N-methylpiperidine

Girgensohnia spp. G. diptera Bge. contains N-methylpiperidine and dipterine, CHH14N2, m.p. 87-8°, [a]D 0° hydrochloride, m.p. 177-8°, picrate, m.p. 189-190°, and picrolonate, m.p. 242-3°, which was later shown to be N-methyltryptamine.i G. oppositiflora Pall, contains N-methylpiperidine and girgensonine, C13H13ON2, m.p. 147-8°, [aJjj 0°. The latter forms a hydrochloride, m.p. 145-8°, and a picrolonate, m.p. 192-4°, and on hydrolysis by alkali yields piperidine, hydrocyanic acid and p-hydroxybenzaldehyde, indicating that it is N-piperidyl-p-hydroxy-phenylacetonitrile, and this has been confirmed by comparison with a synthetic specimen. ( (1) Juraschevski and Stepanova, J. Gen. Chem. Russ., 1939, 9, 2203 Juraschevski, ibid., 1940, 10, 1781. (2) Juraschevski and Stepanova, ibid., 1946, 16, 141). 

Certain amine oxides, especially those derived from six-membered heterocyclic amines e.g. N-methylpiperidine oxide, that cannot go through a planar, five-membered transition state, do not undergo the Cope elimination reaction. 

NH See other ORGANIC BASES 2527. N-Methylpiperidine N-oxide [17206-00-7] / f N+ u c6h13no... 

Glutarimides disubstituted in a or positions were hydrogenolyzed by sodium borohydride in aqueous methanol mainly to disubstituted y-hydroxy-valeramides [7725], but 7V-methylglutarimide was reduced electrolytically in sulfuric acid to a mixture of JV-methylpiperidone (15-68%) and 7V-methylpi-peridine (7-62%) [7727], and by lithium aluminum hydride in ether to N-methylpiperidine in 85% yield [7725]. 

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 (45 X = NH) the a carbon signal is shifted by about 20 p.p.m., to ca. 8 47.7, while in N-methylpiperidine (45 X = Me) it appears at 8 56.7. Quaternization at nitrogen produces further effects similar to replacement of NH by N- alkyl, but simple protonation has only a small effect. N-Acylpiperidines show two distinct a carbon atoms, because of restricted rotation about the amide bond. The chemical shift separation is about 6 p.p.m., and the mean shift is close to that of the unsubstituted amine (45 X = NH). The nitroso compound (45 X = N—NO) is similar, but the shift separation of the two a carbons is somewhat greater (ca. 12 p.p.m.). The j8 and y carbon atoms of piperidines, N- acylpiperidines and piperidinium salts are all upheld of the cyclohexane resonance, by 0-7 p.p.m. 

Pyridinium salts can be reduced more easily than the corresponding pyridines, and yields are higher because the resulting N-methylpiperidines do not poison the catalyst. 

The condensation of the N- methylpiperidine (270) with cyanoacetamide gives the hexahydro-2,7-naphthyridine (271) (67AK(26)489), and the reaction between a-oxoketene S,S- acetals (272) and N- methylcyanoacetamide gives the 2,7-naphthyridine derivatives (273) <78JCS(P1)554>. 

N-Methylpiperidin wurde nach Leuckart aus Piperidin synthe-tesiert, dann destilliert, fiber met. Natiium getrocknet, nochmals destilliert und fiber met. Natrium aufbewahrt. Kp 106,5-107.0° <° 1,4405. 

The reliability of this method depends among other things on the suitability of the model compounds used for the estimation of <5cq and <5ax. Thus for the N-methylpiperidine equilibrium, it was assumed that 57 provided... 

C-NMR Shifts for N-Methylpiperidine,94 1,2-Dimethylhexahydropyridazine,250 1,3-Dimethylhexahydropyrimidines,289 and Chemical Shift Effects Arising from Structural Modification of N-Methylpiperidine96... 

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... 

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