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In the title compound, C13H19NO2, the NH2 group participates in intermolecular hydrogen bonding with the O atoms of neighbouring mol­ecules. The shortest distance between the tropone planes exceeds 4.0 Å; this implies that π–π interaction between the tropone rings can hardly be among those factors which determine the crystal packing of this compound.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801003294/ya6011sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801003294/ya6011Isup2.hkl
Contains datablock I

CCDC reference: 159872

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.005 Å
  • R factor = 0.071
  • wR factor = 0.244
  • Data-to-parameter ratio = 20.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Amber Alert Alert Level B:
ABSMU_01 Alert B The ratio of given/expected absorption coefficient lies outside the range 0.95 <> 1.05 Calculated value of mu = 0.076 Value of mu given = 0.080
Yellow Alert Alert Level C:
PLAT_360 Alert C Short C(sp3)-C(sp3) Bond C(11) - C(12) = 1.39 Ang.
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

Troponoids, being a remarkable class of non-benzenoid π-conjugated systems, frequently play an important role as entities determining the specific properties of molecular assemblies. Recently, we have prepared liquid crystals with a tropone core, such as 5-hydroxytropolone and 2-amino-5-hydroxytropone (Mori & Takeshita, 1995; Mori et al., 1997). The troponoid cores enhanced formation of smectic phases when compared with the corresponding benzenoids. We now report the crystal structure of 2-amino-5-hexyloxytropone, (I), which was determined in order to elucidate the substituent effect at 2- and 5-positions of tropone on the crystal packing.

The hexyl chain has an all-trans conformation thus forming an almost planar zigzag; the deviations of atoms from the least squares plane defined by atoms C8–C13 are all within 0.063 (7) Å. The planarity of the seven-membered ring is fairly good; the deviations of atoms from the least squares plane defined by atoms C1–C7 are within 0.023 (4) Å. The C—C bond lengths of the seven-membered ring, apart from the C1—C2 bond, show no apparent bond alternation in contrast to what has been observed for tropolone (Shimanouchi & Sasada, 1973). The average value of the C—C bond lengths, apart from the C1—C2 bond, is 1.388 Å, which agrees with that of tropolone (1.385 Å) and the standard aromatic C—C bond length of 1.392 Å (Lide, 1990). The C1—C2 bond [1.474 (3) Å] is significantly longer than all other bonds in the cycle; the same structural peculiarity had been noted in the tropolone structure.

The NH2 group participates in an N1—H1···O1 intermolecular hydrogen bond [N1···O1i 2.877 (4) Å; symmetry code: (i) -1/2 + x, 1/2 - y, z]. The N···O distance is close to the standard intermolecular N—H.·O distance [N···O 2.89 Å; Kuleshova & Zorkii, 1981]. These hydrogen bonds link molecules of (I) into infinite chains stretching along the a axis of the crystal. Another relatively short intermolecular contact, N1.·O2ii of 3.312 (4) Å [symmetry code: (ii) 3/2 - x, 1/2 + y, 2 - z], is much longer than the above-mentioned standard N—H.·O hydrogen-bonding distance.

The distance between the tropone planes of neighbouring molecules in crystal is greater than 4.0 Å, which is substantially longer than that in tropolone itself (3.715 Å; Shimanouchi & Sasada, 1973). This makes us believe that the ππ interaction can hardly be among those factors which determine the crystal packing of a title compound.

Experimental top

A methanol (5 ml) solution of 5-hexyloxy-2-methoxytropone (0.327 g, 1.38 mmol) and aqueous ammonia (28%, 2 ml) was heated at 373 K for 12 h in a sealed tube. The mixture was extracted with chloroform (50 ml). The extract was dried over MgSO4 and distilled in vacuo and the residue was chromatographed on a silica-gel column (hexane–ethyl acetate, 1:1 v/v) to give the title compound (I) (0.166 g, 54%). Single crystals of (I) were obtained by recrystallization from ethyl acetate.

