Diethyl 2,6-dimethyl-4-p-tolyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate

Fun, H.-K.; Liew, W.-C.; Reddy, B.P.; Sarveswari, S.; Vijayakumar, V.

doi:10.1107/S1600536809035077

organic compounds

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ISSN: 2056-9890

Volume 65| Part 10| October 2009| Pages o2342-o2343

doi:10.1107/S1600536809035077

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Diethyl 2,6-dimethyl-4-p-tolyl-1,4-dihydropyridine-3,5-dicarboxylate

Hoong-Kun Fun,^a ^*‡ Wei-Ching Liew,^a B. Palakshi Reddy,^b S. Sarveswari ^b and V. Vijayakumar ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bOrganic Chemistry Division, School of Science and Humanities, VIT University, Vellore 632 014, India
^*Correspondence e-mail: hkfun@usm.my

(Received 29 August 2009; accepted 31 August 2009; online 5 September 2009)

In the title compound, C₂₀H₂₅NO₄, the 1,4-dihydropyridine ring adopts a flattened-boat conformation and forms a dihedral angle of 89.77 (8)° with the benzene ring. Intermolecular N—H⋯O hydrogen bonds result in the formation of extended chains parallel to the b axis.

Related literature

For general background and applications of 1,4-dihydropyridine derivatives, see: Böcker & Guengerich (1986 ); Cooper et al. (1992 ); Vo et al. (1995 ); Gaudio et al. (1994 ); Gordeev et al. (1996 ); Sunkel et al. (1992 ). For ring conformations and ring puckering analysis, see: Boeyens (1978 ); Cremer & Pople (1975 ). For related 1,4-dihydropyridine structures, see: Fossheim et al. (1982 ); Teng et al. (2008 ); Bai et al. (2009 ). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

C₂₀H₂₅NO₄
M_r = 343.41
Monoclinic, P 2₁ /c
a = 10.0175 (1) Å
b = 7.4287 (1) Å
c = 25.0974 (3) Å
β = 105.528 (1)°
V = 1799.50 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.31 × 0.15 × 0.05 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.973, T_max = 0.996
20077 measured reflections
5309 independent reflections
3542 reflections with I > 2σ(I)
R_int = 0.046

Refinement

R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.147
S = 1.02
5309 reflections
231 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1ⁱ	0.84	2.15	2.9684 (18)	166
Symmetry code: (i) x, y-1, z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809035077/tk2533sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809035077/tk2533Isup2.hkl

checkCIF report

Comment top

Hantzsch 1,4-dihydropyridines (1,4-DHPS) are biologically active compounds which include various vasodilator, anti-hypertensive, bronchodilator, heptaprotective, anti-tumor, anti-mutagenic, geroprotective and anti-diabetic agents (Gaudio et al., 1994). Nifedipine, Nitrendipine and Nimodipine etc., have found commercial utility as calcium channel blockers (Böcker & Guengerich, 1986; Gordeev et al., 1996). For the treatment of congestive heart failure, a number of DHP calcium antagonists have been introduced (Sunkel et al., 1992; Vo et al., 1995). Some DHPs have been introduced as neuroprotectants and cognition enhancers. In addition, a number of DHPs with platelet anti-aggregatory activity have also been discovered (Cooper et al., 1992).

In the title compound (I, Fig. 1), the bond lengths and angles have normal values and are comparable to closely related structures (Teng et al., 2008; Bai et al., 2009). The dihedral angle between the benzene ring and the mean plane of 1,4-dihydropyridine ring is 89.77 (8)°, indicating that both the rings are perpendicular to each other. The 1,4-dihydropyridine ring adopts a flattened-boat conformation (Boeyens, 1978; Cremer & Pople, 1975) with ring distortions at the nitrogen (Nl) and the tetrahedral carbon (C7). Both atoms are displaced in the same direction from the ring with distances of 0.115 (1) Å and 0.151 (2) Å, respectively, from the plane defined by C8, C9, C10, and C11, and form the apexes of a boat-type conformation (Fossheim et al., 1982).

