Synthesis of Vitamin D (Calciferol)

Synthesis and radical oxidation of steroidal 1-oxo-5α-alcohols

“…In general, the functionalization at C-1 in steroids remains a difficult challenge, which is associated first and foremost with the preparation of vitamin D metabolites. 13 However, the experience accumulated in this field could not be applied in our case because of the necessity of a 5α-hydroxy group. Using a method employed earlier to prepare a germacrane alcohol, allohedycaryol, solved the problem.…”

“…Fortunately, the problem could be solved by a combination of NMR and CD spectroscopy. Full assignment of signals both in 1 H and 13 C spectra in 5,10-seco steroid 13 was based on the analysis of 2D NMR data. Some signals were partially superimposed in CDCl 3 , and similar spectra were obtained for 13 also in C 6 D 6 ( Table 1).…”

“…CD spectra were taken on a JASCO J-20 spectropolarimeter. 1 H and 13 C NMR spectra were obtained using a Bruker AVANCE 500 (Bruker Biospin) spectrometer in CDCl 3 (if not stated otherwise) operating at 500 MHz for 1 H and 125 MHz for 13 C. Chemical shifts were determined relative to the residual solvent peaks (CHCl 3 , δ = 7.26 for hydrogen atoms, δ = 77 for carbon atoms). Full assignment of 1 H and 13 C chemical shifts of 5,10-seco steroid 13 (Table 1) was achieved with the aid of COSY, HSQC, HMBC, J-resolved, TOCSY, NOESY experiments using the standard Bruker pulse programs.…”

Efficient production of active form of vitamin D3 by microbial conversion

“…1A). However, the yield is only about 1 % [2] . It is commercially manufactured despite such low production efficiency, since the active form of VD 3 shows pharmacological effect at very low dose (0.5~several g/day or less), but the price is extremely high.…”

Reações de contração de anel promovidas por sais de tálio (III)

“…Além disso, a cetona de Grundmann, que é um importante intermediário em diversas sínteses da Vitamina D 3 65,66 , também poderia ser um alvo sintético viável. …”