Ethyl 5-methyl-4-(2,5,5-tri­methyl-1,3-dioxan-2-yl)­isoxazole-3-carboxyl­ate

The title compound, C₁₄H₂₁NO₅, possesses an isoxazolyl group in the axial position of the 1,3-dioxanyl ring. The two rings are rotated about the bond joining them such that the two C(methyl)-C(dioxanyl)-C-C torsion angles are 92.1 (2) and -84.1 (2)°. In this conformation, neither the methyl nor ethoxy­carbonyl substituents on the isoxazole are presented towards the dioxanyl chair.

Computing details

Data collection: SMART (Bruker, 1997a); cell refinement: SMART; data reduction: SHELXTL (Bruker, 1997b); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

(I)

Crystal data

C14H21NO5	Z = 2
Mr = 283.32	F(000) = 304
Triclinic, P1	Dx = 1.279 Mg m^−3
a = 8.5710 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.5382 (9) Å	Cell parameters from 74 reflections
c = 10.3449 (9) Å	θ = 2.1–27.0°
α = 105.7991 (10)°	µ = 0.10 mm^−1
β = 94.1123 (11)°	T = 193 K
γ = 112.6952 (13)°	Block, colorless
V = 735.72 (12) Å^3	0.40 × 0.20 × 0.20 mm

Data collection

CCD area detector diffractometer	2392 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tube	Rint = 0.035
Graphite monochromator	θmax = 25.4°, θmin = 2.1°
phi and ω scans	h = −10→9
3851 measured reflections	k = −10→12
2688 independent reflections	l = −12→10

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.047	H-atom parameters constrained
wR(F^2) = 0.120	w = 1/[σ^2(Fo^2) + (0.0451P)^2 + 0.4327P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.005
2688 reflections	Δρmax = 0.30 e Å^−3
182 parameters	Δρmin = −0.30 e Å^−3
0 restraints	Extinction correction: SHELXTL (Bruker, 1997b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.017 (4)

Special details

Experimental. Data were acquired on a three-circle Bruker CCD diffractometer and detector with mounted LT-2 low temperature apparatus operating at 213 K. The crystal was mounted on the glass fiber of the goniometer head using silicone grease for adhesion. The cell constants were determined from 60 thirty-second frames. Data were measured using omega scans of 0.3° and 30 - s per frame until completion of the collection hemisphere. A complete hemisphere consisting of 1272 frames was collected in all with a maximum 0.83 Angstrom resolution. A fourth data collection iteration of 50 frames was collected in order to monitor for crystal decay (<1%). Cell parameters were retrieved using SMART (Bruker, 1997) software and refined using SAINT (Bruker, 1997) on all observed reflections. Data reduction was achieved through the use of the SAINT software, which corrects for Lp and decay. Absorption corrections were applied using SADABS supplied by George Sheldrick based on method of Blessing(1995). The structures are solved by the direct method using the SHELXS97 program (Sheldrick, 1990) and refined by least squares method on F² SHELXL97 (Sheldrick, 1997), incorporated in SHELXTL-PC V 5.10 (Bruker, 1997). Non hydrogen atoms were refined anisotropically, whereas hydrogen atoms were located from difference map and subsequently refined isotropically.

