3,4-Dimethyl-N-(2,4,5-trimeth­oxy­benzyl­idene)-1,2-isoxazol-5-amine

In the title compound, C₁₅H₁₈N₂O₄, the aromatic rings on the azomethine double bond are trans to each other [C-C=N-C torsion angle = -178.29 (12)°] and they are approximately coplanar, the dihedral angle between them being 5.0 (1)°.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.046
• wR factor = 0.139
• Data-to-parameter ratio = 16.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         13
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         14

Alert level G
PLAT154_ALERT_1_G The su's on the Cell Angles are Equal  (x 10000)        100 Deg.

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

   1 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
   1 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 is yet no structural report on a Schiff-base condensation product involving 5-amino-3,4-dimethylisoxazole, a commerically available chemical. We recently reported the spectroscopic characterization of the N-ethylcarbazole-3-aldehyde condensation product of this amine (Asiri et al., 2010). The 2,4,5-trimethyoxybenzaldehyde condensation product (Scheme I, Fig. 1) features an azomethine double-bond whose aromatic substituents are located in trans positions. The rings are coplanar [dihedral angle 5.0 (1)°].

Related literature

For the spectroscopic characterization of a related Schiff base, see: Asiri et al. (2010).

S2. Experimental

5-Amino-3,4-dimethylisoxazole (0.36 g, 3.2 mol) and 2,4,5-trimethoxybenzaldehyde (0.62 g, 3.2 mol) were heated in methanol (15 ml) for 5 h. The solvent was removed and the solid material recrystallized from methanol to give the crystalline Schiff base.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions [C–H 0.95 to 0.98 Å, U(H) 1.2 to 1.5U_eq(C)] and were included in the refinement in the riding model approximation.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

Fig. 1. Anisotropic displacement ellipsoid plot (Barbour, 2001) of C15H18N2O4 at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

3,4-Dimethyl-N-(2,4,5-trimethoxybenzylidene)-1,2-isoxazol-5-amine

Crystal data

C15H18N2O4	Z = 2
Mr = 290.31	F(000) = 308
Triclinic, P1	Dx = 1.342 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.6502 (5) Å	Cell parameters from 3842 reflections
b = 10.9012 (8) Å	θ = 3.1–28.3°
c = 11.2582 (8) Å	µ = 0.10 mm^−1
α = 63.463 (1)°	T = 100 K
β = 83.078 (1)°	Prism, yellow
γ = 79.985 (1)°	0.35 × 0.15 × 0.10 mm
V = 718.20 (9) Å^3

Data collection

Bruker SMART APEX diffractometer	2660 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.026
Graphite monochromator	θmax = 27.5°, θmin = 2.0°
ω scans	h = −8→7
6732 measured reflections	k = −14→14
3274 independent reflections	l = −14→14

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.139	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0858P)^2 + 0.1878P] where P = (Fo^2 + 2Fc^2)/3
3274 reflections	(Δ/σ)max = 0.001
195 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

