Methyl 4-keto-octanoate

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

Later experimental work provided evidence that the 8-carbon polyketoacid intermediate in the synthesis of y-coniceine is derived from octanoic acid since this acid was shown to be readily incorporated into coniine. Further work indicated that 5-keto-octanoic acid and 5-keto-octanal were produced during the biosynthesis of y-coniceine. A transaminase (L-alanine 5-keto-octanal aminotransferase) was obtained from C. maculatum. This transaminase catalyzes the reaction between 5-keto-octanal with L-alanine as the amino group donor to form the piperidine ring and the propyl side chain. Another C. maculatum alkaloid, A-methylconiine, was shown to be produced by another enzyme from the plant a coniine methyltransferase which acts as a transmethylator utilizing 5-adenosyl-L-methionine as a methyl group donor. 

The biological activities of the poison hemlock (Conium maculatum) are due to the content of piperidine alkaloids — coniine (2-propylpiperidine), y-coniceine (2n-propyl-ly-piperidine), conhydrine (2-(l- hydroxypropyl)-piperi-dine), A/-methylc(Miiine (1-methyl-2- propylpiperidine), pseudoconhydrine ((5-hydroxypropyl)-piperidine), conhydrinone ((l-oxo-propyl)-piperidine), W-methylpseudoconhydrine (5-hydroxy-l-methyl-2-propyl-piperidine), and 2-methylpiperidine. The poismiing effect of hemlock supplements by the presence of poly-p-keto acid (2,5,7-tri-oxo-octanoic acid), quercetin, kaempferol, and glycoside dioxymid [4, 12,13, 20, 52, 85, 87]. 

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