N-Phenyl-2-nitro­benz­amide, an acridone alkaloid precursor

The structure of N-phenyl-2-nitro­benz­amide, C₁₃H₁₀N₂O₃, likely to be an intermediate in the biosynthesis of acridone alkaloids, is composed of strongly hydrogen-bonded mol­ecules via amido H and carbonyl O atoms [H...O 1.99, N...O 2.8364 (13) Å and N—H...O 167°], thus forming chains along the b axis. The molecular dimensions are normal and the phenyl rings are inclined at right angles [89.41 (5)°] to each other.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.042
• wR factor = 0.128
• Data-to-parameter ratio = 16.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



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S1. Comment

2,4,6-Trimethoxy-N-methylaminobenzophenone (tecleanone; Waterman, 1975; Khalid & Waterman, 1981) and 1,3-dimethoxy-N-methylacridone (Tillequim et al., 1980) have been isolated from different plants. These compounds have very similar structures and the former is thought to be a precursor in the biosynthesis of the latter. The isolation of both of these compounds from the same plants, Teclea verdoorniana and Oricio suareolens, has led to the proposal that aminobenzophenones are probable intermediates in the biosynthesis of acridone alkaloids (Adams et al., 1981). This step is of great importance in biological systems as acridone alkaloids have reported success as anticancer drugs (Adams et al., 1981). The conclusion that aminobenzophenones are likely intermediates in the synthesis of acridone alkaloids is further supported by the biomimetic synthesis of acronycine from benzophenone precursor. For this purpose, N-substituted-2-nitrobenzamide has been prepared from 2-nitrobenzoic acid as an intermediate. In this preparation, 2-nitrobenzoic acid, (1), was converted to its acid chloride, (2), followed by nucleophillic replacement of the chloride by the nitrogen on the aniline molecule, resulting in N-phenyl-2-nitrobenzamide, (3). The crystal structure of (3) has been determined by X-ray crystallographic method and reported in this paper.

The structure of (3) is presented in Fig. 1. The molecular dimensions in (3) are normal and lie within expected values (Orpen et al., 1994) for the corresponding bond distances and angles, with bond distances as follows: mean C—C_aromatic 1.381 (2), N—O 1.217 (4), N—C_aromatic (nitro) 1.470 (2), N—C_aromatic (amino) 1.4142 (17), Csp₂—N 1.3436 (17), Csp²—Csp² 1.5056 (19) and C═O 1.2212 (15) Å. Both the phenyl rings are essentially planar as expected and their mean planes are inclined at right angles, 89.41 (5)°, with respect to each other. The mean plane of the nitro group is oriented at 21.40 (10)° with the plane of the aromatic ring (C1—C6) to which it is attached. The atoms lying in between the two aromatic rings, i.e. atoms O1/N2/C1/C7/C8 are almost planar, with a maximum deviation of 0.103 (2) Å for C7 and the mean planes of the aromatic rings C1—C6 and C8—C13 form dihedral angles of 58.44 (6) and 31.94 (6)°, respectively, with the mean plane of these atoms.

The structure is stabilized by a strong hydrogen bond between the amido H and carbonyl O atoms [H2···O1 1.99 Å, N2···O1 2.8364 (13) Å and N2—H2···O1 167°], thus linking the molecules into chains along the b axis (Fig. 2). A search of the Cambridge Structural Database (Allen et al., 1993) for similar structures revealed a dozens or so phenylbenzamide derivatives closely related to the structure of (3).

S2. Experimental

2-Nitrobenzoic acid, (1) (10 g), was added to benzene (10 ml) and thionyl chloride (10 ml). The mixture was refluxed on a steam bath for 1 h after which more thionyl chloride (10 ml) was added. The mixture was further refluxed for 2 h. The benzene was removed under reduced pressure. The resulting oil was treated with benzene (10 ml) in order to remove excess thionyl chloride. Benzene was removed under reduced pressure and the residue was cooled, leaving a dark brown oil, 2-nitrobenzoyl chloride, (2) (10.5 g). Aniline (10 ml) was added dropwise to (2) and the reaction mixture was left at room temperature for 1 h. Cold water (150 ml) was added and the contents were kept for half an hour. The solid was filtered, washed with water, dried and crystallized from ethanol to give N-phenyl-2-nitrobenzamide, (3) (12.04 g, 87.69%), in the form of colourless prisms suitable for XRD analysis.

