Ethyl 5-bromo-9-eth­oxy-2-oxo-2H-pyrano[2,3-g]quinoline-8-carboxyl­ate

Oliveira, C.D.; Romeiro, G.A.; Skakle, J.M.S.; Wardell, J.L.; Wardell, S.M.S.V.

doi:10.1107/S1600536806007148

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 62| Part 4| April 2006| Pages o1492-o1493

https://doi.org/10.1107/S1600536806007148

Ethyl 5-bromo-9-ethoxy-2-oxo-2H-pyrano[2,3-g]quinoline-8-carboxylate

César D. de Oliveira,^a Gilberto A. Romeiro,^a Janet M. S. Skakle,^b ^* James L. Wardell ^c and Solange M. S. V. Wardell ^d

^aInstituto de Química, Departamento de Química Inorgânica, Universidade Federal Fluminense, Outeiro de São João Batista s/n, Campus do Valonguinho–Centro, Niterói, RJ 24020-150, Brazil, ^bDepartment of Chemistry, College of Physical Sciences, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, ^cDepartamento de Química Inorgânica, Instituto de Química, Universidade Federal do Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil, and ^dLaboratory of Organic Synthesis of Far-Manguinhos/FIOCRUZ, R. Sizenando Nabuco, 100 Manguinhos, 21041-250 Rio de Janeiro, RJ, Brazil
^*Correspondence e-mail: j.skakle@abdn.ac.uk

(Received 15 February 2006; accepted 27 February 2006; online 22 March 2006)

The title compound, C₁₇H₁₄BrNO₅, was studied as part of a study on the biological properties of pyranoquinoline derivatives. Alkylation of the parent pyranoquinoline was shown to have occurred at the carbonyl rather than the amino site. The molecules are linked by a C—H⋯O hydrogen bond forming C(5) chains along [001].

Comment

As part of a study on the synthesis and biological activities of pyranoquinoline derivatives (da Matta et al., 2000 ; de Oliveira, 2003 ), alkylation of compound (1) (see scheme) using EtBr was carried out. Compound (1) contains two potential reaction sites, viz. the carbonyl and amino sites. While NMR spectroscopy strongly indicated that bromination had occurred predominantly at the carbonyl site to give the pyranoquinoline derivative (2), confirmation was sought using X-ray crystallography.

Structural analysis confirmed that alkylation had indeed occurred at the carbonyl site (Fig. 1). The pyranoquinoline ring system in (2) was confirmed.

Hydrogen bonding occurs via C9—H9⋯O11ⁱ [C9⋯O11ⁱ = 3.367 (4) Å and C9—H9⋯O11ⁱ = 148°; symmetry code: (i) 1 − x, −y, z − $[{1\over 2}]$ ], leading to C(5) chains (Bernstein et al., 1995 ) along [001] (Fig. 2).

The compound is isostructural with the chloro analogue (de Oliveira et al., 2006 ).

Figure 1
The molecular structure of the title compound, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
Part of the crystal structure of the title compound, showing the formation of a C(5) chain (hydrogen bonds as dashed lines) along [001]. [Symmetry code: (i) 1 − x, −y, z − $[{1\over 2}]$ .]

Experimental

The title compound was obtained from the reaction between EtBr and (1) in DMF solution in the presence of K₂CO₃ (de Oliveira, 2003). Pure product (2) was obtained from the reaction mixture by column chromatography using hexane–ethyl acetate as the eluent (gradient 1:4 to 1:1). Crystals suitable for X-ray crystallography were grown from ethyl acetate (67% yield; m.p. 409–410 K).

Crystal data

C₁₇H₁₄BrNO₅
M_r = 392.20
Orthorhombic, P n a 2₁
a = 7.2542 (8) Å
b = 19.542 (2) Å
c = 11.2855 (11) Å
V = 1599.9 (3) Å³
Z = 4
D_x = 1.628 Mg m⁻³
Mo Kα radiation
Cell parameters from 4263 reflections
θ = 3.5–25.3°
μ = 2.60 mm⁻¹
T = 291 (2) K
Prism, pale yellow
0.42 × 0.22 × 0.11 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer
ω scans
Absorption correction: multi-scan(SADABS; Bruker, 2000 )T_min = 0.549, T_max = 0.752
15681 measured reflections
5296 independent reflections
2737 reflections with I > 2σ(I)
R_int = 0.041
θ_max = 32.5°
h = −10 → 10
k = −27 → 29
l = −17 → 14

