organic compounds
R)-6-fluoro-2-[(S)-oxiran-2-yl]chroman
of (aUniversite de Bourgogne, ICMUB–UMR6302, 9 avenue Alain Savary, 21000 Dijon, France, and bCordenPharma-Synkem, 47 rue de Longvic, 21301 Chenove, France
*Correspondence e-mail: yoann.rousselin@u-bourgogne.fr
The title compound, C11H11FO2, is a building block in the synthesis of the active pharmaceutical ingredient DL-nebivolol. The synthesis starting from the enantiomerically pure (R)-6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid resulted in a mixture of two namely (R)-6-fluoro-2-[(S)-oxiran-2-yl]chroman and (R)-6-fluoro-2-[(R)-oxiran-2-yl]chroman. The mixture was separated by but only one stereoisomer crystallized. The X-ray structure analysis revealed that the solid consisted of the R,S isomer. A similar procedure was repeated for (S)-6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid and, in this case, the S,R isomer was produced as a crystalline solid. Thus, all four of the title epoxide were obtained and their was assigned. The crystal studied was refined as an inversion twin.
Keywords: crystal structure; nebivolol; absolute configuration.
CCDC reference: 1409735
1. Related literature
For the synthesis of the enantiopure title product, see: Jas et al. (2011). For pharmacological properties of nebivolol, see: Van Lommen et al. (1990). For a study of related isomers, see: Horiguchi et al. (1997). For the determination of see: Flack (2003).
2. Experimental
2.1. Crystal data
|
Data collection: CrysAlis PRO (Agilent, 2012); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2.
Supporting information
CCDC reference: 1409735
https://doi.org/10.1107/S205698901501261X/gk2636sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901501261X/gk2636Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S205698901501261X/gk2636Isup3.mol
Supporting information file. DOI: https://doi.org/10.1107/S205698901501261X/gk2636Isup4.cml
6-Fluoro-2-(oxiran-2-yl)chroman (Fig. 1) is a building block in the synthesis of dl-nebivolol. This active pharmaceutical ingredient is a highly cardioselective vasodilatory β-receptor blocker used in treatment of hypertension.
The synthesis starts from enantiopure 2-chloro-1-(6-fluoro-chroman-2-yl)-1-ethanol (Jas et al., 2011) that is transformed into enantiopure 6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid. Formation of the epoxide from the carboxylic acid results in a new stereogenic center and a mixture of two
is formed from each enantiopure form: R,S and R,R from the R enantiomer of the acid and S,R and S,S from the S enantiomer. The mixtures of can be separated by and all four in the reactions can be isolated in a pure form (Fig. 2). These epoxide intermediates can be further used in a ring-opening reaction with benzylamine to yield, after catalytic hydrogenation, nebivolol isomer with four chiral center.Of the four stereisomers of the title compound only two form solids, and the remaining two are liquids under normal conditions. X-ray structural analysis from a single crystal of a solid stereoisomer obtained from (R)-6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid revealed that it has R,S configuration at the stereogenic centers (Fig. 1). Crystal data for this stereoisomer are reported in this paper. As expected, X-ray structural analysis of the solid epoxide obtained from the S enantiomer of the acid revealed the S,R configuration at the stereogenic centers.
(R)-6-Fluoro-2-[(S)-oxiran-2-yl]chroman was prepared from enantiopure 2-chloro-1-(6-fluorochroman-2-yl)-1-ethanol according to the procedure reported by Jas et al. (2011).
Crystals suitable for X-ray analysis were obtained in a fraction from
with heptane/ethyl acetate as eluent.Crystal data, data collection and structure
details are summarized in Table 1. All C-bound H atoms were placed at calculated positions and refined as riding on their carriers with C—H = 1.00 Å (methine), 0.99 Å (methylene) or 0.95 Å (aromatic) and with Uiso(H) = 1.2Ueq(C). TWIN/BASF type in SHELXL-2014 (Sheldrick, 2015) was used to determine from using the Flack method (Flack, 2003).6-Fluoro-2-(oxiran-2-yl)chroman (Fig. 1) is a building block in the synthesis of dl-nebivolol. This active pharmaceutical ingredient is a highly cardioselective vasodilatory β-receptor blocker used in treatment of hypertension.