The crystal packing (Fig. 2) is consolidated by intermolecular N1—H1···O1 hydrogen bonds, Table 1, linking the molecules into chains parallel to the b-axis.

Related literature top

For general background and applications of 1,4-dihydropyridine derivatives, see: Böcker & Guengerich (1986); Cooper et al. (1992); Vo et al. (1995); Gaudio et al. (1994); Gordeev et al. (1996); Sunkel et al. (1992). For ring conformations and ring puckering analysis, see: Boeyens (1978); Cremer & Pople (1975). For related 1,4-dihydropyridine structures, see: Fossheim et al. (1982); Teng et al. (2008); Bai et al. (2009). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Experimental top

Compound (I) was prepared according to the Hantzsch pyridine synthesis. A mixture of p-tolylaldehyde (10 mmol), ethylacetoacetate (20 mmol) and ammonium acetate (10 mmol) were heated at 353 K for 2 h (monitored by TLC). After completion of the reaction, the mixture was cooled to room temperature and kept for 2 days to obtain the solid product. The solid that formed was washed using diethyl ether. Solid was collected separately and liquid was kept for solidification. The purity of the crude product was checked through TLC and recrystallized using acetone and ether. The compound was characterized by IR and ¹H NMR. M.p. 383–385 K. IR (KBr):υ (cm^-1), 3358, 2988, 1695, 1652, 1487, 1214;¹H NMR (CDCl₃): δ 1.23 (t, 6H, J = 8), δ 2.34 (s, 6H), δ 3.72 (s, 3H), δ 4.09 (m, 4H, J = 4), δ 4.94 (s, 1H), δ 5.58 (s, 1H), δ 6.76–7.21 (4H, aromatic).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom numbering scheme.
	Fig. 2. Partial unit cell contents for (I) highlighting the formation of supramolecular chains mediated by N-H···O hydrogen bonding (shown as dashed lines).

Diethyl 2,6-dimethyl-4-p-tolyl-1,4-dihydropyridine-3,5-dicarboxylate top

Crystal data top

C₂₀H₂₅NO₄	F(000) = 736
M_r = 343.41	D_x = 1.268 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3769 reflections
a = 10.0175 (1) Å	θ = 2.9–27.7°
b = 7.4287 (1) Å	µ = 0.09 mm⁻¹
c = 25.0974 (3) Å	T = 100 K
β = 105.528 (1)°	Plate, colourless
V = 1799.50 (4) Å³	0.31 × 0.15 × 0.05 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5309 independent reflections
Radiation source: fine-focus sealed tube	3542 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.046
ϕ and ω scans	θ_max = 30.1°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −14→14
T_min = 0.973, T_max = 0.996	k = −10→10
20077 measured reflections	l = −35→30

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.147	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0648P)² + 0.5567P] where P = (F_o² + 2F_c²)/3
5309 reflections	(Δ/σ)_max = 0.001
231 parameters	Δρ_max = 0.33 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₂₀H₂₅NO₄	V = 1799.50 (4) Å³
M_r = 343.41	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.0175 (1) Å	µ = 0.09 mm⁻¹
b = 7.4287 (1) Å	T = 100 K
c = 25.0974 (3) Å	0.31 × 0.15 × 0.05 mm
β = 105.528 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	5309 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3542 reflections with I > 2σ(I)
T_min = 0.973, T_max = 0.996	R_int = 0.046
20077 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.057	0 restraints
wR(F²) = 0.147	H-atom parameters constrained
S = 1.02	Δρ_max = 0.33 e Å⁻³
5309 reflections	Δρ_min = −0.26 e Å⁻³
231 parameters

