摘要:
1 alpha,2 alpha,25 Trihydroxy-19-norvitamin D-3, 1 alpha,2 beta,25-trihydroxy-19-norvitamin D-3, and their alkoxy analogs were efficiently prepared in a convergent synthesis, starting with (-)-quinic acid and a Windaus-Grundmann type ketone. Configurations of the A-ring fragment substituents were determined by H-1,H-1 COSY 2D spectra and H-1 NOE difference spectroscopy. The new analogs exhibited selective activity in stimulating intestinal calcium transport while having little or no activity in mobilizing bone calcium. They also showed HL-60-differentiating activity equal to or 10 times lower than that of 1 alpha,25-dihydroxyvitamin D-3.