(4S)-Benzyl 4-benzyl-5-oxo-1,3-oxazolidine-3-carboxyl­ate

In the title compound, C₁₈H₁₇NO₄, the carboxylate group is approximately coplanar with the oxazolidine ring, the largest deviation from the least-squares plane being 0.144 (2) Å at the nitro­gen atom. The two benzyl rings are located on the same side of this plane, and make dihedral angles with it of 75.23 (4) and 56.97 (7)°.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.031
• wR factor = 0.072
• Data-to-parameter ratio = 8.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.98
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.80 mm
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N1     -   C8      ..       6.65 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C3     -   C4      ..       5.55 su

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.00
           From the CIF: _reflns_number_total               1705
           Count of symmetry unique reflns         1744
           Completeness (_total/calc)             97.76%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C11    = .          S
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title compound (I), has been used to synthesize dipeptides and N-methyl-α-amino acid (Dorow & Gingrich, 1999). The absolute configuration of the stereocentre remains unchanged during the synthetic procedure.

The title compound, C₁₈H₁₇N₁O₄, is built up from an oxazolidine-3-carboxylate moiety attached to two benzyl rings. The carboxylate and the oxazolidine are roughly coplanar with the largest deviation from the least-square plane being -0.144 (2) Å at the nitrogen atom. The two benzyl rings are located on the same side of this plane and make dihedral angle with it of 75.23 (4)° and 56.97 (7)° respectively (Fig. 1). The bond lengths and angles in (I) are in agreement with the values reported in the literature (Lin et al., 2007).

Related literature

For related literature, see: Vidyasagar Reddy et al. (2000); Lin et al. (2007); Dorow & Gingrich (1999).

S2. Experimental

The N-Benzoxycarbonyl-L-phenylalanine (2.99 g, 1 mmol), paraformaldehyde (0.6 g, 2 mmol) and 4-methylbenzenesulfonic acid (0.15 g, 0.6 mmol) were dissolved in benzene (150 ml). The solution was refluxed for 1 h with a Dean-Stark trap. After cooling to room temperature, the mixture was washed with 0.3 M aqueous K₂CO₃ solution, water, and saturated aqueous NaCl solution, then dried over Mg₂SO₄ (Vidyasagar et al., 2000). We got white soild after evaporation of the solvent. Single crystals were obtained by recrystallization from ethanol.

S3. Refinement

All H atoms were fixed geometrically and treated as riding with C—H = 0.93 Å (aromatic), 0.97 Å (methylene) or 0.98 Å (methine) with U_iso(H) = 1.2U_eq(C).

In the absence of significant anomalous scattering, the absolute configuration could not be reliably determined and then the Friedel pairs were merged and any references to the Flack parameter were removed. The absolute configuration was deduced from the synthetic procedure.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. Molecular view of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.

(4S)-Benzyl 4-benzyl-5-oxo-1,3-oxazolidine-3-carboxylate

Crystal data

C18H17NO4	F(000) = 328
Mr = 311.33	Dx = 1.282 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 2497 reflections
a = 11.4729 (11) Å	θ = 4.2–32.7°
b = 5.9019 (4) Å	µ = 0.09 mm^−1
c = 12.5093 (10) Å	T = 173 K
β = 107.81 (1)°	Block, colorless
V = 806.44 (11) Å^3	0.80 × 0.37 × 0.23 mm
Z = 2

Data collection

Bruker APEX area-detector diffractometer	1705 independent reflections
Radiation source: fine-focus sealed tube	1240 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
ϕ and ω scan	θmax = 26.0°, θmin = 4.2°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −14→13
Tmin = 0.934, Tmax = 0.981	k = −7→7
5708 measured reflections	l = −15→13