S3. Refinement

The space group was determined uniquely from the systematic absences. The H atoms were located from difference Fourier synthesis and were included in the refinement at geometrically idealized positions with C—H = 0.93 Å and N—H = 0.86 Å, utilizing riding models.

Computing details

Data collection: COLLECT (Hooft, 1998); cell refinement: HKL DENZO (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SAPI91 (Fan, 1991); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: TEXSAN (Molecular Structure Corportaion, 1994); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. ORTEPII (Johnson, 1976) drawing of (3) with displacement ellipsoids plotted at the 50% probability level.
	Fig. 2. Hydrogen-bonding pattern in (3) showing a hydrogen-bonded polymeric chain along the b axis.

N-phenyl-2-nitrobenzamide

Crystal data

C13H10N2O3	Dx = 1.373 Mg m^−3
Mr = 242.23	Melting point: 426-428 K K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
a = 7.9406 (1) Å	Cell parameters from 2949 reflections
b = 9.4695 (2) Å	θ = 1.0–27.5°
c = 31.1671 (5) Å	µ = 0.10 mm^−1
V = 2343.56 (7) Å^3	T = 293 K
Z = 8	Prismatic, colorless
F(000) = 1008	0.32 × 0.17 × 0.15 mm

Data collection

Nonius KappaCCD diffractometer	2639 independent reflections
Radiation source: fine-focus sealed tube	1945 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω–2ϕ scans	θmax = 27.5°, θmin = 3.8°
Absorption correction: multi-scan method (SORTAV: Blessing, 1995, 1997)	h = −10→10
Tmin = 0.97, Tmax = 0.99	k = −12→12
4857 measured reflections	l = −40→40

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)] = 0.042	H-atom parameters constrained
wR(F^2) = 0.128	w = 1/[σ^2(Fo^2) + (0.065P)^2 + 0.31P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
2639 reflections	Δρmax = 0.14 e Å^−3
164 parameters	Δρmin = −0.16 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.035 (6)

