organic compounds
(4S)-(−)-4-Benzyl-2,2-dimethyl-3-o-toluoyl-1,3-oxazolidine
aFaculty of Pharmacy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, ul. M. Curie Skłodowskiej 9, 85-094 Bydgoszcz, Poland, and bFaculty of Chemistry, A. Mickiewicz University, ul. Grunwaldzka 6, 60-780 Poznań, Poland
*Correspondence e-mail: akgzella@ump.edu.pl
The 20H23NO2, has been confirmed as 4S. The benzyl residue and H atom at the asymmetric C-atom centre occupy pseudo-axial and bisectional positions, respectively. The oxazolidine ring adopts an In the the molecular packing is stabilized by non-classical C—H⋯O hydrogen bonds.
of the title compound, CRelated literature
For details of the synthesis, see: Chrzanowska & Dreas (2004); Chrzanowska et al. (2005). For bond-length data, see: Allen et al. (1987). For a description of the Cambridge Structural Database, see: Allen (2002). For ring puckering parameters, see: Cremer & Pople (1975).
Experimental
Crystal data
|
Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536810040699/bt5373sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810040699/bt5373Isup2.hkl
(4S)-2,2-Dimethyl-3-o-toluoyl-4-benzyloxazolidine has been synthesized from o-toluoyl chloride and (S)-phenylalaninol, according to literature procedure of Chrzanowska and Dreas (2004). Crystals were obtained after crystallization from diethyl ether, mp. 361—363 K, [α]D = -36.35 [c 1.0, CHCl3].
All H atoms were positioned geometrically and were refined in a riding-model approximation with Uiso constrained to be 1.2 (1.5 for methyl groups) times Ueq of the parent atom. The methyl H atoms were refined as rigid groups, which were allowed to rotate. The range of C—H distances was 0.93–0.98 Å. The
of the title compound was established by of the Flack (1983) parameter. The rather large s.u. of the is due to the small contribution of atoms with measurable effects; of the inverse structure leads to a value close to 1 [x = 0.89 (16)], which provides additional proof of the correct assignment of the absolute configuration.(4S)-2,2-Dimethyl-3-o-toluoyl-4-benzyloxazolidine has been succesfully used as a building block and chiral auxiliary in the
of (S)-(-)-O-methylbharatamine, a protoberberine derivative. The key step of the synthesis, in which a new stereogenic centre was created, involved the addition of latherally lithiated chiral o-toluamide to imine. This addition proceeded stereoselectively for cyclic imine as well as acyclic imine (Chrzanowska & Dreas, 2004); Chrzanowska et al., 2005). The title chiral o-toluamide was obtained from commercially available o-toluoyl chloride and (S)-phenylalaninol, followed by protection of functional NH and OH groups in the form of oxazolidine derivative. In order to obtain confirmation of the of the title compound, a single X-ray diffraction study has been undertaken.The results obtained for the title compound confirm the absolute 4S configuration (Fig. 1). The benzyl residue and H atom at the stereogenic C4 centre occupy a pseudo-axial and bisectional positions, respectively, as seen in the angles of the C4—C17 and C4—H4 bond vectors to the Cremer & Pople oxazolidine ring plane normal of 16.52 (7)° and 53.11 (4)° (Cremer & Pople, 1975).
The mutual arrangement of the benzyl and oxazolidine systems is described by the torsion angles C18—C17—C4—N3 177.06 (8)° and C18—C17—C4—C5 66.22 (11)° indicating an antiperiplanar and synclinal conformation of the C18 atom in the phenyl group with respect to the N3 and C5 atom of the oxazolidine ring, respectively. Furthermore, the dihedral angle made by the mean planes of the above mentioned six- and five-membered systems amounts to 49.66 (4)°.
In the solid state, the oxazolidine ring has an φ = 330.13 (16)°], with atom C5 deviating from the planar system defined by the other four atoms by 0.5776 (15) Å.
