Synthesis of new steroidal 11β-substituted spirolactones

摘要

J. CHEM. SOC. PERKIN TRANS. 1 1990 Synthesis of New Steroidal 1I p-Substituted Spirolactones Hassane Faraj," Michel Claire," Anne Rondot,a Andre Aumeiasb and Gilles Auzou a a U 300 INSERM, Faculte de Pharmacie, 15 Avenue Charles Flahault, 34060, Montpellier Cedex 7, France U 264 CNRS-INSERM, Rue de la Cardonille, BP 5055,34094, Montpellier Cedex A stereoselective synthesis of new 3-oxo-l l J3-(3-alkoxypropyl)-l9-nor-l7~t-pregna-4,9-diene-21,17-carbolactones has been achieved. The purpose of this study was to synthesize new llp- substituted spirolactones by a new approach. A variety of NMR techniques were utilized to make complete assignments of this type of steroids in solution. Steroid receptors are closely related structurally and in their mechanisms of action.Nevertheless, they exhibit large dif- ferences in their specificity for the various steroid hormones, and this has led to the identification of receptor superfamily and subfamilies. Steroidal receptor ligands for each of these subfamilies present typical binding areas such as the 4-ene-3- one A-ring, also present specific planarity of the A-ring for androgen receptor (AR), progestin receptor (PR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR).2 Slight modifications of the steroidal skeleton have been found to induce important affinity and specificity variations for the corresponding receptors. Several A-and D-ring-substituted steroidal 7a-alkoxycarbonyl spirolactones have recently been synthesized with the purpose of increasing the aldosterone antagonistic potency relative to the standard drug spirono- la~tone.~Various 11 P-substitutions of 17a-ethynyl or -prop- ynyl 19-norsteroids with PR and GR specificities could drastic- ally modify their affinity for the receptor^.^ The introduction of bulky unsaturated chains (vinylic, aromatic) in the C-11 position was found to enhance affinities for PR, GR,4 or estrogen receptor (ER).' These observations led to the hypothesis that, in the region corresponding to the 1 1 P-position of the steroids, a pocket exists on the GR, PR, and ER receptors, where hydrophobic interactions are probably involved.On the other hand, it has also been observed6 that electronic interactions could be involved in the same area since 1lP- halogen or 11 P-bulky substituents bearing a heteroatom can also enhance PR- or GR-binding a~tivity.~ Putative pocket characteristics have never been explored for MR.Specific 11 P-substituted MR ligands, agonists, or antagonists are necessary to perform this study. In the present paper, we describe the synthesis of new 1 lp-substituted 19-norsteroids bearing a 17y- lactone moiety, this latter is typical of the MR steroidal antagonist. An 11 P-hydroxypropyl chain was chosen first because it enables us to (1) condense various groups on the hydroxy group (2) make a further study of the influence of length, size, and electronic, geometric, and stereochemical interactions of these new llp-arms with a binding affinity for MR.This hydroxypropyl chain could also be easily linked to fluorescent molecules, enabling further hormone receptor interaction studies to be undertaken. Fluorescent label derivatives have been prepared previously with steroidal mineralocorticoids or antimineralocorticoids substituted