organic compounds
6-Hydroxy-2,5,7,8-tetramethyl-3,4-dihydro-2H-1-benzopyran-2-carbonitrile, from synchrotron data
aSynchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Biosciences Division, Bldg. 202, Argonne, IL 60439, USA, and bInstitute of Chemistry, University of Białystok, Piłsudskiego 11/4, 15-443 Białystok, Poland
*Correspondence e-mail: kbrzezinski@anl.gov
The 14H17NO2, solved and refined against synchrotron diffraction data, contains one formula unit in an In the crystal, molecules form right-handed helices located at the 21 screw axis parallel to the a-axis direction, generated by O—H⋯N hydrogen bonding between the hydroxy group and carbonitrile group of an adjacent molecule.
of the title compound, CRelated literature
For background to the chemistry of chroman compounds and their applications as antioxidants and anti-inflammatory agents, see Cohen et al. (1989); van Acker et al. (1993); Boscoboinik et al. (1995). For the preparation of from primary see: Campagna et al. (1977).
Experimental
Crystal data
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Refinement
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Data collection: SER-CAT APS beamline software; cell HKL-2000 (Otwinowski & Minor, 1997); data reduction: HKL-2000; program(s) used to solve structure: SHELXD (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and pyMOL (DeLano, 2002); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536811025517/kp2339sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811025517/kp2339Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536811025517/kp2339Isup3.cml
Anhydrous pyridine (26 µL, 0.32 mmol) and trifluoroacetic anhydride (25 µL, 0.18 mmol) were added dropwise to rac-6-hydroxy- 2,5,7,8-tetramethylchroman-2-carboxamide (40 mg, 0.16 mmol) solution in dry THF (2 mL) at 273 K. The reaction mixture was warmed to room temperature and further stirred for 18 h. The reaction mixture was diluted with CHCl3, washed with water and brine. The organic layer was dried over anhydrous Na2SO4, filtered off and concentrated in vacuo. The crude product was purified by flash δ 4.34 (s, 1H), 2.93 (ddd, J = 17.6, 12.3 and 6.6 Hz, 1H), 2.77 (ddd, J = 17.0, 6.2 and 1.7 Hz, 1H), 2.31 (ddd, J = 13.8, 6.6 and 2.0 Hz, 1H), 2.17 (s, 3H), 2.13 (s, 6H), 1.96 (ddd, J = 13.8, 12.3 and 6.2 Hz, 1H), 1.83 (s, 6H); 13C NMR (100 MHz, CDCl3): δ 146.3, 144.1, 122.9, 121.7, 120.0, 118.6, 116.5, 69.8, 32.6, 26.9, 21.2, 12.1, 11.8, 11.3; IR (KBr) νmax/cm-1: 3527, 2930, 2235 (–CN), 1463, 1261; ESI-MS, m/z: 254 [MNa+, 100%]. The crystallization was carried out at room temperature by slow evaporation of the of 3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carbonitrile solution in acetone yielding homochiral crystals (chiral resolution).
