Das aus dem Chlordifluoracetat (II) in siedendem Diglyme freigesetzte Difluorcarben addiert sich an das Enolacetat (I) zum Addukt (III), dessen Hydrolyse in Gegenwart von Base in wäßrigem tert.‐Butanol ein Gemisch des cis‐ und trans‐Ketons (lV′ liefert.
Bacteriological tests2 have shown that the remarkable activity of the A2-cyclopentenyl group in chaulmoogric acid against the bacillus of tuberculosis in vitro is readily reduced or destroyed by certain changes in this group involving the double bond. One change has been found (addition of two hydroxyl groups) which does not markedly reduce the activity, but on the whole the indications are in favor of allowing the double bond to remain unchanged, in seeking to improve the chaulmoogric acid molecule for medicinal purposes. On the other hand, the superiority of hydnocarpic acid over chaulmoogric acid, as indicated by bacteriological tests, renders desirable the preparation and testing of A2-cyclopentene fatty acids of lower molecular weight.Of these acids one, A2-cyclopentene-acetic acid, was synthesized by J. F. Eykman3 by the malonic ester process, for the purpose of refractometric study. In the present investigation the introduction of two radicals into malonic ester has been applied to the preparation of various 2cyclopentene fatty acids, including bis-A2-cyelopentene-acetic acid. From the nature of the synthesis, the products have the general formula I, in which the cyclopentenyl group is in the alpha position. The synthesis of the -substituted series (II), which includes chaulmoogric acid, has been found more difficult, but an aceto-acetic ester synthesis through the keto acids is now giving us encouraging results, which will be reported in a later paper.
CH=CHEykman condensed sodio-malonic ester in alcoholic solution with chlorocyclopentene. The latter substance, obtained directly from the
A tautomeric equilibrium exists for quinoline-2-thiol and quinoline-2(1H)-thione. Quantum mechanical calculations predict the thione is the major tautomer and this is confirmed by the absorption spectra. The utility of quinolone-2-thiol/quinoline-2(1H)-thione as a chromophore for developing fluorescent sensors is explored. No fluorescence is observed when excited at absorption maxima, however a fluorescence increase is observed when exposed to HNO, a molecule of import as a cardiovascular therapeutic. Alkylated quinoline-2-thiol derivatives are found to be fluorescent and show a reduction in fluorescence when exposed to metals and changes in pH.
In a recent paper2 we have mentioned the desirability, in connection with the study of the treatment of leprosy, of the preparation of compounds similar to chaulmoogric acid, especially those of somewhat lower molecular weights. The compounds described in that paper have the A2-cyclopentenyl group in the alpha position.In order to make an homologous series with Structure I strictly analogous to that of chaulmoogric acid, we have endeavored to find a general method for introducing the A2-cyclopentenyl group in the omega position. The Wurtz synthesis was discarded because preliminary trials gave discouraging results and especially because of the difficulty involved in obtaining the various required omega-halogen substitution products of the fatty acids.Other applicable syntheses lead in general to dicarboxylic acids, keto acids, hydroxy acids8 or similar derivatives. Of the sethe keto derivatives appear to offer the most favorable prospects for transformation into the desired series, thanks to Wolff's method for reducing the ketone group.
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