Diisophorone and related compounds—II: 1-Alkoxy- and 1-carboxy-diisophorane derivatives

The acid catalysed interaction in dioxan of trialkyl orthoformates with diisophor-2(7)-en-ol-3-one, diisophor-2(7)-en-ol, and their bisnor-homologues, provides the corresponding 1-alkoxy-compounds. Their structure is established by the identity of -methoxydiisophor-2(7)-en-3-one obtained by this method, and by the action of sodium methoxide on 1-chlorodiisophor-2(17)-en-3-one. The latter is regenerated from 1-methoxy(or ethoxy) diisophor-2(7)-en-3-one by the action of stannic chloride-acetyl chloride. Catalytic hydrogenation reduces the 3-keto-function in 1-alkoxydiisophor-2(7)-en-3-ones to a methylene unit; simultaneous removal of the 1-alkoxy-group in the case of the 1-isopropoxy-homologue yields the penultimate parent hydrocarbon of this series, diisophor-2(7)-ene.The combined action of silver sulphate and formic acid in concentrated sulphuric acid on 1-chlorodiisophor-2(7)-en-3-one (and its bisnor-homologue) produces the corresponding 1-carboxylic acids. These are also obtainable by the hydrolysis of the 1-cyano-compound, and are esterifiable by the standard methods.