[puckering parameters (Cremer & Pople, 1975) Q = 0.379 (1) Å andThe C=O group of the amide group is
with respect to the C2—N3 bond [the torsion angle O9—C8—N3—C2: 3.59 (15)°]. We assume that this atom arrangement is stabilized by the three-centre intramolecular C6—H6B···O9···H7B—C7 hydrogen bond (Fig. 1, Table 1). The nearly planar tertiary amide group (C2/N3/C4/C8/O9, r.m.s. = 0.010) and the benzene ring (C10—C15) are not conjugated, the dihedral angle between their mean planes being 88.60 (3)°. Simultaneously, the C8—C10 bond distance of 1.5060 (14) Å is comparable with the normal length of the unconjugated (N—)C(=O)—Car bond of 1.500 (5) Å (Allen et al., 1987). The C8–N3 bond distance of 1.3460 (13) Å is the same as the normal C—N tertiary amide distance [1.346 (5) Å; Allen et al., 1987].The internal bond lengths and angles in 2,2-dimethyloxazolidine ring are close to those observed in other dimethyloxazolidine derivatives denoted by the following refcodes EBETUA, PIBSAV, VUMMOF, VUMNEW, WAVPUE (CSD Cambridge, version 5.31, Allen, 2002; R ≤ 0.050).
The molecular packing in the
is stabilized by possible C4—H4···O9i non-classical intermolecular hydrogen bonds which links molecules into chains parallel to the b axis. (Fig. 2, Table 1).For details of the synthesis, see: Chrzanowska & Dreas (2004); Chrzanowska et al. (2005). For bond-length data, see: Allen et al. (1987). For a description of the Cambridge Structural Database, see: Allen (2002). For ring puckering parameters, see: Cremer & Pople (1975).
Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell
CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).C20H23NO2 | Dx = 1.177 Mg m−3 |
Mr = 309.39 | Melting point = 361–363 K |
Orthorhombic, P21212 | Cu Kα radiation, λ = 1.54184 Å |
Hall symbol: P 2 2ab | Cell parameters from 8954 reflections |
a = 10.9951 (2) Å | θ = 2.6–75.3° |
b = 17.2768 (3) Å | µ = 0.59 mm−1 |
c = 9.1899 (2) Å | T = 130 K |
V = 1745.71 (6) Å3 | Prism, colourless |
Z = 4 | 0.30 × 0.20 × 0.09 mm |
F(000) = 664 |
Oxford Diffraction SuperNova Single source at offset Atlas diffractometer | 3332 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 3315 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.013 |
Detector resolution: 5.2679 pixels mm-1 | θmax = 75.5°, θmin = 4.8° |
ω scans | h = −9→13 |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | k = −21→21 |
Tmin = 0.882, Tmax = 1.000 | l = −11→11 |
9043 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.027 | H-atom parameters constrained |
wR(F2) = 0.073 | w = 1/[σ2(Fo2) + (0.0438P)2 + 0.2282P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max = 0.001 |
3332 reflections | Δρmax = 0.14 e Å−3 |
211 parameters | Δρmin = −0.13 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 1301 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.11 (16) |
C20H23NO2 | V = 1745.71 (6) Å3 |
Mr = 309.39 | Z = 4 |
Orthorhombic, P21212 | Cu Kα radiation |