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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
O1	0.22376 (12)	0.93012 (15)	0.99648 (5)	0.0209 (3)
O2	0.11576 (12)	0.74263 (15)	1.04170 (5)	0.0193 (3)
O3	0.51279 (12)	0.43230 (17)	0.85637 (5)	0.0263 (3)
O4	0.43953 (12)	0.71714 (16)	0.86114 (5)	0.0226 (3)
N1	0.28643 (14)	0.30918 (19)	0.97456 (6)	0.0185 (3)
H1	0.2800	0.2043	0.9858	0.022*
C1	0.12624 (18)	0.8380 (2)	0.84689 (7)	0.0239 (4)
H1A	0.1920	0.9293	0.8559	0.029*
C2	0.01109 (18)	0.8600 (3)	0.80172 (7)	0.0257 (4)
H2A	0.0013	0.9654	0.7810	0.031*
C3	−0.08953 (17)	0.7263 (3)	0.78718 (7)	0.0229 (4)
C4	−0.07301 (18)	0.5727 (2)	0.81972 (7)	0.0245 (4)
H4A	−0.1401	0.4829	0.8115	0.029*
C5	0.04298 (17)	0.5511 (2)	0.86473 (7)	0.0216 (4)
H5A	0.0523	0.4465	0.8858	0.026*
C6	0.14465 (16)	0.6828 (2)	0.87865 (6)	0.0161 (3)
C7	0.27351 (16)	0.6541 (2)	0.92694 (6)	0.0155 (3)
H7A	0.3279	0.7655	0.9321	0.019*
C8	0.23295 (15)	0.6169 (2)	0.98026 (6)	0.0147 (3)
C9	0.23531 (15)	0.4472 (2)	1.00053 (6)	0.0162 (3)
C10	0.36055 (16)	0.3373 (2)	0.93593 (7)	0.0172 (3)
C11	0.36349 (15)	0.5037 (2)	0.91449 (7)	0.0164 (3)
C12	−0.21263 (19)	0.7489 (3)	0.73743 (8)	0.0305 (4)
H12A	−0.2578	0.6349	0.7279	0.046*
H12B	−0.1818	0.7931	0.7068	0.046*
H12C	−0.2765	0.8332	0.7460	0.046*
C13	0.19301 (15)	0.7769 (2)	1.00645 (6)	0.0159 (3)
C14	0.08916 (17)	0.8938 (2)	1.07421 (7)	0.0209 (4)
H14A	0.0075	0.8693	1.0868	0.025*
H14B	0.0716	1.0012	1.0514	0.025*
C15	0.2111 (2)	0.9245 (3)	1.12300 (8)	0.0320 (5)
H15A	0.1911	1.0216	1.1449	0.048*
H15B	0.2907	0.9545	1.1104	0.048*
H15C	0.2296	0.8170	1.1450	0.048*
C16	0.44652 (16)	0.5398 (2)	0.87521 (7)	0.0190 (3)
C17	0.50195 (18)	0.7686 (3)	0.81750 (7)	0.0264 (4)
H17A	0.5882	0.7034	0.8220	0.032*
H17B	0.5231	0.8962	0.8204	0.032*
C18	0.4070 (2)	0.7290 (3)	0.76142 (8)	0.0313 (4)
H18A	0.4428	0.7840	0.7335	0.047*
H18B	0.3165	0.7766	0.7592	0.047*
H18C	0.4008	0.6012	0.7557	0.047*
C19	0.19215 (18)	0.3867 (2)	1.05056 (7)	0.0200 (3)
H19A	0.2343	0.4630	1.0814	0.030*
H19B	0.2214	0.2646	1.0592	0.030*