in the 7a-position.' Only one paper' describes the synthesis of a few spirolactones bearing 1 1 P-alkyl, -alkenyl or -cycloalkyl substituents. The authors used different methods, but these methods required several steps. The starting material for the preparation of our new 17-spirolactone derivatives was 3,3-(ethy1enedioxy)estra-5( 10),9( 1 1)-dien- 17-one (1) (Scheme 1). Access to final derivatives was carried out by, first, introduction of the 11 0-function, then the 177-lactone. In so doing, we took advantage (1) of avoiding the 3-deacetalization during hydro- lysis of the intermediate 17-hydroxy-21-carbonitrilemoiety (5) and (2) of having ease of access to dienone (6) in a one step from compound (5). Results and Discussion The key intermediates leading to these compounds are 5a,10a- epoxyestr-9( 10)-enes (2).Selectivity in the a-epoxidation was improved by using hydrogen peroxide in the presence of hexafluoroacetone sesquihydrate.' With these reagents, epoxid- ation affords predominantly the 5a,lOa-epoxide, with only I@ 20 of the SP,lOP-conjugated epoxide, easily separated from the parent compound. When epoxide (2) was treated with the corresponding organomagnesium halide in the presence of a catalytic amount of copper(r) chloride,' the required product was obtained.The reaction is regio- and stereo-specific and only affords the 1 lp-substituted product (3). The most obvious approaches to synthesis of the desired y-lactones involve either propargyl alcohol fixation on the 17- keto derivative followed by hydrogenation and Oppenauer oxidation," ethynylation of the same function with lithium acetylide followed by carboxylation and hydrogenation,' ' or the Sturtz reaction.I2 In our case, these methods gave poor yields and often mixtures of undesired products. Steric hindrance, caused by the 11 P-hydroxypropyl and 18-methyl groups, could be a possible explanation for these results. The procedure we followed for this reaction consisted of methyl transfer to the 17-keto function by reaction with dimethyl- sulphonium methylide,' and condensation of acetonitrile on the thus produced spiro-oxirane (4) according to Creger's method.14 This method enabled us, by a one-step procedure, to convert the 17a-cyanoethyl- 17P-hydroxy steroid (9,after alkaline hydrolysis and acidic treatment into the 17y-spirolactone derivative, which was then deacetylized and concomitantly dehydrated to the dienones (6a-d).Compounds (6b) and (6c)had already been synthesized by another method.* Further hydrolysis of the t-butoxypropyl group of compound (6d) by conc. HC1 in dioxane produced compound (7). Etherification of the hydroxypropyl group by dimethyl sulphate and triethylbenzylammonium chloride as a phase-transfer catalyst (ptc) involving 50 aq.sodium hydroxide gave the methyl ether (8) in higher yields than usually obtained by other methods. In this case, purification involved preparative HPLC prior to chromatography on a silica gel column. The structure assignments were firmly established by a variety of NMR techniques. Generally, all compounds were characterized by COSY and 13C spectra. Using the DEPT sequence, multi- plicities of different carbon signals were defined. Where neces- sary, 'H-'H COSY and heterocorrelated I3C-lH experiments were performed on compound (6d).Results are reported in 3046 