a = 10.9951 (2) Å | µ = 0.59 mm−1 |
b = 17.2768 (3) Å | T = 130 K |
c = 9.1899 (2) Å | 0.30 × 0.20 × 0.09 mm |
Oxford Diffraction SuperNova Single source at offset Atlas diffractometer | 3332 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | 3315 reflections with I > 2σ(I) |
Tmin = 0.882, Tmax = 1.000 | Rint = 0.013 |
9043 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | H-atom parameters constrained |
wR(F2) = 0.073 | Δρmax = 0.14 e Å−3 |
S = 1.05 | Δρmin = −0.13 e Å−3 |
3332 reflections | Absolute structure: Flack (1983), 1301 Friedel pairs |
211 parameters | Absolute structure parameter: 0.11 (16) |
0 restraints |
Experimental. Absorption correction: CrysAlis Pro (Oxford Diffraction, 2009); Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
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. 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 > σ(F2) is used only for calculating R-factors(gt) 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, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.44508 (7) | 0.78744 (5) | 0.89260 (8) | 0.03235 (18) | |
C2 | 0.54700 (10) | 0.81054 (6) | 0.80707 (11) | 0.0279 (2) | |
N3 | 0.54307 (8) | 0.75492 (5) | 0.68336 (9) | 0.02318 (18) | |
C4 | 0.43450 (9) | 0.70515 (6) | 0.69370 (11) | 0.0233 (2) | |
H4 | 0.3950 | 0.6997 | 0.5986 | 0.028* | |
C5 | 0.35771 (10) | 0.75411 (6) | 0.79567 (12) | 0.0289 (2) | |
H5A | 0.3142 | 0.7939 | 0.7426 | 0.035* | |
H5B | 0.2996 | 0.7224 | 0.8482 | 0.035* | |
C6 | 0.65962 (11) | 0.80040 (7) | 0.90053 (13) | 0.0381 (3) | |
H6A | 0.6516 | 0.8307 | 0.9876 | 0.057* | |
H6B | 0.7299 | 0.8173 | 0.8473 | 0.057* | |
H6C | 0.6687 | 0.7468 | 0.9259 | 0.057* | |
C7 | 0.53116 (12) | 0.89341 (7) | 0.75407 (14) | 0.0384 (3) | |
H7A | 0.4563 | 0.8977 | 0.7010 | 0.058* | |
H7B | 0.5979 | 0.9070 | 0.6917 | 0.058* | |
H7C | 0.5293 | 0.9278 | 0.8361 | 0.058* | |
C8 | 0.62546 (9) | 0.75504 (6) | 0.57504 (11) | 0.0249 (2) | |
O9 | 0.71397 (7) | 0.79867 (5) | 0.57306 (9) | 0.03526 (19) | |
C10 | 0.60464 (9) | 0.69888 (6) | 0.45222 (11) | 0.0259 (2) | |
C11 | 0.53690 (10) | 0.72128 (6) | 0.33042 (11) | 0.0280 (2) | |
C12 | 0.52701 (11) | 0.66930 (7) | 0.21500 (12) | 0.0351 (3) | |
H12 | 0.4831 | 0.6833 | 0.1327 | 0.042* | |
C13 | 0.58144 (11) | 0.59718 (8) | 0.22089 (15) | 0.0399 (3) | |
H13 | 0.5733 | 0.5632 | 0.1430 | 0.048* | |
C14 | 0.64789 (12) | 0.57531 (7) | 0.34174 (14) | 0.0385 (3) | |
H14 | 0.6842 | 0.5267 | 0.3455 | 0.046* | |
C15 | 0.65998 (10) | 0.62643 (6) | 0.45739 (13) | 0.0318 (2) | |
H15 | 0.7052 | 0.6122 | 0.5386 | 0.038* | |
C16 | 0.47766 (11) | 0.79954 (7) | 0.32189 (13) | 0.0365 (3) | |
H16A | 0.4368 | 0.8048 | 0.2301 | 0.055* | |
H16B | 0.5386 | 0.8391 | 0.3307 | 0.055* | |
H16C | 0.4197 | 0.8048 | 0.3994 | 0.055* | |
C17 | 0.46564 (9) | 0.62539 (6) | 0.75855 (12) | 0.0273 (2) | |
H17A | 0.5233 | 0.5996 | 0.6951 | 0.033* | |
H17B | 0.5046 | 0.6328 | 0.8522 | 0.033* | |
C18 | 0.35598 (10) | 0.57400 (6) | 0.77822 (12) | 0.0260 (2) | |
