Chemo-enzymatic synthesis of arginine-based gemini surfactants

✍ Scribed by Eulalia Piera; María Rosa Infante; Pere Clapés

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 123 KB
• Volume: 70
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/1097-0290(20001105)70:3<323::aid-bit9>3.0.co;2-n

✦ Synopsis

A novel chemo-enzymatic synthesis of argininebased gemini cationic surfactants bis(Args) is reported. These compounds consist of two single N ␣ -acyl-arginine structures connected through the alfa-carboxylic groups of the arginine residues by a ␣,-diaminoalkane spacer chain. N ␣ -Acyl-L-arginine alkyl ester derivatives were the starting building blocks for the synthesis. The best strategy found consisted of two steps. First, the quantitative acylation of one amino group of the spacer by the carboxylic ester of the N ␣ -acyl-arginine took place spontaneously, at the melting point of the ␣,-diaminoalkane, in a solvent-free system. The second step was the papaincatalyzed reaction between another N ␣ -acyl-arginine alkyl ester and the free aliphatic amino group of the derivative formed in the first step. Reactions were carried out in solid-to-solid and solution systems using low-toxic potential solvents. Changes in reaction performance and product yield were studied for the following variables: organic solvent, support for enzyme deposition and substrate concentration. The best yields (70%) were achieved in solid-to-solid systems and in ethanol at a w = 0.07. Bis(Args) analogs of 8, 10 and 12 carbon atoms using 1,3-diaminopropane and 1,3-diamino-2-hydroxypropane as hydrocarbon spacers were prepared at the 6-7 gram level employing the methodology developed. The overall yields which include reaction and purification varied from 51% to 65% of pure (97-98% by HPLC) product.