130782-01-3Relevant academic research and scientific papers
The design and synthesis of new steroidal compounds as potential mimics of taxoids
Roussi, Fanny,Quoc, Anh Ngo,Thoret, Sylviane,Gueritte, Francoise,Guenard, Daniel
, p. 3952 - 3961 (2007/10/03)
Eight new steroidal compounds bearing the phenylisoserine and benzoate side-chains of docetaxel were synthesised as potential mimics of antitumour taxoids. They were readily obtained either from cholic acid or from 4-androstene-3,17-dione by a reductive T
Substituted Methyl 5β-Cholan-24-oates. I - 17O NMR Spectral Characterization
Kolehmainen, Erkki,Kaartinen, Mari,Kauppinen, Reijo,Kotoneva, Jari,Lappalainen, Kari,et al.
, p. 441 - 445 (2007/10/02)
Methyl esters of four common bile acids, 3α-hydroxy-5β-cholan-24-oic (lithocholic) acid, 3α,7α-dihydroxy-5β-cholan-24-oic (chenodeoxycholic) acid, 3α,12α-dihydroxy-5β-cholan-24-oic (deoxycholic) acid and 3α,7α,12α-trihydroxy-5β-cholan-24-oic (cholic) acid, and 14 acetylated, trifluoroacetylated, mesylated and oxo derivatives of methyl 5β-cholan-24-oates were prepared and their 17O NMR spectra recorded.In spite of their relatively high molecular masses and the rigid molecular structure of the steroid skeleton, most of the oxygens included in these structures gave well resolved 17O NMR resonance lines at natural abundance in 0.25-0.5 M acetonitrile solutions at 75 deg C.In agreement with the present 17O NMR results, molecular mechanics calculations revealed that a hydroxy substituent located at the 3α-position clearly differs from the hydroxyls at the 7α- and 12α-positions.This is due to the fact that the 3α-hydroxyl possesing only two γ-carbons at antiperiplanar positions is less shielded than the other hydroxyls influenced also by the shielding effects of γ-gauche carbons.The spectral deconvolution of the overlapping signals of the 7α- and 12α-hydroxyls is based on a computer-aided method or on chemical substitutions.The oxo groups located at the longitudinal (3-oxo) vs. transversal (7- and 12-oxo) axes of the steroid framework show very different quadrupolar relaxation properties and 17O NMR linewidths owing to the strong anisotropy of overall molecular motion.In contrast, the 17O NMR linewidths of all 3α-, 7α- and 12α-hydroxyls are very similar and clearly smaller than those of the corresponding oxo groups, revealing that their quadrupolar relaxtion is merely determined by their internal rotation rather than by the overall molecular motion. - Keywords: NMR 17O NMR 17O chemical shifts 17O relaxation Methyl 5β-cholan-24-oates Methyl esters of bile acids
New Procedures for Selectively Protected Cholic Acid Derivatives. Regioselective Protection of the 12α-OH Group, and t-Butyl Esterfication of the Carboxyl Group
Bonar-Law, Richard P.,Davis, Anthony P.,Sanders, Jeremy K. M.
, p. 2245 - 2250 (2007/10/02)
Effective procedures have been developed for the preparation of various selectively protected cholic acid derivatives.Treatment of cholic acid or methyl cholate with trifluoroacetic anhydride in THF, followed by partial deacylation under acidic conditions, leads to the 12α-trifluoroacetates (10a) and (10m), respectively.Trifluoroacetic anhydride may also be used as a condensing agent in the synthesis of t-butyl cholates.Particularly notable is the preparation of the ester (10b), which incorporates both these developments and is arguably the most efficient method yet for differentiating between positions 7 and 12 in the cholic acid nucleus.