J. CHEM. SOC. PERKIN TRANS. I 1990 Table 1. The and 'Hchemical-shift assignments for the steroid (6d) (CDCI,; 307 K).6 Atom 'H I li 0// (6)a; R = H b; R=Me C; R=-CH=CH* d; R = -(CHOBu' 0 28 // (8) (7) Scheme 1. Reagents and conditions: i, H,O,-CF,COCF,, 6H,O, CH,CI,-C,H,N, 99: 1, 0 "C; ii, Bu'O(CH,),MgCI, THF, CuCI, -30 OC; iii, NaH-DMSO, 75 "C; Me,SI, -5 "C, THF; iv, LDAMeCN, THF, -40 "C; v, KOH-MeOH, HCI-MeOH, reflux; vi, HCI-Diox, room temp; vii, TEBA-CI, NaOH, CH,Cl,, room temp. Table 1. The molecules synthesized in this study are now being tested for MR and GR affinities and activities. Further details of the relative affinity of these derivatives for the MR receptor and structure-reactivity studies will be published elsewhere. ExperimentalM.p.s were determined on a Bioblock melting point apparatus and were uncorrected.IR spectra were recorded on a Perkin- Elmer 983 spectrophotometer for potassium bromide discs unless otherwise stated. NMR data were recorded on a WM 360 WB spectrometer (Brucker) at 360 MHz for 'H, and 90 MHz for the 13C nuclei. Compounds were dissolved in CDC1, from which the residual signal was taken as reference at tiH7.24 for 1 37.18 2.42 2 26.35 2.83 and 2.60 3 199.35 4 122.48 5.67 5 157.15 6 30.48 2.38 7 29.30 2.50 8 36.33 2.44 9 126.73 10 149.05 11 36.91 3.07 12 34.34 1.75 and 1.58 13 45.76 14 50.48 1.29 15 22.86 1.68 and 1.47 16 35.72 2.29 and 1.83 17 96.24 18 16.89 1.14 19 26.89 1.94 and 1.29 20 31.70 2.35 and 1.91 21 176.39 22 33.19 1.59 23 29.48 1.57 and 1.44 24 61.03 3.28 25 72.05 26, 27, 28 27.51 1.14 'H and tic 77.0 for 13C.In two-dimensional experiments, the 'H-'H COSY spectra was recorded in 512 experiments under standard condition^,'^ and the 'H-' 3C spectra were obtained in 160 experiments according to Bax's sequence.16 Optical rotations on chloroform solutions were measured with a Roussel-Jouan micropolarimeter. All reactions were carried out under argon with dry solvents being used under anhydrous conditions. Column chromatography was carried out with silica gel (Merck 60 A CC). Analytical and small-scale preparative HPLC were carried out on a 25 cm x 4.6 mm i.d. stainless steel column packed with 5p Hypersil (Beckman). Preparative HPLC purification of compound (7) was carried out on a 25 cm x 22.5 mm i.d.stainless steel column packed with 5j.1 Hypersil (S.F.C.C.). A mobile phase of methanol-water (7 :3) was used and detection was at 254 nm on a Gilson Model 111 LC detector. Analytical results were determined for C and H and were within 0.3 of the calculated values. All new compounds described in this Experimental section were homogeneous on TLC. Epoxidation of estra-5( 10),9( 1 1)-diene (1) was carried out by a standard method,' and yielded mainly the 5aYl0a-epoxide (2). Light petroleum refers to the fraction boiling in the range 148-150 "C. 1 1j3-(3-t-ButoxyprOpyl)-3-0~0-19-nor- 17a-pregna-4,9-diene- 21,17-carbolactone (a).-A 1.4M-SOlUtiOn of (3-t-butoxyprop- y1)magnesium chloride (22 ml, 31 mmol) was cooled to -30 "C and a solution of copper(1) chloride (480 mg, 4.9 mmol) in tetrahydrofuran (THF) (20 ml) was added.The reaction mixture was stirred for 0.5 h and then a solution of the pure epoxide (2) (2.9 g, 8.8 mmol) in THF (30 ml) was added dropwise, and the mixture was stirred for 3 h while the temperature rose from -30 to -10 "C. The reaction mixture was poured into cold, saturated aq. ammonium chloride and extracted with AcOEt. The extract was washed successively with saturated brine and water, dried over sodium sulphate, and J. CHEM.SOC. PERKIN TRANS. 