Ethyl 2-methyl-4-phenyl-pyrido[1,2-a]benzimidazole-3-carboxyl-ate.

The title compound, C(21)H(18)N(2)O(2), was synthesized using a novel tandem annulation reaction between (1H-benzimidazol-2-yl)(phen-yl)methanone and (E)-ethyl 4-bromo-but-2-enoate under mild conditions. The dihedral angles between the mean planes of the five-membered imidazole ring and the pyridine, benzene and phenyl rings are 0.45 (6), 1.69 (1) and 70.96 (8)°, respectively. In the crystal, mol-ecules are linked through inter-molecular C-H⋯N hydrogen bonds.

Related literature

For applications of nitro­gen-containing heterocyclic compounds in the agrochemical and pharmaceutical fields, see: Ge et al. (2009 ▶). For the synthesis of the title compound, see: Ge et al. (2011 ▶). For the structure of 2,7,8-trimethyl-3-eth­oxy­carbonyl-4- phenyl­pyrido[1,2-a]benzimidazole, see: Ge et al.(2011 ▶). Some pyrido[1,2-a]benzimidazole derivatives are of inter­est for their biological activity, such as anti­neoplastic activity and central GABA-A receptor modulators for the treatment of anxiety, see: Badawey & Kappe (1999 ▶).

Experimental

Crystal data

C21H18N2O2

M = 330.37

Monoclinic,

a = 10.1176 (13) Å

b = 14.9136 (18) Å

c = 12.2648 (15) Å

β = 108.487 (2)°

V = 1755.1 (4) Å3

Z = 4

Mo Kα radiation

μ = 0.08 mm−1

T = 298 K

0.26 × 0.22 × 0.19 mm

Data collection

Bruker SMART APEX CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.979, T max = 0.985

8867 measured reflections

3093 independent reflections

2515 reflections with I > 2σ(I)

R int = 0.021

Refinement

R[F 2 > 2σ(F 2)] = 0.036

wR(F 2) = 0.096

S = 1.06

3093 reflections

227 parameters

H-atom parameters constrained

Δρmax = 0.18 e Å−3

Δρmin = −0.16 e Å−3

Data collection: SMART (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811039973/fj2449sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811039973/fj2449Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811039973/fj2449Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C21H18N2O2	F(000) = 696
Mr = 330.37	Dx = 1.250 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4793 reflections
a = 10.1176 (13) Å	θ = 2.2–28.2°
b = 14.9136 (18) Å	µ = 0.08 mm−1
c = 12.2648 (15) Å	T = 298 K
β = 108.487 (2)°	BLOCK, yellow
V = 1755.1 (4) Å3	0.26 × 0.22 × 0.19 mm
Z = 4

Bruker SMART APEX CCD diffractometer	3093 independent reflections
Radiation source: fine-focus sealed tube	2515 reflections with I > 2σ(I)
graphite	Rint = 0.021
φ and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→12
Tmin = 0.979, Tmax = 0.985	k = −10→17
8867 measured reflections	l = −14→14

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)] = 0.036	H-atom parameters constrained
wR(F2) = 0.096	w = 1/[σ2(Fo2) + (0.0406P)2 + 0.4084P] where P = (Fo2 + 2Fc2)/3
S = 1.06	(Δ/σ)max < 0.001
3093 reflections	Δρmax = 0.18 e Å−3
227 parameters	Δρmin = −0.16 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0077 (13)

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.

