Reference

Determination of the optical purity of L-selenomethionine-75Se

Determination of the optical purity of L-selenomethionine-75Se. Otto, P. P. H. L.; Van Veen-Van Staalduinen, G. F. (Cent. Lab., TNO, Delft, Neth.). J. Radioanal. Chem., 35(1), 37-44 (English) 1977. CODEN: JRACBN. DOCUMENT TYPE: Journal CA Section: 34 (Synthesis of Amino Acids, Peptides, and Proteins) Section cross-reference(s): 22 Optical purity of D-selenomethionine-Se75 was detd. by treating the D and L mixt. with (-)-camphorsulfonyl chloride and treating the products to thin layer chromatog. From the ratio of the radioactivities of the 2 spots on the chromatogram, the optical purity was calcd. and given in % D. For a sample of L-methionine-14C the following value was found: 0.53 .+-. 0.05 (S. D. of mean, n = 7). For a sample of DL-methionine-14C the percentage of D found was: 48.5 .+-. 39262-22-1 and 62653-77-4 which are cas registry numbers of chemicals are mentioned. 0.5 (S.D. of mean n = 7). Of 30 different samples of L-selenomethionine-75Se the percentages of D-isomer were detd. in duplicate. From the 30 differences between duplicates of the S.D. of a single measurement is calcd. to be 0.2. .

Effect of the medium on enantioselectivity in the formation of sulfonamides

Effect of the medium on enantioselectivity in the formation of sulfonamides. Popov, A. F.; Dereza, L. I.; Litvinenko, L. M. (Inst. Fiz.-Org. Khim. Uglekhim., Donetsk, USSR). Zh.Several reagents with their cas registry numbers 39262-22-1 and 2627-86-3 are used here. Org. Khim., 12(12), 2528-32 (Russian) 1976. CODEN: ZORKAE. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) Kinetics of reaction of (-)-10-camphorsulfonyl chloride with (+)- and (-)-PhCHMeNH2 were detd. at 25.degree. in PhCl, o-C6HCl2, 1:1 PhCl-o-C6H4Cl2, and in PhCl with 1, 4, and 11% PhNO2; the (+)-isomer was the faster reacting. Two reaction paths were followed in parallel; catalyzed and uncatalyzed (by the amine) amination. The enantiomeric selectivity (ratio of rate consts.) on going from PhCl to PhCl contg. 11% PhNO2 increased from 2.27 to 3.73, but on going from PhCl to o-C6H4Cl2 it decreased to 1.05. .