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

	x	y	z	Uiso*/Ueq
O1	0.67464 (14)	0.25815 (9)	0.12636 (4)	0.0575 (3)
O2	0.81040 (19)	−0.15887 (15)	0.02559 (5)	0.0861 (5)
O3	0.87071 (15)	0.04153 (13)	0.05372 (4)	0.0671 (4)
N1	0.77326 (17)	−0.05512 (13)	0.04633 (4)	0.0515 (3)
N2	0.80030 (15)	0.05103 (11)	0.14434 (4)	0.0444 (3)
H2	0.7933	−0.0389	0.1410	0.053*
C1	0.56302 (18)	0.04938 (13)	0.09612 (4)	0.0406 (3)
C2	0.39453 (19)	0.06428 (16)	0.10733 (5)	0.0550 (4)
H2A	0.3649	0.1262	0.1292	0.066*
C3	0.2705 (2)	−0.0113 (2)	0.08651 (7)	0.0682 (5)
H3	0.1583	0.0010	0.0942	0.082*
C4	0.3113 (2)	−0.1047 (2)	0.05447 (6)	0.0666 (5)
H4	0.2273	−0.1569	0.0411	0.080*
C5	0.4765 (2)	−0.12086 (17)	0.04223 (5)	0.0567 (4)
H5	0.5047	−0.1834	0.0204	0.068*
C6	0.60025 (18)	−0.04335 (13)	0.06269 (4)	0.0422 (3)
C7	0.68841 (17)	0.13027 (13)	0.12274 (5)	0.0406 (3)
C8	0.92844 (17)	0.10094 (13)	0.17196 (4)	0.0397 (3)
C9	1.0050 (2)	0.23047 (15)	0.16618 (5)	0.0524 (4)
H9	0.9736	0.2880	0.1434	0.063*
C10	1.1289 (2)	0.27446 (17)	0.19454 (6)	0.0654 (5)
H10	1.1797	0.3620	0.1907	0.078*
C11	1.1772 (2)	0.19029 (18)	0.22815 (6)	0.0650 (5)
H11	1.2595	0.2208	0.2472	0.078*
C12	1.1025 (2)	0.05965 (17)	0.23334 (5)	0.0588 (4)
H12	1.1353	0.0018	0.2560	0.071*
C13	0.9798 (2)	0.01447 (15)	0.20530 (5)	0.0492 (4)
H13	0.9315	−0.0742	0.2088	0.059*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0644 (7)	0.0268 (5)	0.0813 (8)	0.0038 (4)	−0.0136 (6)	−0.0095 (5)
O2	0.0914 (10)	0.0793 (9)	0.0877 (10)	0.0056 (7)	0.0279 (8)	−0.0350 (7)
O3	0.0525 (7)	0.0706 (8)	0.0782 (8)	−0.0103 (6)	0.0071 (6)	−0.0048 (6)
N1	0.0571 (8)	0.0501 (7)	0.0474 (7)	0.0016 (6)	0.0041 (6)	−0.0052 (6)
N2	0.0535 (7)	0.0254 (5)	0.0541 (7)	−0.0007 (5)	−0.0108 (5)	−0.0064 (4)
C1	0.0432 (8)	0.0298 (6)	0.0488 (7)	0.0017 (5)	−0.0046 (6)	−0.0015 (5)
C2	0.0467 (9)	0.0514 (8)	0.0669 (10)	0.0075 (7)	−0.0033 (7)	−0.0115 (7)
C3	0.0427 (9)	0.0787 (12)	0.0831 (12)	−0.0004 (8)	−0.0076 (8)	−0.0063 (10)
C4	0.0562 (11)	0.0696 (11)	0.0739 (11)	−0.0136 (8)	−0.0184 (9)	−0.0073 (9)
C5	0.0672 (11)	0.0510 (8)	0.0518 (9)	−0.0066 (8)	−0.0107 (7)	−0.0102 (7)
C6	0.0471 (8)	0.0350 (7)	0.0444 (7)	0.0003 (6)	−0.0025 (6)	−0.0013 (5)
C7	0.0455 (8)	0.0279 (6)	0.0484 (7)	0.0007 (5)	0.0000 (6)	−0.0047 (5)
C8	0.0418 (7)	0.0332 (6)	0.0440 (7)	0.0030 (5)	−0.0008 (6)	−0.0085 (5)
C9	0.0586 (9)	0.0403 (8)	0.0582 (9)	−0.0066 (7)	−0.0121 (7)	0.0013 (6)
C10	0.0621 (10)	0.0458 (9)	0.0883 (13)	−0.0085 (8)	−0.0219 (9)	−0.0066 (8)
C11	0.0612 (10)	0.0593 (10)	0.0746 (12)	0.0082 (8)	−0.0261 (9)	−0.0183 (8)
C12	0.0595 (10)	0.0591 (10)	0.0577 (9)	0.0151 (8)	−0.0126 (8)	−0.0017 (7)
C13	0.0495 (9)	0.0400 (7)	0.0582 (9)	0.0054 (6)	−0.0011 (7)	0.0005 (6)

Geometric parameters (Å, º)

