Citation: Jing-Xin Zhang, David C. Labaree, Richard B. Hochberg. Synthesis of 11β-ether-17α-ethinyl-3,17β-estradiols with strong ER antagonist activities[J]. Chinese Chemical Letters, ;2014, 25(4): 567-570. doi: 10.1016/j.cclet.2014.01.015 shu

Synthesis of 11β-ether-17α-ethinyl-3,17β-estradiols with strong ER antagonist activities

1.
Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA

Corresponding author: Jing-Xin Zhang, Richard B. Hochberg,
Received Date: 3 August 2013
Available Online: 27 November 2013

Wehave previously found that several families of nonpolar short chain 11β-ethers and esters of estradiol are selective estrogen receptor modulators (SERMs). Surprisingly, the transformation from potent estrogen to anti-estrogen occurs when the 11β-side chain is increased slightly in length from four to five non-hydrogen atoms. To generate strong antagonists for preclinical development, we have synthesized other similar ER ligands with 11β-ethers and with an additional ethinyl group at the 17α-position in order to slow metabolism of the steroidal moiety. Here we report the synthesis and biological activity of two such compounds (11β-i-PrO-propyl and 11β-t-BuO-propyl ethers) with extremely strong antagonist activities.
- Estrogen receptor,
- SERM,
- Antagonist,
- Estradiol
1. [1]
  [1] S.X. Lin, J. Chen, M. Mazumdar, et al., Molecular therapy of breast cancer: progress and future directions, Nat. Rev. Endocrinol. 6 (2010) 485-493.
2. [2]
  [2] J.X. Zhang, D.C. Labaree, G. Mor, et al., Estrogen to antiestrogen with a single methylene group resulting in an unusual steroidal selective estrogen receptor modulator, J. Clin. Endocrinol. Metab. 89 (2004) 3527-3535.
3. [3]
  [3] J.X. Zhang, D.C. Labaree, R.B. Hochberg, Nonpolar and short side chain groups at C-11b of estradiol result in antiestrogens, J. Med. Chem. 48 (2005) 1428-1447.
4. [4]
  [4] S.M. Hyder, C. Chiappetta, G.M. Stancel, Synthetic estrogen 17α-ethinyl estradiol induces pattern of uterine gene expression similar to endogenous estrogen, J. Pharmacol. Exp. Ther. 290 (1990) 740-747.
5. [5]
  [5] J. Salmon, D. Coussediere, C. Cousty, J.P. Raynaud, Pharmaco kinetics and metabolism of moxestrol in animals (rat, dog, monkey), J. Ster. Biochem. 19 (1983) 1223-1234.
6. [6]
  [6] W.C. Still, M. Kahn, A. Mitra, Rapid chromatographic technique for preparative separations with moderate resolution, J. Org. Chem. 43 (1978) 2923-2925.
7. [7]
  [7] D.C. Labaree, J.X. Zhang, H.A. Harris, et al., Synthesis and evaluation of B-, C-, and D-ring-substituted estradiol carboxylic acid esters as locally active estrogens, J. Med. Chem. 46 (2003) 1886-1904.
8. [8]
  [8] R. Tedesco, R. Fiaschi, E. Napolitano, Novel stereoselective synthesis of 11 b-carbon-substituted estradiol derivatives, J. Org. Chem. 60 (1995) 5316-5318.
9. [9]
  [9] H.A. Harris, A.R. Bapat, D.S. Gonder, D.E. Frail, The ligand binding profiles of estrogen receptors alpha and beta are species dependent, Steroids 67 (2002) 379-384.
10. [10]
  [10] B.A. Littlefield,E.Gurpide,L.Markiewicz, et al.,Asimpleandsensitivemicrotiterplate estrogen bioassay based on stimulation of alkaline phosphatase in Ishikawa cells: estrogenic action of delta 5 adrenal steroids, Endocrinology 127 (1990) 2757-2762.