Refinement top

H atoms bonded to C atoms were included in the refinement at calculated positions as riding models, with C—H set to 0.93 Å for aromatic, 0.96 Å for for CH3 and 0.97 Å for CH2. The H atoms of the NH2 group were located in the difference synthesis and subsequently included in the refinement in an isotropic approximation.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Xtal_GX (Hall & du Boulay, 1995); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. Packing diagram of (I) viewed down the c axis. The H atoms, except for NH2, have been omitted for clarity. The ellipsoids with octant shading and ellipsoids with principal ellipses represent N and O atoms, respectively. Hydrogen bonds are shown as dotted lines.
2-Amino-5-hexyloxytropone top
Crystal data top
C13H19NO2F(000) = 480
Mr = 221.29Dx = 1.133 Mg m3
Monoclinic, P21/aMo Kα radiation, λ = 0.71073 Å
a = 10.7540 (4) ÅCell parameters from 25 reflections
b = 13.9616 (5) Åθ = 10.7–18.2°
c = 8.9464 (4) ŵ = 0.08 mm1
β = 104.9458 (12)°T = 296 K
V = 1297.80 (9) Å3Prism, yellow
Z = 40.40 × 0.37 × 0.17 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
1461 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.019
Graphite monochromatorθmax = 28.0°, θmin = 2.8°
ω–2θ scansh = 140
Absorption correction: ψ scan
(North et al., 1968)
k = 018
Tmin = 0.987, Tmax = 1.000l = 1111
3274 measured reflections3 standard reflections every 120 min
3113 independent reflections intensity decay: 3.1%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.071Hydrogen site location: mixed
wR(F2) = 0.244H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.1195P)2 + 0.2445P]
where P = (Fo2 + 2Fc2)/3
3113 reflections(Δ/σ)max < 0.001
153 parametersΔρmax = 0.48 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C13H19NO2V = 1297.80 (9) Å3
Mr = 221.29Z = 4
Monoclinic, P21/aMo Kα radiation
a = 10.7540 (4) ŵ = 0.08 mm1
b = 13.9616 (5) ÅT = 296 K
c = 8.9464 (4) Å0.40 × 0.37 × 0.17 mm
β = 104.9458 (12)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
1461 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.019
Tmin = 0.987, Tmax = 1.0003 standard reflections every 120 min
3274 measured reflections intensity decay: 3.1%
3113 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0710 restraints
wR(F2) = 0.244H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.48 e Å3
3113 reflectionsΔρmin = 0.27 e Å3
153 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
N10.6758 (3)0.2549 (2)1.0734 (4)0.0696 (8)
O10.90866 (18)0.22072 (15)1.0657 (3)0.0748 (7)
O20.6451 (2)0.08804 (15)0.6873 (3)0.0768 (7)
C10.8277 (2)0.1644 (2)0.9862 (3)0.0562 (7)
C20.6924 (2)0.17955 (19)0.9878 (3)0.0517 (7)
C30.5876 (2)0.1245 (2)0.9134 (3)0.0621 (8)
H30.50960.14620.92710.074*
C40.5768 (3)0.0433 (2)0.8225 (4)0.0627 (8)
H40.49390.01890.78790.075*
C50.6701 (3)0.0069 (2)0.7755 (3)0.0596 (7)
C60.8015 (3)0.0179 (2)0.8111 (4)0.0670 (8)
H60.85200.02180.76740.080*
C70.8660 (3)0.0901 (2)0.8986 (4)0.0654 (8)
H70.95320.09140.90240.079*
C80.5158 (3)0.1230 (2)0.6366 (4)0.0666 (8)
H8A0.46080.07510.57410.080*
H8B0.48260.13760.72510.080*
C90.5181 (3)0.2115 (2)0.5434 (4)0.0788 (10)
H9A0.55180.19530.45590.095*
H9B0.57670.25730.60660.095*
C100.3908 (4)0.2577 (3)0.4852 (5)0.0970 (12)
H10A0.33220.21290.41970.116*
H10B0.35620.27360.57200.116*
C110.3995 (5)0.3487 (4)0.3933 (6)0.1266 (17)
H11A0.42730.33010.30250.152*
H11B0.46700.38840.45620.152*
C120.2905 (6)0.4054 (4)0.3438 (7)0.151 (2)
H12A0.22360.36700.27700.182*
