COA of Formula: C10H13ClO3《Enzymatic Process for N-Substituted (3S)- and (3R)-3-Hydroxypyrrolidin-2-ones》 was published in 2015. The authors were Singh, Amarjit;Falabella, James;LaPorte, Thomas L.;Goswami, Animesh, and the article was included in《Organic Process Research & Development》. The author mentioned the following in the article:
Lipase PS 30 (immobilized on polypropylene) from Pseudomonas cepacia was used for enantioselective esterification of (RS)-1-(2-fluoro-4-iodophenyl)-3-hydroxypyrrolidin-2-one by using succinic anhydride and 2-methyltetrahydrofuran at 4 °C. The isolation of desired alc. avoided use of column chromatog., a simple solvent extraction of undesired (R)-4-((1-(2-fluoro-4-iodophenyl)-2-oxopyrrolidin-3-yl)oxy)-4-oxobutanoic acid into 5% potassium bicarbonate solution separated pure desired (S)-1-(2-fluoro-4-iodophenyl)-3-hydroxypyrrolidin-2-one into the 2-methyltetrahydrofuran solution The reaction conditions were optimized, and (S)-1-(2-fluoro-4-iodophenyl)-3-hydroxypyrrolidin-2-one was prepared in high enantiomeric excess >99% and yield ∼40% (theor. possible yield 50%). Novozym 435 (Candida antarctica lipase B) was found to be a suitable biocatalyst for the resolution of (RS)-1-(6-bromo-2-methylpyridin-3-yl)-2-oxopyrrolidin-3-yl acetate to form the undesired S-acetate and the desired R-alc. The optimized reaction conditions gave (R)-1-(6-bromo-2-methylpyridin-3-yl)-3-hydroxypyrrolidin-2-one in ∼37% isolated yield (maximum possible yield 50%) and high enantiomeric excess (ee >99.4%). The enzymic resolution of (RS)-1-(6-bromo-2-methylpyridin-3-yl)-2-oxopyrrolidin-3-yl acetate followed by chromatog. was successfully implemented to deliver material for two successive (4.1 kg, ee >99.4% and 5.5 kg, ee >99.5%) campaigns. The undesired S-alc. was recycled back to the desired R-alc. using a Mitsunobu inversion of stereochem. in gram scale. An increase in the chain length from acetate to hexanoate improved the selectivity and subsequent optimization decreased the enzyme loading and enhanced the substrate input. Separation of the desired (R)-1-(6-bromo-2-methylpyridin-3-yl)-3-hydroxypyrrolidin-2-one from (S)-1-(6-bromo-2-methylpyrrolidin-3-yl)-2-oxopyrrolidin-3-yl hexanoate was achieved using a solvent extraction The process for the preparation of (S)-1-(2-fluoro-4-iodophenyl)-3-hydroxypyrrolidin-2-one and (R)-1-(6-bromo-2-methylpyridin-3-yl)-3-hydroxypyrrolidin-2-one is scalable, economical, and highly efficient and avoids chromatog. To complete the study, the researchers used (1S)-4,7,7-Trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carbonyl chloride(Chunks or pellets) (cas: 39637-74-6) .
(1S)-4,7,7-Trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carbonyl chloride(Chunks or pellets) (cas: 39637-74-6 COA of Formula: C10H13ClO3) is used as a resolving agent for alcohols as the diastereomeric esters by crystallization or chromatography and as a chiral derivatization reagent for determination of enantiomeric excess of alcohols and amines.
Reference:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics