Mellander, Alfred published the artcileStereoisomers of α-alkylmercapto- and α-alkylsulfonepropionic acids, Product Details of C4H7BrO2, the publication is Arkiv. Kemi, Mineral. Geol. (1937), 12A(No. 16), 32 pp., database is CAplus.
The dl-form of α-propylmercaptopropionic acid, MeCH (SPr) CO2H, was prepared by the addition of PrI (185 g.) to 106 g. α-thiolactic acid, 143 g. Na2CO3.10H2O in 150 cc. H2O and 41 g. caustic soda in 130 cc. H2O. The α-iso-Pr derivative was similarly prepared Data are given for the following alkyl-mercapto derivatives (m. and b. ps. corrected): Me, m. 17.3°, b9 106.5°, d420 1.1464, nD20 1.4843, MD (mol. refraction by Lorenz-Lorentz’s formula) 29.99, k25 (affinity constant by conductivity measurement) 1.73 × 10-4; Et, b9 115.5°, d420 1.1087, nD20 1.4798, MD 34.35, k25 1.60 × 10-4; Pr, b8 128.5°, d420 1.0595, nD20 1.4765, MD 39.47, k26 1.53 × 10-3; isd-Pr, b9 121.4°, m. 14.6°, d420 1.0482, nD20 1.4724, MD 39.61, k25 1.67 × 10-4. The corresponding sulfones, CH3CH(SO2R)CO2H, were prepared by oxidation of the sulfides with KMnO4 in alk. solution Their data follow: Me, m. 96.6°, k25 3.6 × 10-3; Et, m. 62.6°, k25 3.25 × 10-3; Pr, m. 59.5°; k25 3.11 × 10-3; iso-Pr, m. 105.0°; k25 3.01 × 10-3. Addition of Br to the sulfones gave the corresponding α-bromo-α-alkylsulfonepropionic acids as follows: Me, m. 173° (decomposition); Et, m. 96.5°; Pr, m. 125.4°; iso-Pr, m. 64.3°. Reduction of the Br derivatives with N2H4 gave the corresponding unsubstituted α-alkyl-sulfonepropionic acids. Resolution of dl-α-MeCH(SEt)CO2H by crystallization of the brucine salt gave the l-form, [α]D -111.8°, [α]Hg -132.6°. Crystallization of the quinidine salt, m. 66-7°, from the mother liquor gave the d-form, [α]D 111.8°, [α]Hg 132.6°. The quinine salt of the l-Pr acid, m. 92.5-94°; the l-acid [α]D -106.0°, [α]Hg -126.0°. The d-acid was not isolated. d-Iso-Pr acid, [α]D 113.7°, [α]Hg 135.4°, was obtained by crystallization of the brucine salt, m. 76-77.5°. l-Acid, [α]D -113.8°, [α]Hg -135.5°, was prepared through the quinine salt, m. 132.2-4.4°. The above values of [α] were obtained by graphic interpolation of [α] values for a series of aqueous solutions of concentrations varying around 1%. The sp. rotation in aqueous solutions decreases on dilution, indicating that the undissociated acid has greater rotatory power than the ion. Distillation of the active form of the acids results in racemization. The active forms of the α-alkylsulfonepropionic acids were prepared by oxidation of the corresponding active sulfides, using KMnO4 and phosphate buffer (pH 6.98). The pure active forms could not be prepared by resolution of the dl-sulfones. The interpolated values of [α] for the sulfones are: l-Me [α]D -24.5°, [α]Hg -29.6°; d-Me [α]D 24.5°, [α]Hg 29.7°; l-Et [α]D -32.7°, [α]Hg -39.2°; d-Et [α]D 32.6°, [α]Hg 39.2°; l-Pr [α]D -33.6°, [α]Hg -40.6°; l-iso-Pr [α]D -36.5°, [α]Hg -44.2°; d-iso-Pr [α]D 36.5°, [α]Hg 44.2°.
Arkiv. Kemi, Mineral. Geol. published new progress about 56970-78-6. 56970-78-6 belongs to bromides-buliding-blocks, auxiliary class Bromide,Carboxylic acid,Aliphatic hydrocarbon chain,Inhibitor, name is 3-Bromo-2-methylpropanoic acid, and the molecular formula is C4H7BrO2, Product Details of C4H7BrO2.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary