W-Methylpiperidine

W-Methylpiperidine, 52, 127 3-Methyl-3-sulfolene, in Diels-Alder reaction, 50, 48 MODIFIED CLEMMENSEN REDUCTION CHOLESTANE, 53, 86... 

Dipole-dipole repulsions may invalidate the assumption that, e.g., the dipole moment of 4-(p-chlorophenyl)-l-methylpiperidine is the vector sum of that of p-chlorophenylcyclohexane and W-methylpiperidine.93,94 The assumption119 that the iV-methylpiperidine moment is equally inclined to the N-Me and to the two N—C bonds may be invalid.125... 

The existence of a linear correlation between 15N shifts of piperidine derivatives with predominantly axial N-H bonds and those with predominantly equatorial N-U bonds and the 13C shifts of hydrocarbon analogs showed that, whereas 15N chemical shifts of N-methylpiperidines depend on the configuration of the V-substituent, those of W-H-substituted piperidines... 

A nitrogen atom at X results in a variable downfield shift of the a carbons, depending in its extent on what else is attached to the nitrogen. In piperidine (41 X = NH) the a carbon signal is shifted by about 20 ppm, to ca. 8 47.7, while in yV-methylpiperidine (41 X=NMe) it appears at 8 56.7. Quatemization at nitrogen produces further effects similar to replacement of NH by Aralkyl, but simple protonation has only a small effect. W-Acylpiperidines (41, X = NCOR) show two distinct a carbon atoms, because of restricted rotation about the amide bond. The chemical shift separation is about 6 ppm, and the mean shift is close to that of the unsubstituted amine (41 X = NH). The nitroso compound (41 X = N-NO) is similar, but the shift separation of the two a carbons is somewhat greater (ca. 12 ppm). The (3 and y carbon atoms of piperidines, W acyl piperidines and piperidinium salts are all upheld of the cyclohexane resonance, by 0-7 ppm. 

Abbreviations conform to Tarr s nomenclature F, formic acid A, acetic acid fA, trifluoroacetic acid KNm, dimethylformamide mSO, methylsulfoxide MOH, methanol EOH, ethanol MCN, acetonitrile M5KN, N-methyl-pyrrolidone 6N, pyridine N, ammonia ENm, dimethylethylamine M6N, N-methylpiperidine M6NO, N-methylmorpholine E6NO, N-ethylmorpholine ENip, diisopropylethylamine eN, triethylamine fmK, hexafluoroacetone (hydrate) cit, citric acid W, water NaA, sodium acetate eN+, tetraethylammonium MNT, methylthiocarbamyl NT, phenylthiocarbamyl MNGS, methylisothiocyanate ONCS, phenylisothiocyanate NPN-TNdab, N-aminopropyl-N -p-dimethylaminoazobenzene thiourea. 

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]. 

Woycicki, W. Sadowska, K. W. Heats and volumes of mixing in the systems N-methylpiperidine with cyclohexane, methylcyclohexane, benzene, toluene, piperidine and. alpha.-pipecoline Bull. Acad. Pol. ScL, Ser. ScL Chim. 1968,16,531-536... 

Diethyl hepta-l,6-diyne-l,7-dicarboxylate refluxed 3 hrs. with a soln. of excess methylamine in ethanol 2,6-di(ethoxycarbonylmethylene)-l-methylpiperidine. Y 83-90%. F. e. s. W. Parker, R. A. Raphael, and D. I. Wilkinson, Soc. 1959, 2433. N-Heterocyclics from ketenes s. 13, 682... 

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