The cyclization of 3-alkenoic acids with 80% sulphuric acid in the synthesis of γ γ γ γ γ-lactones is always associated with fumes of sulphur dioxide gas and traces of cyclopentenones. The cyclopentenones formed during the reaction give off-odours to the γ γ γ γ γ -lactones formed. Two catalysts, p-toluene sulphonic acid and o-phosphoric acid, with a catalytic amount of perchloric acid, were tried in the lactonization reaction to obtain γ γ γ γ γ -lactones in high yields, and the reaction was free from sulphur dioxide gas fumes and cyclopentenones. A comparison of these catalysts with 80% sulphuric acid in the synthesis of γ γ γ γ γ -lactones was also made.

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Nitriles Q 0520Acetonitrile: A Convenient Reagent for the One-Pot Preparation of Perfumery Nitriles from Aldehydes. -The one-pot procedure is easy to operate and affords nitriles (II) in high yields. -(KANETKAR*, V. R.; ZOPE, D. D.; SUBRAHMANYAM, Y.

We have developed a new synthetic method for the preparation of dihydrojasmone via a five-step synthesis from n-octanol. Oxidation of n-octanol gave n-octanal, which after Mannich reaction and hydrogenation yields 2-methyl octanal. Knoevenagel condensation of this substituted aldehyde gave 4-methyldec-3-enoic acid, which on cyclization furnished dihydrojasmone. The process is simple and may be substituted for the existing process of synthesizing dihydrojasmone by the use of 1,4-dicarbonyl ketones.