Design and efficient synthesis of new stable 1α,25-dihydroxy-19-norvitamin D3 analogues containing amide bond

The design and synthesis of new 1α,25-dihydroxy-19-norvitamin D3 analogues 3a–c, which have an amide bond in the molecule instead of the diene, are described. The A-ring moiety was constructed by a (3S,5S)-3,5-dihydroxypiperidine derivative (9, 11, or 13) prepared from -mannose, and a CD-ring carboxylic acid 16 was synthesized from Grundmannʹs ketone. Coupling those parts gave desired 3a–c in good yield. This strategy can be applied in combinatorial chemistry; therefore, those compounds would be applicable as useful tools in the development of new drugs.