H19C	0.0932	0.3939	1.0431	0.030*
C20	0.43324 (17)	0.1719 (2)	0.92385 (7)	0.0226 (4)
H20A	0.4138	0.1559	0.8846	0.034*
H20B	0.4011	0.0688	0.9399	0.034*
H20C	0.5313	0.1852	0.9394	0.034*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0275 (6)	0.0144 (6)	0.0225 (6)	0.0008 (5)	0.0094 (5)	0.0009 (5)
O2	0.0255 (6)	0.0153 (6)	0.0205 (6)	−0.0024 (5)	0.0120 (5)	−0.0047 (5)
O3	0.0255 (6)	0.0317 (8)	0.0250 (7)	0.0015 (5)	0.0126 (5)	−0.0034 (6)
O4	0.0257 (6)	0.0240 (7)	0.0217 (6)	−0.0031 (5)	0.0124 (5)	0.0043 (5)
N1	0.0245 (7)	0.0110 (7)	0.0214 (7)	−0.0001 (5)	0.0086 (6)	0.0007 (6)
C1	0.0240 (8)	0.0217 (9)	0.0259 (9)	−0.0020 (7)	0.0066 (7)	0.0049 (8)
C2	0.0272 (9)	0.0271 (10)	0.0233 (9)	0.0056 (7)	0.0076 (7)	0.0110 (8)
C3	0.0217 (8)	0.0322 (10)	0.0157 (8)	0.0069 (7)	0.0063 (6)	−0.0008 (7)
C4	0.0245 (8)	0.0242 (10)	0.0229 (9)	−0.0027 (7)	0.0031 (7)	−0.0037 (8)
C5	0.0267 (8)	0.0185 (9)	0.0184 (8)	−0.0019 (7)	0.0038 (7)	0.0026 (7)
C6	0.0184 (7)	0.0171 (8)	0.0146 (7)	0.0022 (6)	0.0076 (6)	−0.0006 (6)
C7	0.0180 (7)	0.0132 (8)	0.0159 (7)	−0.0017 (6)	0.0057 (6)	0.0001 (6)
C8	0.0164 (7)	0.0147 (8)	0.0127 (7)	−0.0010 (6)	0.0034 (6)	−0.0010 (6)
C9	0.0167 (7)	0.0165 (8)	0.0147 (7)	−0.0021 (6)	0.0033 (6)	−0.0011 (6)
C10	0.0170 (7)	0.0171 (8)	0.0172 (8)	−0.0016 (6)	0.0042 (6)	−0.0040 (7)
C11	0.0164 (7)	0.0168 (8)	0.0163 (8)	−0.0005 (6)	0.0047 (6)	−0.0031 (6)
C12	0.0288 (9)	0.0388 (12)	0.0212 (9)	0.0094 (8)	0.0023 (7)	0.0010 (8)
C13	0.0148 (7)	0.0181 (8)	0.0134 (7)	−0.0008 (6)	0.0015 (6)	0.0011 (6)
C14	0.0245 (8)	0.0176 (9)	0.0239 (9)	0.0005 (7)	0.0122 (7)	−0.0041 (7)
C15	0.0378 (11)	0.0348 (12)	0.0213 (9)	0.0069 (9)	0.0042 (8)	−0.0089 (8)
C16	0.0156 (7)	0.0243 (9)	0.0158 (8)	−0.0028 (6)	0.0022 (6)	−0.0029 (7)
C17	0.0266 (9)	0.0334 (11)	0.0219 (9)	−0.0067 (8)	0.0114 (7)	0.0030 (8)
C18	0.0316 (10)	0.0387 (12)	0.0233 (10)	−0.0062 (8)	0.0071 (8)	0.0032 (8)
C19	0.0271 (8)	0.0146 (8)	0.0195 (8)	−0.0006 (7)	0.0086 (7)	0.0015 (7)
C20	0.0218 (8)	0.0193 (9)	0.0275 (9)	0.0026 (7)	0.0079 (7)	−0.0015 (7)