C19 | 0.27740 (11) | 0.55825 (7) | 0.66370 (13) | 0.0346 (3) | |
H19 | 0.2917 | 0.5800 | 0.5727 | 0.042* | |
C20 | 0.17747 (12) | 0.51009 (7) | 0.68425 (16) | 0.0432 (3) | |
H20 | 0.1252 | 0.5003 | 0.6069 | 0.052* | |
C21 | 0.15498 (11) | 0.47678 (6) | 0.81733 (17) | 0.0428 (3) | |
H21 | 0.0885 | 0.4442 | 0.8298 | 0.051* | |
C22 | 0.23189 (11) | 0.49212 (7) | 0.93230 (16) | 0.0413 (3) | |
H22 | 0.2174 | 0.4698 | 1.0227 | 0.050* | |
C23 | 0.33108 (10) | 0.54099 (6) | 0.91312 (13) | 0.0331 (2) | |
H23 | 0.3816 | 0.5518 | 0.9917 | 0.040* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0323 (4) | 0.0396 (4) | 0.0251 (4) | 0.0008 (3) | 0.0023 (3) | −0.0044 (3) |
C2 | 0.0275 (5) | 0.0295 (5) | 0.0267 (5) | −0.0001 (4) | −0.0019 (4) | −0.0035 (4) |
N3 | 0.0208 (4) | 0.0241 (4) | 0.0246 (4) | −0.0013 (3) | −0.0005 (3) | 0.0001 (3) |
C4 | 0.0186 (5) | 0.0263 (5) | 0.0249 (4) | −0.0017 (4) | −0.0005 (4) | 0.0020 (4) |
C5 | 0.0232 (5) | 0.0333 (5) | 0.0301 (5) | 0.0017 (4) | 0.0027 (4) | 0.0000 (4) |
C6 | 0.0360 (6) | 0.0437 (6) | 0.0346 (6) | −0.0030 (5) | −0.0113 (5) | −0.0059 (5) |
C7 | 0.0435 (7) | 0.0281 (5) | 0.0437 (6) | 0.0016 (5) | −0.0014 (6) | −0.0028 (5) |
C8 | 0.0214 (5) | 0.0265 (4) | 0.0267 (5) | 0.0005 (4) | −0.0007 (4) | 0.0044 (4) |
O9 | 0.0286 (4) | 0.0387 (4) | 0.0385 (4) | −0.0101 (3) | 0.0048 (3) | −0.0005 (4) |
C10 | 0.0216 (5) | 0.0292 (5) | 0.0267 (5) | −0.0013 (4) | 0.0054 (4) | 0.0018 (4) |
C11 | 0.0235 (5) | 0.0316 (5) | 0.0287 (5) | −0.0025 (4) | 0.0028 (4) | 0.0025 (4) |
C12 | 0.0305 (6) | 0.0446 (6) | 0.0302 (5) | −0.0032 (5) | −0.0006 (5) | −0.0029 (5) |
C13 | 0.0387 (7) | 0.0406 (6) | 0.0405 (7) | −0.0029 (5) | 0.0039 (5) | −0.0132 (5) |
C14 | 0.0374 (6) | 0.0311 (5) | 0.0471 (7) | 0.0041 (5) | 0.0071 (6) | −0.0036 (5) |
C15 | 0.0295 (5) | 0.0319 (5) | 0.0340 (6) | 0.0040 (5) | 0.0036 (4) | 0.0030 (4) |
C16 | 0.0356 (6) | 0.0368 (6) | 0.0372 (6) | 0.0035 (5) | −0.0058 (5) | 0.0040 (5) |
C17 | 0.0218 (5) | 0.0286 (5) | 0.0313 (5) | 0.0000 (4) | −0.0004 (4) | 0.0047 (4) |
C18 | 0.0220 (5) | 0.0220 (4) | 0.0341 (5) | 0.0027 (4) | 0.0012 (4) | −0.0007 (4) |
C19 | 0.0346 (6) | 0.0323 (5) | 0.0370 (6) | −0.0013 (4) | −0.0036 (5) | −0.0028 (5) |
C20 | 0.0326 (6) | 0.0342 (6) | 0.0627 (8) | −0.0016 (5) | −0.0125 (6) | −0.0102 (6) |
C21 | 0.0258 (5) | 0.0251 (5) | 0.0774 (9) | −0.0036 (4) | 0.0050 (6) | −0.0030 (5) |
C22 | 0.0361 (6) | 0.0337 (6) | 0.0542 (7) | −0.0049 (5) | 0.0087 (6) | 0.0100 (6) |
C23 | 0.0298 (6) | 0.0315 (5) | 0.0379 (6) | −0.0022 (5) | −0.0004 (5) | 0.0071 (5) |
O1—C2 | 1.4258 (13) | C12—C13 | 1.3834 (18) |
O1—C5 | 1.4311 (13) | C12—H12 | 0.9300 |
C2—N3 | 1.4892 (13) | C13—C14 | 1.3820 (18) |
C2—C6 | 1.5172 (15) | C13—H13 | 0.9300 |
C2—C7 | 1.5224 (15) | C14—C15 | 1.3882 (17) |
N3—C8 | 1.3460 (13) | C14—H14 | 0.9300 |
N3—C4 | 1.4742 (12) | C15—H15 | 0.9300 |
C4—C5 | 1.5187 (14) | C16—H16A | 0.9600 |