The synthesis starts from enantiopure 2-chloro-1-(6-fluoro-chroman-2-yl)-1-ethanol (Jas et al., 2011) that is transformed into enantiopure 6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid. Formation of the epoxide from the carboxylic acid results in a new stereogenic center and a mixture of two
is formed from each enantiopure form: R,S and R,R from the R enantiomer of the acid and S,R and S,S from the S enantiomer. The mixtures of can be separated by and all four in the reactions can be isolated in a pure form (Fig. 2). These epoxide intermediates can be further used in a ring-opening reaction with benzylamine to yield, after catalytic hydrogenation, nebivolol isomer with four chiral center.Of the four stereisomers of the title compound only two form solids, and the remaining two are liquids under normal conditions. X-ray structural analysis from a single crystal of a solid stereoisomer obtained from (R)-6-fluoro-4-oxo-3,4-dihydro-2H-chromene-2-carboxylic acid revealed that it has R,S configuration at the stereogenic centers (Fig. 1). Crystal data for this stereoisomer are reported in this paper. As expected, X-ray structural analysis of the solid epoxide obtained from the S enantiomer of the acid revealed the S,R configuration at the stereogenic centers.
For the synthesis of the
title product, see: Jas et al. (2011). For pharmacological properties of nebivolol, see: Van Lommen et al. (1990). For a study of related isomers, see: Horiguchi et al. (1997). For the determination of see: Flack (2003).(R)-6-Fluoro-2-[(S)-oxiran-2-yl]chroman was prepared from enantiopure 2-chloro-1-(6-fluorochroman-2-yl)-1-ethanol according to the procedure reported by Jas et al. (2011).
Crystals suitable for X-ray analysis were obtained in a fraction from
with heptane/ethyl acetate as eluent. detailsCrystal data, data collection and structure
details are summarized in Table 1. All C-bound H atoms were placed at calculated positions and refined as riding on their carriers with C—H = 1.00 Å (methine), 0.99 Å (methylene) or 0.95 Å (aromatic) and with Uiso(H) = 1.2Ueq(C). TWIN/BASF type in SHELXL-2014 (Sheldrick, 2015) was used to determine from using the Flack method (Flack, 2003).Data collection: CrysAlis PRO (Agilent, 2012); cell
CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).Fig. 1. View of the molecular structure of the title compound with 50% probability displacement ellipsoids for the non-hydrogen atoms. | |
Fig. 2. Reaction scheme for the synthesis of nebivolol |
C11H11FO2 | F(000) = 204 |
Mr = 194.20 | Dx = 1.435 Mg m−3 |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54184 Å |
a = 9.3742 (3) Å | Cell parameters from 7897 reflections |
b = 4.76845 (12) Å | θ = 4.4–76.3° |
c = 11.0212 (3) Å | µ = 0.94 mm−1 |
β = 114.202 (4)° | T = 100 K |
V = 449.35 (3) Å3 | Needle, colourless |
Z = 2 | 0.05 × 0.05 × 0.02 mm |
Agilent SuperNova Dual Source diffractometer with an Atlas detector | 1847 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 1820 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.050 |
