7-Acetyl­amino-2,4-dimethyl-1,8-naphthyridine

The air-stable title compound, C₁₂H₁₃N₃O, which is of inter­est due to its anti­bacterial properties, is an almost planar mol­ecule in which the ten atoms forming the 1,8-naphthyridine ring have an r.m.s. deviation of 0.03 Å from the least-squares plane calculated using the ten atoms. The plane of the acetyl­amino group is slightly inclined [11.7 (2)°] to the plane of the 1,8-naphthyridine ring.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.048
• wR factor = 0.153
• Data-to-parameter ratio = 13.5

checkCIF/PLATON results

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PLAT148_ALERT_3_B su on the      a  - Axis is Too Large (x 1000) .          8 Ang.

Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C11

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S1. Comment

The 1,8-naphthyridine compounds have been the focus of studies and practical applications as antibacterial agents (Mogilaiah et al., 2001). Recent parallels in biological activity of this class of compounds have been found in the form of antibacterial (Chen et al., 2001), antiinflammatory (Roma et al., 2000), antihypertensive (Ferrarini et al., 2000), and antiplatelet activity (Ferrarini et al., 1997). In addition to medicinal applications, this class of compounds have been employed in the study of bioorganic and bioorganometallic processes (Saito et al., 2001; He et al., 2001; Nakatani et al., 2000). The structure of the C₁₂H₁₃N₃O in (I) is shown in Fig. 1 and selected bond lengths and angles are given in Table. 1. The structure of this compound is a rigid nearly planar molecule with an r.m.s. deviation of 0.03 Å for the ten atoms making up the 1,8-naphthyridine ring. The least square plane calculated from the atoms of the acetyl amino group make an dihedral angle of 11.7 (2) ° to the least square plane of the 1,8-naphthyridine ring All bond distances are essentially identical to those found in the literature (Catalano et al., 2000).

Related literature

For related literature, see: Bergerhoff (1996); Bruker (2000); Catalano et al. (2000); Chen et al. (2001); Ferrarini et al. (1997, 2000); He & Lippard (2001); Henry & Hammond (1977); Mogilaiah et al. (2001); Nakatani et al. (2000); Roma et al. (2000); Saito et al. (2001).

S2. Experimental

2-amino-5, 7-Dimethyl-1, 8-naphthyridine (Henry et al., 1977) (4.0 g, 0.10 mol) was added to a Ac₂O (15 ml) solution under an atmosphere of N₂. After the solution was stirred at reflux temperature for 1 h, excess solvent was removed and the final product was obtained following flash chromatography. Then, the compound was dissolved in CH₂Cl₂ and recrystallized by slow diffusion of aether into the CH₂Cl₂ solution. Yellow crystals suitable for X-ray diffraction were obtained.

S3. Refinement

All H atoms were placed in calculated positions. The H atoms were then constrained to an ideal geometry with C—H distances of 0.93–0.96 Å, U_iso(H) = 1.2U_eq(C) and N—H distance of 0.86 Å with U_iso(H) = 1.2U_eq(N).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996) and XP (Bruker, 2000); software used to prepare material for publication: SHELXTL (Sheldrick, 2000).

Figures

	Fig. 1. The molecular structure of the title compound drawn with DIAMOND (Bergerhoff, 1996). Displacement ellipsoids at the 30% probability level.
	Fig. 2. The packing of the title compound viewed along the c axis, drawn with XP (Bruker, 2000). H atoms have been omitted. The molecules shown are centered around z=0.0.