1 1990 evaporated to dryness. Chromatography on silica gel with light petroleum-thy1 acetate (7 :3) as eluant yielded 1 1 P-(3-t- butoxypropyl)-3,3-ethylenedioxy-5-hydroxy-19-nor-5a-estr-9-ene-17-one (3)(2.9 g, 74) as a white powder from hexane, m.p.78-80 "C (Found: C, 72.6; H, 9.55. C2205 requires C, 72.6; H, 9.5); aD -214.5" (C 0.5);v,,, 3504 (OH), 1743 (17~- ketone) and 1606 cm-' (CS); tiH 1.00 (3 H, S, 18-H3), 3.25 (2 H, m, OCH2), 3.95 (4 H, m, OCH2CH20) and 4.25 (1 H, s, OH).A suspension of 60 sodium hydride (0.3 g, 7.5 mmol) in mineral oil in dimethyl sulphoxide (DMSO) (14 ml) was stirred and heated at 70 "C for 1 h. The cooled mixture was diluted with THF (20 ml) and further cooled to -5 "C. Next, a solution of trimethylsulphonium iodide (1.4 g, 6.9 mmol) in DMSO (10 ml) was added and the reaction mixture was stirred for 35 min at below 0 "C, followed by treatment with a solution of compound (3) (880 mg, 2 mmol) in THF (8 ml). The mixture was then stirred at 0 "C for 2 h, and then at room temperature for 20 h.The reaction mixture was poured into cold aq. ammonium chloride and extracted with AcOEt. The extract was washed with water, dried over sodium sulphate, and evaporated to dryness. The product, purified by column silica gel chromato- graphy with cyclohexane-AcOEt (4: 1) as eluant, yielded the 17- oxirane (4) (550 mg, 60). This amorphous residue was characterized by IR spectroscopy (absence of 17-c--O at 1742 cm-') and was then used immediately for the next step without further purification. A standard solution of butyl-lithium in hexane (1.6~; 1.7 mi, 2.6 mmol) was added to a solution of diisopropylamine (0.27 g, 2.6 mmol) in anhydrous THF (10 ml) at -30 "C and the mixture was stirred for 35 min.Next a solution of acetonitrile (0.15 ml, 2.6 mmol) in THF (3 ml) was added and the mixture was stirred at -30 to -20 "C for 1 h. A solution of the 17- oxirane (4) (0.4 g, 0.87 mmol) in THF (6 ml) was added dropwise during 10 min and the reaction mixture was stirred at ambient temperature for 20 h, poured into aq. ammonium chloride, and extracted with AcOEt. The extract was washed with water, dried over sodium sulphate and evaporated to dryness. The crude product (0.7 g) was purified by column silica gel chromatography with methylene dichloride-AcOEt (7 :3) as eluant to yield 1 1 ~-(3-t-butoxypropyl)-3,3-ethylenedioxy-5,17~-dih ydrox y-5a-estr-9-ene-21 -carboni trile (5) (350 mg, 80.5), vmax3457 (OH) and 2249 cm-' (CN).A mixture of compound (5) (300 mg, 0.6 mmol), methanol (0.4 ml) and ~M-KOH (0.35 ml) was heated to reflux for 4 h. The cooled mixture was acidified with conc. HCl (0.4 ml) and refluxed for 1.5 h. The solution was diluted with water and extracted with AcOEt. The extract was washed with water, dried over sodium sulphate, and evaporated to dryness to give a crude product (0.26 g). Chromatography on silica gel with CH2C12-AcOEt (4: 1) as eluant yielded 11 p-(3-t-butoxypropyl)- 3-0x0- 19-nor- 17a-pregna-4,9-diene-21,17-carbolactone(6d) (130 mg, 50) (Found: C, 76.2; H, 9.5. C28H4002 requires C, 76.3; H, 9.15);.ID -36.l0(c0.5)asa whitepowderfromdiethylether-pentane, m.p.122-123 "C; v,,, 1772 (y-lactone), 1662 (a$-unsaturated ketone) and 1610 cm-' (CS); 6,1.14 (12 H, m, Bu', 18-H), 3.07 (1 H, m, 11-H) and 5.67 (1 H, s, 4-H). 