(1′S,2′S,5′R)-3-(2-Bromo­propion­yl)-2′-isopropyl-5′-methyl­spiro­[2H-1,3-benzoxazine-2,1′-cyclo­hexa­n]-4(3H)-one

The absolute configuration of the title compound, C₂₀H₂₆BrNO₃, was determined from both the synthetic precursor and anomalous scattering effects. In the crystal structure, non-classical C—H...O hydrogen bonds link the mol­ecules into a sheet parallel to the b axis.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.032
• wR factor = 0.069
• Data-to-parameter ratio = 19.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT480_ALERT_4_C Long H...A H-Bond Reported H9     ..  O1      ..       2.62 Ang.

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           27.47
           From the CIF: _reflns_number_total               4380
           Count of symmetry unique reflns         2553
           Completeness (_total/calc)            171.56%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1827
           Fraction of Friedel pairs measured     0.716
           Are heavy atom types Z>Si present        yes

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

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

---

Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

(1'S,2'S,5'R)-3-(2-Bromopropionyl)-2'-isopropyl-5'- methylspiro[2H-1,3-benzoxazine-2,1'-cyclohexan]-4(3H)-one

Crystal data

C20H26BrNO3	F(000) = 848
Mr = 408.33	Dx = 1.389 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: P 2ac 2ab	Cell parameters from 19890 reflections
a = 8.7388 (3) Å	θ = 1.5–27.5°
b = 14.0200 (8) Å	µ = 2.12 mm^−1
c = 15.9341 (7) Å	T = 295 K
V = 1952.21 (16) Å^3	Block, colorless
Z = 4	0.36 × 0.30 × 0.26 mm

Data collection

Rigaku RAXIS-RAPID diffractometer	3817 reflections with I > 2σ(I)
Detector resolution: 10.00 pixels mm^-1	Rint = 0.036
ω scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −10→11
Tmin = 0.438, Tmax = 0.575	k = −18→18
18127 measured reflections	l = −20→20
4380 independent reflections

Refinement

Refinement on F^2	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0369P)^2 + 0.3642P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.032	(Δ/σ)max = 0.001
wR(F^2) = 0.069	Δρmax = 0.25 e Å^−3
S = 1.04	Δρmin = −0.46 e Å^−3
4380 reflections	Absolute structure: Flack (1983)
230 parameters	Absolute structure parameter: 0.001 (7)
0 restraints

Special details

Experimental. ¹H NMR (500 MHz, CDCl₃): δ 0.78–1.10 (m, 11H), 1.56 (m, 3H),1.60–1.82 (m,5H), 1.91 (m, 3H), 2.25 (m, 1H), 2.57 (m, 1H), 5.25 (dd, 1H), 6.95 (m, 1H), 7.12 (m, 1H), 7.53 (m, 1H), 7.98 (m, 1H); ESI-MS: m/z = 430 [M + Na]⁺.

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.

