Monolayer studies on derivatives of sphinganine and 4t-sphingenine

The pressure-area isotherms (π-A-isotherms) at temperatures between 4° and 47°C of the following derivatives of sphinganine and 4t-sphingenine have been determined.N-palmitoyl-D,L-sphingenine (I), N-palmitoyl-diacetyl-D,L-sphingenine (II), N-acetyl-sphingenine (III), N-acetyl-D,L-erythro-sphinganine (IV), N-acetyl-D,L-threo-sphinganine (V), triacetyl-D,L-erythro-sphinganine (VI), N-acetyl-3-dehydrosphingenine (VII), N-acetyl-3-dehydro-D,L-sphinganine (VIII) and diacetyl-3-dehydro-D,L-sphinganine (IX).The phases of the monolayer films have been discussed. Compounds III, V, VI, VIII and IX form trilayers when their monolayers are compressed beyond the collapse point. The folding to a trilayer is only possible from the liquid expanded state of the monolayer. In addition the formation of trilayer films occurs only when the area of the hydrophilic group exceeds that of the alkane chain of the long chain base.