Detector resolution: 5.2474 pixels mm-1 | θmax = 76.5°, θmin = 4.4° |
CCD rotation images, thick slices scans | h = −11→11 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012) | k = −5→5 |
Tmin = 0.64, Tmax = 1 | l = −13→13 |
14207 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.032 | H-atom parameters constrained |
wR(F2) = 0.092 | w = 1/[σ2(Fo2) + (0.0529P)2 + 0.0952P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max < 0.001 |
1847 reflections | Δρmax = 0.20 e Å−3 |
128 parameters | Δρmin = −0.16 e Å−3 |
1 restraint | Absolute structure: crystal refined as an inversion twin (Flack, 2003) |
0 constraints | Absolute structure parameter: 0.0 (2) |
C11H11FO2 | V = 449.35 (3) Å3 |
Mr = 194.20 | Z = 2 |
Monoclinic, P21 | Cu Kα radiation |
a = 9.3742 (3) Å | µ = 0.94 mm−1 |
b = 4.76845 (12) Å | T = 100 K |
c = 11.0212 (3) Å | 0.05 × 0.05 × 0.02 mm |
β = 114.202 (4)° |
Agilent SuperNova Dual Source diffractometer with an Atlas detector | 1847 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012) | 1820 reflections with I > 2σ(I) |
Tmin = 0.64, Tmax = 1 | Rint = 0.050 |
14207 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | H-atom parameters constrained |
wR(F2) = 0.092 | Δρmax = 0.20 e Å−3 |
S = 1.10 | Δρmin = −0.16 e Å−3 |
1847 reflections | Absolute structure: crystal refined as an inversion twin (Flack, 2003) |
128 parameters | Absolute structure parameter: 0.0 (2) |
1 restraint |
Experimental. Analyzes were recorded in the "Pole Chimie Moleculaire", the technological platform for chemical analysis and molecular synthesis (http://www.wpcm.fr) which relies on the Institute of the Molecular Chemistry of University of Burgundy and Welience"TM", a Burgundy University private subsidiary. 1H and 13C NMR measurements were performed in deuterated methanol on Bruker Avance III, recorded at 500 MHz and 125 MHz, respectively. Chemical shifts (δ) and coupling constants are reported respectively in p.p.m. and hertz (Hz). The optical rotation was measured using a UV Visible Perkin Elmer Lambda 12, polarimeter at 589 nm. High-resolution mass spectrometry (HRMS) was performed in ESI a positive mode. The infrared spectrum (IR) was generated by ATR using a Spectrometer Infrared Avatar 370. A scan range of 4000 - 400 cm-1 was used. (2S,2R)-(6-fluoro-2-chromanyl)oxirane: δ(1H, DMSO-d6, 300 MHz, ppm): 1.72 (1H, m); 2.00 (1H, m); 2.74 (2H, m); 2.82 (2H, m); 3.17 (1H, ddd); 3.94 (1H, ddd); 6.77 (1H, dd); 6.92 (2H, m). δ(13C DMSO-d6, 75.47MHz, ppm): 23.4, 23.7, 44.5, 52.3, 75.3, 113.7 (d, 23.2 Hz), 115.2 (d, 22.3 Hz), 117.2 (d, 8.2 Hz), 123.5(d, 7.5 Hz), 150.1 (d, 1.5 Hz), 156.0(d, 234.8 Hz). [α]29D +67.5o (c =1.0 in CHCl3) HRMS (ESI) for C18H21FNO2[M+H]+ m/z = 195.08158, found m/z = 195.08120. IR (cm-1) 3050, 3001, 2951, 1492, 1220 Data CCDC-1407326 contains the enantiomer structure of (S)-6-Fluoro-2-[(R)-oxiran-2-yl]chroman. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refined as a 2-component inversion twin. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.7376 (2) | 0.5622 (5) | 0.50701 (19) | 0.0255 (4) | |
