Conformational analysis of intramolecular bonded amino alcohols

Aaron, Herbert S.; Ferguson, C. P.

doi:10.1016/s0040-4020(01)97140-6

Cited by 22 publications

(8 citation statements)

References 43 publications

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“…Similarly, the conformational equilibrium of the 8a-OH isomer (3) is expressed by °3 = -RT In (3b)/(3a) = °3 -AG°3a (3) and that of the 8/3-OH isomer (4) by AG°4 = -RT In (4b)/(4a) = AG°4b ~AG°4a (4) If the free-energy difference between 3a and 2a, and, respectively, 3b and 2b are now defined by the difference between their syn-axial and equivalent (to a good approximation9) peri interactions (e.g., 0° /( ):, etc. )10 that result from introduction of the substituent OH group, one obtains AG°3a -AG°2a = (AG°OH/(N):)3a " ( 0° /( ):) 3 (5) and AG°3b -°2 = (AG°OH/(N)H)3b -(AG°H/(N)H)2b (6) Similarly, the free-energy difference between 4a and 2a, and 4b and 2b, may be defined by G0 4a -AG°2 a = ( ° /( ) + 2AG°OH/H)4a -( ° /( ) + 2 ° / )23 (7) and AG°4b -AG°2b = ( ° /( ): + 2AG°OH/H)4b -( ° /( ): + 2AG°H/H)2b (8) Subtracting eq 6 from eq 5 and, respectively, eq 8 from eq 7 gives, after canceling common terms and regrouping, (AG°3a -° /( ):) -( ° /( ) -° /( ) ) (9) and {AG°4a ~AG°4b) -(AG°2a " AG°2b) = (AG°OH/(N)H -° /( ) ) -( ° /( ): -° /( ):) (10) If one now adds eq 9 and 10 to get (AG°3a -SG°3b) + ( °4a -AG°4b) and substitutes from eq 2, 3, and 4, one obtains RT In (3b)/(3a) + RT In (4b)/(4a) = -2AG°2 (12)…”

Section: Discussionmentioning

confidence: 99%

Conformational analysis of intramolecular hydrogen-bonded amino alcohols. Determination of the NH/N-electron pair equilibrium and assignment of conformational free energies for interactions in decahydroquinoline and piperidine compounds in a dilute nonpolar medium

Aaron¹,

Ferguson²

1976

J. Am. Chem. Soc.

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Section: Discussionmentioning

confidence: 99%

Conformational analysis of intramolecular hydrogen-bonded amino alcohols. Determination of the NH/N-electron pair equilibrium and assignment of conformational free energies for interactions in decahydroquinoline and piperidine compounds in a dilute nonpolar medium

Aaron¹,

Ferguson²

1976

J. Am. Chem. Soc.

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“…In the spectra of lupinine in solution (in any concentration), apart from the VoH band assigned to the bonded hydroxyl group, a very small band due to a 'free' hydroxyl group exists at about 3600 cm -~. Aaron & Ferguson (1974) explained that the absorption of a 'free' hydroxyl group in lupinine is due to the presence of rotamers.…”

Section: N~cm2oh (I)mentioning

confidence: 98%

“…In the IR spectra of lupinine in the solid state, the absorption band of the hydroxyl group was broad and situated at 3170 cm -1. In chloroform and carbon tetrachloride solutions the same band was still broad and shifted to 3200 and to 3290 cm -~, respectively (Wiewi6rowski, 1977;Aaron & Ferguson, 1974). The stability of the absorption frequency in the course of dilution in GEl 4 was interpreted as the intramolecular hydrogen bonding in lupinine also being present in concentrated solutions.…”

Section: N~cm2ohmentioning

confidence: 99%

Structure of the alkaloid lupinine

Kozioł¹,

Kosturkiewicz²,

Podkowińska³

1978

Acta Crystallogr Sect B

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“…In previously published papers (2)(3)(4) it has been shown that the lupinine rotamer with an intramolecular hydrogen bond predominates in solution, in contrast to the solid state, where only a crystal structure with an anti11 80" lupinine conformation was found (5).…”

Section: Introductionmentioning

confidence: 99%

A comparative study on the dynamics of epimeric 1-hydroxymethylquinolizidines: I. Conformational analysis of monomers and spectroscopic data for solid state, liquid state, and dilute solutions

Kulińska¹,

Wiewiórowski²

1987

Can. J. Chem.

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This paper is dedicated to Dr. 0. E. (Ted) Edwards K. KULIIGSKA and M. WIEWI~ROWSKI. Can. J. Chem. 65, 205 (1987).A systematic comparative study of the conformational dynamics of lupinine and epilupinine, two 1-hydroxymethyl quinolizidine epimers, as a function of phase transition and of their protonation is presented. Lupinine and epilupinine have a trans-quinolizidine configuration and they differ only in the position of the CH20H group. The axial position of this group allows the formation of an intramolecular hydrogen bond OH.. . N in lupinine, in contrast to epilupinine in which this group is in the equatorial position. lntrinsic conformational equilibria for both epimers have been defined. Despite the significant difference in the population of the preferred rotamers of lupinine and epilupinine, both epimers adopt very similar crystal structures, but in all other states and forms, e.g., pure liquids, solutions in inert and polar solvents, and protonated salts, they behave in drastically different ways. On prCsente une Ctude comparative systkmatique des dynamiques conformationnelles de la lupinine et de 1'Cpilupinine (deux Cpimtres de I'hydroxymCthyl-1 quinolizidine) en fonction de la transition de phase ainsi que de leur protonation. La lupinine et 1'Cpilupinine possiident une configuration trans au niveau de la quinolizidine et leur seule diffkrence rCside dans la position du groupement CH20H. Le fait que ce groupement soit en position axiale dans la lupinine lui fournit I'occasion de former des liaisons hydrogtnes intramolCculaires OH.. . N qui ne se foment pas dans le cas de 1'Cpilupinine dans laquelle le groupement se trouve en position Cquatoriale. On a dCfini les Cquilibres conformationnels intrinstques des deux Cpimtres. MalgrC l'existence de differences importantes dans les populations des rotameres prkfCrks dans la lupinine et dans llCpilupinine, chacun des Cpimtres existe dans des structures cristallines assez semblables; toutefois, dans tous les autres Ctats et formes (liquides purs, solutions dans des solvants inertes etpolaires et sous formes de sels protonCs), il se comportent triis diffkremment.[Traduit par la revue] Introduction Two 1-hydroxymethyl quinolizidine epimers, lupinine and epilupinine (Fig. l), have a trans-quinolizidine configuration (trans Q) (1). Rotation of the exocyclic hydroxymethylene group makes three staggered conformers of lupinine and epilupinine (Fig. 2) possible. The axial position of the CH20H group creates good stereochemical conditions for the formation

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Conformational analysis of intramolecular bonded amino alcohols

Cited by 22 publications

References 43 publications

Conformational analysis of intramolecular hydrogen-bonded amino alcohols. Determination of the NH/N-electron pair equilibrium and assignment of conformational free energies for interactions in decahydroquinoline and piperidine compounds in a dilute nonpolar medium

Conformational analysis of intramolecular hydrogen-bonded amino alcohols. Determination of the NH/N-electron pair equilibrium and assignment of conformational free energies for interactions in decahydroquinoline and piperidine compounds in a dilute nonpolar medium

Structure of the alkaloid lupinine

A comparative study on the dynamics of epimeric 1-hydroxymethylquinolizidines: I. Conformational analysis of monomers and spectroscopic data for solid state, liquid state, and dilute solutions

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