	x	y	z	Uiso*/Ueq
O1	0.10877 (12)	0.07612 (10)	0.79576 (12)	0.0806 (4)
O2	0.26487 (10)	−0.01607 (7)	0.91064 (10)	0.0565 (3)
N1	0.57376 (11)	0.22116 (7)	0.87282 (9)	0.0359 (3)
N2	0.60190 (12)	0.26824 (8)	1.05384 (9)	0.0436 (3)
C1	0.68800 (13)	0.27812 (9)	0.90225 (11)	0.0375 (3)
C2	0.70311 (14)	0.30576 (9)	1.01441 (11)	0.0398 (3)
C3	0.81352 (16)	0.36238 (11)	1.07098 (13)	0.0508 (4)
H3	0.8262	0.3817	1.1457	0.061*
C4	0.90241 (16)	0.38855 (11)	1.01303 (14)	0.0545 (4)
H4	0.9767	0.4260	1.0496	0.065*
C5	0.88497 (16)	0.36077 (11)	0.90058 (14)	0.0540 (4)
H5	0.9473	0.3804	0.8640	0.065*
C6	0.77758 (15)	0.30500 (10)	0.84297 (13)	0.0468 (4)
H6	0.7654	0.2862	0.7681	0.056*
C7	0.52624 (13)	0.21772 (9)	0.96751 (11)	0.0365 (3)
C8	0.40891 (14)	0.16270 (9)	0.95981 (11)	0.0385 (3)
C9	0.35444 (14)	0.15819 (10)	1.05942 (12)	0.0406 (3)
C10	0.42867 (17)	0.11386 (11)	1.15914 (13)	0.0511 (4)
H10	0.5136	0.0872	1.1647	0.061*
C11	0.3766 (2)	0.10917 (13)	1.25066 (14)	0.0637 (5)
H11	0.4261	0.0784	1.3170	0.076*
C12	0.2527 (2)	0.14964 (13)	1.24415 (16)	0.0677 (5)
H12	0.2186	0.1466	1.3061	0.081*
C13	0.17917 (19)	0.19447 (12)	1.14640 (17)	0.0634 (5)
H13	0.0956	0.2225	1.1422	0.076*
C14	0.22908 (16)	0.19811 (11)	1.05370 (14)	0.0517 (4)
H14	0.1778	0.2277	0.9869	0.062*
C15	0.34899 (14)	0.11679 (9)	0.85925 (11)	0.0389 (3)
C16	0.39968 (14)	0.12299 (9)	0.76289 (11)	0.0400 (3)
C17	0.51144 (14)	0.17530 (9)	0.77255 (11)	0.0398 (3)
H17	0.5464	0.1803	0.7112	0.048*
C18	0.33086 (17)	0.07371 (12)	0.65248 (12)	0.0548 (4)
H18A	0.3839	0.0823	0.6008	0.082*
H18B	0.2382	0.0965	0.6179	0.082*
H18C	0.3265	0.0109	0.6682	0.082*
C19	0.22564 (15)	0.05809 (10)	0.85009 (12)	0.0443 (3)
C20	0.15708 (18)	−0.07492 (11)	0.92566 (16)	0.0598 (4)
H20A	0.1769	−0.1366	0.9109	0.072*
H20B	0.0673	−0.0587	0.8717	0.072*
C21	0.15356 (18)	−0.06592 (12)	1.04557 (16)	0.0656 (5)
H21A	0.2437	−0.0800	1.0985	0.098*
H21B	0.0855	−0.1064	1.0572	0.098*
H21C	0.1292	−0.0055	1.0583	0.098*

	U11	U22	U33	U12	U13	U23
O1	0.0426 (7)	0.0950 (10)	0.0882 (9)	−0.0126 (6)	−0.0019 (6)	0.0330 (8)
O2	0.0439 (6)	0.0466 (6)	0.0797 (8)	−0.0035 (5)	0.0206 (5)	0.0096 (6)
N1	0.0368 (6)	0.0431 (6)	0.0287 (5)	−0.0039 (5)	0.0119 (5)	0.0010 (5)
N2	0.0455 (7)	0.0532 (7)	0.0345 (6)	−0.0091 (6)	0.0160 (5)	−0.0049 (5)
C1	0.0355 (7)	0.0412 (7)	0.0352 (7)	−0.0016 (6)	0.0105 (6)	0.0041 (6)
C2	0.0404 (7)	0.0438 (8)	0.0347 (7)	−0.0027 (6)	0.0111 (6)	0.0021 (6)
C3	0.0526 (9)	0.0554 (9)	0.0407 (8)	−0.0105 (7)	0.0093 (7)	−0.0024 (7)
C4	0.0449 (8)	0.0561 (10)	0.0555 (10)	−0.0134 (7)	0.0062 (7)	0.0057 (7)
C5	0.0443 (8)	0.0637 (10)	0.0559 (10)	−0.0092 (7)	0.0187 (7)	0.0121 (8)
C6	0.0468 (8)	0.0558 (9)	0.0408 (8)	−0.0046 (7)	0.0182 (7)	0.0061 (7)
C7	0.0375 (7)	0.0438 (8)	0.0295 (6)	−0.0014 (6)	0.0125 (5)	0.0014 (6)
C8	0.0372 (7)	0.0455 (8)	0.0336 (7)	−0.0006 (6)	0.0126 (6)	0.0031 (6)
C9	0.0414 (8)	0.0452 (8)	0.0386 (7)	−0.0096 (6)	0.0176 (6)	−0.0036 (6)
C10	0.0502 (9)	0.0640 (10)	0.0421 (8)	−0.0040 (8)	0.0187 (7)	0.0028 (7)
C11	0.0735 (12)	0.0798 (12)	0.0428 (9)	−0.0143 (10)	0.0257 (8)	0.0046 (8)
C12	0.0809 (13)	0.0801 (13)	0.0603 (11)	−0.0246 (11)	0.0483 (10)	−0.0144 (10)
C13	0.0583 (10)	0.0676 (11)	0.0788 (13)	−0.0100 (9)	0.0425 (10)	−0.0138 (10)
C14	0.0472 (8)	0.0547 (9)	0.0572 (9)	−0.0036 (7)	0.0224 (7)	−0.0012 (7)
C15	0.0365 (7)	0.0430 (8)	0.0362 (7)	−0.0008 (6)	0.0100 (6)	0.0037 (6)
C16	0.0421 (8)	0.0440 (8)	0.0320 (7)	−0.0008 (6)	0.0090 (6)	0.0008 (6)
C17	0.0445 (8)	0.0480 (8)	0.0278 (7)	−0.0012 (6)	0.0129 (6)	0.0000 (6)
C18	0.0591 (10)	0.0625 (10)	0.0397 (8)	−0.0102 (8)	0.0113 (7)	−0.0080 (7)
C19	0.0394 (8)	0.0531 (9)	0.0398 (7)	−0.0045 (7)	0.0115 (6)	−0.0019 (7)
C20	0.0554 (10)	0.0456 (9)	0.0834 (12)	−0.0115 (7)	0.0291 (9)	0.0012 (8)
C21	0.0583 (10)	0.0596 (11)	0.0838 (13)	0.0024 (8)	0.0294 (10)	0.0088 (9)