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.072	H-atom parameters constrained
S = 0.95	w = 1/[σ^2(Fo^2) + (0.0454P)^2] where P = (Fo^2 + 2Fc^2)/3
1705 reflections	(Δ/σ)max < 0.001
208 parameters	Δρmax = 0.11 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.42377 (15)	0.7609 (3)	0.84565 (14)	0.0362 (4)
C8	0.36781 (19)	0.8526 (4)	0.91468 (16)	0.0400 (5)
O1	0.28778 (13)	0.7072 (2)	0.93711 (12)	0.0457 (4)
O3	0.58323 (14)	0.7171 (3)	0.77604 (14)	0.0522 (4)
C11	0.41290 (18)	0.5305 (4)	0.80224 (17)	0.0380 (5)
H11	0.4233	0.4231	0.8642	0.046*
O2	0.38833 (15)	1.0438 (3)	0.95256 (13)	0.0540 (4)
C1	0.08937 (19)	0.8764 (4)	0.91329 (16)	0.0391 (5)
O4	0.55782 (18)	0.3612 (3)	0.71837 (16)	0.0665 (5)
C7	0.2070 (2)	0.8026 (5)	0.99621 (18)	0.0520 (6)
H7A	0.2465	0.9312	1.0411	0.062*
H7B	0.1908	0.6897	1.0462	0.062*
C13	0.25038 (19)	0.6702 (4)	0.62687 (17)	0.0412 (5)
C6	0.0774 (2)	1.0868 (4)	0.86208 (19)	0.0470 (6)
H6	0.1430	1.1873	0.8806	0.056*
C18	0.1527 (2)	0.8044 (4)	0.63085 (17)	0.0473 (6)
H18	0.1126	0.7714	0.6834	0.057*
C12	0.2927 (2)	0.4786 (4)	0.70912 (18)	0.0443 (6)
H12A	0.3042	0.3443	0.6687	0.053*
H12B	0.2294	0.4455	0.7434	0.053*
C10	0.5233 (2)	0.5193 (4)	0.7604 (2)	0.0464 (6)
C2	−0.0100 (2)	0.7305 (4)	0.88517 (19)	0.0478 (6)
H2	−0.0031	0.5892	0.9195	0.057*
C9	0.5257 (2)	0.8793 (4)	0.8266 (2)	0.0531 (6)
H9A	0.4975	1.0078	0.7771	0.064*
H9B	0.5818	0.9328	0.8969	0.064*
C3	−0.1181 (2)	0.7913 (5)	0.8076 (2)	0.0592 (7)
H3	−0.1839	0.6913	0.7892	0.071*
C15	0.2702 (3)	0.9083 (5)	0.4770 (2)	0.0657 (8)
H15	0.3108	0.9443	0.4253	0.079*
C17	0.1129 (2)	0.9859 (4)	0.5590 (2)	0.0549 (7)
H17	0.0462	1.0717	0.5624	0.066*
C5	−0.0318 (3)	1.1480 (5)	0.7835 (2)	0.0578 (7)
H5	−0.0392	1.2887	0.7485	0.069*
C14	0.3083 (2)	0.7238 (5)	0.54794 (18)	0.0553 (6)
H14	0.3734	0.6355	0.5424	0.066*
C16	0.1727 (3)	1.0383 (5)	0.48261 (19)	0.0614 (7)
H16	0.1475	1.1614	0.4347	0.074*
C4	−0.1294 (3)	1.0006 (5)	0.7571 (2)	0.0638 (8)
H4	−0.2031	1.0425	0.7049	0.077*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0350 (9)	0.0346 (10)	0.0357 (9)	−0.0039 (8)	0.0061 (8)	−0.0009 (8)
C8	0.0378 (12)	0.0417 (13)	0.0317 (10)	0.0002 (11)	−0.0022 (9)	0.0031 (11)
O1	0.0428 (9)	0.0458 (9)	0.0495 (9)	0.0026 (8)	0.0155 (7)	0.0040 (7)
O3	0.0434 (8)	0.0498 (9)	0.0658 (10)	−0.0059 (9)	0.0204 (8)	0.0041 (8)
C11	0.0405 (12)	0.0315 (10)	0.0411 (11)	−0.0006 (10)	0.0112 (9)	0.0035 (10)
O2	0.0617 (10)	0.0457 (10)	0.0511 (9)	−0.0065 (9)	0.0121 (8)	−0.0122 (8)
C1	0.0453 (13)	0.0426 (12)	0.0345 (11)	0.0021 (11)	0.0196 (10)	−0.0027 (10)
O4	0.0763 (12)	0.0482 (10)	0.0890 (13)	0.0123 (10)	0.0463 (10)	0.0088 (10)
C7	0.0531 (14)	0.0663 (16)	0.0383 (12)	0.0082 (13)	0.0166 (11)	0.0061 (11)
C13	0.0399 (12)	0.0472 (13)	0.0312 (11)	−0.0092 (11)	0.0031 (9)	−0.0082 (9)
C6	0.0587 (16)	0.0400 (14)	0.0451 (13)	−0.0027 (12)	0.0203 (12)	−0.0026 (10)
C18	0.0464 (13)	0.0572 (14)	0.0349 (12)	−0.0048 (12)	0.0074 (10)	−0.0004 (11)
C12	0.0445 (12)	0.0399 (12)	0.0446 (13)	−0.0095 (10)	0.0079 (11)	−0.0039 (10)
C10	0.0467 (13)	0.0422 (14)	0.0495 (13)	0.0045 (12)	0.0135 (11)	0.0095 (12)
C2	0.0564 (14)	0.0467 (13)	0.0487 (13)	−0.0005 (13)	0.0285 (12)	−0.0025 (11)
C9	0.0518 (14)	0.0463 (13)	0.0630 (15)	−0.0135 (12)	0.0201 (12)	−0.0061 (12)
C3	0.0484 (15)	0.0724 (18)	0.0593 (15)	−0.0075 (13)	0.0202 (13)	−0.0162 (14)
C15	0.0684 (18)	0.092 (2)	0.0355 (13)	−0.0063 (17)	0.0144 (13)	0.0131 (14)
C17	0.0622 (16)	0.0579 (16)	0.0403 (13)	0.0052 (13)	0.0094 (12)	−0.0033 (12)
C5	0.0779 (18)	0.0519 (14)	0.0428 (13)	0.0208 (15)	0.0174 (14)	0.0012 (11)
C14	0.0496 (13)	0.0779 (17)	0.0374 (13)	0.0003 (14)	0.0117 (11)	−0.0026 (13)
C16	0.0737 (18)	0.0630 (16)	0.0371 (13)	−0.0034 (16)	0.0017 (13)	0.0046 (12)
C4	0.0502 (16)	0.088 (2)	0.0465 (14)	0.0222 (17)	0.0043 (12)	−0.0156 (16)

