Optical Enrichment Of Dansyl‐rac‐amino Acids By Formation Of Crystalline Inclusion Complexes With Cyclodextrins

Abstract

Optical enrichment from racemic dansyl‐leucine, dansyl‐norleucine, and dansyl‐phenylalanine with both β‐ and γ‐cyclodextrins in water is reported. Initial crystallization yielded the dansyl‐L‐leucine isomer complexed in excess with β‐cyclodextrin with an optical purity of 62–78% depending on experimental conditions. The optical purities obtained for L‐norleucine and L‐phenylalanine were 71 and 64%, respectively. The optical purity can be increased with continued recrystallization. The dansyl‐D‐leucine isomer was obtained in the mother liquor with an optical purity of 54–93% depending on experimental conditions. The optical purities obtained for D‐norleucine and D‐phenylalanine were 72 and 58%. The optical purity of the isomer depended on the molar ratio of host:guest and the pH value of the solution. Optimum enrichment of both enantiomers was achieved with host:guest ratios of 2 : 1 and 3 : 1. Although maximum crystalline yield of the dansyl‐leucine/CD inclusion complex was obtained at a pH of 3.5, optical purity of both enantiomers was less than that obtained at other pHs. The influence of the molar ratio of host:guest and the pH value of the solution are discussed. This method is suitable for large‐scale enantiomeric separations. Copyright © 1989 Alan R. Liss, Inc.

Department(s)

Chemistry

Comments

National Institute of General Medical Sciences, Grant R01GM036292

Keywords and Phrases

dansyl‐D‐leucine; dansyl‐D‐norleucine; dansyl‐D‐phenylalanine; dansyl‐L‐leucine; dansyl‐L‐norleucine; dansyl‐L‐phenylalanine; racemic mixture; resolution by crystallization; β‐cyclodextrin; γ‐cyclodextrin

International Standard Serial Number (ISSN)

1520-636X; 0899-0042

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 Wiley, All rights reserved.

Publication Date

01 Jan 1989

PubMed ID

2642042

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