1 1 p-(3-Hydroxypropyl)-3-oxo- 1 nor- 17a-pregna-4,9-diene- 21,17-carbolactone (7).-Conc. HCl (2.3 ml) was added to a solution of compound (4d)(900 mg, 1.6 mmol) in 1,4-dioxane (6 ml). The reaction mixture was stirred for 1.5 h, then poured onto cold water and extracted with AcOEt. The extract was washed successively with saturated aq. sodium carbonate and water, dried over sodium sulphate, and evaporated to dryness. The crude product was purified by preparative reversed-phase HPLC with a mobile phase of methanol-water (7:3) to yield compound (7) (650 mg, 83) as a major component, separated as a white powder from light petroleum, m.p.157-159 "C (Found: C, 74.65; H, 8.55.C24H3204 requires C, 74.95; H, 8.4); .ID -78.5" (c 0.3); v,,, 3437 (OH), 1771 (y-lactone) and 1656 an-'(u.,p-unsaturated ketone); 8H1.16 (3 H, s, 18-H3), 3.09 (1 H, m, 11-H), 3.63 (2 H, m, CH20) and 5.7 (1 H, s, 4-H). 11j3-(3-Methoxypropyl)-3-oxo-1nor- 17a-pregna-4,g-diene- 2 1,17-carboluctone (!I).-Triethylbenzylammonium chloride (3 mg, 0.01 mmol) and 50 aq. NaOH (30 mg, 0.75 mmol) was added to a solution of compound (7) (40 mg, 0.1 mmol) in methylene dichloride (1.2 ml). Dimethyl sulphate (30 mg, 0.23 mmol) is then added dropwise, with cooling, for 1 h at a rate such that the temperature did not exceed 35°C.The whole mixture was then stirred for 24 h with frequent TLC controls. After addition of methylene dichloride (24 ml) the mixture was finally poured in aq. NH4C1 and the organic phase was separated, washed with water, and dried over Na2S04. Elution with CH2C12-AcOEt (9:l) gave compound (8) with some impurities. By reversed-phase HPLC with a mobile phase of methanol-water (7:3), compound (8) (22.5 mg, 54) was separated as a white powder from pentanediethyl ether (8: 2), m.p. 119-121 "C (Found: C, 75.5; H, 8.45. C25H3404 requires C, 75.3; H, 8.6); a)D -20" (c 0.5);v,,, 1772 (y-lactone) and 1665 cm-' (unsaturated ketone); tiH 1.16 (3 H, s, 18-H3), 3.30 (3 H, s, OMe), 3.33 (2 H, m, OCH2) and 5.70 (1 H, s, 4-H). 3-0x0-19-nor-17a-pregna-4,9-diene-21,17-carbolactone (6a).-Similar treatment of the ketone (1) as described for the reaction (3)-(4) yielded the 17-oxirane (81) (absence of 17-c--O at 1740 cm-').When treated as for reaction (4) --(5), the 17-oxirane steroid afforded the 17a-cyanoethyl-l7~-hydroxy compound (74) purified by chromatography on silica gel with CH2C12-AcOEt (9: 1) as eluant; v,,, 2245 cm-'.Similar treatment as described for reaction (5) (6d) afforded compound (6a)as needles after recrystallization from diethyl ether, m.p. 172-175°C (Found: C, 77.1; H, 8.0. C21H26O3 requires C, 77.3; H, 8.0); .ID -214.5' (c 0.55);v,,, 1765 (y-lactone) and 1655 cm-' (a$-unsaturated ketone); tiH 1.02 (3 H, s, 18-H3) and 5.7 (1 H, s, 4-H). 1 1 p-Methyl-3-0x0- 19-norpregna-4,9-diene-21,17-carbolactone (6b).