C4—C17 | 1.5398 (14) | C16—H16B | 0.9600 |
C4—H4 | 0.9800 | C16—H16C | 0.9600 |
C5—H5A | 0.9700 | C17—C18 | 1.5082 (14) |
C5—H5B | 0.9700 | C17—H17A | 0.9700 |
C6—H6A | 0.9600 | C17—H17B | 0.9700 |
C6—H6B | 0.9600 | C18—C19 | 1.3886 (16) |
C6—H6C | 0.9600 | C18—C23 | 1.3918 (15) |
C7—H7A | 0.9600 | C19—C20 | 1.3911 (17) |
C7—H7B | 0.9600 | C19—H19 | 0.9300 |
C7—H7C | 0.9600 | C20—C21 | 1.374 (2) |
C8—O9 | 1.2310 (12) | C20—H20 | 0.9300 |
C8—C10 | 1.5060 (14) | C21—C22 | 1.379 (2) |
C10—C15 | 1.3926 (15) | C21—H21 | 0.9300 |
C10—C11 | 1.3990 (15) | C22—C23 | 1.3905 (16) |
C11—C12 | 1.3940 (16) | C22—H22 | 0.9300 |
C11—C16 | 1.5029 (16) | C23—H23 | 0.9300 |
C2—O1—C5 | 107.28 (7) | C13—C12—C11 | 121.11 (11) |
O1—C2—N3 | 102.56 (8) | C13—C12—H12 | 119.4 |
O1—C2—C6 | 107.28 (9) | C11—C12—H12 | 119.4 |
N3—C2—C6 | 112.42 (9) | C14—C13—C12 | 120.42 (11) |
O1—C2—C7 | 110.47 (10) | C14—C13—H13 | 119.8 |
N3—C2—C7 | 111.06 (9) | C12—C13—H13 | 119.8 |
C6—C2—C7 | 112.53 (10) | C13—C14—C15 | 119.47 (11) |
C8—N3—C4 | 126.41 (8) | C13—C14—H14 | 120.3 |
C8—N3—C2 | 122.96 (8) | C15—C14—H14 | 120.3 |
C4—N3—C2 | 110.53 (8) | C14—C15—C10 | 120.25 (11) |
N3—C4—C5 | 99.50 (8) | C14—C15—H15 | 119.9 |
N3—C4—C17 | 111.52 (8) | C10—C15—H15 | 119.9 |
C5—C4—C17 | 112.53 (9) | C11—C16—H16A | 109.5 |
N3—C4—H4 | 110.9 | C11—C16—H16B | 109.5 |
C5—C4—H4 | 110.9 | H16A—C16—H16B | 109.5 |
C17—C4—H4 | 110.9 | C11—C16—H16C | 109.5 |
O1—C5—C4 | 103.59 (8) | H16A—C16—H16C | 109.5 |
O1—C5—H5A | 111.0 | H16B—C16—H16C | 109.5 |
C4—C5—H5A | 111.0 | C18—C17—C4 | 113.29 (8) |
O1—C5—H5B | 111.0 | C18—C17—H17A | 108.9 |
C4—C5—H5B | 111.0 | C4—C17—H17A | 108.9 |
H5A—C5—H5B | 109.0 | C18—C17—H17B | 108.9 |
C2—C6—H6A | 109.5 | C4—C17—H17B | 108.9 |
C2—C6—H6B | 109.5 | H17A—C17—H17B | 107.7 |
H6A—C6—H6B | 109.5 | C19—C18—C23 | 118.19 (10) |
C2—C6—H6C | 109.5 | C19—C18—C17 | 121.46 (10) |
H6A—C6—H6C | 109.5 | C23—C18—C17 | 120.35 (10) |
H6B—C6—H6C | 109.5 | C18—C19—C20 | 120.38 (12) |
C2—C7—H7A | 109.5 | C18—C19—H19 | 119.8 |
C2—C7—H7B | 109.5 | C20—C19—H19 | 119.8 |
H7A—C7—H7B | 109.5 | C21—C20—C19 | 120.90 (12) |
C2—C7—H7C | 109.5 | C21—C20—H20 | 119.6 |
H7A—C7—H7C | 109.5 | C19—C20—H20 | 119.6 |
H7B—C7—H7C | 109.5 | C20—C21—C22 | 119.41 (11) |
O9—C8—N3 | 122.95 (10) | C20—C21—H21 | 120.3 |
O9—C8—C10 | 120.24 (9) | C22—C21—H21 | 120.3 |
N3—C8—C10 | 116.81 (8) | C21—C22—C23 | 120.03 (12) |
C15—C10—C11 | 120.57 (10) | C21—C22—H22 | 120.0 |
C15—C10—C8 | 119.15 (9) | C23—C22—H22 | 120.0 |
C11—C10—C8 | 120.15 (9) | C22—C23—C18 | 121.07 (11) |
C12—C11—C10 | 118.17 (10) | C22—C23—H23 | 119.5 |
C12—C11—C16 | 120.40 (10) | C18—C23—H23 | 119.5 |
C10—C11—C16 | 121.42 (10) | ||
C5—O1—C2—N3 | −28.52 (10) | C15—C10—C11—C12 | −0.25 (15) |
C5—O1—C2—C6 | −147.11 (9) | C8—C10—C11—C12 | 175.64 (9) |
C5—O1—C2—C7 | 89.91 (10) | C15—C10—C11—C16 | −179.28 (10) |
O1—C2—N3—C8 | −179.07 (9) | C8—C10—C11—C16 | −3.39 (15) |
C6—C2—N3—C8 | −64.17 (13) | C10—C11—C12—C13 | 0.67 (16) |