7-Acetylamino-2,4-dimethyl-1,8-naphthyridine

Crystal data

C12H13N3O	F(000) = 456.0
Mr = 215.25	Dx = 1.288 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1274 reflections
a = 7.970 (8) Å	θ = 2.7–25.2°
b = 7.309 (7) Å	µ = 0.09 mm^−1
c = 19.071 (18) Å	T = 298 K
β = 91.883 (14)°	Block, pale yellow
V = 1110.4 (18) Å^3	0.52 × 0.36 × 0.24 mm
Z = 4

Data collection

SMART 1K CCD diffractometer	1959 independent reflections
Radiation source: fine-focus sealed tube	1169 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
Detector resolution: 10 pixels mm^-1	θmax = 25.0°, θmin = 2.1°
φ and ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	k = −8→8
Tmin = 0.970, Tmax = 0.980	l = −18→22
5375 measured reflections

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.153	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0724P)^2 + 0.2527P] where P = (Fo^2 + 2Fc^2)/3
1959 reflections	(Δ/σ)max < 0.001
145 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Special details

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
N1	0.8038 (2)	0.1591 (3)	0.16857 (10)	0.0416 (5)
N2	0.6692 (2)	−0.1164 (3)	0.15749 (10)	0.0443 (6)
N3	0.9292 (3)	0.4340 (3)	0.18935 (10)	0.0483 (6)
H3	0.8956	0.4199	0.2314	0.058*
O1	1.0871 (3)	0.6171 (3)	0.12288 (10)	0.0856 (8)
C1	0.7455 (3)	0.0253 (3)	0.12480 (11)	0.0391 (6)
C2	0.6113 (3)	−0.2514 (4)	0.11782 (13)	0.0480 (7)
C3	0.6280 (3)	−0.2537 (4)	0.04464 (14)	0.0546 (7)
H3A	0.5891	−0.3546	0.0192	0.066*
C4	0.6991 (3)	−0.1130 (4)	0.01004 (12)	0.0472 (7)
C5	0.7602 (3)	0.0348 (3)	0.05134 (12)	0.0410 (6)
C6	0.8324 (3)	0.1936 (4)	0.02437 (13)	0.0498 (7)
H6	0.8425	0.2063	−0.0238	0.060*
C7	0.8875 (3)	0.3283 (4)	0.06768 (13)	0.0519 (7)
H7	0.9331	0.4351	0.0499	0.062*
C8	0.8742 (3)	0.3032 (3)	0.14080 (12)	0.0415 (6)
C9	0.5235 (4)	−0.4030 (4)	0.15366 (15)	0.0654 (8)
H9A	0.5582	−0.4054	0.2023	0.098*
H9B	0.5514	−0.5173	0.1322	0.098*
H9C	0.4045	−0.3839	0.1496	0.098*
C10	0.7102 (4)	−0.1127 (4)	−0.06836 (13)	0.0670 (9)
H10A	0.6876	−0.2334	−0.0861	0.100*
H10B	0.8208	−0.0758	−0.0809	0.100*
H10C	0.6291	−0.0287	−0.0882	0.100*
C11	1.0292 (3)	0.5810 (4)	0.17874 (14)	0.0531 (7)
C12	1.0655 (4)	0.6957 (4)	0.24196 (16)	0.0728 (9)
H12A	1.1689	0.7605	0.2364	0.109*
H12B	1.0749	0.6188	0.2827	0.109*
H12C	0.9759	0.7818	0.2475	0.109*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0491 (12)	0.0434 (12)	0.0325 (11)	−0.0017 (10)	0.0048 (9)	0.0003 (10)
N2	0.0509 (12)	0.0426 (13)	0.0394 (12)	0.0014 (10)	0.0001 (9)	0.0032 (10)
N3	0.0605 (13)	0.0505 (14)	0.0348 (11)	−0.0094 (11)	0.0131 (10)	−0.0031 (10)
O1	0.1048 (17)	0.1011 (18)	0.0518 (13)	−0.0489 (14)	0.0190 (12)	0.0028 (12)
C1	0.0413 (13)	0.0436 (15)	0.0323 (13)	0.0071 (11)	0.0007 (10)	−0.0007 (11)
C2	0.0502 (15)	0.0443 (16)	0.0490 (16)	0.0052 (12)	−0.0052 (13)	0.0001 (13)
C3	0.0593 (17)	0.0520 (18)	0.0515 (17)	0.0047 (14)	−0.0120 (14)	−0.0105 (14)
C4	0.0478 (15)	0.0560 (17)	0.0376 (14)	0.0117 (13)	−0.0033 (11)	−0.0068 (13)
C5	0.0408 (13)	0.0503 (16)	0.0318 (13)	0.0076 (12)	0.0005 (10)	0.0005 (12)
C6	0.0562 (15)	0.0649 (18)	0.0285 (13)	0.0037 (14)	0.0053 (11)	0.0025 (13)
C7	0.0626 (17)	0.0556 (17)	0.0381 (14)	−0.0031 (14)	0.0096 (12)	0.0073 (13)
C8	0.0463 (14)	0.0448 (15)	0.0339 (13)	0.0024 (12)	0.0073 (11)	0.0011 (12)
C9	0.073 (2)	0.0542 (19)	0.069 (2)	−0.0094 (15)	−0.0014 (16)	0.0020 (15)
C10	0.078 (2)	0.085 (2)	0.0372 (15)	0.0111 (17)	−0.0053 (14)	−0.0135 (15)
C11	0.0555 (16)	0.0564 (18)	0.0479 (16)	−0.0107 (14)	0.0118 (13)	0.0033 (14)
C12	0.087 (2)	0.068 (2)	0.065 (2)	−0.0249 (18)	0.0199 (16)	−0.0170 (16)