H12B0.26060.42280.43360.182*
C130.3053 (5)0.4937 (4)0.2606 (7)0.143 (2)
H13A0.22440.52670.23100.215*
H13B0.36840.53410.32680.215*
H13C0.33300.47780.16990.215*
H10.596 (4)0.268 (2)1.075 (4)0.084 (10)*
H20.741 (4)0.285 (2)1.124 (4)0.078 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0368 (13)0.0711 (17)0.100 (2)0.0032 (12)0.0167 (13)0.0172 (15)
O10.0379 (10)0.0833 (15)0.1048 (16)0.0130 (10)0.0213 (11)0.0149 (12)
O20.0557 (12)0.0769 (14)0.0984 (16)0.0052 (10)0.0212 (11)0.0224 (12)
C10.0367 (13)0.0620 (17)0.0714 (17)0.0038 (12)0.0167 (12)0.0066 (14)
C20.0346 (12)0.0544 (16)0.0662 (16)0.0015 (11)0.0130 (11)0.0055 (13)
C30.0328 (12)0.0688 (19)0.0841 (19)0.0034 (12)0.0142 (12)0.0021 (16)
C40.0365 (13)0.0683 (18)0.0814 (19)0.0024 (12)0.0116 (12)0.0046 (16)
C50.0489 (15)0.0612 (17)0.0693 (17)0.0011 (13)0.0165 (13)0.0028 (14)
C60.0456 (15)0.076 (2)0.084 (2)0.0038 (14)0.0261 (14)0.0062 (17)
C70.0365 (13)0.077 (2)0.088 (2)0.0013 (13)0.0257 (14)0.0048 (17)
C80.0575 (17)0.0671 (19)0.0730 (19)0.0061 (14)0.0127 (14)0.0007 (15)
C90.080 (2)0.075 (2)0.084 (2)0.0099 (17)0.0251 (18)0.0159 (18)
C100.105 (3)0.097 (3)0.092 (3)0.036 (2)0.030 (2)0.026 (2)
C110.124 (4)0.137 (4)0.127 (4)0.045 (3)0.047 (3)0.054 (3)
C120.124 (4)0.163 (5)0.190 (5)0.051 (4)0.082 (4)0.087 (4)
C130.118 (4)0.132 (4)0.190 (5)0.029 (3)0.056 (4)0.089 (4)
Geometric parameters (Å, º) top
N1—C21.340 (4)C8—H8A0.9700
N1—H10.89 (4)C8—H8B0.9700
N1—H20.84 (4)C9—C101.481 (5)
O1—C11.250 (3)C9—H9A0.9700
O2—C51.367 (3)C9—H9B0.9700
O2—C81.433 (3)C10—C111.530 (5)
C1—C21.474 (3)C10—H10A0.9700
C1—C71.423 (4)C10—H10B0.9700
C2—C31.385 (4)C11—C121.390 (6)
C3—C41.382 (4)C11—H11A0.9700
C3—H30.9300C11—H11B0.9700
C4—C51.376 (4)C12—C131.469 (6)
C4—H40.9300C12—H12A0.9700
C5—C61.409 (4)C12—H12B0.9700
C6—C71.353 (4)C13—H13A0.9600
C6—H60.9300C13—H13B0.9600
C7—H70.9300C13—H13C0.9600
C8—C91.495 (4)
C2—N1—H1116 (2)C10—C9—C8114.1 (3)
C2—N1—H2119 (2)C10—C9—H9A108.7
H1—N1—H2124 (3)C8—C9—H9A108.7
C5—O2—C8119.7 (2)C10—C9—H9B108.7
O1—C1—C7120.9 (2)C8—C9—H9B108.7
O1—C1—C2116.6 (3)H9A—C9—H9B107.6
C7—C1—C2122.5 (2)C9—C10—C11111.8 (4)
N1—C2—C3120.0 (2)C9—C10—H10A109.3
N1—C2—C1113.3 (2)C11—C10—H10A109.3
C3—C2—C1126.7 (3)C9—C10—H10B109.3
C4—C3—C2132.3 (3)C11—C10—H10B109.3
C4—C3—H3113.9H10A—C10—H10B107.9
C2—C3—H3113.9C12—C11—C10118.7 (4)
C5—C4—C3129.8 (3)C12—C11—H11A107.6
C5—C4—H4115.1C10—C11—H11A107.6
C3—C4—H4115.1C12—C11—H11B107.6
O2—C5—C4123.3 (3)C10—C11—H11B107.6
O2—C5—C6111.7 (2)H11A—C11—H11B107.1
C4—C5—C6125.0 (3)C11—C12—C13116.5 (5)
C7—C6—C5130.4 (3)C11—C12—H12A108.2
C7—C6—H6114.8C13—C12—H12A108.2
C5—C6—H6114.8C11—C12—H12B108.2
C6—C7—C1133.1 (3)C13—C12—H12B108.2
C6—C7—H7113.4H12A—C12—H12B107.3
C1—C7—H7113.4C12—C13—H13A109.5
O2—C8—C9107.7 (3)C12—C13—H13B109.5
O2—C8—H8A110.2H13A—C13—H13B109.5
C9—C8—H8A110.2C12—C13—H13C109.5
O2—C8—H8B110.2H13A—C13—H13C109.5
C9—C8—H8B110.2H13B—C13—H13C109.5
H8A—C8—H8B108.5
O1—C1—C2—N11.6 (4)O2—C5—C6—C7177.5 (3)
C7—C1—C2—N1178.0 (3)C4—C5—C6—C72.5 (6)
O1—C1—C2—C3177.7 (3)C5—C6—C7—C11.1 (6)
C7—C1—C2—C32.7 (4)O1—C1—C7—C6176.1 (3)
N1—C2—C3—C4178.3 (3)C2—C1—C7—C64.3 (5)
C1—C2—C3—C40.9 (5)C5—O2—C8—C9180.0 (3)
C2—C3—C4—C51.5 (6)O2—C8—C9—C10178.7 (3)
C8—O2—C5—C41.5 (4)C8—C9—C10—C11179.0 (4)
C8—O2—C5—C6178.5 (3)C9—C10—C11—C12173.7 (5)
C3—C4—C5—O2178.6 (3)C10—C11—C12—C13178.0 (5)
C3—C4—C5—C61.4 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.89 (4)2.00 (4)2.877 (4)171.87
N1—H2···O2ii0.84 (4)2.54 (3)3.312 (4)154.38
Symmetry codes: (i) x1/2, y+1/2, z; (ii) x+3/2, y+1/2, z+2.