C7—C2—N3—C8 | 62.91 (13) | C16—C11—C12—C13 | 179.71 (11) |
O1—C2—N3—C4 | 4.37 (10) | C11—C12—C13—C14 | −0.47 (18) |
C6—C2—N3—C4 | 119.27 (10) | C12—C13—C14—C15 | −0.17 (19) |
C7—C2—N3—C4 | −113.65 (10) | C13—C14—C15—C10 | 0.58 (18) |
C8—N3—C4—C5 | −157.19 (9) | C11—C10—C15—C14 | −0.37 (16) |
C2—N3—C4—C5 | 19.22 (10) | C8—C10—C15—C14 | −176.31 (10) |
C8—N3—C4—C17 | 83.88 (12) | N3—C4—C17—C18 | 177.06 (8) |
C2—N3—C4—C17 | −99.71 (9) | C5—C4—C17—C18 | 66.22 (11) |
C2—O1—C5—C4 | 41.88 (10) | C4—C17—C18—C19 | 53.80 (13) |
N3—C4—C5—O1 | −35.86 (9) | C4—C17—C18—C23 | −126.17 (10) |
C17—C4—C5—O1 | 82.31 (10) | C23—C18—C19—C20 | −0.61 (16) |
C4—N3—C8—O9 | 179.58 (9) | C17—C18—C19—C20 | 179.41 (10) |
C2—N3—C8—O9 | 3.59 (15) | C18—C19—C20—C21 | −0.49 (18) |
C4—N3—C8—C10 | 0.08 (14) | C19—C20—C21—C22 | 0.75 (18) |
C2—N3—C8—C10 | −175.92 (9) | C20—C21—C22—C23 | 0.10 (18) |
O9—C8—C10—C15 | 86.97 (13) | C21—C22—C23—C18 | −1.22 (18) |
N3—C8—C10—C15 | −93.51 (11) | C19—C18—C23—C22 | 1.46 (16) |
O9—C8—C10—C11 | −88.98 (12) | C17—C18—C23—C22 | −178.56 (10) |
N3—C8—C10—C11 | 90.54 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O9i | 0.98 | 2.54 | 3.4487 (13) | 154 |
C6—H6B···O9 | 0.96 | 2.55 | 3.0683 (15) | 114 |
C7—H7B···O9 | 0.96 | 2.51 | 3.0800 (15) | 118 |
Symmetry code: (i) x−1/2, −y+3/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C20H23NO2 |
Mr | 309.39 |
Crystal system, space group | Orthorhombic, P21212 |
Temperature (K) | 130 |
a, b, c (Å) | 10.9951 (2), 17.2768 (3), 9.1899 (2) |
V (Å3) | 1745.71 (6) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.59 |
Crystal size (mm) | 0.30 × 0.20 × 0.09 |
Data collection | |
Diffractometer | Oxford Diffraction SuperNova Single source at offset Atlas |
Absorption correction | Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) |
Tmin, Tmax | 0.882, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9043, 3332, 3315 |
Rint | 0.013 |
(sin θ/λ)max (Å−1) | 0.628 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.073, 1.05 |
No. of reflections | 3332 |
No. of parameters | 211 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.14, −0.13 |
Absolute structure | Flack (1983), 1301 Friedel pairs |
Absolute structure parameter | 0.11 (16) |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O9i | 0.98 | 2.54 | 3.4487 (13) | 154 |
Symmetry code: (i) x−1/2, −y+3/2, −z+1. |
References
Allen, F. H. (2002). Acta Cryst. B58, 380–388. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
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Chrzanowska, M. & Dreas, A. (2004). Tetrahedron Asymmetry, 15, 2561–2567. Web of Science CrossRef CAS Google Scholar
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Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
