(IUCr) Crystallography Journals Online

Abstract top

In the title compound, C₁₁H₁₂N₂O₄, a new hydroxamic acid which belonging to the isoquinole family, the heterocyclic ring adopts a half-chair conformation. The nitro group is essentially coplanar with the aromatic ring. Intermolecular O-HO hydrogen bonds assemble the molecules around inversion centres to form pseudo-dimers.

Comment top

Hydroxamic acids are strong metal ion chelators (Kurzak et al., 1992), they posses a wide spectrum of biological activities, such as antibacterial, antifungal, anti-inflammatory, and anti-asthmatic properties, etc. (Weber, 1983; Miller 1989).

The growing number of published synthetic methods further points to the biological significance of hydroxamic acids (Porcheddu & Giacomelli, 2006). Among this family of hydroxamic acids is the title compound (1). We report herein its synthesis and its crystal structure determination. Synthesis of the title compound has been prepared from the corresponding dihydroisoquinoleine (2) by metachloroperbenzoic acid oxidation (Fig. 1). Imine (2) was described by Bohé and Kammoun (2004), in three steps from the commercially available tertiary alcohol (3).

In the title compound, the heterocyclic ring adopts a half-chair conformation as indicated by the puckering parameters: Q = 0.4224 (14)Å, θ = 57.87 (18)°, φ = 281.2 (2)° (Cremer & Pople, 1975). The nitro group attached on C7 is essentially coplanar with the aromatic nucleus (Fig. 2). The methyl substituent in position 3 of the heterocyclic ring is pseudo-axial, the second methyl in position 3 is pseudo-equatorial.

The conformation of (1) is stabilized by an intramolecular hydrogen bond between the hydroxyl O12—H12 group and atom O11 (Table 1).The molecules are assembled by intermolecualr O-H···O hydrogen bonds to form pseudo dimer arranged around inversion centre (Table 1, Fig. 3)

2-Hydroxy-3,3-dimethyl-7-nitro-3,4-dihydroisoquinolin-1(2H)-one top

Crystal data top

C₁₁H₁₂N₂O₄	F₀₀₀ = 496
M_r = 236.23	D_x = 1.449 Mg m⁻³
Monoclinic, P2₁/n	Melting point: 418 K
Hall symbol: -P 2yn	Mo Kα radiation λ = 0.71073 Å
a = 5.8805 (9) Å	Cell parameters from 2421 reflections
b = 18.605 (4) Å	θ = 2.5–23.2º
c = 10.1588 (17) Å	µ = 0.11 mm⁻¹
β = 103.056 (12)º	T = 296 K
V = 1082.7 (3) Å³	Prism, colourless
Z = 4	0.60 × 0.51 × 0.22 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	3286 independent reflections
Radiation source: sealed tube	2051 reflections with I > 2σ(I)
Monochromator: graphite	R_int = 0.021
T = 296 K	θ_max = 30.4º
φ and ω scans	θ_min = 2.2º
Absorption correction: multi-scan (Coppens et al., 1965)	h = −8→8
T_min = 0.938, T_max = 0.975	k = 0→26
7659 measured reflections	l = 0→14

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.044	H-atom parameters constrained
wR(F²) = 0.151	w = 1/[σ²(F_o²) + (0.0543P)² + 0.0949P] where P = (F_o² + 2F_c²)/3
S = 1.11	(Δ/σ)_max = 0.001
3286 reflections	Δρ_max = 0.26 e Å⁻³
157 parameters	Δρ_min = −0.27 e Å⁻³
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Crystal data top

C₁₁H₁₂N₂O₄	V = 1082.7 (3) Å³
M_r = 236.23	Z = 4
Monoclinic, P2₁/n	Mo Kα
a = 5.8805 (9) Å	µ = 0.11 mm⁻¹
b = 18.605 (4) Å	T = 296 K
c = 10.1588 (17) Å	0.60 × 0.51 × 0.22 mm
β = 103.056 (12)º