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.069
S = 0.80
5296 reflections
219 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.034P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.29 e Å⁻³
Absolute structure: Flack (1983 )
Flack parameter: 0.013 (7)

All H atoms were located in difference maps and then treated as riding atoms, with C—H distances of 0.95 (aromatic) or 0.96 Å (methyl) and U_iso(H) values of 1.2U_eq(C) (aromatic) or 1.5U_eq(C) (methyl). PLATON (Spek, 2003 ) was used for the hydrogen-bonding analysis.

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: OSCAIL (McArdle, 2003 ) and SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: CIFTAB (Sheldrick, 1997).

Supporting information

Crystal structure: contains datablocks global, 2. DOI: https://doi.org/10.1107/S1600536806007148/wk2003sup1.cif

Structure factors: contains datablock 2. DOI: https://doi.org/10.1107/S1600536806007148/wk20032sup2.hkl

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: CIFTAB (Sheldrick, 1997).

Ethyl 5-bromo-9-ethoxy-2-oxo-2H-pyrano[2,3-g]quinoline-8-carboxylate top

Crystal data top

C₁₇H₁₄BrNO₅	F(000) = 792
M_r = 392.20	D_x = 1.628 Mg m⁻³
Orthorhombic, Pna2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 4263 reflections
a = 7.2542 (8) Å	θ = 3.5–25.3°
b = 19.542 (2) Å	µ = 2.60 mm⁻¹
c = 11.2855 (11) Å	T = 291 K
V = 1599.9 (3) Å³	Prism, pale yellow
Z = 4	0.42 × 0.22 × 0.11 mm

Data collection top

Bruker SMART 1000 CCD area-detector diffractometer	5296 independent reflections
Radiation source: fine-focus sealed tube	2737 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.041
ω scans	θ_max = 32.5°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −10→10
T_min = 0.549, T_max = 0.752	k = −27→29
15681 measured reflections	l = −17→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)] = 0.032	H-atom parameters constrained
wR(F²) = 0.069	w = 1/[σ²(F_o²) + (0.034P)²] where P = (F_o² + 2F_c²)/3
S = 0.80	(Δ/σ)_max < 0.001
5296 reflections	Δρ_max = 0.35 e Å⁻³
219 parameters	Δρ_min = −0.29 e Å⁻³
1 restraint	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.013 (7)

Special details top

Experimental. IR (KBr, cm^-1): 2977, 1749, 1718, 1624, 1590, 1340, 1300. ¹H NMR (DMSO-d₆, 300 MHz): δ 1.51 (t, J = 7.2 Hz, 3H), 1.58 (t, J = 6.9 Hz, 3H), 4.43 (q, J = 6.9 Hz, 2H), 4.54 (q, J = 7.2 Hz, 2H), 6.89 (d, J = 9.9 Hz, 1H), 8.12 (s, 1H), 8.47 (d, J = 9.9 Hz, 1H), 9.19 (s, 1H). ¹³C NMR (DMSO-d₆, 75 MHz): δ 14.1, 15.6, 61.9, 72.5, 108.7, 114.7, 120.7, 123.0, 15.1, 125.6, 142.1, 143.5, 150.7, 152.2, 158.7, 162.3, 164.4.

