Kittaka Atsushi, Hara Hideki, Takano Masashi, Sawada Daisuke, Arai Midori A, Takagi Kenichiro, Chida Takayuki, Harada Yoshifumi, Saito Hiroshi, Takenouchi Kazuya, Ishizuka Seiichi, Hayashi Keiko, Ikushiro Shinichi, Sakaki Toshiyuki, Sugiura Takayuki, Chen Tai C
Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Sagamihara, Kanagawa 229-0195, Japan.
Anticancer Res. 2009 Sep;29(9):3563-9.
The 14-epimer of MART-10, namely 14-epi-MART-10 (14-epi-2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D3) and its 2-epimeric analog (14-epi-MART-11) were efficiently synthesized using the Julia coupling reaction to connect between the C5 and C6 positions (steroid numbering). An A-ring precursor was prepared from (-)-quinic acid as shown in the previous MART-10 synthesis. The novel 14-epi-CD-ring coupling partner with an elongated two carbon unit as a sulfone was synthesized from 14-epi-25-hydroxy Grundmann's ketone in good yield. The subsequent coupling reaction followed by a deprotection step afforded a mixture of 14-epi-MART-10 and 14-epi-MART-11 in 40% yield. To separate 14-epi-MART-10 and 14-epi-MART-11, each primary hydroxyl group was esterified with a pivaloyl group and the resulting pivalates 2alpha and 2beta were separated by high performance liquid chromatography. After the separation, the C2-stereochemistry of each (2alpha or 2beta) was determined by 1H NMR (nuclear magnetic resonance) studies including NOE (nuclear Overhauser effect) experiments. The pivaloyl group was removed under basic conditions to obtain the target molecules of 14-epi-MART-10 and 14-epi-MART-11, respectively. The VDR (vitamin D receptor)-binding affinity, HL-60 (human promyelocytic leukemia) cell differentiation activity, antiproliferative activity in PZ-HPV-7 (immortalized normal prostate) cells and transactivation activity of the osteocalcin promoter in HOS (human osteoblast cell line) cells (serum-free conditions) were investigated. In addition, the effects on bone mineral density (BMD) and the blood and urine calcium concentrations of ovariectomized (OVX) rats were examined. 14-epi-MART-10 has much greater antiproliferative and cell differentiation activities compared to 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3).
利用Julia偶联反应在C5和C6位（甾体编号）之间进行连接，高效合成了MART - 10的14 - 差向异构体，即14 - 表 - MART - 10（14 - 表 - 2α - (3 - 羟丙基)-1α,25 - 二羟基 - 19 - 去甲维生素D3）及其2 - 差向异构体类似物（14 - 表 - MART - 11）。如之前合成MART - 10时所示，由(-)-奎尼酸制备A环前体。以14 - 表 - 25 - 羟基Grundmann酮为原料，高产率合成了带有延长两个碳单元的新型14 - 表 - C - D环偶联伙伴砜。随后的偶联反应及脱保护步骤得到了产率为40%的14 - 表 - MART - 10和14 - 表 - MART - 11混合物。为分离14 - 表 - MART - 10和14 - 表 - MART - 11，将每个伯羟基用新戊酰基酯化，所得新戊酸酯2α和2β通过高效液相色谱分离。分离后，通过包括NOE（核Overhauser效应）实验的1H NMR（核磁共振）研究确定每个（2α或2β）的C2 - 立体化学。在碱性条件下去除新戊酰基，分别得到目标分子14 - 表 - MART - 10和14 - 表 - MART - 11。研究了它们的VDR（维生素D受体）结合亲和力、HL - 60（人早幼粒细胞白血病）细胞分化活性、在PZ - HPV - 7（永生化正常前列腺）细胞中的抗增殖活性以及在HOS（人成骨细胞系）细胞（无血清条件下）中骨钙素启动子的反式激活活性。此外，还检测了对去卵巢（OVX）大鼠骨矿物质密度（BMD）以及血液和尿液钙浓度的影响。与1α,25 - 二羟基维生素D3（1α,25(OH)2D3）相比，14 - 表 - MART - 10具有更强的抗增殖和细胞分化活性。
