The synthesis and properties of a key intermediate for arsonolipids, rac-1,2-dihydroxypropyl-3-arsonic acid and its salts, are described. The mechanism of the Meyer reaction with β-hydroxy alkyl halides is discussed.

A new class of lipids, arsonolipids or rac-1,2-diacyloxypropyl-3-arsonic acids, have been synthesized by acylating tetrabutyl ammonium hydrogen rac-1,2-dihydroxypropyl-3-arsonate with myristic, palmitic and stearic anhydrides in the presence of pyridine. The yields are moderate to low due to decomposition of rac-1,2-dihydroxypropyl-3-arsonic acid and its salts by acylating agents. Acid salts of arsonolipids were prepared by neutralization but neutral salts could not be made.

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.

Benzylarsonic acid is decomposed by palmitoyl chloride. slowly in the absence and rapidly in the presence of pyridine, giving benzyl chloride. Benzylarsonic acid is decomposed by palmitic anhydride in the presence, but not in the absence, of pyridine giving benzyl palmitate and benzyl pyridinium cation.