Geometric parameters (Å, º) top

O1—C13	1.223 (2)	C9—C19	1.502 (2)
O2—C13	1.3463 (19)	C10—C11	1.351 (2)
O2—C14	1.454 (2)	C10—C20	1.500 (2)
O3—C16	1.213 (2)	C11—C16	1.475 (2)
O4—C16	1.361 (2)	C12—H12A	0.9600
O4—C17	1.450 (2)	C12—H12B	0.9600
N1—C9	1.385 (2)	C12—H12C	0.9600
N1—C10	1.386 (2)	C14—C15	1.498 (2)
N1—H1	0.8370	C14—H14A	0.9700
C1—C6	1.386 (2)	C14—H14B	0.9700
C1—C2	1.394 (2)	C15—H15A	0.9600
C1—H1A	0.9300	C15—H15B	0.9600
C2—C3	1.392 (3)	C15—H15C	0.9600
C2—H2A	0.9300	C17—C18	1.502 (2)
C3—C4	1.387 (3)	C17—H17A	0.9700
C3—C12	1.511 (2)	C17—H17B	0.9700
C4—C5	1.396 (2)	C18—H18A	0.9600
C4—H4A	0.9300	C18—H18B	0.9600
C5—C6	1.387 (2)	C18—H18C	0.9600
C5—H5A	0.9300	C19—H19A	0.9600
C6—C7	1.531 (2)	C19—H19B	0.9600
C7—C11	1.520 (2)	C19—H19C	0.9600
C7—C8	1.524 (2)	C20—H20A	0.9600
C7—H7A	0.9800	C20—H20B	0.9600
C8—C9	1.357 (2)	C20—H20C	0.9600
C8—C13	1.465 (2)

C13—O2—C14	116.54 (13)	H12A—C12—H12C	109.5
C16—O4—C17	116.64 (14)	H12B—C12—H12C	109.5
C9—N1—C10	123.54 (14)	O1—C13—O2	122.08 (15)
C9—N1—H1	117.3	O1—C13—C8	123.33 (15)
C10—N1—H1	118.7	O2—C13—C8	114.57 (14)
C6—C1—C2	121.28 (17)	O2—C14—C15	110.15 (14)
C6—C1—H1A	119.4	O2—C14—H14A	109.6
C2—C1—H1A	119.4	C15—C14—H14A	109.6
C3—C2—C1	120.86 (16)	O2—C14—H14B	109.6
C3—C2—H2A	119.6	C15—C14—H14B	109.6
C1—C2—H2A	119.6	H14A—C14—H14B	108.1
C4—C3—C2	117.94 (16)	C14—C15—H15A	109.5
C4—C3—C12	121.34 (17)	C14—C15—H15B	109.5
C2—C3—C12	120.72 (17)	H15A—C15—H15B	109.5
C3—C4—C5	120.87 (16)	C14—C15—H15C	109.5
C3—C4—H4A	119.6	H15A—C15—H15C	109.5
C5—C4—H4A	119.6	H15B—C15—H15C	109.5
C6—C5—C4	121.24 (16)	O3—C16—O4	122.14 (15)
C6—C5—H5A	119.4	O3—C16—C11	127.33 (16)
C4—C5—H5A	119.4	O4—C16—C11	110.53 (14)
C1—C6—C5	117.77 (15)	O4—C17—C18	111.28 (14)
C1—C6—C7	121.68 (15)	O4—C17—H17A	109.4
C5—C6—C7	120.54 (14)	C18—C17—H17A	109.4
C11—C7—C8	111.04 (13)	O4—C17—H17B	109.4
C11—C7—C6	111.12 (13)	C18—C17—H17B	109.4
C8—C7—C6	110.72 (12)	H17A—C17—H17B	108.0
C11—C7—H7A	107.9	C17—C18—H18A	109.5
C8—C7—H7A	107.9	C17—C18—H18B	109.5
C6—C7—H7A	107.9	H18A—C18—H18B	109.5
C9—C8—C13	124.37 (14)	C17—C18—H18C	109.5
C9—C8—C7	121.06 (14)	H18A—C18—H18C	109.5
C13—C8—C7	114.56 (14)	H18B—C18—H18C	109.5
C8—C9—N1	118.86 (15)	C9—C19—H19A	109.5
C8—C9—C19	127.69 (15)	C9—C19—H19B	109.5
N1—C9—C19	113.42 (14)	H19A—C19—H19B	109.5
C11—C10—N1	119.30 (14)	C9—C19—H19C	109.5
C11—C10—C20	127.24 (15)	H19A—C19—H19C	109.5
N1—C10—C20	113.44 (14)	H19B—C19—H19C	109.5
C10—C11—C16	120.59 (15)	C10—C20—H20A	109.5
C10—C11—C7	120.89 (14)	C10—C20—H20B	109.5
C16—C11—C7	118.37 (14)	H20A—C20—H20B	109.5
C3—C12—H12A	109.5	C10—C20—H20C	109.5
C3—C12—H12B	109.5	H20A—C20—H20C	109.5
H12A—C12—H12B	109.5	H20B—C20—H20C	109.5
C3—C12—H12C	109.5