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

	x	y	z	U_iso*/U_eq
C1	0.5465 (4)	0.26565 (12)	0.79440 (19)	0.0403 (5)
C2	0.5712 (4)	0.32561 (14)	0.8664 (2)	0.0431 (6)
O2	0.6179 (3)	0.31203 (10)	0.97852 (13)	0.0573 (5)
C21	0.7329 (4)	0.35662 (13)	1.0487 (2)	0.0532 (7)
H21A	0.6590	0.3919	1.0861	0.064*
H21B	0.8252	0.3784	0.9993	0.064*
C22	0.8232 (5)	0.31265 (16)	1.1406 (3)	0.0746 (8)
H22A	0.7308	0.2938	1.1920	0.112*
H22B	0.9076	0.3398	1.1862	0.112*
H22C	0.8890	0.2762	1.1024	0.112*
C3	0.5449 (4)	0.38935 (12)	0.8149 (2)	0.0444 (6)
C31	0.5426 (4)	0.45529 (14)	0.8793 (2)	0.0521 (7)
O31	0.6127 (3)	0.50489 (9)	0.81235 (17)	0.0669 (6)
O32	0.4762 (3)	0.46482 (10)	0.97594 (16)	0.0718 (6)
C32	0.5945 (5)	0.57525 (15)	0.8543 (3)	0.0793 (10)
H32A	0.6574	0.5808	0.9296	0.095*
H32B	0.4656	0.5869	0.8650	0.095*
C33	0.6788 (6)	0.61979 (16)	0.7632 (3)	0.0887 (11)
H33A	0.8093	0.6118	0.7606	0.133*
H33B	0.6559	0.6669	0.7826	0.133*
H33C	0.6260	0.6096	0.6872	0.133*
C4	0.4998 (4)	0.38994 (13)	0.6918 (2)	0.0476 (6)
H4	0.4916	0.4327	0.6559	0.057*
N5	0.4691 (3)	0.33752 (10)	0.62482 (17)	0.0463 (5)
C6	0.4915 (3)	0.27423 (11)	0.67461 (19)	0.0389 (5)
C7	0.4597 (3)	0.21492 (13)	0.6070 (2)	0.0432 (6)
Br7	0.38160 (3)	0.224825 (12)	0.44876 (3)	0.05827 (9)
C8	0.4855 (3)	0.14966 (13)	0.6517 (2)	0.0424 (5)
C9	0.4568 (4)	0.08662 (15)	0.5862 (2)	0.0555 (7)
H9	0.4138	0.0882	0.5086	0.067*
C10	0.4920 (4)	0.02688 (15)	0.6370 (3)	0.0621 (8)
H10	0.4719	−0.0128	0.5934	0.075*
C11	0.5597 (4)	0.02044 (16)	0.7560 (3)	0.0585 (7)
O11	0.6006 (4)	−0.03111 (11)	0.8062 (2)	0.0831 (7)
O12	0.5771 (3)	0.08092 (9)	0.81977 (15)	0.0539 (5)
C13	0.5460 (3)	0.14392 (12)	0.7696 (2)	0.0427 (6)
C14	0.5759 (3)	0.19997 (13)	0.8405 (2)	0.0447 (6)
H14	0.6153	0.1944	0.9183	0.054*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0370 (12)	0.0495 (15)	0.0342 (12)	−0.0018 (11)	−0.0001 (10)	0.0032 (10)
C2	0.0450 (16)	0.0529 (17)	0.0314 (13)	−0.0058 (12)	0.0022 (10)	−0.0016 (11)
O2	0.0836 (14)	0.0540 (10)	0.0344 (11)	−0.0195 (10)	−0.0123 (8)	0.0045 (7)
C21	0.067 (2)	0.0550 (16)	0.0381 (13)	−0.0098 (14)	−0.0046 (12)	−0.0074 (11)
C22	0.090 (2)	0.082 (2)	0.0516 (16)	−0.0017 (19)	−0.0200 (16)	0.0001 (15)
C3	0.0458 (14)	0.0496 (16)	0.0377 (13)	−0.0007 (12)	0.0012 (11)	−0.0010 (11)
C31	0.0584 (18)	0.0506 (18)	0.0473 (17)	0.0066 (13)	−0.0022 (13)	−0.0035 (13)
O31	0.0949 (16)	0.0458 (11)	0.0599 (12)	−0.0074 (11)	0.0144 (10)	−0.0113 (9)
O32	0.0991 (17)	0.0641 (12)	0.0522 (13)	0.0133 (12)	0.0118 (10)	−0.0052 (9)
C32	0.113 (3)	0.0495 (17)	0.075 (2)	−0.0023 (18)	0.007 (2)	−0.0234 (15)
C33	0.118 (3)	0.0493 (18)	0.099 (3)	−0.007 (2)	−0.004 (2)	−0.0037 (18)
C4	0.0507 (17)	0.0478 (15)	0.0444 (13)	0.0039 (12)	−0.0004 (11)	0.0029 (12)
N5	0.0532 (13)	0.0467 (13)	0.0390 (11)	0.0026 (10)	−0.0036 (10)	0.0027 (9)
C6	0.0360 (13)	0.0481 (14)	0.0326 (11)	−0.0006 (12)	0.0013 (9)	−0.0032 (11)
C7	0.0403 (13)	0.0601 (17)	0.0292 (11)	0.0006 (12)	0.0008 (9)	−0.0018 (10)
Br7	0.06948 (16)	0.06983 (14)	0.03550 (11)	−0.00117 (13)	−0.01183 (16)	−0.00210 (16)
C8	0.0418 (14)	0.0484 (15)	0.0370 (12)	−0.0008 (11)	0.0052 (10)	−0.0030 (10)
C9	0.0608 (17)	0.0620 (18)	0.0438 (15)	−0.0048 (15)	0.0020 (13)	−0.0078 (13)
C10	0.078 (2)	0.0468 (18)	0.0613 (18)	−0.0034 (16)	0.0012 (16)	−0.0107 (14)
C11	0.0665 (19)	0.0496 (17)	0.0595 (17)	−0.0031 (15)	0.0010 (15)	−0.0029 (14)
O11	0.115 (2)	0.0488 (13)	0.0849 (16)	0.0071 (13)	−0.0164 (13)	0.0045 (12)
O12	0.0656 (13)	0.0456 (10)	0.0505 (11)	−0.0022 (9)	−0.0056 (8)	0.0022 (8)
C13	0.0406 (13)	0.0495 (15)	0.0380 (13)	−0.0019 (11)	0.0012 (10)	0.0079 (11)
C14	0.0477 (16)	0.0516 (14)	0.0349 (12)	−0.0052 (12)	−0.0031 (10)	0.0038 (11)