(hexane/ethyl acetate 85:15) to give the title compound as a tan solid (15.2 mg, 41% yield). M.p. 423–425 K (from ethyl acetate/hexane v/v 1:2); 1H NMR (400 MHz, CDCl3):The
at C2 has not been established. Hydrogen atoms were constrained to idealised positions with C—H distances fixed at 0.98–0.99 Å and Uiso(H) = 1.5Ueq(C) for methyl and hydroxy hydrogen atoms and 1.2Ueq(C) for methylene ones. The sum of occupancies of alternative positions of disordered atoms of was constrained to unity.Data collection: SER-CAT APS beamline software; cell
HKL-2000 (Otwinowski & Minor, 1997); data reduction: HKL-2000 (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXD (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and pyMOL (DeLano, 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C14H17NO2 | F(000) = 496 |
Mr = 231.29 | Dx = 1.285 Mg m−3 |
Orthorhombic, P212121 | Synchrotron radiation, λ = 0.75000 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 1841 reflections |
a = 5.890 (5) Å | θ = 2.2–30.9° |
b = 10.30 (1) Å | µ = 0.09 mm−1 |
c = 19.710 (19) Å | T = 100 K |
V = 1195.7 (19) Å3 | Needle, colourless |
Z = 4 | 0.1 × 0.03 × 0.01 mm |
MAR 300 CCD diffractometer | 1818 independent reflections |
Radiation source: SER-CAT 22-ID synchrotron beamline APS, USA | 1815 reflections with I > 2σ(I) |
Si111 double crystal monochromator | Rint = 0.031 |
ω scans | θmax = 30.9°, θmin = 2.2° |
Absorption correction: multi-scan (SCALEPACK; Otwinowski et al., 2003) | h = 0→8 |
Tmin = 0.991, Tmax = 0.999 | k = 0→14 |
15411 measured reflections | l = 0→26 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.032 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.089 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0505P)2 + 0.297P] where P = (Fo2 + 2Fc2)/3 |
1818 reflections | (Δ/σ)max < 0.001 |
158 parameters | Δρmax = 0.27 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C14H17NO2 | V = 1195.7 (19) Å3 |
Mr = 231.29 | Z = 4 |
Orthorhombic, P212121 | Synchrotron radiation, λ = 0.75000 Å |
a = 5.890 (5) Å | µ = 0.09 mm−1 |
b = 10.30 (1) Å | T = 100 K |
c = 19.710 (19) Å | 0.1 × 0.03 × 0.01 mm |
MAR 300 CCD diffractometer | 1818 independent reflections |
Absorption correction: multi-scan (SCALEPACK; Otwinowski et al., 2003) | 1815 reflections with I > 2σ(I) |
Tmin = 0.991, Tmax = 0.999 | Rint = 0.031 |
15411 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | 0 restraints |
wR(F2) = 0.089 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.27 e Å−3 |
1818 reflections | Δρmin = −0.20 e Å−3 |
158 parameters |
Experimental. The crystal was mounted with vaseline on a pin-attached capillary. Upon mounting, the crystal was quenched to 100 K in a nitrogen-gas stream supplied by an Oxford Cryo-Jet. Diffraction data were measured at the station 22-ID of the APS synchrotron by rotation method. |