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

	x	y	z	Uiso*/Ueq
Br1	0.77307 (3)	0.141459 (17)	0.533053 (19)	0.05205 (9)
O1	0.6407 (3)	0.23318 (11)	0.35334 (10)	0.0493 (5)
O2	0.62001 (18)	0.51921 (10)	0.33761 (9)	0.0335 (3)
O3	0.85457 (17)	0.36674 (12)	0.52246 (10)	0.0418 (4)
N1	0.6868 (2)	0.37838 (11)	0.41284 (11)	0.0282 (4)
C1	0.6001 (4)	0.2850 (2)	0.61486 (16)	0.0545 (7)
H1A	0.5329	0.3391	0.6123	0.082*
H1B	0.6894	0.3012	0.6469	0.082*
H1C	0.5481	0.2327	0.6411	0.082*
C2	0.6476 (2)	0.25668 (14)	0.52625 (14)	0.0330 (4)
H2	0.5567	0.2446	0.4918	0.040*
C3	0.7436 (2)	0.33582 (13)	0.48726 (13)	0.0305 (4)
C4	0.6345 (3)	0.31904 (15)	0.34816 (14)	0.0338 (5)
C5	0.5733 (3)	0.36866 (16)	0.27397 (13)	0.0346 (5)
C6	0.5134 (4)	0.31716 (18)	0.20665 (16)	0.0481 (7)
H6	0.5176	0.2509	0.2069	0.058*
C7	0.4483 (3)	0.3643 (2)	0.13996 (16)	0.0554 (7)
H7	0.4088	0.3300	0.0950	0.066*
C8	0.4416 (3)	0.4631 (2)	0.13990 (16)	0.0494 (7)
H8	0.3963	0.4946	0.0950	0.059*
C9	0.5013 (3)	0.51518 (18)	0.20561 (14)	0.0410 (6)
H9	0.4975	0.5815	0.2052	0.049*
C10	0.5668 (3)	0.46687 (16)	0.27180 (13)	0.0314 (5)
C11	0.7348 (3)	0.47884 (13)	0.39153 (12)	0.0293 (4)
C12	0.7333 (3)	0.54652 (13)	0.46800 (13)	0.0328 (4)
H12	0.8121	0.5231	0.5066	0.039*
C13	0.5820 (3)	0.54761 (16)	0.51779 (15)	0.0395 (5)
H13	0.5445	0.4818	0.5196	0.047*
C14	0.4536 (3)	0.6085 (2)	0.48171 (19)	0.0577 (7)
H14A	0.4842	0.6742	0.4816	0.087*
H14B	0.3634	0.6011	0.5155	0.087*
H14C	0.4322	0.5884	0.4253	0.087*
C15	0.6134 (4)	0.5779 (2)	0.60842 (17)	0.0620 (8)
H15A	0.5186	0.5807	0.6388	0.093*
H15B	0.6610	0.6396	0.6088	0.093*
H15C	0.6802	0.5323	0.6345	0.093*
C16	0.7868 (3)	0.64563 (16)	0.43793 (15)	0.0432 (5)
H16A	0.7140	0.6703	0.3974	0.052*
H16B	0.7889	0.6891	0.4853	0.052*
C17	0.9437 (3)	0.6418 (2)	0.39838 (17)	0.0533 (6)
H17A	1.0172	0.6204	0.4399	0.064*
H17B	0.9730	0.7054	0.3808	0.064*
C18	0.9491 (3)	0.57510 (19)	0.32293 (15)	0.0438 (6)
H18	0.8812	0.6008	0.2795	0.053*
C19	1.1096 (4)	0.5688 (3)	0.2868 (2)	0.0637 (8)
H19A	1.1777	0.5430	0.3283	0.096*
H19B	1.1437	0.6313	0.2709	0.096*
H19C	1.1089	0.5281	0.2384	0.096*