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

	x	y	z	Uiso*/Ueq
O1	0.73187 (15)	0.64886 (10)	0.40960 (10)	0.0229 (2)
O2	0.14017 (16)	0.97942 (10)	0.20733 (9)	0.0222 (2)
O3	−0.06033 (15)	0.89581 (10)	0.43158 (9)	0.0225 (2)
O4	0.72778 (15)	0.35850 (10)	0.86306 (9)	0.0212 (2)
N1	0.42768 (18)	0.50963 (11)	0.76624 (11)	0.0190 (3)
N2	0.79017 (19)	0.25984 (12)	0.99100 (11)	0.0223 (3)
C1	0.4264 (2)	0.66108 (13)	0.53406 (13)	0.0184 (3)
C2	0.5358 (2)	0.70964 (14)	0.41095 (13)	0.0185 (3)
C3	0.4429 (2)	0.81575 (14)	0.29816 (13)	0.0191 (3)
H3	0.5160	0.8470	0.2144	0.023*
C4	0.2442 (2)	0.87494 (13)	0.30920 (13)	0.0184 (3)
C5	0.1333 (2)	0.82831 (14)	0.43353 (13)	0.0187 (3)
C6	0.2246 (2)	0.72188 (14)	0.54297 (13)	0.0188 (3)
H6	0.1498	0.6889	0.6261	0.023*
C7	0.8522 (2)	0.69800 (16)	0.28703 (14)	0.0248 (3)
H7A	0.9905	0.6468	0.3013	0.037*
H7B	0.8592	0.7968	0.2555	0.037*
H7C	0.7891	0.6840	0.2205	0.037*
C8	0.2345 (2)	1.02354 (15)	0.07629 (13)	0.0215 (3)
H8A	0.1427	1.0982	0.0126	0.032*
H8B	0.2623	0.9454	0.0530	0.032*
H8C	0.3632	1.0572	0.0736	0.032*
C9	−0.1756 (2)	0.85422 (16)	0.55545 (14)	0.0246 (3)
H9A	−0.3094	0.9116	0.5426	0.037*
H9B	−0.1021	0.8657	0.6195	0.037*
H9C	−0.1944	0.7569	0.5894	0.037*
C10	0.5224 (2)	0.55118 (14)	0.65057 (13)	0.0187 (3)
H10	0.6573	0.5089	0.6419	0.022*
C11	0.5270 (2)	0.40739 (13)	0.87469 (13)	0.0182 (3)
C12	0.4552 (2)	0.34506 (13)	1.00327 (13)	0.0179 (3)
C13	0.2444 (2)	0.36953 (15)	1.05885 (14)	0.0241 (3)
H13A	0.1663	0.4497	0.9908	0.036*
H13B	0.2527	0.3874	1.1360	0.036*
H13C	0.1762	0.2876	1.0862	0.036*
C14	0.6264 (2)	0.25434 (13)	1.07118 (13)	0.0187 (3)
C15	0.6394 (2)	0.15920 (15)	1.21572 (14)	0.0242 (3)
H15A	0.7754	0.1046	1.2323	0.036*
H15B	0.5354	0.0969	1.2428	0.036*
H15C	0.6161	0.2135	1.2670	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0179 (5)	0.0253 (5)	0.0175 (5)	0.0020 (4)	0.0022 (4)	−0.0046 (4)
O2	0.0224 (5)	0.0221 (5)	0.0123 (5)	0.0029 (4)	0.0006 (4)	−0.0011 (4)
O3	0.0194 (5)	0.0247 (5)	0.0143 (5)	0.0027 (4)	0.0013 (4)	−0.0029 (4)
O4	0.0193 (5)	0.0218 (5)	0.0152 (5)	0.0017 (4)	−0.0003 (4)	−0.0033 (4)
N1	0.0199 (6)	0.0176 (5)	0.0150 (5)	−0.0004 (4)	−0.0012 (4)	−0.0039 (4)
N2	0.0238 (6)	0.0207 (6)	0.0161 (6)	0.0018 (5)	−0.0034 (5)	−0.0036 (5)
C1	0.0197 (7)	0.0176 (6)	0.0150 (6)	−0.0017 (5)	−0.0004 (5)	−0.0051 (5)
C2	0.0168 (7)	0.0190 (6)	0.0175 (6)	−0.0003 (5)	0.0004 (5)	−0.0070 (5)
C3	0.0205 (7)	0.0186 (6)	0.0145 (6)	−0.0030 (5)	0.0016 (5)	−0.0045 (5)
C4	0.0217 (7)	0.0159 (6)	0.0133 (6)	−0.0009 (5)	−0.0010 (5)	−0.0030 (5)
C5	0.0184 (7)	0.0198 (6)	0.0153 (6)	−0.0015 (5)	0.0004 (5)	−0.0059 (5)
C6	0.0202 (7)	0.0194 (6)	0.0129 (6)	−0.0024 (5)	0.0013 (5)	−0.0043 (5)
C7	0.0191 (7)	0.0323 (8)	0.0198 (7)	−0.0035 (6)	0.0055 (5)	−0.0102 (6)
C8	0.0255 (7)	0.0218 (7)	0.0116 (6)	−0.0016 (5)	0.0013 (5)	−0.0034 (5)
C9	0.0218 (7)	0.0284 (7)	0.0165 (7)	−0.0006 (6)	0.0035 (5)	−0.0058 (6)
C10	0.0185 (7)	0.0173 (6)	0.0175 (6)	−0.0001 (5)	−0.0012 (5)	−0.0059 (5)
C11	0.0176 (7)	0.0168 (6)	0.0180 (6)	0.0006 (5)	−0.0016 (5)	−0.0065 (5)
C12	0.0196 (7)	0.0157 (6)	0.0160 (6)	−0.0004 (5)	−0.0015 (5)	−0.0053 (5)
C13	0.0210 (7)	0.0262 (7)	0.0182 (7)	0.0002 (5)	0.0012 (5)	−0.0054 (6)
C14	0.0223 (7)	0.0159 (6)	0.0162 (6)	−0.0004 (5)	−0.0020 (5)	−0.0059 (5)
C15	0.0285 (8)	0.0220 (7)	0.0163 (6)	0.0015 (6)	−0.0042 (6)	−0.0042 (5)

Geometric parameters (Å, º)