C6 | 0.8296 (2) | 0.4711 (5) | 0.4448 (2) | 0.0254 (4) | |
H6 | 0.9095 | 0.3366 | 0.4870 | 0.030* | |
C5 | 0.8061 (2) | 0.5754 (4) | 0.32005 (19) | 0.0226 (4) | |
C4 | 0.6872 (2) | 0.7732 (4) | 0.26151 (18) | 0.0214 (4) | |
C3 | 0.5962 (2) | 0.8655 (5) | 0.3267 (2) | 0.0255 (4) | |
H3 | 0.5165 | 1.0009 | 0.2857 | 0.031* | |
C2 | 0.6216 (2) | 0.7604 (5) | 0.4512 (2) | 0.0261 (4) | |
H2 | 0.5608 | 0.8231 | 0.4968 | 0.031* | |
C7 | 0.9061 (2) | 0.4801 (4) | 0.24929 (19) | 0.0253 (4) | |
H7A | 0.8759 | 0.2868 | 0.2157 | 0.030* | |
H7B | 1.0172 | 0.4770 | 0.3132 | 0.030* | |
C8 | 0.8876 (2) | 0.6721 (5) | 0.13380 (19) | 0.0240 (4) | |
H8A | 0.9306 | 0.5803 | 0.0755 | 0.029* | |
H8B | 0.9458 | 0.8488 | 0.1678 | 0.029* | |
C9 | 0.7148 (2) | 0.7350 (5) | 0.05528 (19) | 0.0235 (4) | |
H9 | 0.6568 | 0.5539 | 0.0267 | 0.028* | |
C10 | 0.6765 (2) | 0.9185 (5) | −0.0645 (2) | 0.0271 (4) | |
H10 | 0.5651 | 0.9814 | −0.1082 | 0.033* | |
C11 | 0.7573 (2) | 0.8967 (5) | −0.1530 (2) | 0.0286 (5) | |
H11A | 0.8377 | 0.7487 | −0.1340 | 0.034* | |
H11B | 0.6968 | 0.9384 | −0.2485 | 0.034* | |
O1 | 0.65326 (15) | 0.8871 (3) | 0.13795 (13) | 0.0246 (3) | |
O2 | 0.79031 (19) | 1.1254 (4) | −0.06003 (15) | 0.0329 (4) | |
F1 | 0.76157 (14) | 0.4549 (3) | 0.62882 (12) | 0.0333 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0249 (9) | 0.0259 (10) | 0.0236 (9) | −0.0037 (8) | 0.0079 (7) | −0.0017 (8) |
C6 | 0.0206 (8) | 0.0216 (10) | 0.0299 (10) | 0.0010 (7) | 0.0064 (7) | 0.0003 (8) |
C5 | 0.0191 (8) | 0.0202 (10) | 0.0261 (9) | −0.0036 (8) | 0.0070 (7) | −0.0049 (8) |
C4 | 0.0185 (8) | 0.0201 (10) | 0.0238 (9) | −0.0035 (8) | 0.0070 (7) | −0.0029 (8) |
C3 | 0.0214 (9) | 0.0265 (11) | 0.0276 (9) | 0.0035 (7) | 0.0090 (7) | −0.0011 (8) |
C2 | 0.0245 (9) | 0.0274 (11) | 0.0282 (10) | −0.0013 (8) | 0.0128 (8) | −0.0051 (8) |
C7 | 0.0224 (8) | 0.0220 (10) | 0.0303 (9) | 0.0040 (8) | 0.0097 (8) | −0.0013 (8) |
C8 | 0.0180 (8) | 0.0252 (10) | 0.0288 (9) | 0.0010 (7) | 0.0096 (7) | −0.0042 (8) |
C9 | 0.0201 (8) | 0.0252 (11) | 0.0266 (9) | 0.0009 (7) | 0.0109 (7) | −0.0042 (8) |
C10 | 0.0225 (9) | 0.0309 (11) | 0.0273 (9) | 0.0016 (8) | 0.0096 (7) | −0.0015 (9) |
C11 | 0.0272 (9) | 0.0315 (11) | 0.0286 (9) | −0.0033 (9) | 0.0130 (8) | −0.0049 (9) |
O1 | 0.0224 (6) | 0.0275 (8) | 0.0247 (6) | 0.0066 (6) | 0.0106 (5) | 0.0019 (6) |
O2 | 0.0442 (9) | 0.0260 (9) | 0.0323 (7) | −0.0047 (7) | 0.0195 (6) | −0.0041 (6) |
F1 | 0.0343 (6) | 0.0384 (8) | 0.0268 (6) | 0.0030 (6) | 0.0121 (5) | 0.0062 (6) |
C1—C6 | 1.374 (3) | C7—C8 | 1.519 (3) |
C1—C2 | 1.381 (3) | C8—H8A | 0.9900 |
C1—F1 | 1.366 (2) | C8—H8B | 0.9900 |
C6—H6 | 0.9500 | C8—C9 | 1.521 (2) |
C6—C5 | 1.392 (3) | C9—H9 | 1.0000 |
C5—C4 | 1.399 (3) | C9—C10 | 1.500 (3) |
C5—C7 | 1.514 (2) | C9—O1 | 1.456 (2) |
C4—C3 | 1.393 (3) | C10—H10 | 1.0000 |
C4—O1 | 1.377 (2) | C10—C11 | 1.463 (3) |
C3—H3 | 0.9500 | C10—O2 | 1.439 (3) |
C3—C2 | 1.387 (3) | C11—H11A | 0.9900 |
C2—H2 | 0.9500 | C11—H11B | 0.9900 |
C7—H7A | 0.9900 | C11—O2 | 1.440 (3) |
C7—H7B | 0.9900 | ||
C6—C1—C2 | 122.35 (18) | C7—C8—H8B | 109.9 |