(4S)-2,2-Dimethyl-3-o-toluoyl-4-benzyloxazolidine has been succesfully used as a building block and chiral auxiliary in the asymmetric synthesis of (S)-(-)-O-methylbharatamine, a protoberberine derivative. The key step of the synthesis, in which a new stereogenic centre was created, involved the addition of latherally lithiated chiral o-toluamide to imine. This addition proceeded stereoselectively for cyclic imine as well as acyclic imine (Chrzanowska & Dreas, 2004); Chrzanowska et al., 2005). The title chiral o-toluamide was obtained from commercially available o-toluoyl chloride and (S)-phenylalaninol, followed by protection of functional NH and OH groups in the form of oxazolidine derivative. In order to obtain confirmation of the absolute configuration of the title compound, a single X-ray diffraction study has been undertaken.
The results obtained for the title compound confirm the absolute 4S configuration (Fig. 1). The benzyl residue and H atom at the stereogenic C4 centre occupy a pseudo-axial and bisectional positions, respectively, as seen in the angles of the C4—C17 and C4—H4 bond vectors to the Cremer & Pople oxazolidine ring plane normal of 16.52 (7)° and 53.11 (4)° (Cremer & Pople, 1975).
The mutual arrangement of the benzyl and oxazolidine systems is described by the torsion angles C18—C17—C4—N3 177.06 (8)° and C18—C17—C4—C5 66.22 (11)° indicating an antiperiplanar and synclinal conformation of the C18 atom in the phenyl group with respect to the N3 and C5 atom of the oxazolidine ring, respectively. Furthermore, the dihedral angle made by the mean planes of the above mentioned six- and five-membered systems amounts to 49.66 (4)°.
In the solid state, the oxazolidine ring has an envelope conformation [puckering parameters (Cremer & Pople, 1975) Q = 0.379 (1) Å and φ = 330.13 (16)°], with atom C5 deviating from the planar system defined by the other four atoms by 0.5776 (15) Å.
The C=O group of the amide group is synperiplanar with respect to the C2—N3 bond [the torsion angle O9—C8—N3—C2: 3.59 (15)°]. We assume that this atom arrangement is stabilized by the three-centre intramolecular C6—H6B···O9···H7B—C7 hydrogen bond (Fig. 1, Table 1). The nearly planar tertiary amide group (C2/N3/C4/C8/O9, r.m.s. = 0.010) and the benzene ring (C10—C15) are not conjugated, the dihedral angle between their mean planes being 88.60 (3)°. Simultaneously, the C8—C10 bond distance of 1.5060 (14) Å is comparable with the normal length of the unconjugated (N—)C(=O)—Car bond of 1.500 (5) Å (Allen et al., 1987). The C8–N3 bond distance of 1.3460 (13) Å is the same as the normal C—N tertiary amide distance [1.346 (5) Å; Allen et al., 1987].
The internal bond lengths and angles in 2,2-dimethyloxazolidine ring are close to those observed in other dimethyloxazolidine derivatives denoted by the following refcodes EBETUA, PIBSAV, VUMMOF, VUMNEW, WAVPUE (CSD Cambridge, version 5.31, Allen, 2002; R ≤ 0.050).
The molecular packing in the crystal lattice is stabilized by possible C4—H4···O9i non-classical intermolecular hydrogen bonds which links molecules into chains parallel to the b axis. (Fig. 2, Table 1).