O1—C2	1.3576 (16)	C7—H7A	0.9800
O1—C7	1.4330 (16)	C7—H7B	0.9800
O2—C4	1.3570 (16)	C7—H7C	0.9800
O2—C8	1.4316 (15)	C8—H8A	0.9800
O3—C5	1.3647 (17)	C8—H8B	0.9800
O3—C9	1.4269 (16)	C8—H8C	0.9800
O4—C11	1.3623 (16)	C9—H9A	0.9800
O4—N2	1.4171 (14)	C9—H9B	0.9800
N1—C10	1.2932 (18)	C9—H9C	0.9800
N1—C11	1.3755 (17)	C10—H10	0.9500
N2—C14	1.3197 (18)	C11—C12	1.3611 (18)
C1—C6	1.403 (2)	C12—C14	1.4148 (19)
C1—C2	1.4020 (18)	C12—C13	1.4951 (19)
C1—C10	1.4474 (18)	C13—H13A	0.9800
C2—C3	1.4001 (18)	C13—H13B	0.9800
C3—C4	1.3830 (19)	C13—H13C	0.9800
C3—H3	0.9500	C14—C15	1.4919 (18)
C4—C5	1.4171 (18)	C15—H15A	0.9800
C5—C6	1.3752 (18)	C15—H15B	0.9800
C6—H6	0.9500	C15—H15C	0.9800
C2—O1—C7	118.39 (11)	O2—C8—H8C	109.5
C4—O2—C8	117.96 (10)	H8A—C8—H8C	109.5
C5—O3—C9	116.69 (10)	H8B—C8—H8C	109.5
C11—O4—N2	107.97 (10)	O3—C9—H9A	109.5
C10—N1—C11	119.06 (12)	O3—C9—H9B	109.5
C14—N2—O4	105.38 (11)	H9A—C9—H9B	109.5
C6—C1—C2	119.14 (12)	O3—C9—H9C	109.5
C6—C1—C10	120.67 (12)	H9A—C9—H9C	109.5
C2—C1—C10	120.18 (13)	H9B—C9—H9C	109.5
O1—C2—C3	123.52 (12)	N1—C10—C1	121.13 (13)
O1—C2—C1	116.28 (12)	N1—C10—H10	119.4
C3—C2—C1	120.21 (12)	C1—C10—H10	119.4
C4—C3—C2	119.75 (12)	C12—C11—O4	110.29 (11)
C4—C3—H3	120.1	C12—C11—N1	128.95 (12)
C2—C3—H3	120.1	O4—C11—N1	120.70 (12)
O2—C4—C3	124.84 (12)	C11—C12—C14	103.98 (12)
O2—C4—C5	114.60 (12)	C11—C12—C13	127.53 (12)
C3—C4—C5	120.55 (12)	C14—C12—C13	128.48 (12)
O3—C5—C6	125.95 (12)	C12—C13—H13A	109.5
O3—C5—C4	114.91 (11)	C12—C13—H13B	109.5
C6—C5—C4	119.13 (13)	H13A—C13—H13B	109.5
C5—C6—C1	121.19 (13)	C12—C13—H13C	109.5
C5—C6—H6	119.4	H13A—C13—H13C	109.5
C1—C6—H6	119.4	H13B—C13—H13C	109.5
O1—C7—H7A	109.5	N2—C14—C12	112.38 (12)
O1—C7—H7B	109.5	N2—C14—C15	119.39 (13)
H7A—C7—H7B	109.5	C12—C14—C15	128.23 (13)
O1—C7—H7C	109.5	C14—C15—H15A	109.5
H7A—C7—H7C	109.5	C14—C15—H15B	109.5
H7B—C7—H7C	109.5	H15A—C15—H15B	109.5
O2—C8—H8A	109.5	C14—C15—H15C	109.5
O2—C8—H8B	109.5	H15A—C15—H15C	109.5
H8A—C8—H8B	109.5	H15B—C15—H15C	109.5
C11—O4—N2—C14	0.25 (14)	C4—C5—C6—C1	1.4 (2)
C7—O1—C2—C3	1.6 (2)	C2—C1—C6—C5	−0.3 (2)
C7—O1—C2—C1	−178.00 (12)	C10—C1—C6—C5	178.63 (12)
C6—C1—C2—O1	178.43 (12)	C11—N1—C10—C1	−178.29 (12)
C10—C1—C2—O1	−0.54 (19)	C6—C1—C10—N1	−2.4 (2)
C6—C1—C2—C3	−1.2 (2)	C2—C1—C10—N1	176.54 (13)
C10—C1—C2—C3	179.87 (12)	N2—O4—C11—C12	−0.41 (15)
O1—C2—C3—C4	−177.98 (12)	N2—O4—C11—N1	177.21 (11)
C1—C2—C3—C4	1.6 (2)	C10—N1—C11—C12	−177.34 (14)
C8—O2—C4—C3	6.2 (2)	C10—N1—C11—O4	5.53 (19)
C8—O2—C4—C5	−174.26 (12)	O4—C11—C12—C14	0.40 (15)
C2—C3—C4—O2	179.01 (12)	N1—C11—C12—C14	−176.98 (13)
C2—C3—C4—C5	−0.5 (2)	O4—C11—C12—C13	179.52 (13)
C9—O3—C5—C6	1.8 (2)	N1—C11—C12—C13	2.1 (2)
C9—O3—C5—C4	−178.54 (12)	O4—N2—C14—C12	0.00 (15)
O2—C4—C5—O3	−0.17 (18)	O4—N2—C14—C15	−179.83 (11)
C3—C4—C5—O3	179.42 (12)	C11—C12—C14—N2	−0.24 (16)
O2—C4—C5—C6	179.47 (12)	C13—C12—C14—N2	−179.36 (13)
C3—C4—C5—C6	−0.9 (2)	C11—C12—C14—C15	179.57 (14)
O3—C5—C6—C1	−179.04 (13)	C13—C12—C14—C15	0.5 (2)