Geometric parameters (Å, º) top

C1—C14	1.401 (3)	C33—H33A	0.9600
C1—C6	1.419 (3)	C33—H33B	0.9600
C1—C2	1.437 (3)	C33—H33C	0.9600
C2—O2	1.336 (3)	C4—N5	1.292 (3)
C2—C3	1.388 (3)	C4—H4	0.9300
O2—C21	1.443 (3)	N5—C6	1.368 (3)
C21—C22	1.497 (4)	C6—C7	1.407 (3)
C21—H21A	0.9700	C7—C8	1.384 (3)
C21—H21B	0.9700	C7—Br7	1.883 (2)
C22—H22A	0.9600	C8—C13	1.406 (3)
C22—H22B	0.9600	C8—C9	1.452 (4)
C22—H22C	0.9600	C9—C10	1.326 (4)
C3—C4	1.427 (3)	C9—H9	0.9300
C3—C31	1.480 (3)	C10—C11	1.435 (4)
C31—O32	1.206 (3)	C10—H10	0.9300
C31—O31	1.330 (3)	C11—O11	1.193 (3)
O31—C32	1.460 (3)	C11—O12	1.390 (3)
C32—C33	1.480 (5)	O12—C13	1.374 (3)
C32—H32A	0.9700	C13—C14	1.373 (3)
C32—H32B	0.9700	C14—H14	0.9300