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
O1	0.68566 (16)	0.50891 (15)	0.94588 (13)	0.0346 (3)
O2	0.4294 (2)	−0.01121 (17)	0.73592 (14)	0.0453 (4)
O3	0.31381 (18)	0.05417 (15)	0.91888 (13)	0.0371 (3)
O4	0.21280 (15)	0.15184 (14)	0.61285 (12)	0.0292 (3)
O5	0.34379 (15)	0.40112 (14)	0.57755 (12)	0.0286 (3)
N1	0.6131 (2)	0.35593 (19)	0.96175 (15)	0.0340 (4)
C1	0.6080 (2)	0.5001 (2)	0.82283 (17)	0.0289 (4)
C2	0.4866 (2)	0.3484 (2)	0.75691 (17)	0.0255 (4)
C3	0.4981 (2)	0.2639 (2)	0.84897 (17)	0.0281 (4)
C4	0.4097 (2)	0.0868 (2)	0.82610 (17)	0.0296 (4)
C5	0.2298 (3)	−0.1158 (2)	0.9064 (2)	0.0427 (5)
H5A	0.3157	−0.1617	0.9042	0.051*
H5B	0.1413	−0.1766	0.8208	0.051*
C6	0.1474 (3)	−0.1264 (3)	1.0288 (2)	0.0471 (5)
H6A	0.0898	−0.2392	1.0238	0.071*
H6B	0.0623	−0.0810	1.0297	0.071*
H6C	0.2362	−0.0658	1.1128	0.071*
C7	0.6729 (3)	0.6518 (2)	0.7889 (2)	0.0383 (5)
H7A	0.6093	0.6334	0.6989	0.057*
H7B	0.7960	0.6870	0.7872	0.057*
H7C	0.6560	0.7350	0.8585	0.057*
C8	0.3712 (2)	0.2792 (2)	0.61569 (17)	0.0259 (4)
C9	0.1001 (2)	0.2027 (2)	0.68997 (19)	0.0313 (4)
H9A	0.1541	0.2488	0.7886	0.038*
H9B	−0.0099	0.1084	0.6777	0.038*
C10	0.0629 (2)	0.3280 (2)	0.64413 (19)	0.0308 (4)
C11	0.2389 (2)	0.4620 (2)	0.65640 (18)	0.0290 (4)
H11A	0.2233	0.5450	0.6237	0.035*
H11B	0.2981	0.5131	0.7539	0.035*
C12	0.4534 (3)	0.2072 (2)	0.50732 (19)	0.0378 (5)
H12A	0.3765	0.1636	0.4175	0.057*
H12B	0.4732	0.1209	0.5290	0.057*
H12C	0.5638	0.2907	0.5053	0.057*
C13	−0.0370 (3)	0.2545 (2)	0.4957 (2)	0.0411 (5)
H13A	−0.0598	0.3362	0.4678	0.062*
H13B	−0.1467	0.1644	0.4887	0.062*
H13C	0.0315	0.2159	0.4357	0.062*
C14	−0.0375 (3)	0.3947 (3)	0.7400 (2)	0.0438 (5)
H14A	0.0288	0.4411	0.8342	0.066*
H14B	−0.1488	0.3077	0.7350	0.066*
H14C	−0.0569	0.4780	0.7124	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0337 (7)	0.0352 (7)	0.0308 (7)	0.0134 (6)	−0.0007 (5)	0.0079 (5)
O2	0.0656 (10)	0.0397 (8)	0.0409 (8)	0.0308 (7)	0.0196 (7)	0.0134 (6)
O3	0.0488 (8)	0.0312 (7)	0.0368 (7)	0.0187 (6)	0.0152 (6)	0.0150 (6)
O4	0.0291 (6)	0.0258 (6)	0.0337 (7)	0.0128 (5)	0.0038 (5)	0.0098 (5)
O5	0.0337 (7)	0.0325 (7)	0.0279 (6)	0.0180 (5)	0.0087 (5)	0.0157 (5)
N1	0.0392 (9)	0.0358 (9)	0.0301 (8)	0.0188 (7)	0.0032 (7)	0.0118 (7)
C1	0.0272 (9)	0.0349 (9)	0.0267 (9)	0.0157 (7)	0.0055 (7)	0.0090 (7)
C2	0.0259 (8)	0.0314 (9)	0.0260 (8)	0.0170 (7)	0.0092 (7)	0.0113 (7)
C3	0.0310 (9)	0.0339 (9)	0.0255 (8)	0.0194 (8)	0.0076 (7)	0.0102 (7)
C4	0.0352 (9)	0.0351 (10)	0.0259 (9)	0.0215 (8)	0.0037 (7)	0.0118 (7)
C5	0.0543 (12)	0.0320 (10)	0.0445 (11)	0.0169 (9)	0.0101 (10)	0.0183 (9)
C6	0.0498 (13)	0.0466 (12)	0.0552 (13)	0.0211 (10)	0.0156 (10)	0.0298 (10)
C7	0.0363 (10)	0.0332 (10)	0.0402 (11)	0.0089 (8)	0.0050 (8)	0.0132 (8)
C8	0.0296 (9)	0.0269 (8)	0.0262 (8)	0.0151 (7)	0.0064 (7)	0.0114 (7)
C9	0.0272 (9)	0.0338 (10)	0.0377 (10)	0.0140 (7)	0.0088 (7)	0.0169 (8)
C10	0.0283 (9)	0.0326 (9)	0.0365 (10)	0.0162 (8)	0.0054 (7)	0.0142 (8)
C11	0.0312 (9)	0.0289 (9)	0.0321 (9)	0.0164 (7)	0.0060 (7)	0.0126 (7)
C12	0.0478 (11)	0.0470 (12)	0.0276 (9)	0.0295 (10)	0.0118 (8)	0.0109 (8)
C13	0.0379 (10)	0.0385 (11)	0.0450 (11)	0.0175 (9)	−0.0062 (9)	0.0127 (9)
C14	0.0390 (11)	0.0503 (12)	0.0551 (13)	0.0274 (10)	0.0169 (10)	0.0220 (10)