Data collection top

Bruker SMART CCD area-detector diffractometer	3286 independent reflections
Absorption correction: multi-scan (Coppens et al., 1965)	2051 reflections with I > 2σ(I)
T_min = 0.938, T_max = 0.975	R_int = 0.021
7659 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	157 parameters
wR(F²) = 0.151	H-atom parameters constrained
S = 1.11	Δρ_max = 0.26 e Å⁻³
3286 reflections	Δρ_min = −0.27 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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

	x	y	z	U_iso*/U_eq
C1	0.7652 (2)	0.53911 (7)	0.36105 (13)	0.0323 (3)
C3	0.7990 (2)	0.67410 (7)	0.36068 (15)	0.0380 (3)
C4	0.8660 (3)	0.66689 (8)	0.22427 (15)	0.0426 (3)
H4A	0.7256	0.6692	0.1527	0.051*
H4B	0.9645	0.7072	0.2127	0.051*
C5	1.1554 (3)	0.59404 (8)	0.13045 (14)	0.0393 (3)
H5	1.1903	0.6347	0.0857	0.047*
C6	1.2662 (3)	0.52948 (8)	0.11699 (14)	0.0410 (3)
H6	1.3779	0.5268	0.0653	0.049*
C7	1.2075 (2)	0.46956 (7)	0.18163 (13)	0.0339 (3)
C8	1.0435 (2)	0.47108 (7)	0.25982 (13)	0.0330 (3)
H8	1.0052	0.4297	0.3015	0.040*
C9	0.9371 (2)	0.53674 (7)	0.27418 (12)	0.0296 (2)
C10	0.9923 (2)	0.59838 (7)	0.21048 (13)	0.0338 (3)
C13	1.0066 (3)	0.68808 (8)	0.47591 (16)	0.0471 (3)
H13A	0.9566	0.6890	0.5596	0.071*
H13B	1.0752	0.7335	0.4625	0.071*
H13C	1.1200	0.6506	0.4789	0.071*
C14	0.6172 (3)	0.73411 (8)	0.35087 (19)	0.0538 (4)
H14A	0.4823	0.7226	0.2813	0.081*
H14B	0.6829	0.7787	0.3294	0.081*
H14C	0.5727	0.7386	0.4358	0.081*
N2	0.6880 (2)	0.60494 (6)	0.38233 (13)	0.0402 (3)
N15	1.3238 (2)	0.40117 (7)	0.16643 (13)	0.0438 (3)
O11	0.69294 (19)	0.48475 (5)	0.40857 (11)	0.0437 (3)
O12	0.5448 (2)	0.61049 (6)	0.47313 (13)	0.0542 (3)
H12	0.5129	0.5702	0.4961	0.081*
O16	1.4723 (3)	0.40057 (7)	0.09958 (16)	0.0701 (4)
O17	1.2691 (3)	0.34788 (6)	0.22078 (16)	0.0724 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0312 (5)	0.0344 (6)	0.0338 (6)	−0.0011 (5)	0.0129 (4)	−0.0013 (5)
C3	0.0393 (7)	0.0316 (6)	0.0463 (8)	0.0024 (5)	0.0163 (5)	0.0012 (5)
C4	0.0514 (8)	0.0382 (7)	0.0403 (7)	0.0039 (6)	0.0146 (6)	0.0078 (5)
C5	0.0468 (8)	0.0409 (7)	0.0340 (7)	−0.0071 (5)	0.0172 (5)	0.0027 (5)
C6	0.0422 (7)	0.0506 (8)	0.0357 (7)	−0.0047 (6)	0.0203 (5)	−0.0025 (6)
C7	0.0331 (6)	0.0385 (7)	0.0323 (6)	−0.0022 (5)	0.0118 (4)	−0.0066 (5)
C8	0.0341 (6)	0.0356 (6)	0.0316 (6)	−0.0023 (4)	0.0125 (4)	−0.0028 (5)
C9	0.0251 (5)	0.0356 (6)	0.0300 (5)	−0.0015 (4)	0.0102 (4)	−0.0009 (4)
C10	0.0369 (6)	0.0378 (7)	0.0283 (6)	−0.0015 (5)	0.0104 (4)	0.0001 (5)
C13	0.0491 (8)	0.0449 (8)	0.0478 (8)	−0.0067 (6)	0.0120 (6)	−0.0062 (6)
C14	0.0549 (10)	0.0395 (8)	0.0710 (11)	0.0094 (7)	0.0224 (8)	0.0025 (7)
N2	0.0398 (6)	0.0384 (6)	0.0484 (7)	0.0012 (5)	0.0225 (5)	−0.0004 (5)
N15	0.0435 (7)	0.0449 (7)	0.0484 (7)	−0.0015 (5)	0.0216 (5)	−0.0107 (5)
O11	0.0474 (6)	0.0392 (5)	0.0530 (6)	−0.0016 (4)	0.0290 (5)	0.0036 (4)
O12	0.0577 (7)	0.0439 (6)	0.0759 (8)	0.0026 (5)	0.0466 (6)	−0.0024 (5)
O16	0.0803 (10)	0.0621 (8)	0.0872 (10)	0.0148 (7)	0.0593 (9)	0.0031 (7)
O17	0.0887 (11)	0.0377 (6)	0.1104 (12)	−0.0020 (6)	0.0633 (10)	−0.0055 (7)