O1—C19	1.1894 (18)	C10—C11	1.385 (2)
O2—C19	1.3211 (18)	C10—H10	0.9300
O2—C20	1.4564 (18)	C11—C12	1.371 (3)
N1—C17	1.3733 (16)	C11—H11	0.9300
N1—C1	1.3868 (17)	C12—C13	1.368 (3)
N1—C7	1.3917 (16)	C12—H12	0.9300
N2—C7	1.3270 (17)	C13—C14	1.384 (2)
N2—C2	1.3818 (17)	C13—H13	0.9300
C1—C6	1.3887 (19)	C14—H14	0.9300
C1—C2	1.3973 (19)	C15—C16	1.4328 (19)
C2—C3	1.397 (2)	C15—C19	1.4992 (19)
C3—C4	1.368 (2)	C16—C17	1.3477 (19)
C3—H3	0.9300	C16—C18	1.5036 (19)
C4—C5	1.397 (2)	C17—H17	0.9300
C4—H4	0.9300	C18—H18A	0.9600
C5—C6	1.373 (2)	C18—H18B	0.9600
C5—H5	0.9300	C18—H18C	0.9600
C6—H6	0.9300	C20—C21	1.488 (3)
C7—C8	1.4214 (19)	C20—H20A	0.9700
C8—C15	1.3722 (19)	C20—H20B	0.9700
C8—C9	1.4926 (19)	C21—H21A	0.9600
C9—C14	1.383 (2)	C21—H21B	0.9600
C9—C10	1.384 (2)	C21—H21C	0.9600
C19—O2—C20	118.17 (12)	C13—C12—H12	120.0
C17—N1—C1	130.26 (11)	C11—C12—H12	120.0
C17—N1—C7	123.15 (11)	C12—C13—C14	120.04 (16)
C1—N1—C7	106.58 (10)	C12—C13—H13	120.0
C7—N2—C2	104.76 (11)	C14—C13—H13	120.0
N1—C1—C6	131.99 (13)	C9—C14—C13	120.62 (16)
N1—C1—C2	105.00 (11)	C9—C14—H14	119.7
C6—C1—C2	122.99 (13)	C13—C14—H14	119.7
N2—C2—C3	129.47 (13)	C8—C15—C16	122.51 (12)
N2—C2—C1	111.30 (12)	C8—C15—C19	118.60 (12)
C3—C2—C1	119.21 (13)	C16—C15—C19	118.88 (12)
C4—C3—C2	117.93 (14)	C17—C16—C15	118.34 (12)
C4—C3—H3	121.0	C17—C16—C18	119.87 (13)
C2—C3—H3	121.0	C15—C16—C18	121.79 (13)
C3—C4—C5	122.03 (15)	C16—C17—N1	120.08 (12)
C3—C4—H4	119.0	C16—C17—H17	120.0
C5—C4—H4	119.0	N1—C17—H17	120.0
C6—C5—C4	121.30 (14)	C16—C18—H18A	109.5
C6—C5—H5	119.4	C16—C18—H18B	109.5
C4—C5—H5	119.4	H18A—C18—H18B	109.5
C5—C6—C1	116.54 (14)	C16—C18—H18C	109.5
C5—C6—H6	121.7	H18A—C18—H18C	109.5
C1—C6—H6	121.7	H18B—C18—H18C	109.5
N2—C7—N1	112.36 (11)	O1—C19—O2	124.91 (14)
N2—C7—C8	129.73 (12)	O1—C19—C15	124.47 (14)
N1—C7—C8	117.91 (11)	O2—C19—C15	110.62 (12)
C15—C8—C7	117.99 (12)	O2—C20—C21	108.91 (14)
C15—C8—C9	122.73 (12)	O2—C20—H20A	109.9
C7—C8—C9	119.27 (12)	C21—C20—H20A	109.9