Geometric parameters (Å, º)

O1—C1	1.359 (2)	C7—H7A	0.9800
O1—N1	1.410 (2)	C7—H7B	0.9800
O2—C4	1.201 (2)	C7—H7C	0.9800
O3—C4	1.331 (2)	C8—C12	1.514 (2)
O3—C5	1.462 (2)	C9—C10	1.528 (2)
O4—C8	1.422 (2)	C9—H9A	0.9900
O4—C9	1.438 (2)	C9—H9B	0.9900
O5—C8	1.418 (2)	C10—C11	1.523 (2)
O5—C11	1.436 (2)	C10—C14	1.526 (3)
N1—C3	1.309 (2)	C10—C13	1.531 (3)
C1—C2	1.357 (2)	C11—H11A	0.9900
C1—C7	1.486 (3)	C11—H11B	0.9900
C2—C3	1.425 (2)	C12—H12A	0.9800
C2—C8	1.520 (2)	C12—H12B	0.9800
C3—C4	1.501 (2)	C12—H12C	0.9800
C5—C6	1.502 (3)	C13—H13A	0.9800
C5—H5A	0.9900	C13—H13B	0.9800
C5—H5B	0.9900	C13—H13C	0.9800
C6—H6A	0.9800	C14—H14A	0.9800
C6—H6B	0.9800	C14—H14B	0.9800
C6—H6C	0.9800	C14—H14C	0.9800
C1—O1—N1	108.82 (13)	O4—C8—C2	110.15 (13)
C4—O3—C5	115.16 (14)	C12—C8—C2	111.17 (14)
C8—O4—C9	114.37 (12)	O4—C9—C10	111.44 (14)
C8—O5—C11	113.54 (12)	O4—C9—H9A	109.3
C3—N1—O1	104.81 (14)	C10—C9—H9A	109.3
C2—C1—O1	110.05 (15)	O4—C9—H9B	109.3
C2—C1—C7	134.39 (16)	C10—C9—H9B	109.3
O1—C1—C7	115.55 (15)	H9A—C9—H9B	108.0
C1—C2—C3	103.36 (15)	C11—C10—C14	109.40 (15)
C1—C2—C8	129.33 (15)	C11—C10—C9	105.59 (14)
C3—C2—C8	127.23 (15)	C14—C10—C9	109.82 (16)
N1—C3—C2	112.96 (16)	C11—C10—C13	110.58 (16)
N1—C3—C4	118.36 (15)	C14—C10—C13	110.89 (16)
C2—C3—C4	128.40 (15)	C9—C10—C13	110.41 (15)
O2—C4—O3	125.16 (17)	O5—C11—C10	111.16 (14)
O2—C4—C3	122.60 (17)	O5—C11—H11A	109.4
O3—C4—C3	112.21 (14)	C10—C11—H11A	109.4
O3—C5—C6	107.30 (16)	O5—C11—H11B	109.4
O3—C5—H5A	110.3	C10—C11—H11B	109.4
C6—C5—H5A	110.3	H11A—C11—H11B	108.0
O3—C5—H5B	110.3	C8—C12—H12A	109.5
C6—C5—H5B	110.3	C8—C12—H12B	109.5