Geometric parameters (Å, º)

N1—C8	1.313 (3)	C5—C6	1.401 (3)
N1—C1	1.357 (3)	C6—C7	1.349 (4)
N2—C2	1.318 (3)	C6—H6	0.9300
N2—C1	1.363 (3)	C7—C8	1.414 (3)
N3—C11	1.357 (3)	C7—H7	0.9300
N3—C8	1.392 (3)	C9—H9A	0.9600
N3—H3	0.8600	C9—H9B	0.9600
O1—C11	1.204 (3)	C9—H9C	0.9600
C1—C5	1.411 (3)	C10—H10A	0.9600
C2—C3	1.406 (4)	C10—H10B	0.9600
C2—C9	1.488 (4)	C10—H10C	0.9600
C3—C4	1.356 (4)	C11—C12	1.489 (4)
C3—H3A	0.9300	C12—H12A	0.9600
C4—C5	1.414 (3)	C12—H12B	0.9600
C4—C10	1.501 (4)	C12—H12C	0.9600
C8—N1—C1	118.2 (2)	C8—C7—H7	120.8
C2—N2—C1	117.4 (2)	N1—C8—N3	114.4 (2)
C11—N3—C8	128.2 (2)	N1—C8—C7	123.3 (2)
C11—N3—H3	115.9	N3—C8—C7	122.3 (2)
C8—N3—H3	115.9	C2—C9—H9A	109.5
N1—C1—N2	114.5 (2)	C2—C9—H9B	109.5
N1—C1—C5	122.5 (2)	H9A—C9—H9B	109.5
N2—C1—C5	123.0 (2)	C2—C9—H9C	109.5
N2—C2—C3	122.4 (2)	H9A—C9—H9C	109.5
N2—C2—C9	117.0 (2)	H9B—C9—H9C	109.5
C3—C2—C9	120.5 (2)	C4—C10—H10A	109.5
C4—C3—C2	121.9 (2)	C4—C10—H10B	109.5
C4—C3—H3A	119.0	H10A—C10—H10B	109.5
C2—C3—H3A	119.0	C4—C10—H10C	109.5
C3—C4—C5	116.7 (2)	H10A—C10—H10C	109.5
C3—C4—C10	121.7 (2)	H10B—C10—H10C	109.5
C5—C4—C10	121.6 (3)	O1—C11—N3	123.3 (3)
C6—C5—C1	117.0 (2)	O1—C11—C12	121.6 (3)
C6—C5—C4	124.5 (2)	N3—C11—C12	115.1 (2)
C1—C5—C4	118.5 (2)	C11—C12—H12A	109.5
C7—C6—C5	120.6 (2)	C11—C12—H12B	109.5
C7—C6—H6	119.7	H12A—C12—H12B	109.5
C5—C6—H6	119.7	C11—C12—H12C	109.5
C6—C7—C8	118.4 (2)	H12A—C12—H12C	109.5
C6—C7—H7	120.8	H12B—C12—H12C	109.5