Experimental details

Crystal data
Chemical formulaC13H19NO2
Mr221.29
Crystal system, space groupMonoclinic, P21/a
Temperature (K)296
a, b, c (Å)10.7540 (4), 13.9616 (5), 8.9464 (4)
β (°) 104.9458 (12)
V3)1297.80 (9)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.40 × 0.37 × 0.17
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.987, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
3274, 3113, 1461
Rint0.019
(sin θ/λ)max1)0.661
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.071, 0.244, 1.03
No. of reflections3113
No. of parameters153
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.48, 0.27

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, MolEN (Fair, 1990), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), Xtal_GX (Hall & du Boulay, 1995), SHELXL97.

Selected geometric parameters (Å, º) top
N1—C21.340 (4)C1—C71.423 (4)
N1—H10.89 (4)C2—C31.385 (4)
N1—H20.84 (4)C3—C41.382 (4)
O1—C11.250 (3)C4—C51.376 (4)
O2—C51.367 (3)C5—C61.409 (4)
C1—C21.474 (3)C6—C71.353 (4)
C5—O2—C8—C9180.0 (3)C9—C10—C11—C12173.7 (5)
O2—C8—C9—C10178.7 (3)C10—C11—C12—C13178.0 (5)
C8—C9—C10—C11179.0 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.89 (4)2.00 (4)2.877 (4)171.87
N1—H2···O2ii0.84 (4)2.54 (3)3.312 (4)154.38
Symmetry codes: (i) x1/2, y+1/2, z; (ii) x+3/2, y+1/2, z+2.
 

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