H5A—C5—H5B	108.5	H12A—C12—H12B	109.5
C5—C6—H6A	109.5	C8—C12—H12C	109.5
C5—C6—H6B	109.5	H12A—C12—H12C	109.5
H6A—C6—H6B	109.5	H12B—C12—H12C	109.5
C5—C6—H6C	109.5	C10—C13—H13A	109.5
H6A—C6—H6C	109.5	C10—C13—H13B	109.5
H6B—C6—H6C	109.5	H13A—C13—H13B	109.5
C1—C7—H7A	109.5	C10—C13—H13C	109.5
C1—C7—H7B	109.5	H13A—C13—H13C	109.5
H7A—C7—H7B	109.5	H13B—C13—H13C	109.5
C1—C7—H7C	109.5	C10—C14—H14A	109.5
H7A—C7—H7C	109.5	C10—C14—H14B	109.5
H7B—C7—H7C	109.5	H14A—C14—H14B	109.5
O5—C8—O4	111.63 (13)	C10—C14—H14C	109.5
O5—C8—C12	106.73 (14)	H14A—C14—H14C	109.5
O4—C8—C12	106.27 (14)	H14B—C14—H14C	109.5
O5—C8—C2	110.76 (13)
C1—O1—N1—C3	0.43 (18)	C11—O5—C8—C12	169.54 (14)
N1—O1—C1—C2	0.34 (18)	C11—O5—C8—C2	−69.31 (17)
N1—O1—C1—C7	−178.79 (15)	C9—O4—C8—O5	−52.55 (18)
O1—C1—C2—C3	−0.89 (18)	C9—O4—C8—C12	−168.54 (14)
C7—C1—C2—C3	178.00 (19)	C9—O4—C8—C2	70.94 (17)
O1—C1—C2—C8	−177.80 (15)	C1—C2—C8—O5	−26.4 (2)
C7—C1—C2—C8	1.1 (3)	C3—C2—C8—O5	157.39 (15)
O1—N1—C3—C2	−1.03 (19)	C1—C2—C8—O4	−150.38 (16)
O1—N1—C3—C4	173.42 (14)	C3—C2—C8—O4	33.4 (2)
C1—C2—C3—N1	1.23 (19)	C1—C2—C8—C12	92.1 (2)
C8—C2—C3—N1	178.22 (16)	C3—C2—C8—C12	−84.1 (2)
C1—C2—C3—C4	−172.54 (16)	C8—O4—C9—C10	55.23 (19)
C8—C2—C3—C4	4.5 (3)	O4—C9—C10—C11	−54.89 (18)
C5—O3—C4—O2	0.5 (3)	O4—C9—C10—C14	−172.74 (15)
C5—O3—C4—C3	−177.43 (15)	O4—C9—C10—C13	64.67 (19)
N1—C3—C4—O2	−113.8 (2)	C8—O5—C11—C10	−58.18 (18)
C2—C3—C4—O2	59.7 (3)	C14—C10—C11—O5	174.55 (14)
N1—C3—C4—O3	64.2 (2)	C9—C10—C11—O5	56.42 (18)
C2—C3—C4—O3	−122.30 (18)	C13—C10—C11—O5	−63.03 (18)
C4—O3—C5—C6	172.98 (16)	C2—C8—O4—C9	70.9 (2)
C11—O5—C8—O4	53.83 (17)	C2—C8—O5—C11	−69.3 (2)