11. [11]
  [11] G.G. Kuiper, B. Carlsson, K. Grandien, et al., Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors alpha and beta, Endocrinology 138 (1997) 863-870.
12. [12]
  [12] Detailed experimental procedures and data for compounds 7a, 8a, 9a, 10a and 10b:3-t-Butyldiphenylsiloxy-11β-(3-isopropoxypropyl)estra-1,3,5(10)-trien- 17β-ol (7a). A solution of 16 mg (0.0432 mmol) of E11-3,i-Prether (6a), t-butyldiphenylsilyl chloride (124 mL, 0.475 mmol), dimethylaminopyridine (10 mg, 0.08 mmol) and triethylamine (200 mL, 1.434 mmol) in CH₂Cl₂ (1 mL) was allowed to stir at r.t. overnight. The reaction was poured into H₂O (50 mL) and extracted with EtOAc (3×50 mL). Combined organic extracts were dried over Na₂SO₄ and concentrated in vacuo giving a clear colorless oil. Purification by flash chromatography on a 2 cm×17 cm column of silica gel using 2:1 hexanes/EtOAc as eluent gave 14.4 mg (54%) of 7a. Data for 7a: TLC, T-1, Rf 0.35.3-t-Butyldiphenylsiloxy- 11β-(3-isopropoxypropyl)estra-1,3,5(10)-trien-17-one (8a). A solution of 7a, NaOAc (1 mg) in CH₂Cl₂ (2 mL) was stirred at r.t. as PCC (8 mg, 0.035 mmol) was added. The reaction was stirred at r.t. for 2 h, poured into H₂O (30 mL) and extracted with EtOAc (3×20 mL). Combined organic extracts were dried over Na₂SO₄ and concentrated in vacuo giving a brown film. Purification by flash chromatography on a 2 17 cm column of silica gel using 4:1 hexanes/EtOAc as eluent gave 10.3 mg (71%) of 8a. Data for 8a: TLC, T-1, Rf 0.55.3-Hydroxy-11β- (3-isopropoxypropyl)estra-1,3,5(10)-trien-17-one (9a). A solution of 1 mol/L tetra-n-butylammonium fluoride in THF (1 mL) was added to 8a (10.3 mg, 0.0169 mmol) and stirred at r.t. for 1.5 h. The reaction was poured into H₂O (70 mL) and extracted with EtOAc (3×20 mL). Combined organic extracts were dried over Na₂SO₄ and concentrated in vacuo giving a clear colorless oil. Purification by flash chromatography on a 2 cm×17 cm column of silica gel using 2:1 hexanes/EtOAc as eluent gave 5 mg (79%) of 9a. Data for 9a: TLC, T-1, Rf 3.75; ¹H NMR (400 MHz, CDCl3): d 1.05 (s, 3H, H-18), 1.11 (d, 3H, J = 6.1 Hz, -CH₃), 1.12 (d, 3H, J = 6.1 Hz, -CH₃), 2.18 (dd, 1H, J = 13.9, 1.6 Hz, H-12b), 2.50-2.55 (m, 1H, H- 11), 2.54 (dd, 1H, J = 18.9, 8.6 Hz, H-16b), 2.60 (dd, 1H, J = 10.9, 4.6 Hz, H-9), 2.72- 2.87 (m, 2H, H-6), 3.28-3.37 (m, 2H, CH₂O), 3.51 (septet, 1H, J = 6.1 Hz, CH(CH₃)₂), 4.70 (br s, 1H, OH), 6.56 (d, 1H, J = 2.7 Hz, H-4), 6.65 (dd, 1H, J = 8.5, 2.7 Hz, H-2), 7.04 (d, 1H, J = 8.5 Hz, H-1).11β-(3-Isopropoxypropyl)estra-17α-ethinyl- 1,3,5(10)-trien-3,17β-diol (10a). A solution of 9a (5 mg) in DMSO (2 mL) was stirred at r.t. as an 18% solution of sodium acetylide in xylene/mineral oil (1 mL) was added over 5 min. The reaction was stirred at r.t. for 3.5 h, poured into saturated aqueous NH4Cl (30 mL) and extracted with EtOAc (3×30 mL). Combined organic extracts were dried over Na₂SO₄ and concentrated in vacuo giving a yellow oil (DMSO was azeotroped off with toluene). Purification by flash chromatography on a 1 cm×17 cm column of silica gel using 1:1 hexanes/EtOAc as eluent gave product contaminated with a nonpolar