Geometry. All e.s.d.'s 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. Refinement of F2 against all reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.64100 (17) | 0.44132 (9) | 0.20022 (4) | 0.0181 (2) | |
C2 | 0.5481 (2) | 0.32600 (13) | 0.22950 (6) | 0.0185 (3) | |
C3 | 0.2980 (2) | 0.31287 (15) | 0.21136 (6) | 0.0216 (3) | |
H3A | 0.2131 | 0.3877 | 0.2301 | 0.026* | |
H3B | 0.2363 | 0.2328 | 0.2322 | 0.026* | |
C4 | 0.2641 (2) | 0.30738 (13) | 0.13455 (6) | 0.0189 (2) | |
H4A | 0.2914 | 0.2176 | 0.1186 | 0.023* | |
H4B | 0.1049 | 0.3302 | 0.1237 | 0.023* | |
C5 | 0.3920 (2) | 0.42209 (11) | 0.02739 (6) | 0.0139 (2) | |
C6 | 0.5435 (2) | 0.50415 (11) | −0.00586 (6) | 0.0139 (2) | |
C7 | 0.7196 (2) | 0.56738 (11) | 0.02858 (6) | 0.0146 (2) | |
C8 | 0.7490 (2) | 0.54480 (11) | 0.09804 (6) | 0.0143 (2) | |
C9 | 0.6003 (2) | 0.45959 (12) | 0.13083 (5) | 0.0141 (2) | |
C10 | 0.4216 (2) | 0.39890 (11) | 0.09736 (6) | 0.0141 (2) | |
C11 | 0.5889 (3) | 0.33520 (14) | 0.30557 (6) | 0.0246 (3) | |
H11A | 0.5030 | 0.4086 | 0.3241 | 0.037* | |
H11B | 0.7511 | 0.3482 | 0.3142 | 0.037* | |
H11C | 0.5387 | 0.2547 | 0.3274 | 0.037* | |
C12 | 0.6795 (2) | 0.21322 (13) | 0.20181 (6) | 0.0190 (3) | |
N13 | 0.7821 (2) | 0.12765 (12) | 0.18050 (6) | 0.0254 (3) | |
C14 | 0.2015 (2) | 0.35690 (13) | −0.01042 (6) | 0.0205 (3) | |
H14A | 0.0587 | 0.3702 | 0.0141 | 0.031* | 0.66 (2) |
H14B | 0.2327 | 0.2637 | −0.0140 | 0.031* | 0.66 (2) |
H14C | 0.1891 | 0.3944 | −0.0560 | 0.031* | 0.66 (2) |
H14D | 0.2646 | 0.2943 | −0.0428 | 0.031* | 0.34 (2) |
H14E | 0.1131 | 0.4224 | −0.0349 | 0.031* | 0.34 (2) |
H14F | 0.1028 | 0.3115 | 0.0218 | 0.031* | 0.34 (2) |
O15 | 0.52747 (19) | 0.52971 (9) | −0.07450 (4) | 0.0209 (2) | |
H15 | 0.4404 | 0.4753 | −0.0927 | 0.031* | |
C16 | 0.8761 (2) | 0.65795 (13) | −0.00891 (7) | 0.0212 (3) | |
H16A | 0.8337 | 0.6602 | −0.0570 | 0.032* | 0.68 (2) |
H16B | 1.0328 | 0.6272 | −0.0045 | 0.032* | 0.68 (2) |
H16C | 0.8635 | 0.7454 | 0.0103 | 0.032* | 0.68 (2) |
H16D | 0.7888 | 0.7077 | −0.0423 | 0.032* | 0.32 (2) |
H16E | 0.9937 | 0.6075 | −0.0322 | 0.032* | 0.32 (2) |
H16F | 0.9475 | 0.7177 | 0.0234 | 0.032* | 0.32 (2) |
C15 | 0.9388 (2) | 0.61130 (12) | 0.13588 (6) | 0.0189 (2) | |
H17A | 0.9342 | 0.5857 | 0.1837 | 0.028* | 0.85 (3) |
H17B | 0.9205 | 0.7056 | 0.1323 | 0.028* | 0.85 (3) |
H17C | 1.0849 | 0.5858 | 0.1162 | 0.028* | 0.85 (3) |
H17D | 0.9953 | 0.5538 | 0.1717 | 0.028* | 0.15 (3) |
H17E | 0.8819 | 0.6918 | 0.1562 | 0.028* | 0.15 (3) |
H17F | 1.0624 | 0.6315 | 0.1043 | 0.028* | 0.15 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0230 (4) | 0.0199 (4) | 0.0114 (4) | −0.0028 (4) | −0.0020 (4) | 0.0008 (3) |
C2 | 0.0221 (6) | 0.0208 (6) | 0.0125 (5) | 0.0001 (5) | 0.0020 (4) | 0.0019 (4) |