O1—C7	1.2212 (15)	C4—H4	0.9300
O2—N1	1.2124 (16)	C5—C6	1.383 (2)
O3—N1	1.2205 (17)	C5—H5	0.9300
N1—C6	1.470 (2)	C8—C9	1.3808 (19)
N2—C7	1.3436 (17)	C8—C13	1.385 (2)
N2—C8	1.4142 (17)	C9—C10	1.387 (2)
N2—H2	0.8600	C9—H9	0.9300
C1—C2	1.390 (2)	C10—C11	1.371 (2)
C1—C6	1.3942 (19)	C10—H10	0.9300
C1—C7	1.5056 (19)	C11—C12	1.382 (3)
C2—C3	1.380 (2)	C11—H11	0.9300
C2—H2A	0.9300	C12—C13	1.376 (2)
C3—C4	1.372 (3)	C12—H12	0.9300
C3—H3	0.9300	C13—H13	0.9300
C4—C5	1.375 (3)
O2—N1—O3	123.65 (14)	C1—C6—N1	120.35 (13)
O2—N1—C6	118.28 (13)	O1—C7—N2	124.52 (13)
O3—N1—C6	118.05 (12)	O1—C7—C1	119.75 (12)
C7—N2—C8	126.45 (11)	N2—C7—C1	115.42 (11)
C7—N2—H2	116.8	C9—C8—C13	119.57 (13)
C8—N2—H2	116.8	C9—C8—N2	122.29 (13)
C2—C1—C6	117.12 (13)	C13—C8—N2	118.13 (12)
C2—C1—C7	116.51 (12)	C8—C9—C10	119.73 (15)
C6—C1—C7	126.31 (13)	C8—C9—H9	120.1
C3—C2—C1	121.07 (15)	C10—C9—H9	120.1
C3—C2—H2A	119.5	C11—C10—C9	120.74 (16)
C1—C2—H2A	119.5	C11—C10—H10	119.6
C4—C3—C2	120.52 (17)	C9—C10—H10	119.6
C4—C3—H3	119.7	C10—C11—C12	119.31 (15)
C2—C3—H3	119.7	C10—C11—H11	120.3
C3—C4—C5	119.95 (15)	C12—C11—H11	120.3
C3—C4—H4	120.0	C13—C12—C11	120.53 (15)
C5—C4—H4	120.0	C13—C12—H12	119.7
C4—C5—C6	119.41 (15)	C11—C12—H12	119.7
C4—C5—H5	120.3	C12—C13—C8	120.08 (14)
C6—C5—H5	120.3	C12—C13—H13	120.0
C5—C6—C1	121.89 (15)	C8—C13—H13	120.0
C5—C6—N1	117.66 (13)
C6—C1—C2—C3	0.9 (2)	C8—N2—C7—C1	−178.92 (13)
C7—C1—C2—C3	−176.39 (15)	C2—C1—C7—O1	−56.26 (19)
C1—C2—C3—C4	0.8 (3)	C6—C1—C7—O1	126.76 (16)
C2—C3—C4—C5	−1.5 (3)	C2—C1—C7—N2	117.69 (15)
C3—C4—C5—C6	0.5 (3)	C6—C1—C7—N2	−59.29 (19)
C4—C5—C6—C1	1.2 (2)	C7—N2—C8—C9	−30.2 (2)
C4—C5—C6—N1	−175.15 (15)	C7—N2—C8—C13	151.10 (14)
C2—C1—C6—C5	−1.9 (2)	C13—C8—C9—C10	−1.9 (2)
C7—C1—C6—C5	175.05 (13)	N2—C8—C9—C10	179.39 (14)
C2—C1—C6—N1	174.38 (13)	C8—C9—C10—C11	0.5 (3)
C7—C1—C6—N1	−8.7 (2)	C9—C10—C11—C12	0.7 (3)
O2—N1—C6—C5	−22.0 (2)	C10—C11—C12—C13	−0.4 (3)
O3—N1—C6—C5	156.65 (14)	C11—C12—C13—C8	−1.0 (2)
O2—N1—C6—C1	161.55 (14)	C9—C8—C13—C12	2.2 (2)
O3—N1—C6—C1	−19.8 (2)	N2—C8—C13—C12	−179.05 (14)
C8—N2—C7—O1	−5.3 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O1^i	0.86	1.99	2.8364 (13)	167

Symmetry code: (i) −x+3/2, y−1/2, z.