Geometric parameters (Å, º)

N1—C8	1.338 (3)	C6—H6	0.9300
N1—C9	1.444 (3)	C18—C17	1.383 (3)
N1—C11	1.455 (3)	C18—H18	0.9300
C8—O2	1.218 (3)	C12—H12A	0.9700
C8—O1	1.348 (3)	C12—H12B	0.9700
O1—C7	1.464 (3)	C2—C3	1.368 (4)
O3—C10	1.339 (3)	C2—H2	0.9300
O3—C9	1.416 (3)	C9—H9A	0.9700
C11—C10	1.512 (3)	C9—H9B	0.9700
C11—C12	1.539 (3)	C3—C4	1.376 (4)
C11—H11	0.9800	C3—H3	0.9300
C1—C6	1.385 (3)	C15—C16	1.375 (4)
C1—C2	1.386 (3)	C15—C14	1.388 (4)
C1—C7	1.493 (3)	C15—H15	0.9300
O4—C10	1.197 (3)	C17—C16	1.371 (4)
C7—H7A	0.9700	C17—H17	0.9300
C7—H7B	0.9700	C5—C4	1.376 (4)
C13—C14	1.385 (3)	C5—H5	0.9300
C13—C18	1.386 (3)	C14—H14	0.9300
C13—C12	1.506 (3)	C16—H16	0.9300
C6—C5	1.383 (4)	C4—H4	0.9300
C8—N1—C9	118.93 (18)	C11—C12—H12B	108.9
C8—N1—C11	128.01 (17)	H12A—C12—H12B	107.7
C9—N1—C11	111.83 (18)	O4—C10—O3	121.3 (2)
O2—C8—N1	123.5 (2)	O4—C10—C11	127.7 (2)
O2—C8—O1	124.9 (2)	O3—C10—C11	111.0 (2)
N1—C8—O1	111.62 (18)	C3—C2—C1	120.9 (2)
C8—O1—C7	115.91 (17)	C3—C2—H2	119.5
C10—O3—C9	111.44 (18)	C1—C2—H2	119.5
N1—C11—C10	100.64 (17)	O3—C9—N1	104.96 (18)
N1—C11—C12	115.04 (18)	O3—C9—H9A	110.8
C10—C11—C12	112.36 (18)	N1—C9—H9A	110.8
N1—C11—H11	109.5	O3—C9—H9B	110.8
C10—C11—H11	109.5	N1—C9—H9B	110.8
C12—C11—H11	109.5	H9A—C9—H9B	108.8
C6—C1—C2	118.8 (2)	C2—C3—C4	119.9 (3)
C6—C1—C7	121.6 (2)	C2—C3—H3	120.1
C2—C1—C7	119.6 (2)	C4—C3—H3	120.1
O1—C7—C1	109.80 (16)	C16—C15—C14	120.4 (2)
O1—C7—H7A	109.7	C16—C15—H15	119.8
C1—C7—H7A	109.7	C14—C15—H15	119.8
O1—C7—H7B	109.7	C16—C17—C18	119.5 (3)
C1—C7—H7B	109.7	C16—C17—H17	120.3
H7A—C7—H7B	108.2	C18—C17—H17	120.3
C14—C13—C18	117.7 (2)	C4—C5—C6	119.9 (3)
C14—C13—C12	122.3 (2)	C4—C5—H5	120.0
C18—C13—C12	120.0 (2)	C6—C5—H5	120.0
C5—C6—C1	120.2 (2)	C13—C14—C15	120.6 (2)
C5—C6—H6	119.9	C13—C14—H14	119.7
C1—C6—H6	119.9	C15—C14—H14	119.7
C17—C18—C13	121.9 (2)	C17—C16—C15	119.9 (2)
C17—C18—H18	119.0	C17—C16—H16	120.1
C13—C18—H18	119.0	C15—C16—H16	120.1
C13—C12—C11	113.25 (17)	C3—C4—C5	120.2 (2)
C13—C12—H12A	108.9	C3—C4—H4	119.9
C11—C12—H12A	108.9	C5—C4—H4	119.9
C13—C12—H12B	108.9