Stereochemistry of isomeric 1,2,5-trimethyl-4-phenylpiperidin-4-ols: a 1H nuclear magnetic resonance study

Casy, A. F.; McErlane, Keith M.

doi:10.1039/p19720000334

Cited by 12 publications

(10 citation statements)

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“…All other carbon shifts in this isomer agree with the configuration t and the preferred conformation (3) for the solution of y-26 in dei~terocl~loroforn~, also assigned on the basis of the p.m.r. resi~lts (12). The same stereochemistry has been shown to be true for y-2b in the solid state (14).…”

Section: Resultsmentioning

confidence: 69%

“…Similar deshielding effects at the 5'-methyl group are apparent in the p.ni.r. spectrum of P-2b (12). The conformation 4 is thus preferred by the P-2b isomer in deuterochloroform solution.…”

Section: Resultsmentioning

confidence: 99%

“…However, this structure does not account for the deshielding effect noted at C-5' in the carbon-13 spectrum or the larger of the two 3J,H coupling constants of the 3-methylene protons (4.5 and 6.0 Hz, CDCl,). (12). The conformation that best accommodates these data is the skew-boat 6 (R = H).…”

Section: Resultsmentioning

confidence: 99%

“…All compounds were prepared and purified by methods previously described (12,13), and were dissolved in deuterochloroform. Tetramethylsilane was used as internal reference.…”

Section: Methodsmentioning

confidence: 99%

“…However, in the present paper we describe a modified stereochemistry for the a-alcohol isomer which enables total reconciliation with earlier p.m.r. studies (12). In addi3The a and 0-isomers 2a are difficult to distinguish by m.p.…”

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Carbon-13 Magnetic Resonance: the Stereochemistry of Pharmacologically Active 1,2,5-Trimethyl-4-phenyl-piperidine Derivatives

Jones¹,

Beeman²,

Casy³

et al. 1973

Can. J. Chem.

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The carbon-13 magnetic resonance spectra of three diastereoisomers of 1,2,5-trimethyl-4-phenylpiperidin-4-01 and their esters and corresponding hydrochlorides have been determined in deuterochloroform and/or dimethylsulfoxide-d,. Chemical shifts observed support the configurations t-2-Me, c-5-Me (y), c-2-Me, r-5-Me (B), and c-2-Me, c-5-Me, r-4-OH (a) for the isomers specified in parentheses. Chair conformations are preferred for y (eq-Ph) and B (ax-Ph) piperidinols while the a-form favors a skew-boat.Evidence is presented for conformational changes in the a -and Dforms after N-protonation. The y-and p-esters have conformations similar to the parent Cpiperidinols while the u-acetate base and hydrochloride prefer chair conformations but with different Cphenyl orientations (base ax-Ph, HCI eq-Ph).On a dttermint dans le deutirochloroforme et/ou dans le sulfoxyde de dimethyle les spectres en rtsonance magnttique du carbone-I3 de trois diasttrtoisomtres du trimtthyl-1,2,5, phtnyl-4 piperidinol-4 ainsi que les esters et les chlorhydrates correspondants. Les dkplacements chimiques observis ont confirm6 les configurations Me-2-t, Me-5-c (y), Me-2-c, Me-5-r (B), et Me-2-c, MeS-c, O H 4 r (u) pour les isomtres indiquts entre les parentheses. Les piptridinols y (Ph-eq) et 0 (Ph-ax) possMent prtfkrentielle ment une conformation du type chaise alors que la forme u possede une conformation du type bateaucroist. Les changements conformationnels dans les formes a et 0 apres protonation de l'azote ont Ctt mis en Cvidence. Les esters y e t B possedent des conformations similaires aux piptridinols-4 parents alors que la base et le chlorhydrate de l'a-acetate prkferent une conformation du type chaise mais avec des orientations difftrentes du groupe phbnyl-4 (base Ph-ax, HCI Ph-eq).[Traduit par le journal]Can. J. Chem.. 51, 1790 (1973) Stereochemical studies on narcotic analgesics have been primarily concerned with the determination of stereostructural-activity relationships in order to provide greater insight into the nature of analgesic-receptor interaction. (1) In previous papers (2-4) we have illustrated the potential of the carbon-13 magnetic resonance techniaue as a tool in the determination of stereochemistry in analgesics. Empirical substituent parameters have been derived from carbon-13 studies of a series of substituted 4-piperidones (2) and 4-phenylpiperidines (3, 4) of pharmacological interest. The parameters have been related to charge polarization (5) or steric (6) effects and correlate reasonably well with the known stereochemistry of the systems. The most valuable of these fundamental parameters is that arising from the steric compression

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…All compounds were prepared and purified by methods previously described (12,13), and were dissolved in deuterochloroform. Tetramethylsilane was used as internal reference.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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