The following compounds, i. e., dihydropyran (I), anhydro-baceto-n-butyl alcohol (III), anhydro-7-aceto-n-propyl alcohol (VI), and 3-methyl-2,3-dihydrofuran (VIII) formed cyclic acetals (or ketals) with a secondary alcohol (cholesterol and other compounds). (I), and 6-hydroxy-valeraldehyde (11) reacted with an aromatic thiol compound (2-naphthalenethiol) to give the same mixed acetal. (I), (11), 6-aceto-n-butyl alcohol (IV), 3-hydroxy-6-aceto-n-butyl alcohol (V), and y-aceto-npropyl alcohol (VII) all reacted with a primary alcohol (Prenderol) to produce cyclic acetals and ketals. (I), (II), and (111) also reacted with phenols (diethylstilbestrol and hexestrol) to form the corresponding cyclic acetals and ketals. The stability of the products varied widely. In general, the derivatives of phenols were less stable than the corresponding derivatives of primary and secondary alcohols, and the derivatives containing furanose ring system were less stable than those containing a pyranose ring system.
HE PROCEDURES USED to synthesize some Tcyclic acetals and ketals from the reactions of certain y-and 8-hydroxy aldehydes and ketones, and with stilbestrol, hexestrol, Prenderol@, 2-naphthalenethiol, and some steroids are described. y-and 8-Hydroxy aldehydes and ketones exist in equilibrium with their cyclic hemiacetal and hemiketal forms (1, 2, 3). In the presence of a trace of acid as a catalyst, and
Received January 25, 1956, from the College of Pharmacy, University of Minnesota, Minneapolis. Minn. Abstracted in part from a dissertation submitted to the Graduate School of the University of Minnesota by Robert V. Petersen. in partial fulfillment of the requirements for the degree of Doctor of Philosophy.