C20	0.8894 (3)	0.47709 (16)	0.34841 (14)	0.0355 (5)
H20A	0.8821	0.4375	0.2986	0.043*
H20B	0.9632	0.4476	0.3858	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.04328 (12)	0.03013 (11)	0.08274 (19)	0.00304 (10)	−0.00087 (13)	0.01514 (12)
O1	0.0839 (13)	0.0233 (8)	0.0408 (9)	−0.0030 (8)	−0.0065 (9)	−0.0022 (7)
O2	0.0435 (9)	0.0231 (7)	0.0341 (8)	0.0038 (6)	−0.0097 (7)	−0.0003 (6)
O3	0.0398 (8)	0.0330 (8)	0.0526 (9)	−0.0046 (7)	−0.0137 (8)	0.0065 (8)
N1	0.0340 (9)	0.0209 (9)	0.0296 (9)	−0.0019 (6)	−0.0002 (8)	−0.0003 (6)
C1	0.073 (2)	0.0496 (16)	0.0411 (14)	−0.0056 (14)	0.0101 (14)	0.0024 (12)
C2	0.0315 (10)	0.0284 (10)	0.0392 (11)	0.0012 (8)	−0.0005 (11)	0.0068 (10)
C3	0.0326 (11)	0.0229 (9)	0.0360 (11)	0.0047 (8)	0.0018 (10)	−0.0006 (7)
C4	0.0419 (12)	0.0268 (11)	0.0327 (11)	−0.0029 (9)	0.0019 (11)	−0.0007 (9)
C5	0.0422 (12)	0.0290 (11)	0.0326 (11)	−0.0040 (10)	−0.0015 (9)	−0.0018 (9)
C6	0.0739 (19)	0.0321 (13)	0.0382 (13)	−0.0113 (12)	−0.0091 (14)	−0.0037 (10)
C7	0.0766 (19)	0.0526 (16)	0.0370 (12)	−0.0165 (16)	−0.0143 (13)	−0.0019 (12)
C8	0.0587 (17)	0.0537 (16)	0.0358 (13)	−0.0032 (13)	−0.0140 (13)	0.0058 (11)
C9	0.0469 (14)	0.0360 (13)	0.0402 (12)	0.0020 (10)	−0.0067 (11)	0.0044 (10)
C10	0.0313 (11)	0.0314 (11)	0.0317 (11)	−0.0017 (9)	0.0008 (9)	−0.0024 (8)
C11	0.0356 (11)	0.0206 (8)	0.0317 (10)	−0.0008 (9)	−0.0055 (10)	0.0009 (7)
C12	0.0418 (11)	0.0230 (8)	0.0336 (10)	−0.0007 (8)	−0.0063 (12)	−0.0036 (8)
C13	0.0464 (13)	0.0297 (11)	0.0422 (13)	0.0010 (9)	0.0029 (11)	−0.0044 (9)
C14	0.0508 (15)	0.0614 (17)	0.0610 (17)	0.0179 (12)	0.0001 (15)	−0.0080 (14)
C15	0.072 (2)	0.072 (2)	0.0418 (15)	0.0092 (17)	0.0046 (15)	−0.0091 (14)
C16	0.0611 (14)	0.0225 (10)	0.0461 (12)	−0.0091 (12)	−0.0031 (11)	−0.0036 (9)
C17	0.0679 (16)	0.0392 (13)	0.0528 (15)	−0.0271 (14)	0.0002 (13)	−0.0012 (13)
C18	0.0491 (14)	0.0417 (14)	0.0406 (13)	−0.0128 (12)	−0.0001 (12)	0.0063 (11)
C19	0.0554 (17)	0.073 (2)	0.0629 (18)	−0.0212 (16)	0.0105 (15)	0.0048 (16)
C20	0.0388 (12)	0.0336 (12)	0.0340 (11)	−0.0040 (9)	−0.0010 (10)	0.0020 (9)