impurity. Further purification in 6 portions by semiprep HPLC (RP-18) eluting at 3 mL/min with 50/50 CH₃CN/ H₂O (tR, 15 min) followed by crystallization from acetone-petroleum ether gave 3.4 mg (63%) of 10a. Data for 10a: TLC, T-1, 0.35; 1HNMR(400 MHz, CDCl3): d 1.04 (s, 3H, H-18), 1.12 (d, 3H, J = 6.1 Hz, -CH₃), 1.13 (d, 3H, J = 6.1 Hz, -CH₃), 2.51-2.56 (m, 1H, H-11), 2.60 (dd, 1H, J = 10.5, 4.3 Hz, H-9), 2.64 (s, 1H, ethinyl-H), 2.67-2.83 (m, 2H, H-6), 3.32 (t, 2H, J = 6.9 Hz, CH₂O), 3.52 (septet, 1H, J = 6.1 Hz, -CH(CH₃)₂), 6.54 (d, 1H, J = 2.7 Hz, H-4), 6.64 (dd, 1H, J = 8.5, 2.7 Hz, H-2), 7.05 (d, J = 8.5 Hz, H- 1); HPLC system: H-2, tR = 11.16 min; system H-1, tR 15 min, >99% pure.11β-(3- t-Butoxypropyl)estra-17α-ethinyl-1,3,5(10)-trien-3,17β-diol (10b). A solution of 9b (5.3 mg, 0.01378 mmol) inDMSO (2 mL) was stirred at r.t. as an 18% solution of sodium acetylide in xylene/mineral oil (2 mL) was added dropwise over 5 min. The reaction was stirred at r.t. for 3.5 h, poured into saturated aqueous NH4Cl (60 mL) and extracted with EtOAc (2×50 mL). Combined organic extracts were dried over Na₂SO₄ and concentrated in vacuo (DMSO was azeotroped off with toluene). Purification by flash chromatography on a 1×17 cm column of silica gel using 2:1 hexanes/EtOAc as eluent gave 3.7 mg of product which was further purified by semiprep HPLC using an RP-18 column eluting with 50/50 CH₃CN/H₂O giving 2.7 mg 10b. Crystallization from acetone-petroleum ether gave 1.9 mg (33%) of 10b as a white solid. Data for 10b: TLC, T-2, Rf 0.67; ¹H NMR (400 MHz, CDCl3): d 1.04 (s, 3H, CH₃), 1.15 (s, 9H, tBu), 2.52 (m, 1H, H-11), 2.59 (dd, 1H, J = 10.2, 4.9 Hz, H-9), 2.63 (s, 1H, ethinyl-H), 2.67-2.83 (m, 2H, H-6), 3.20-3.29 (m, 2H, CH₂O), 6.54 (d, 1H, J = 2.7 Hz, H-4), 6.64 (dd, 1H, J = 8.6, 2.7 Hz, H-2), 7.05 (d, 1H, J = 8.6 Hz, H-1); HPLC system: H-2, tR = 10.6 min, >92% pure; system: H-1, tR 17.2 min, >99% pure.
1. [1]
  Junjun Huang , Ran Chen , Yajian Huang , Hang Zhang , Anran Zheng , Qing Xiao , Dan Wu , Ruxia Duan , Zhi Zhou , Fei He , Wei Yi . Discovery of an enantiopure N-[2-hydroxy-3-phenyl piperazine propyl]-aromatic carboxamide derivative as highly selective α_1D/1A-adrenoceptor antagonist and homology modelling. Chinese Chemical Letters, 2024, 35(11): 109594-. doi: 10.1016/j.cclet.2024.109594
2. [2]
  Zhibin Ren , Shan Li , Xiaoying Liu , Guanghao Lv , Lei Chen , Jingli Wang , Xingyi Li , Jiaqing Wang . Penetrating efficiency of supramolecular hydrogel eye drops: Electrostatic interaction surpasses ligand-receptor interaction. Chinese Chemical Letters, 2024, 35(11): 109629-. doi: 10.1016/j.cclet.2024.109629
3. [3]
  Kai Wang , Yun Wang , Lihang Wang , Zhuhai Li , Xi Yu , Xuanhe You , Diwei Wu , Yueming Song , Jiancheng Zeng , Zongke Zhou , Shishu Huang , Yunfeng Lin . Therapeutic siRNA targeting CC chemokine receptor 2 loaded with tetrahedral framework nucleic acid alleviates neuropathic pain by regulating microglial polarization. Chinese Chemical Letters, 2025, 36(3): 109868-. doi: 10.1016/j.cclet.2024.109868

Get Citation

PDF

XML

Metrics

PDF Downloads(0)
Abstract views(646)
HTML views(16)

通讯作者: 陈斌, bchen63@163.com

1.
沈阳化工大学材料科学与工程学院沈阳 110142