Enantiospecific enzymatic preparation of (2S,3S)-3-alkylaspartic acids of current interest in the synthesis of stereoregular poly[β-(2S,3S)-3-alkylmalic acids] as new optically active functional polyesters
✍ Scribed by Claire Monne; Daniel Robic; Geneviève Campion; Richard Bourbouze; Alain Rimbault; Michèle Masure; Valérie Langlois; Patrick Hemery; Philippe Guerin
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 479 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0899-0042
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✦ Synopsis
2S,3S)-3-methyl-and 3-isopropylaspartic acids were synthesized by bioconversion of the corresponding alkylfumarates (mesaconate and 3-isopropylfumarate) using pmethylaspartase from cell-free extracts of Clostridium tetanomorphum. Optically pure (2S,3S)-3-alkylaspartic acids were transformed in several steps to benzyl (3S,4R)-3-alkylmalolactonates without any racemization of the two chiral centers. These optically active a$-substituted-plactones were polymerized by anionic ring opening polymerization yielding optically active semi-crystalline polyesters. 13C NMR analysis of poly [benzyl p-3-isopropylmalate] in CDCl, has shown that only the iso-type stereosequence is present in the polymer, indicating that the macromolecular chain is constituted by the only units of benzyl p-(2S,3S)-3-isopropylmalate monomer. The polymerization reaction was done without any racemization of the two stereogenic centers as in the case of benzyl (3S,4R)-3-methylmalolactonate. o 1996 WiIey-Liss, Inc.
KEY WORDS: p-methylaspartase, alkylfumarates, (2S,3S)-3-methylaspartic acid, (2S,3S)-3isopropylaspartic acid, bioconversion, (3S,4R)-benzyl 3-alkylmalolactonates, poly [benzyl-p-(2S,3S)-3-alkylmalatesl
The interest in introducing stereogenic centers in the macromolecular chain of synthetic polymers is now well recognized for the modulation of their physical and mechanical properties.