Societies and Academies

Abstract

DUBLIN. Royal Irish Academy, June 28.—H. Ryan, J Keane, and B. O'Donoghue: Some derivatives of γ - piperonylidene - methylethylketone. The present communication describes the results of experiments carried out with this substance and some aromatic aldehydes. The starting substance, CH3.CO.C(CH3) = CH.C6H3.O2CH2, was prepared by the condensation of piperonal and methylethylketone in the presence of hydrochloric acid. By the action of piperonal on γ-piperonylidene-methiylethylketone in the presence of alkali, a compound having the formula C20H16O5 was obtained. This dicondensation derivative did not react with a further quantity of piperonal in the presence of alkali, and it was regarded as being 1-methyl-4.5-dipiperonyl-cyclopenten (3)-one (2). On treating this compound with alcoholic hydrochloric acid, it was converted into the isomeric 1-methyl-4.5-dipiperonyl-cyclopenten (4)-one (2). This substance reacted with piperonal in the presence of alkali to form a tricondensation compound C28H20O7. By the action of piperonal on γ-piperonylidene-methylethylketone or on the C20H18O5 body in the presence of hydrochloric acid, the same tricondensation compound C38H30O7, was obtained. This derivative is regarded as being 3-piperonylidene 1-methyl-4.5-dipiperonyl-cyclopenten (4)-one (2). The results obtained in this research are similar to those found by Ryan and Lennon in their investigation on the condensations of aldehydes with methylethylketone.—H. Ryan, J. Keane, and B. O'Donoghue: Some derivatives of α- piperonylidene - methylethylketone. The -results of the interaction of α-piperonylidene-methylethylketone and some aromatic aldehydes are described. By the action of piperonal on the starting substance, a compound having the formula C20H10O5 was obtained. This dicondensation derivative of methylethylketone and piperonal was not identical with either of compounds having the same molecular formula obtained by the action of piperonal on γ-pipe-ronylidene-methylethylketone. The last-mentioned derivatives are regarded as isomeric cyclopentenones. The C20H16O5 body prepared by the action of piperonal on α- piperonylidene - methylethylketone formed a tetrabromide and did not react with a further quantity of piperonal. It is regarded as α-γ-dipiperonylidene-methylethylketone. By the action of piperonal oil α-piperonylidene-methyiethylketone in the presence of hydrochloric acid, a tricondensation compound C28H20O7, was obtained. This body was also prepared by the action of piperonal on γ-piperonylidene-methylethylketone and was proved to be 3-piperonyli-dene-1-methyl 4.5-dipiperonyl-cyclopenten (4)-one (2).—R. K. Boylan: Atmospheric dust and condensation nuclei. As a result of observations made in Dublin between October 1925 and June 1926, using Owens' jet dust counter and Aitken's apparatus, the following average values were obtained: dust particles per c.c. 1580, nuclei per c.c. 23,800. The correlation coefficient between the concentrations of the two bodies was 0.73 + 0.056. It was found, in confirmation of the results of Wigand, that dust particles would not act as centres for cloudy condensation even in the absence of the ordinary nuclei.