-Similar treatment of the epoxide (2) as described for reaction (2) __+ (3), but using methylmagnesium bromide, afforded the 11p-methyl intermediate with 10 of the disubstituted 1 1 PJ7a-dimethyl moiety easily separated by chromatography on silica gel with hexane-AcOEt (6 :4) as eluant.The 17-oxirane (75) was obtained as for compound (4) (absence of 17-GO at 1740 cm-') and treated as for reaction (4) -(5) to yield the 17a-cyanoethyl-17P-hydroxysteroid (72), purified by chromatography on silica gel with CH2Cl,-AcOEt (8 :2) as eluant; v,,,(KBr) 2250 cm-' (CN). Similar treatment as described for (6d) afforded compound (6b)as needles after recrystallization from diethyl ether, m.p.208-210 "C (lit.,8 198-201 "C) (Found: C, 77.6; H, 8.3. Calc. for C22H2803: C, 77.1; H, 8.00); .ID -91.8" (C 0.5);v,,, 1722 (y-lactone), 1656 (unsaturated ketone) and 1607 cm-' (CX); GH(CDC13) 1.13 (3 H, s, 18-H3), 1.17 (3 H, d, 11-Me), 3.23 (1 H, m, 11-H) and 5.63 (1 H, s, 4-H). 1 1 P-Vinyl-3-0x0-19-norpregna-4,9-diene-21,17-cavbolactone (6c).-Similar treatment of the epoxide (2) with vinylmagnesium bromide afforded the 1 1 P-vinyl intermediate (7573, with 15 of the 11 p,17a-divinyl moiety, easily separated by chromatography on silica gel with hexane-AcOEt (6:4) as eluant. The 17-oxirane (73) was obtained as for compound (4) (absence of 17-C=0 at 1740 cm-') and treated in the usual way to yield the 172- cyanoethyl- 17P-hydroxy steroid (85), purified by chromato- graphy on silica gel with hexane-AcOEt (7:3) as eluant; v,,, 2247 cm-' (CN).Similar treatment as described for (6d) afforded compound (6c) as a white powder after recrystallization from diethyl ether, m.p. 143-144 "C (lit.,8 133-135 "C) (Found: C, 77.95; H, 7.9. Calc. for C23H2803: c, 78.36; H, 8.02); .ID -30" (c 0.5); vmax1770(y-lactone), 1664(a$-unsaturated ketone), 1630(C=C 11P-vinyl) and 1608 cm-' (C=C); 1.04 (3 H, s, 18-H,), 3.77 (1 H, m, 11-H), 4.75 (1 H, m, J 17.2 Hz, 22-H), 4.95 (1 H, m, J 10.2 Hz, 23-H), 5.70 (1 H, s, 4-H) and 5.82 (1 H, m, J 10.2 and 17.2 Hz, 23-H). Acknowledgements We are very grateful to Mr. A. Ramet of Roussel Uclaf for his generous gift of 3,3-(ethylenedioxy)-estra-5( 10),9(11)-dien-17-one.References 1 R.M. Evans, Science, 1988,240,s. 2 W. L. Duax, J. F. Griffin, C. M. Weeks and Z. Wawrzak, J. Steroid Biochem., 1988,31,481. 3 K. Nickisch, D. Bittler, H. Laurent, W. Losert, Y. Nishino, E. Schillinger and R. Wiechert, J. Med. Chem., 1990,33,509. J. CHEM. SOC. PERKIN TRANS. I 1990 4 G. Teutsch, in Adrenal Steroid Antagonism, ed. M. K. Agarwal, Walter de Gruyter, Berlin, 1984, p. 43. 5 G. Teutsch, T. Ojasso and J. P.Raynaud, J. Steroid Biochem., 1988, 31, 549. 6 F. J. Zelen, Trends Pharrnacol. Sci., 1983,520. 7 G. Auzou, F. Nique and L. Nedelec, Steroids, 1988,51,465. 8 K. Nickisch, K. Annen, H. Laurent, R. Wiechert, S. Beier and W. Elger, GP 3410 880/1985 (Chem. Abstr., 1986,104,662). 9 G. Teutsch, A. Belanger, D. Philibert and C. Tournemine, Steroids, 1982,39,607. 10 K. Nickisch, D. Bittler, H. Laurent, W.Losert, J. Casals-Stenzel,Y. Nishino, E. Schillinger and R. Wiechert, J.Med. Chem., 1987,30,1403. 11 S. Kamata, H. Haga, T. Mitsugi, E. Kondo, W. Nagata, M. Nakamura, K. Miyata, K. Odaguchi, T. Shimizu, T. Kawabata, T. Suzuki, M.Ishabashi and F. Yamada, J. Med. Chem., 1985,28,428. 12 G. Sturtz and J. J. Yaouanc, Synthesis, 1980,289. 13 E. J. Corey and M. Chaykovsky, J.Am. Chem. Soc., 1962,84,867. 14 P. L. Creger, J. Org. Chem., 1972,37, 1907. 15 W. P. Aue, E. Bartholdi and R. R. Emst, J. Chem. Phys., 1976, 64, 2229. 16 A. Bax and G. A. Morris, J.Magn. Reson., 1981,42,501. Paper 0/02301I Received 23rd May 1990 Accepted 13th July 1990