C14—C1—C6	120.3 (2)	H33A—C33—H33B	109.5
C14—C1—C2	121.2 (2)	C32—C33—H33C	109.5
C6—C1—C2	118.5 (2)	H33A—C33—H33C	109.5
O2—C2—C3	127.6 (2)	H33B—C33—H33C	109.5
O2—C2—C1	113.9 (2)	N5—C4—C3	127.0 (2)
C3—C2—C1	118.5 (2)	N5—C4—H4	116.5
C2—O2—C21	123.1 (2)	C3—C4—H4	116.5
O2—C21—C22	106.6 (2)	C4—N5—C6	117.1 (2)
O2—C21—H21A	110.4	N5—C6—C7	120.2 (2)
C22—C21—H21A	110.4	N5—C6—C1	122.1 (2)
O2—C21—H21B	110.4	C7—C6—C1	117.7 (2)
C22—C21—H21B	110.4	C8—C7—C6	122.6 (2)
H21A—C21—H21B	108.6	C8—C7—Br7	118.76 (18)
C21—C22—H22A	109.5	C6—C7—Br7	118.63 (18)
C21—C22—H22B	109.5	C7—C8—C13	117.4 (2)
H22A—C22—H22B	109.5	C7—C8—C9	125.2 (2)
C21—C22—H22C	109.5	C13—C8—C9	117.3 (2)
H22A—C22—H22C	109.5	C10—C9—C8	120.0 (3)
H22B—C22—H22C	109.5	C10—C9—H9	120.0
C2—C3—C4	116.5 (2)	C8—C9—H9	120.0
C2—C3—C31	125.2 (2)	C9—C10—C11	123.2 (3)
C4—C3—C31	118.0 (2)	C9—C10—H10	118.4
O32—C31—O31	123.6 (3)	C11—C10—H10	118.4
O32—C31—C3	125.7 (3)	O11—C11—O12	116.7 (3)
O31—C31—C3	110.5 (2)	O11—C11—C10	127.1 (3)
C31—O31—C32	117.9 (2)	O12—C11—C10	116.2 (3)
O31—C32—C33	106.9 (2)	C13—O12—C11	122.3 (2)
O31—C32—H32A	110.3	C14—C13—O12	116.7 (2)
C33—C32—H32A	110.3	C14—C13—C8	122.5 (2)
O31—C32—H32B	110.3	O12—C13—C8	120.9 (2)
C33—C32—H32B	110.3	C13—C14—C1	119.4 (2)
H32A—C32—H32B	108.6	C13—C14—H14	120.3
C32—C33—H33A	109.5	C1—C14—H14	120.3
C32—C33—H33B	109.5

C14—C1—C2—O2	−1.9 (4)	C2—C1—C6—C7	−177.1 (2)
C6—C1—C2—O2	178.2 (2)	N5—C6—C7—C8	178.0 (2)
C14—C1—C2—C3	178.3 (2)	C1—C6—C7—C8	−2.1 (4)
C6—C1—C2—C3	−1.6 (4)	N5—C6—C7—Br7	−1.2 (3)
C3—C2—O2—C21	−31.6 (4)	C1—C6—C7—Br7	178.68 (18)
C1—C2—O2—C21	148.6 (2)	C6—C7—C8—C13	0.0 (4)
C2—O2—C21—C22	−154.4 (3)	Br7—C7—C8—C13	179.23 (18)
O2—C2—C3—C4	178.4 (3)	C6—C7—C8—C9	−179.4 (2)
C1—C2—C3—C4	−1.8 (4)	Br7—C7—C8—C9	−0.1 (4)
O2—C2—C3—C31	−7.6 (5)	C7—C8—C9—C10	177.7 (3)
C1—C2—C3—C31	172.2 (3)	C13—C8—C9—C10	−1.7 (4)
C2—C3—C31—O32	−38.1 (5)	C8—C9—C10—C11	−0.4 (5)
C4—C3—C31—O32	135.7 (3)	C9—C10—C11—O11	−177.1 (3)
C2—C3—C31—O31	146.4 (3)	C9—C10—C11—O12	3.7 (4)
C4—C3—C31—O31	−39.7 (4)	O11—C11—O12—C13	175.6 (3)
O32—C31—O31—C32	−5.1 (4)	C10—C11—O12—C13	−5.1 (4)
C3—C31—O31—C32	170.5 (3)	C11—O12—C13—C14	−177.1 (2)
C31—O31—C32—C33	−178.7 (3)	C11—O12—C13—C8	3.3 (4)
C2—C3—C4—N5	4.9 (4)	C7—C8—C13—C14	1.3 (4)
C31—C3—C4—N5	−169.5 (3)	C9—C8—C13—C14	−179.3 (2)
C3—C4—N5—C6	−3.8 (4)	C7—C8—C13—O12	−179.1 (2)
C4—N5—C6—C7	179.7 (2)	C9—C8—C13—O12	0.3 (4)
C4—N5—C6—C1	−0.2 (4)	O12—C13—C14—C1	−179.9 (2)
C14—C1—C6—N5	−177.1 (2)	C8—C13—C14—C1	−0.4 (4)
C2—C1—C6—N5	2.8 (4)	C6—C1—C14—C13	−1.8 (4)
C14—C1—C6—C7	3.0 (4)	C2—C1—C14—C13	178.3 (2)

Acknowledgements

We thank the University of Aberdeen for funding of the X-ray diffractometer, and acknowledge the use of the EPSRC's Chemical Database Service at Daresbury Laboratory (Fletcher et al., 1996 ).

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