C3 | 0.0197 (6) | 0.0291 (6) | 0.0161 (5) | −0.0006 (6) | 0.0032 (5) | 0.0042 (5) |
C4 | 0.0177 (5) | 0.0226 (6) | 0.0164 (5) | −0.0046 (5) | 0.0003 (5) | 0.0033 (4) |
C5 | 0.0156 (5) | 0.0128 (5) | 0.0134 (5) | 0.0006 (4) | −0.0004 (4) | −0.0012 (4) |
C6 | 0.0186 (5) | 0.0121 (5) | 0.0112 (5) | 0.0014 (4) | 0.0005 (4) | 0.0001 (4) |
C7 | 0.0166 (6) | 0.0119 (5) | 0.0154 (5) | 0.0001 (4) | 0.0022 (4) | 0.0003 (4) |
C8 | 0.0142 (5) | 0.0135 (5) | 0.0154 (5) | 0.0004 (4) | −0.0001 (4) | −0.0031 (4) |
C9 | 0.0165 (5) | 0.0148 (5) | 0.0109 (4) | 0.0018 (5) | −0.0001 (4) | −0.0006 (4) |
C10 | 0.0145 (5) | 0.0144 (5) | 0.0133 (5) | 0.0002 (4) | 0.0011 (4) | 0.0006 (4) |
C11 | 0.0305 (7) | 0.0306 (7) | 0.0128 (5) | 0.0027 (6) | 0.0004 (5) | 0.0017 (5) |
C12 | 0.0217 (6) | 0.0217 (6) | 0.0136 (5) | −0.0018 (5) | 0.0003 (5) | 0.0024 (4) |
N13 | 0.0292 (6) | 0.0258 (6) | 0.0212 (5) | 0.0014 (5) | 0.0015 (5) | 0.0008 (4) |
C14 | 0.0210 (6) | 0.0218 (6) | 0.0187 (5) | −0.0054 (5) | −0.0039 (5) | −0.0012 (5) |
O15 | 0.0296 (5) | 0.0211 (4) | 0.0119 (4) | −0.0058 (4) | −0.0021 (4) | 0.0021 (3) |
C16 | 0.0224 (6) | 0.0187 (5) | 0.0224 (5) | −0.0052 (5) | 0.0034 (5) | 0.0030 (5) |
C15 | 0.0172 (5) | 0.0191 (5) | 0.0205 (5) | −0.0019 (5) | −0.0023 (5) | −0.0037 (4) |
O1—C9 | 1.4011 (18) | C11—H11B | 0.9800 |
O1—C2 | 1.4296 (18) | C11—H11C | 0.9800 |
C2—C12 | 1.499 (2) | C12—N13 | 1.148 (2) |
C2—C11 | 1.521 (2) | C14—H14A | 0.9800 |
C2—C3 | 1.522 (2) | C14—H14B | 0.9800 |
C3—C4 | 1.528 (2) | C14—H14C | 0.9800 |
C3—H3A | 0.9900 | C14—H14D | 0.9800 |
C3—H3B | 0.9900 | C14—H14E | 0.9800 |
C4—C10 | 1.5121 (18) | C14—H14F | 0.9800 |
C4—H4A | 0.9900 | O15—H15 | 0.8400 |
C4—H4B | 0.9900 | C16—H16A | 0.9800 |
C5—C6 | 1.3928 (18) | C16—H16B | 0.9800 |
C5—C10 | 1.4103 (19) | C16—H16C | 0.9800 |
C5—C14 | 1.5050 (19) | C16—H16D | 0.9800 |
C6—O15 | 1.3815 (18) | C16—H16E | 0.9800 |
C6—C7 | 1.4006 (18) | C16—H16F | 0.9800 |
C7—C8 | 1.400 (2) | C15—H17A | 0.9800 |
C7—C16 | 1.5051 (19) | C15—H17B | 0.9800 |
C8—C9 | 1.3981 (18) | C15—H17C | 0.9800 |
C8—C15 | 1.5080 (19) | C15—H17D | 0.9800 |
C9—C10 | 1.3909 (18) | C15—H17E | 0.9800 |
C11—H11A | 0.9800 | C15—H17F | 0.9800 |
C9—O1—C2 | 116.12 (10) | C5—C14—H14E | 109.4 |
O1—C2—C12 | 107.40 (12) | H14A—C14—H14E | 72.0 |
O1—C2—C11 | 106.61 (11) | H14B—C14—H14E | 137.6 |
C12—C2—C11 | 109.00 (11) | H14C—C14—H14E | 40.3 |
O1—C2—C3 | 110.46 (11) | H14D—C14—H14E | 109.5 |
C12—C2—C3 | 110.22 (12) | C5—C14—H14F | 109.5 |
C11—C2—C3 | 112.95 (11) | H14A—C14—H14F | 40.3 |
C2—C3—C4 | 111.25 (11) | H14B—C14—H14F | 72.0 |
C2—C3—H3A | 109.4 | H14C—C14—H14F | 137.6 |
C4—C3—H3A | 109.4 | H14D—C14—H14F | 109.5 |
C2—C3—H3B | 109.4 | H14E—C14—H14F | 109.5 |
C4—C3—H3B | 109.4 | C6—O15—H15 | 109.5 |