F1—C1—C6 | 119.21 (18) | C7—C8—C9 | 108.92 (16) |
F1—C1—C2 | 118.43 (17) | H8A—C8—H8B | 108.3 |
C1—C6—H6 | 119.9 | C9—C8—H8A | 109.9 |
C1—C6—C5 | 120.12 (19) | C9—C8—H8B | 109.9 |
C5—C6—H6 | 119.9 | C8—C9—H9 | 108.9 |
C6—C5—C4 | 118.06 (17) | C10—C9—C8 | 115.48 (16) |
C6—C5—C7 | 121.35 (18) | C10—C9—H9 | 108.9 |
C4—C5—C7 | 120.59 (17) | O1—C9—C8 | 110.18 (15) |
C3—C4—C5 | 121.04 (18) | O1—C9—H9 | 108.9 |
O1—C4—C5 | 122.66 (16) | O1—C9—C10 | 104.31 (16) |
O1—C4—C3 | 116.30 (17) | C9—C10—H10 | 115.1 |
C4—C3—H3 | 119.9 | C11—C10—C9 | 122.88 (19) |
C2—C3—C4 | 120.19 (19) | C11—C10—H10 | 115.1 |
C2—C3—H3 | 119.9 | O2—C10—C9 | 117.62 (16) |
C1—C2—C3 | 118.22 (17) | O2—C10—H10 | 115.1 |
C1—C2—H2 | 120.9 | O2—C10—C11 | 59.51 (13) |
C3—C2—H2 | 120.9 | C10—C11—H11A | 117.8 |
C5—C7—H7A | 109.3 | C10—C11—H11B | 117.8 |
C5—C7—H7B | 109.3 | H11A—C11—H11B | 115.0 |
C5—C7—C8 | 111.62 (16) | O2—C11—C10 | 59.42 (13) |
H7A—C7—H7B | 108.0 | O2—C11—H11A | 117.8 |
C8—C7—H7A | 109.3 | O2—C11—H11B | 117.8 |
C8—C7—H7B | 109.3 | C4—O1—C9 | 115.60 (15) |
C7—C8—H8A | 109.9 | C10—O2—C11 | 61.08 (13) |
C1—C6—C5—C4 | 0.0 (3) | C7—C5—C4—O1 | 1.0 (3) |
C1—C6—C5—C7 | 179.71 (17) | C7—C8—C9—C10 | −178.77 (17) |
C6—C1—C2—C3 | 1.3 (3) | C7—C8—C9—O1 | 63.4 (2) |
C6—C5—C4—C3 | 0.7 (3) | C8—C9—C10—C11 | 38.9 (3) |
C6—C5—C4—O1 | −179.29 (18) | C8—C9—C10—O2 | −31.0 (3) |
C6—C5—C7—C8 | −165.51 (18) | C8—C9—O1—C4 | −49.5 (2) |
C5—C4—C3—C2 | −0.4 (3) | C9—C10—C11—O2 | −105.1 (2) |
C5—C4—O1—C9 | 17.2 (2) | C9—C10—O2—C11 | 113.8 (2) |
C5—C7—C8—C9 | −44.7 (2) | C10—C9—O1—C4 | −174.00 (14) |
C4—C5—C7—C8 | 14.2 (2) | O1—C4—C3—C2 | 179.56 (17) |
C4—C3—C2—C1 | −0.5 (3) | O1—C9—C10—C11 | 159.93 (19) |
C3—C4—O1—C9 | −162.78 (17) | O1—C9—C10—O2 | 90.0 (2) |
C2—C1—C6—C5 | −1.0 (3) | F1—C1—C6—C5 | 179.30 (18) |
C7—C5—C4—C3 | −178.99 (18) | F1—C1—C2—C3 | −179.04 (19) |
Experimental details
Crystal data | |
Chemical formula | C11H11FO2 |
Mr | 194.20 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 100 |
a, b, c (Å) | 9.3742 (3), 4.76845 (12), 11.0212 (3) |
β (°) | 114.202 (4) |
V (Å3) | 449.35 (3) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 0.94 |
Crystal size (mm) | 0.05 × 0.05 × 0.02 |
Data collection | |
Diffractometer | Agilent SuperNova Dual Source diffractometer with an Atlas detector |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2012) |
Tmin, Tmax | 0.64, 1 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14207, 1847, 1820 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.631 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.092, 1.10 |
No. of reflections | 1847 |
No. of parameters | 128 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.20, −0.16 |
Absolute structure | Crystal refined as an inversion twin (Flack, 2003) |
Absolute structure parameter | 0.0 (2) |
Computer programs: CrysAlis PRO (Agilent, 2012), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), OLEX2 (Dolomanov et al., 2009).
Acknowledgements
We thank Ms Marie-Jose Penouilh for the NMR spectra and the ESI mass spectra.
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