Side-chain and ring <i>D</i> conformation in cholanic acids

Giglio, E.; Quagliata, C.

doi:10.1107/s056774087500372x

Cited by 27 publications

(11 citation statements)

References 12 publications

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“…With the exceptions of derivatives, compounds 4 and 5 (for which it is gauche), the other 46 crystal structures have trans conformations in the C13-C17-C20-C22 torsion angle. This predominant conformation is a consequence of the torsion angle C13-C17-C20-C21, which, being in the narrow range −53/−60 • , corresponds to a minimum in the energy profile for cholanic acids and related compounds [63]. This minimum is also associated with values of about 60 and −170 • for C17-C20-C22-C23 (the second torsion angle), corresponding to gauche and trans conformations, respectively.…”

Section: Compoundmentioning

confidence: 98%

A Standard Structure for Bile Acids and Derivatives

et al. 2018

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Abstract:The crystal structures of two ester compounds (a monomer in its methyl ester form, with an amino isophthalic group, and a dimer in which the two steroid units are linked by a urea bridge recrystallized from ethyl acetate/methanol) derived from cholic acid are described. Average bond lengths and bond angles from the crystal structures of 26 monomers and four dimers (some of them in several solvents) of bile acids and esters (and derivatives) are used for proposing a standard steroid nucleus. The hydrogen bond network and conformation of the lateral chain are also discussed. This standard structure was used to compare with the structures of both progesterone and cholesterol.

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Section: Compoundmentioning

confidence: 98%

A Standard Structure for Bile Acids and Derivatives

et al. 2018

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“…62 So, only the resolved signals, which have been assigned to Me-18, Me-19 and Me-21 are used to derive the conclusions. 64 So, the change in the proton spectrum [ Fig. Upon gradual addition of IL (up to 11.2 wt%), the Me-18 peak is shifted upfield and the Me-19 peak overlaps with the peak of H-a of [bmim]-BF 4 and the H-a peak is shifted downfield.…”

Section: H Nmr Spectramentioning

confidence: 99%

Modulation of the aggregation properties of sodium deoxycholate in presence of hydrophilic imidazolium based ionic liquid: water dynamics study to probe the structural alteration of the aggregates

Kundu

Banik

Roy

et al. 2015

Phys. Chem. Chem. Phys.

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In this article, we have investigated the effect of a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]-BF4), on the aggregation properties of a biological surfactant, sodium deoxycholate (NaDC), in water. In solution, unlike conventional surfactants it shows stepwise aggregation and the effect of the conventional ionic liquid on the aggregation properties is rather interesting. We have observed concentration dependent dual role of the ionic liquid; at their low concentration, the aggregated structure of NaDC reorganizes itself into an elongated rod like structure. However, the aggregated network is disintegrated into small aggregates upon further addition of ionic liquid. TEM (Transmission Electron Microscopy), SEM (Scanning Electron Microscopy) and FLIM (Fluorescence Lifetime Imaging Microscopy) images also confirmed the structural alteration of NaDC upon varying the concentration of the ionic liquid. The proton NMR data indicate that hydrophobic as well as electrostatic interaction is solely responsible for such structural adaptation of NaDC in the presence of an ionic liquid. The host-guest interaction inside the aggregates is monitored using Coumarin-153 (C-153) and the location of C-153 is probed by varying the excitation wavelength from 375 nm to 440 nm and the two binding sites of the aggregates are affected in a different fashion in the presence of ionic liquid. Excitation in the blue region selects the fluorophores which preferably bind to the buried region of the aggregates, whereas 440 nm excitation corresponds to the guest molecules which are exposed to the solvent molecules. The average solvation time of C-153 is increased in the presence of 1.68 wt% [bmim]-BF4 at λexc = 440 nm i.e. the probe molecules relocate themselves to a more restricted region. However, the average solvation time became 2.6 times faster in the presence of 11.2 wt% [bmim]-BF4, which corresponds to a more polar and exposed region. The time resolved anisotropy measurements and polarity determined by pyrene also supported our results in addition to solvation dynamics measurements. In summary, ionic liquids can modulate the host-guest interaction of bile salt aggregates, which can be used as nanocarriers for drug delivery.