H3A—C3—H3B | 108.0 | C7—C16—H16A | 109.5 |
C10—C4—C3 | 112.16 (11) | C7—C16—H16B | 109.5 |
C10—C4—H4A | 109.2 | H16A—C16—H16B | 109.5 |
C3—C4—H4A | 109.2 | C7—C16—H16C | 109.5 |
C10—C4—H4B | 109.2 | H16A—C16—H16C | 109.5 |
C3—C4—H4B | 109.2 | H16B—C16—H16C | 109.5 |
H4A—C4—H4B | 107.9 | C7—C16—H16D | 109.4 |
C6—C5—C10 | 118.93 (11) | H16A—C16—H16D | 37.3 |
C6—C5—C14 | 121.01 (12) | H16B—C16—H16D | 136.3 |
C10—C5—C14 | 120.05 (11) | H16C—C16—H16D | 75.0 |
O15—C6—C5 | 122.20 (11) | C7—C16—H16E | 109.5 |
O15—C6—C7 | 115.88 (11) | H16A—C16—H16E | 74.9 |
C5—C6—C7 | 121.92 (12) | H16B—C16—H16E | 37.3 |
C8—C7—C6 | 119.24 (11) | H16C—C16—H16E | 136.2 |
C8—C7—C16 | 120.50 (12) | H16D—C16—H16E | 109.5 |
C6—C7—C16 | 120.26 (12) | C7—C16—H16F | 109.5 |
C7—C8—C9 | 118.62 (11) | H16A—C16—H16F | 136.2 |
C7—C8—C15 | 120.00 (11) | H16B—C16—H16F | 75.0 |
C9—C8—C15 | 121.38 (12) | H16C—C16—H16F | 37.3 |
C10—C9—C8 | 122.48 (12) | H16D—C16—H16F | 109.5 |
C10—C9—O1 | 122.14 (11) | H16E—C16—H16F | 109.5 |
C8—C9—O1 | 115.37 (11) | C8—C15—H17A | 109.5 |
C9—C10—C5 | 118.77 (11) | C8—C15—H17B | 109.5 |
C9—C10—C4 | 120.97 (11) | H17A—C15—H17B | 109.5 |
C5—C10—C4 | 120.26 (11) | C8—C15—H17C | 109.5 |
C2—C11—H11A | 109.5 | H17A—C15—H17C | 109.5 |
C2—C11—H11B | 109.5 | H17B—C15—H17C | 109.5 |
H11A—C11—H11B | 109.5 | C8—C15—H17D | 109.5 |
C2—C11—H11C | 109.5 | H17A—C15—H17D | 32.1 |
H11A—C11—H11C | 109.5 | H17B—C15—H17D | 133.5 |
H11B—C11—H11C | 109.5 | H17C—C15—H17D | 79.9 |
N13—C12—C2 | 179.29 (15) | C8—C15—H17E | 109.5 |
C5—C14—H14A | 109.5 | H17A—C15—H17E | 79.9 |
C5—C14—H14B | 109.5 | H17B—C15—H17E | 32.1 |
H14A—C14—H14B | 109.5 | H17C—C15—H17E | 133.5 |
C5—C14—H14C | 109.5 | H17D—C15—H17E | 109.5 |
H14A—C14—H14C | 109.5 | C8—C15—H17F | 109.5 |
H14B—C14—H14C | 109.5 | H17A—C15—H17F | 133.5 |
C5—C14—H14D | 109.5 | H17B—C15—H17F | 79.9 |
H14A—C14—H14D | 137.6 | H17C—C15—H17F | 32.1 |
H14B—C14—H14D | 40.3 | H17D—C15—H17F | 109.5 |
H14C—C14—H14D | 72.0 | H17E—C15—H17F | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
O15—H15···N13i | 0.84 | 2.23 | 3.013 (2) | 155 |
Symmetry code: (i) x−1/2, −y+1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C14H17NO2 |
Mr | 231.29 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 100 |
a, b, c (Å) | 5.890 (5), 10.30 (1), 19.710 (19) |
V (Å3) | 1195.7 (19) |
Z | 4 |
Radiation type | Synchrotron, λ = 0.75000 Å |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.1 × 0.03 × 0.01 |
Data collection | |
Diffractometer | MAR 300 CCD diffractometer |
Absorption correction | Multi-scan (SCALEPACK; Otwinowski et al., 2003) |
Tmin, Tmax | 0.991, 0.999 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15411, 1818, 1815 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.686 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.089, 1.00 |
