Synthesis of diosgenin p-nitrobenzoate by Steglich method, its crystal structure and quantum chemical studies

Complete 1H NMR Assignment of Diosgenin Benzoate

“…The remaining vicinal coupling constants J 14,15 α , J 14,15 β , J 15 α ,16 , J 15 α ,16 J 16,17 , and J 17,20 in the cyclopentane D-ring and tetrahydrofuran E-ring followed a Karplus-type relationship and are in accordance with a tendency toward twist and envelope conformations, respectively. 27,30 It is worth mentioning that the vicinal constants of the sterane system are coincident with those found for cholesterol determined by HiFSA. 3…”

“…Inspection of the geminal coupling constant ( 2 J HH ) of methylenes at C-1, C-2, C-4, C-11, C-12, C-23, C-24, and C-26 of 1b showed values between −10.95 and −13.79 Hz, in accordance with A-, C-, and F-ring chair conformations. 27,30 For the B-ring, the 2 J HH of the methylene at C-7 (−17.71 Hz) was 3 Hz larger than the common vicinal coupling according to the torsion angle (˂ 20 o ) adopted for the proximity of a double bond at C-5 and C-6. 31 For CH 2 -15 of the five-membered D-ring, 2 J HH was −12.05 Hz, which is in line with values for some steroids measured by selective indirect J spectroscopy.…”

Synthesis of α,β-unsaturated esters of perfluoropolyalkylethers (PFPAEs) based on hexafluoropropylene oxide units for photopolymerization

“…19 More recent procedures used only a slight excess of the carboxylic acid or the alcohol with a high efficiency of reactivity. [20][21][22] Before working on the long uorinated oligo(HFPO) methylene alcohol, experiments were carried out on hydrogenated or partially uorinated alcohols to determine if the desired product could be obtained. Different alcohols were used as model molecules: methanol, 1-pentanol, 1-octanol and 2,2,3,3,4,4,5,5-octauoro-1-pentanol.…”