SYNTHESIS OF (R)- AND (S)-1,2-DIACYLOXYPROPYL-3-ARSONIC ACIDS: OPTICALLY ACTIVE ARSONOLIPIDS

Abstract

Reaction of trisodium arsenite with (R)- and (S)-glycidol affords in good yields the (R)- and (S)-1,2-dihydroxypropyl-3-arsonic acid, the tetrabutylammonium salt of which upon acylation with myristic, palmitic and stearic anhydrides in the presence of pyridine gives, in moderate to low yields, optically active arsonolipids, i.e., (R)- and (S)-1,2-diacyloxypropyl-3-arsonic acids. The thermotropic phase transitions of these arsonolipids are characterized. Results show that the transition temperatures and enthalpies of fusion of the racemates are lower than those of the enantiomers in the powder form presumably because of conglomerate formation. The thermotropic transition characteristics of the aqueous dispersions of the arsonolipids change with the acyl chain lengths, and the overall behaviour is similar to that of the aqueous dispersions of phospholipids.

Key Words:

• Optically active arsonic acids
• acylation
• decomposition
• optically active arsonolipids
• thermotropic phase transitions
• conglomerates