No. of reflections | 1818 |
No. of parameters | 158 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.20 |
Computer programs: SER-CAT APS beamline software, HKL-2000 (Otwinowski & Minor, 1997), SHELXD (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and pyMOL (DeLano, 2002).
D—H···A | D—H | H···A | D···A | D—H···A |
O15—H15···N13i | 0.84 | 2.23 | 3.013 (2) | 155 |
Symmetry code: (i) x−1/2, −y+1/2, −z. |
Acknowledgements
This work was supported in part by the Intramural Research Program of the NIH, National Cancer Institute, Center for Cancer Research. X-ray data were collected at Southeast Regional Collaborative Access Team (SER-CAT) 22-ID beamline at the Advanced Photon Source, Argonne National Laboratory. Use of the APS was supported by the US Department of Energy under contract No. W-31–109-Eng-38.
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2-Substituded chromans (3,4-dihydro-2H-1-benzopyrans) are an important class of compounds possessing significant biological properties (Cohen et al., 1989). The title compound is potentially more active as an antioxidant than 6-hydroxy-2,2,5,7,8-pentamethylchroman, the model compound of α-tocopherol (Van Acker et al., 1993). Carbonitrile derivatives appear to inhibit smooth muscle cell proliferation by the non-antioxidant mechanism (Boscoboinik et al., 1995).
The asymmetric unit contains one molecule of the title compound (Fig. 1). The crystal, formed spontaneously, contains a homochiral molecule (not established experimentally). Hydrogen atoms of C14, C16 and C17 methyl groups are partially disorded and are modelled in two alternative conformations. For one conformation of the C14 methyl group, notable is a short intramolecular interaction between hydroxy H15 and H14C atoms. Such a short distance could indicate some refinement problem but on the other hand problematic hydrogen atom positions are clearly confirmed by OMIT map (Fig. 2). The hydrogen bond network is based on the interaction between hydroxy group and carbonitrile group of a subsequent molecule. Such interactions generate the right handed helices located at the 21 screw axis parallel to a direction (Fig. 3). A high quality diffraction data revealed a detailed electron density distribution among a molecule of the title compound. The difference Fourier synthesis indicates clearly a presence of valence electrons for most of covalent bonds (Fig. 4a). This is especially noticeable for tetrahedral deformation of electron density distribution at C2 atom and its neighbourhood (Fig. 4 b). In this case positive peaks are located on covalent bonds and correspond to valence electrons. Negative peaks are positioned in a regular and symmetrical manner indicating the electron density shift in the bond direction.