Stallberg, Gunnel’s team published research in Arkiv foer Kemi in 12 | CAS: 56970-78-6

Stallberg, Gunnel published the artcileSynthesis and configuration of enantiometric β-bromoisobutyric acids, Safety of 3-Bromo-2-methylpropanoic acid, the publication is Arkiv foer Kemi (1957), 95-8, database is CAplus.

The enantiomeric β-bromoisobutyric acids could not be obtained by resolution of the inactive compound with brucine. They were, however, prepared by the Hunsdiecker degradation (C.A. 37, 3734⁴) of the enantiomeric half-esters of methyl succinic acid. Thus, to 0.047 mole (-)-Me 2L-methyl-3-carboxypropionate, neutralized with dilute NH₃, was added 0.049 mole aqueous AgNO₃ with cooling and stirring. After 3 hrs. the Ag salt (I) was filtered off, washed with water, MeOH, and Et₂O, and dried 48 hrs. at 90-5°. To 10.7 g. I in dry CCl₄ was added dry Br with cooling and shaking until the color persisted. After standing 6 hrs. at room temperature, the mixture was filtered, the filtrate washed with aqueous NaHCO₃ and water, dried, and fractionated yielding (+)-Me β-bromoisobutyrate (II), b₃₇ 85°, n²⁵_D 1.4532, d₂₅ 1.422, [α]²⁵_D 15.9° [M]²⁵_D 28.8°. II (4.9 g.) was refluxed 24 hrs. with 30 ml. AcOH containing 2 ml. 48% HBr and fractionated yielding (+)-β-bromoisobutyric acid, b_1.5 81.5°, n²⁵_D 1.4748, d₂₅ 1.579, [α]²⁵_D 10.5°, [M]²⁵_D 17.5°. Similarly, (+)-Me 2D-methyl-3-carboxypropionate was converted to (-)-Me β-bromoisobutyrate, b₁₂ 97.5-8.5°, n²⁵_D 1.4533, d₂₅ 1.422, [α]²⁵_D -15.9, and then to (-)-β-bromoisobutyric acid, b₂ 69-70°, n²⁵_D 1.4744, d₂₅ 1.576, [α]²⁵_D-10.5°.

Arkiv foer Kemi 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 C8H10O2, Safety of 3-Bromo-2-methylpropanoic acid.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary