-disubstituted derivatives of 2-butylthio-2-penten-1-ol-4-one in 41–65% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1669–1670, July, 1973.     

Solvent Effect on the Volume of the Diels-Alder Reaction between Tetracyanoethylene and trans,trans-1,4-Diphenyl-1,3-butadiene

From the partial molar volumes of tetracyanoethylene, trans,trans-1,4-diphenyl-1,3-butadiene, and their Diels-Alder adduct, the volumes of the reaction in a series of solvents at 25°C (cm³ mol^{- 1}) were calculated: in dioxane, -26.4; in chloroform, -34.9; in ethyl acetate, -34.5; in acetonitrile, -4.4; in cyclohexanone, -34.0; in 1,2-dichloroethane, -31.8; in benzene, -26.9; in toluene, -24.5; in o-xylene, -21.1; and in mesitylene, -16.9. The solvent effects on the activation and reaction volumes and on the partial molar volumes of the reactants, activated complex, and adduct were discussed.