Geometric parameters (Å, °) top

C1—O11	1.2366 (15)	C7—C8	1.3816 (17)
C1—N2	1.3407 (16)	C7—N15	1.4690 (18)
C1—C9	1.4851 (16)	C8—C9	1.3950 (17)
C3—N2	1.4818 (18)	C8—H8	0.9300
C3—C13	1.511 (2)	C9—C10	1.3905 (17)
C3—C4	1.530 (2)	C13—H13A	0.9600
C3—C14	1.533 (2)	C13—H13B	0.9600
C4—C10	1.497 (2)	C13—H13C	0.9600
C4—H4A	0.9700	C14—H14A	0.9600
C4—H4B	0.9700	C14—H14B	0.9600
C5—C6	1.388 (2)	C14—H14C	0.9600
C5—C10	1.3927 (18)	N2—O12	1.3862 (14)
C5—H5	0.9300	N15—O17	1.2130 (17)
C6—C7	1.3768 (19)	N15—O16	1.2215 (16)
C6—H6	0.9300	O12—H12	0.8200

O11—C1—N2	121.69 (11)	C9—C8—H8	121.1
O11—C1—C9	123.22 (11)	C10—C9—C8	121.09 (11)
N2—C1—C9	115.07 (11)	C10—C9—C1	120.91 (11)
N2—C3—C13	109.91 (12)	C8—C9—C1	118.00 (11)
N2—C3—C4	105.70 (11)	C9—C10—C5	119.18 (12)
C13—C3—C4	112.86 (12)	C9—C10—C4	119.07 (12)
N2—C3—C14	108.53 (12)	C5—C10—C4	121.68 (12)
C13—C3—C14	110.76 (13)	C3—C13—H13A	109.5
C4—C3—C14	108.88 (12)	C3—C13—H13B	109.5
C10—C4—C3	113.20 (11)	H13A—C13—H13B	109.5
C10—C4—H4A	108.9	C3—C13—H13C	109.5
C3—C4—H4A	108.9	H13A—C13—H13C	109.5
C10—C4—H4B	108.9	H13B—C13—H13C	109.5
C3—C4—H4B	108.9	C3—C14—H14A	109.5
H4A—C4—H4B	107.8	C3—C14—H14B	109.5
C6—C5—C10	120.56 (12)	H14A—C14—H14B	109.5
C6—C5—H5	119.7	C3—C14—H14C	109.5
C10—C5—H5	119.7	H14A—C14—H14C	109.5
C7—C6—C5	118.67 (12)	H14B—C14—H14C	109.5
C7—C6—H6	120.7	C1—N2—O12	117.02 (11)
C5—C6—H6	120.7	C1—N2—C3	126.35 (11)
C6—C7—C8	122.71 (12)	O12—N2—C3	112.85 (10)
C6—C7—N15	118.59 (11)	O17—N15—O16	122.81 (13)
C8—C7—N15	118.70 (12)	O17—N15—C7	118.86 (12)
C7—C8—C9	117.77 (11)	O16—N15—C7	118.34 (12)
C7—C8—H8	121.1	N2—O12—H12	109.5

Hydrogen-bond geometry (Å, °) top

D—H···A	D—H	H···A	D···A	D—H···A
O12—H12···O11ⁱ	0.82	1.99	2.7013 (14)	144
O12—H12···O11	0.82	2.20	2.6305 (15)	113

Symmetry codes: (i) −x+1, −y+1, −z+1.

Table 1
Hydrogen-bond geometry (Å, °) top

D—H···A	D—H	H···A	D···A	D—H···A
O12—H12···O11ⁱ	0.82	1.99	2.7013 (14)	144
O12—H12···O11	0.82	2.20	2.6305 (15)	113

Symmetry codes: (i) −x+1, −y+1, −z+1.

supplementary materials

2-Hydroxy-3,3-dimethyl-7-nitro-3,4-dihydroisoquinolin-1(2H)-one

H. Ben Salah, M. Kammoun, B. Hamdi, L. Bohé and M. Damak

	Fig. 1. Chemical pathway of the formation of hydroxamic acid.
	Fig. 2. Molecular view of the title compound with the atom-labelling scheme. Ellispsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.
	Fig. 3. Partial packing view showing the formation of pseudo dimer through O-H···O hydrogen bonds. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bondings have been omitted for clarity. [Symmetry code: (i) 1-x, 1-y, 1-z]