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“…The geometry and the conformation of both side chain and D ring of the two DCA molecules are comparable to each other and to those of the other orthorhombic and tetragonal crystals (Coiro, Giglio, Mazza, Pavel & Pochetti, 1982;Coiro, D'Andrea & Giglio, 1979). The conformation of the side chain is gauche and the D ring approaches half-chair symmetry (Giglio & Quagliata, 1975). The torsion angles are listed in Table 2, according to the convention of Klyne & Prelog (1960), together with the phase angle of pseudorotation A and the maximum angle of torsion ~m (Altona, Geise & Romers, 1968).…”

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confidence: 65%

The structure of the 2/1 'channel' inclusion compound between deoxycholic acid and pinacolone, 2C24H40O4.C6H12O

Coiro¹,

Mazza²,

Pochetti³

et al. 1985

Acta Crystallogr C

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WER.NINCK, BLAIR., MILBURN, ANDO, BLOOR, MOTEVALLI AND HUR.STHOUSE 229 be a minimum, hence defining a least-motion reaction path. The r.m.s, displacement for MSHD is also large so that it does not provide a critical test of the criteria. The crystal structure data for other diacetylenes suggests, however, that the simple criterion of Schmidt is adequate for the assessment of solid-state reactivity of diacetylenes.The larger monomer separation for MSHD relative to TSHD and BSHD [5.774(2) Abstract. Mr-885.32 , orthorhombic, P212121, a= 27.132 (7), b= 13.543 (2), c= 14.228 (2) A, V= 5228 (2) A 3, Z=4, D x=l.12Mgm -3, CuKa, 2= 1.5418/~,, /z=0.6 mm -1, F(000)= 1952, room temperature, R = 0.078 and R w = 0.079 for 3067 independent reflections with I > 1.5 a(/). The crystal packing is very similar to those found in the deoxycholic acid inclusion compounds with norbornadiene and quadricyclane (tetracyclo[2.2.1.02.6.0a,5]heptane), and is characterized by an assembly of antiparallel pleated bilayers of the steroid molecules, which pack together leaving empty spaces occupied by the guest molecules. The cross section of the channels is almost square. The centers of gravity of pinacolone, which assumes in the channels two different orientations related by a pseudo twofold axis, have coordinates approximately equal to those of norbornadiene and quadricyclane. energy (Hautala, Little & Sweet, 1977). Because of the lack of overlap between the electronic absorption spectrum of NBD and the solar radiance spectrum, the direct conversion NBD--,QDC by sunlight is precluded. However, this conversion is still achievable by means of photosensitizers. Since the quantum efficiency of the reaction and the purity of QDC could be improved inside the channels of an inclusion compound, those of the deoxycholic acid (DCA) were chosen for this purpose.The inclusion compounds between DCA and NBD (DCANBD; D'Andrea, Fedeli, Giglio, Mazza & Pavel, 1981) and QDC (DCAQDC; Coiro, Giglio, Mazza & Pavel, 1984) were studied in order to establish whether the DCA host lattices are nearly equal. Since the DCA host lattice does not change, it is possible to foresee that it can easily tolerate the lattice-controlled photoinduced reaction NBD--,QDC, without destroying the crystal structure of the inclusion compound. Furthermore, the structural information gained from the crystal packing of DCANBD and DCAQDC is useful for the choice of

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Side-chain and ring D conformation in cholanic acids

Cited by 27 publications

References 12 publications

A Standard Structure for Bile Acids and Derivatives

A Standard Structure for Bile Acids and Derivatives

Modulation of the aggregation properties of sodium deoxycholate in presence of hydrophilic imidazolium based ionic liquid: water dynamics study to probe the structural alteration of the aggregates

The structure of the 2/1 'channel' inclusion compound between deoxycholic acid and pinacolone, 2C24H40O4.C6H12O

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