화학공학소재연구정보센터
Biotechnology and Bioengineering, Vol.70, No.3, 323-331, 2000
Chemo-enzymatic synthesis of arginine-based gemini surfactants
A novel chemo-enzymatic synthesis of arginine-based gemini cationic surfactants bis(Args) is reported. These compounds consist of two single N-alpha-acyl-arginine structures connected through the alfa-carboxylic groups of the arginine residues by a alpha,omega-diaminoalkane spacer chain. N-alpha-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-alpha-acyl-arginine took place spontaneously, at the melting point of the alpha,omega-diaminoalkane, in a solvent-free system. The second step was the papain-catalyzed reaction between another N-alpha-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-hydroxy-propane 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.