Geometric parameters (Å, º)

Br1—C2	1.956 (2)	C12—C13	1.542 (3)
O1—C4	1.208 (3)	C12—C16	1.542 (3)
O2—C10	1.362 (3)	C12—H12	0.9800
O2—C11	1.437 (3)	C13—C14	1.522 (3)
O3—C3	1.201 (3)	C13—C15	1.530 (4)
N1—C4	1.401 (3)	C13—H13	0.9800
N1—C3	1.417 (3)	C14—H14A	0.9600
N1—C11	1.508 (2)	C14—H14B	0.9600
C1—C2	1.524 (4)	C14—H14C	0.9600
C1—H1A	0.9600	C15—H15A	0.9600
C1—H1B	0.9600	C15—H15B	0.9600
C1—H1C	0.9600	C15—H15C	0.9600
C2—C3	1.524 (3)	C16—C17	1.510 (4)
C2—H2	0.9800	C16—H16A	0.9700
C4—C5	1.472 (3)	C16—H16B	0.9700
C5—C10	1.378 (3)	C17—C18	1.524 (4)
C5—C6	1.395 (3)	C17—H17A	0.9700
C6—C7	1.375 (4)	C17—H17B	0.9700
C6—H6	0.9300	C18—C19	1.519 (4)
C7—C8	1.385 (4)	C18—C20	1.525 (3)
C7—H7	0.9300	C18—H18	0.9800
C8—C9	1.379 (4)	C19—H19A	0.9600
C8—H8	0.9300	C19—H19B	0.9600
C9—C10	1.378 (3)	C19—H19C	0.9600
C9—H9	0.9300	C20—H20A	0.9700
C11—C20	1.516 (3)	C20—H20B	0.9700
C11—C12	1.545 (3)
C10—O2—C11	119.12 (16)	C16—C12—H12	106.5
C4—N1—C3	118.67 (16)	C11—C12—H12	106.5
C4—N1—C11	118.66 (16)	C14—C13—C15	109.5 (2)
C3—N1—C11	118.96 (16)	C14—C13—C12	116.3 (2)
C2—C1—H1A	109.5	C15—C13—C12	109.6 (2)
C2—C1—H1B	109.5	C14—C13—H13	107.0
H1A—C1—H1B	109.5	C15—C13—H13	107.0
C2—C1—H1C	109.5	C12—C13—H13	107.0
H1A—C1—H1C	109.5	C13—C14—H14A	109.5
H1B—C1—H1C	109.5	C13—C14—H14B	109.5
C3—C2—C1	109.73 (18)	H14A—C14—H14B	109.5
C3—C2—Br1	108.37 (13)	C13—C14—H14C	109.5
C1—C2—Br1	108.47 (16)	H14A—C14—H14C	109.5
C3—C2—H2	110.1	H14B—C14—H14C	109.5
C1—C2—H2	110.1	C13—C15—H15A	109.5
Br1—C2—H2	110.1	C13—C15—H15B	109.5
O3—C3—N1	121.4 (2)	H15A—C15—H15B	109.5
O3—C3—C2	121.13 (19)	C13—C15—H15C	109.5
N1—C3—C2	117.06 (18)	H15A—C15—H15C	109.5
O1—C4—N1	121.8 (2)	H15B—C15—H15C	109.5
O1—C4—C5	122.8 (2)	C17—C16—C12	111.9 (2)
N1—C4—C5	115.38 (18)	C17—C16—H16A	109.2
C10—C5—C6	118.8 (2)	C12—C16—H16A	109.2
C10—C5—C4	120.48 (19)	C17—C16—H16B	109.2
C6—C5—C4	120.6 (2)	C12—C16—H16B	109.2
C7—C6—C5	120.0 (2)	H16A—C16—H16B	107.9
C7—C6—H6	120.0	C16—C17—C18	112.3 (2)
C5—C6—H6	120.0	C16—C17—H17A	109.1
C6—C7—C8	119.9 (2)	C18—C17—H17A	109.1
C6—C7—H7	120.1	C16—C17—H17B	109.1
C8—C7—H7	120.1	C18—C17—H17B	109.1
C9—C8—C7	120.9 (2)	H17A—C17—H17B	107.9
C9—C8—H8	119.6	C19—C18—C17	111.3 (2)
C7—C8—H8	119.6	C19—C18—C20	111.4 (2)
C10—C9—C8	118.5 (2)	C17—C18—C20	109.4 (2)
C10—C9—H9	120.7	C19—C18—H18	108.2
C8—C9—H9	120.7	C17—C18—H18	108.2
O2—C10—C9	117.8 (2)	C20—C18—H18	108.2
O2—C10—C5	120.3 (2)	C18—C19—H19A	109.5
C9—C10—C5	121.8 (2)	C18—C19—H19B	109.5
O2—C11—N1	107.96 (16)	H19A—C19—H19B	109.5
O2—C11—C20	110.95 (16)	C18—C19—H19C	109.5
N1—C11—C20	109.56 (17)	H19A—C19—H19C	109.5
O2—C11—C12	102.93 (15)	H19B—C19—H19C	109.5
N1—C11—C12	113.18 (16)	C11—C20—C18	114.3 (2)
C20—C11—C12	112.02 (18)	C11—C20—H20A	108.7
C13—C12—C16	114.24 (18)	C18—C20—H20A	108.7
C13—C12—C11	114.79 (17)	C11—C20—H20B	108.7
C16—C12—C11	107.81 (17)	C18—C20—H20B	108.7
C13—C12—H12	106.5	H20A—C20—H20B	107.6

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O3^i	0.98	2.37	3.187 (2)	141
C9—H9···O1^ii	0.93	2.62	3.430 (3)	146

Symmetry codes: (i) x−1/2, −y+1/2, −z+1; (ii) −x+1, y+1/2, −z+1/2.