C14—C9—C10	118.86 (14)	O2—C20—H20B	109.9
C14—C9—C8	120.66 (13)	C21—C20—H20B	109.9
C10—C9—C8	120.48 (13)	H20A—C20—H20B	108.3
C9—C10—C11	120.09 (16)	C20—C21—H21A	109.5
C9—C10—H10	120.0	C20—C21—H21B	109.5
C11—C10—H10	120.0	H21A—C21—H21B	109.5
C12—C11—C10	120.43 (17)	C20—C21—H21C	109.5
C12—C11—H11	119.8	H21A—C21—H21C	109.5
C10—C11—H11	119.8	H21B—C21—H21C	109.5
C13—C12—C11	119.93 (15)
C17—N1—C1—C6	−2.2 (2)	C15—C8—C9—C10	109.59 (17)
C7—N1—C1—C6	178.59 (15)	C7—C8—C9—C10	−71.49 (18)
C17—N1—C1—C2	179.46 (13)	C14—C9—C10—C11	0.7 (2)
C7—N1—C1—C2	0.20 (14)	C8—C9—C10—C11	−179.29 (14)
C7—N2—C2—C3	−177.76 (15)	C9—C10—C11—C12	−1.2 (3)
C7—N2—C2—C1	0.44 (16)	C10—C11—C12—C13	0.5 (3)
N1—C1—C2—N2	−0.40 (15)	C11—C12—C13—C14	0.7 (3)
C6—C1—C2—N2	−178.98 (13)	C10—C9—C14—C13	0.5 (2)
N1—C1—C2—C3	178.00 (13)	C8—C9—C14—C13	−179.52 (14)
C6—C1—C2—C3	−0.6 (2)	C12—C13—C14—C9	−1.2 (3)
N2—C2—C3—C4	178.25 (15)	C7—C8—C15—C16	−0.4 (2)
C1—C2—C3—C4	0.2 (2)	C9—C8—C15—C16	178.50 (13)
C2—C3—C4—C5	0.3 (2)	C7—C8—C15—C19	179.67 (12)
C3—C4—C5—C6	−0.5 (3)	C9—C8—C15—C19	−1.4 (2)
C4—C5—C6—C1	0.1 (2)	C8—C15—C16—C17	0.7 (2)
N1—C1—C6—C5	−177.72 (14)	C19—C15—C16—C17	−179.38 (13)
C2—C1—C6—C5	0.4 (2)	C8—C15—C16—C18	−178.70 (14)
C2—N2—C7—N1	−0.31 (15)	C19—C15—C16—C18	1.2 (2)
C2—N2—C7—C8	179.29 (14)	C15—C16—C17—N1	−0.1 (2)
C17—N1—C7—N2	−179.25 (12)	C18—C16—C17—N1	179.34 (13)
C1—N1—C7—N2	0.07 (15)	C1—N1—C17—C16	−179.97 (13)
C17—N1—C7—C8	1.10 (19)	C7—N1—C17—C16	−0.8 (2)
C1—N1—C7—C8	−179.58 (12)	C20—O2—C19—O1	−8.9 (2)
N2—C7—C8—C15	179.97 (14)	C20—O2—C19—C15	171.09 (13)
N1—C7—C8—C15	−0.45 (19)	C8—C15—C19—O1	105.81 (18)
N2—C7—C8—C9	1.0 (2)	C16—C15—C19—O1	−74.1 (2)
N1—C7—C8—C9	−179.42 (12)	C8—C15—C19—O2	−74.15 (16)
C15—C8—C9—C14	−70.36 (19)	C16—C15—C19—O2	105.95 (15)
C7—C8—C9—C14	108.56 (16)	C19—O2—C20—C21	−106.00 (16)

D—H···A	D—H	H···A	D···A	D—H···A
C17—H17···N2i	0.93	2.31	3.2092 (18)	164

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C17—H17⋯N2i	0.93	2.31	3.2092 (18)	164

Symmetry code: (i) .