Hydrogen bonding. XIX. Intramolecular hydrogen bonding in aliphatic hydroxy ketones

Joris, L.; Schleyer, Paul von Ragué

doi:10.1021/ja01019a016

Cited by 55 publications

(10 citation statements)

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“…The intra‐molecular C = O stretching frequency will increase when there are weaker H‐bonding interactions. It is likely that strong H‐bonding interactions to the alcohols in the crystal structure will cause a decrease in C = O stretch frequency . Peak shifts in the C = O stretching vibration are observed at 1716, 1710, 1684, 1693, 1694 cm −1 for form I, form II, ethanol solvate, propanol solvate and isopropanol solvate, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis, characterization and thermal analysis of ursolic acid solid forms

Zhou

Tong

et al. 2015

Crystal Research and Technology

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This study performed a solid‐state characterization of ursolic acid (UA) crystalline forms, a poorly water‐soluble triterpene with anticancer activity. Two new polymorphs (form I, II), two new solvates (propanol and isopropanol solvates), and a known ethanol solvate were determined and elucidated using a combination of multi‐techniques, including X‐ray single crystal and powder diffraction, Fourier transform infrared spectroscopy (FT‐IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A colorless single crystal of UA was grown from a propanol solution, and its crystalline structure was determined through X‐ray single crystal diffraction. It was determined that the propanol solvate was crystallized in the orthorhombic space group P212121 with unit‐cell parameters a = 7.17200 (8) Å, b = 12.24100 (16) Å, c = 33.8950 (4) Å and Z = 4. The ethanol solvate and propanol solvate were isomorphous crystals. The results of the thermal analysis demonstrate that form I is a meta‐stable form, while form II is a stable form that is monotropically related.

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Section: Resultsmentioning

confidence: 99%

“…The intra-molecular C = O stretching frequency will increase when there are weaker H-bonding interactions. It is likely that strong H-bonding interactions to the alcohols in the crystal structure will cause a decrease in C = O stretch frequency [34].…”

Section: Ft-ir Analysismentioning

confidence: 99%

Synthesis, characterization and thermal analysis of ursolic acid solid forms

Zhou

Tong

et al. 2015

Crystal Research and Technology

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“…The large substituents are more nearly eclipsed in the latter case, as indicated by the relevant dihedral angles; C(6)-C(7)-C(11)-C(12) is 25.9 ° and C(8)-C(7)-C(11)-C (13) In solution, intermolecular hydrogen bonds to carbonyl groups are generally supposed to involve the non-bonding ('n') electrons of the carbonyl group, having bonding directions in the plane of the bonds of the carbonyl carbon atom. A study of intramolecular hydrogen bonding in hydroxyketones (Joris & Schleyer, 1968) strongly suggests that 'n'-type bonding occurs when geometry permits. Evidence for hydrogen bonding directed outside the plane of the carbonyl group was found only when molecular geometry required the C=O..-H angle to be acute.…”

Section: !!I I! I!? !! !!Io Ii'~i !{mentioning

confidence: 99%

The structure and absolute configuration of solstitialin, C₁₅H₂₀O₅

Thiessen¹,

Hope²

1970

Acta Crystallogr Sect B

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The molecular structure of solstitialin, C15H2005, a new, toxic sesquiterpenoid from Centaurea solstitialis L., has been elucidated via its crystal structure. Solstitialin crystallizes in the orthorhombic system with a = 10-007 (4), b = 22.789 (4), c = 5.844 (3)/~, space group P212121 with four molecules in the unit cell. Copper K~ data were gathered by use of a Picker automatic diffractometer. The structure was solved by symbolic addition and tangent formula procedures and refined by Fourier and full-matrix least-squares methods to a final R index of 0.026 (1506 reflections). Estimated standard deviations of the bond lengths not involving hydrogen are 0.002-0.003 A. The absolute configuration was determined by use of the anomalous scattering from oxygen. Solstitialin possesses the guaianolide structure H,, t "and has the absolute configuration shown. The lactone carbonyl group is involved in intermolecular hydrogen bonding directed in a plane about 65 ° from the plane of the lactone group.

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“…spectrum of a pure liquid (melt) film of 1 and 26 on sodium chloride plates. It is apparent from these data that 2a is intramolecularly hydrogen-bonded involving the hydroxyl group as donor and the carbonyl oxygen as acceptor site (7,8), while the isomeric ketols 1 and 2b form intermolecular hydrogen bonds at high concentrations. The possibility of weak C1 .…”

Section: Butanone and Cl~loral Hydratementioning

confidence: 97%

Chloral–ketone condensations in acetic anhydride. Reaction of chloral with butanone, 3-pentanone, cyclohexanone, and 4-methyl-2-pentanone

Kiehlmann¹,

Loo²

1969

Can. J. Chem.

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In the presence of sodium acetate as catalyst, chloral hydrate undergoes a mixed aldol condensation with aliphatic and alicyclic ketones in acetic anhydride as solvent. Contrary to previous literature reports, reaction occurs at both the methyl and the methylene group in cr-position to the carbonyl group of butanone, to give a mixture of I, I, I-trichloro-2-hydroxy-4-hexanone (1) and I, 1 ,I-trichloro-2-hydroxy-3-methyl-4-pentanone (2a and 26, diastereomers). 3-Pentanone, cyclohexanone, and 4-methyl-2-pentanone yield 1,1,1-trichloro-2-hydroxy-3-methyl-4-hexanone (3a and 36, diastereomers), 2-(1-hydroxy-2,2,2-trichloroethyl-)cyclohexanone (4a and 46, diastereomers), and I,l,l-trichloro-2-hydroxy-6-methyl-4-heptanone (5), respectively. Compound 5 is the exclusive product formed from chloral hydrate and 4-methyl-2-pentanone since attack at the methylene group is sterically hindered. The low-melting diastereomers 2a, 3a, and 4a which have not been characterized before, exhibit strong intramolecular hydrogen bonding and have been assigned the threo configuration on the basis of nuclear magnetic resonance and molecular model studies.

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Hydrogen bonding. XIX. Intramolecular hydrogen bonding in aliphatic hydroxy ketones

Cited by 55 publications

References 8 publications

Synthesis, characterization and thermal analysis of ursolic acid solid forms

Synthesis, characterization and thermal analysis of ursolic acid solid forms

The structure and absolute configuration of solstitialin, C₁₅H₂₀O₅

Chloral–ketone condensations in acetic anhydride. Reaction of chloral with butanone, 3-pentanone, cyclohexanone, and 4-methyl-2-pentanone

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Hydrogen bonding. XIX. Intramolecular hydrogen bonding in aliphatic hydroxy ketones

Cited by 55 publications

References 8 publications

Synthesis, characterization and thermal analysis of ursolic acid solid forms

Synthesis, characterization and thermal analysis of ursolic acid solid forms

The structure and absolute configuration of solstitialin, C15H20O5

Chloral–ketone condensations in acetic anhydride. Reaction of chloral with butanone, 3-pentanone, cyclohexanone, and 4-methyl-2-pentanone

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The structure and absolute configuration of solstitialin, C₁₅H₂₀O₅