Partial resolutionn of some organic racemates by solvent extraction

Abstract

Partial resolutions of a series of organic racemates' have been achieved by partitioning the racemates between an aqueous phase and an optically active ester of d-tartaric acid. A semiquantitative treatment of the data indicates that the observed results are in agreement with those predicted from the normal relationships dealing with solvent extractions. lthough the differences in chemical interactions port of the U. S . Army Research Office, Durham, in conducting this investigation. We also wish to acknowledge the contributions of M. S . Barry and N. Sartoris who conducted certain preliminary studies.Abstract : The reaction of methyl 3-amino-P-~-xylopyranoside (5) with nitrous acid effected a ring contraction to give methyl 3-deoxy-3-C-formyl-P-~-erythrofuranoside (6) as the main product along with small amounts of methyl 2-deoxy-2-C-formyl-~-~-erythrofuranoside (16). Reduction of the aldehyde function with sponge nickel to the diols 7 and 17 followed by esterification, acetolysis, and nucleoside condensation gave 9-(3-deoxy-3-hydroxymethyl-&(and a)-D-erythrofuranosy1)adenine (13) and 9-(2-deoxy-2-hydroxymethyl-P-(and a)-D-erythrofuranosy1)adenine (21). Intervention by a 1,2 ortho ester ion afforded a 5 : 1 ratio of 13b : 13a. No intervention by a 1,3 ortho ester ion was indicated by the 1 : 1 ratio of a and fi anomers in the 2-branched series. Double-resonance nmr was used to identify the 3-branched series.n recent years, branched chain sugars have been dis-

Influence of process parameters on extraction equilibria for the chiral separation of amines and amino‐alcohols with a chiral crown ether

“…Fractional reactive extraction was already reported as a chiral separation technique in the 1960s 5, 6. For instance, Takeuchi and coworkers7 designed a rotating glass cylinder set‐up to demonstrate the resolution of valine with N ‐dodecyl‐ L ‐hydroxyproline/Cu(II) in butanol and Ding et al 8 applied hollow fibre membrane modules for leucine separation.…”

Enantioselective liquid‐liquid extraction of DL‐mandelic acid using chiral diphosphine ligands as extractants

“…Enantioselective liquid-liquid extraction is an attractive technique that is often used in resolution of chiral enantiomers. 1,2 Tartaric acid, 3 crown ether, 4 cyclodextrin, 5 cinchona alkaloid, 6 and metal complex 7 are common chiral extractants that are widely used in enantioselective liquid-liquid extractions. Among these chiral extractants, metal complex has attracted more and more attention just because of its high enantioselectivity and efficiency.…”

Synthesis of CuPF6‐(S)‐BINAP loaded resin and its enantioselectivity toward phenylalanine enantiomers

“…Enantioselective liquid-liquid extraction is a useful method to separate chiral enantiomers. 1,2 In the past decades, several chiral extractants, such as tartaric acid, 3 crown ether, 4 cyclodextrin, 5 cinchona alkaloid 6 and metal complex, 7 were widely used in the resolution of enantiomers. Among them, metal complex is one of the most important chiral extractants for its good stereoselectivity and extraction behaviors.…”

“…Enantioselective liquid–liquid extraction is a useful method to separate chiral enantiomers . In the past decades, several chiral extractants, such as tartaric acid, crown ether, cyclodextrin, cinchona alkaloid and metal complex, were widely used in the resolution of enantiomers.…”