C6—C1—C2—C3	0.2 (3)	C9—N1—C10—C11	−12.4 (2)
C1—C2—C3—C4	1.4 (3)	C9—N1—C10—C20	166.21 (14)
C1—C2—C3—C12	−178.65 (17)	N1—C10—C11—C16	177.23 (14)
C2—C3—C4—C5	−1.7 (3)	C20—C10—C11—C16	−1.1 (2)
C12—C3—C4—C5	178.29 (16)	N1—C10—C11—C7	−7.3 (2)
C3—C4—C5—C6	0.6 (3)	C20—C10—C11—C7	174.40 (15)
C2—C1—C6—C5	−1.4 (3)	C8—C7—C11—C10	22.6 (2)
C2—C1—C6—C7	177.57 (15)	C6—C7—C11—C10	−101.07 (17)
C4—C5—C6—C1	1.0 (2)	C8—C7—C11—C16	−161.75 (13)
C4—C5—C6—C7	−177.94 (15)	C6—C7—C11—C16	74.54 (17)
C1—C6—C7—C11	−112.17 (17)	C14—O2—C13—O1	−9.6 (2)
C5—C6—C7—C11	66.73 (19)	C14—O2—C13—C8	172.05 (13)
C1—C6—C7—C8	123.94 (17)	C9—C8—C13—O1	160.80 (15)
C5—C6—C7—C8	−57.15 (19)	C7—C8—C13—O1	−19.1 (2)
C11—C7—C8—C9	−21.7 (2)	C9—C8—C13—O2	−20.9 (2)
C6—C7—C8—C9	102.23 (17)	C7—C8—C13—O2	159.24 (13)
C11—C7—C8—C13	158.16 (13)	C13—O2—C14—C15	−80.96 (18)
C6—C7—C8—C13	−77.91 (16)	C17—O4—C16—O3	7.0 (2)
C13—C8—C9—N1	−174.47 (14)	C17—O4—C16—C11	−172.52 (13)
C7—C8—C9—N1	5.4 (2)	C10—C11—C16—O3	3.5 (3)
C13—C8—C9—C19	3.4 (3)	C7—C11—C16—O3	−172.17 (15)
C7—C8—C9—C19	−176.74 (15)	C10—C11—C16—O4	−177.07 (14)
C10—N1—C9—C8	13.3 (2)	C7—C11—C16—O4	7.31 (19)
C10—N1—C9—C19	−164.90 (14)	C16—O4—C17—C18	80.78 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.84	2.15	2.9684 (18)	166

Symmetry code: (i) x, y−1, z.

Experimental details

Crystal data
Chemical formula	C₂₀H₂₅NO₄
M_r	343.41
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	10.0175 (1), 7.4287 (1), 25.0974 (3)
β (°)	105.528 (1)
V (Å³)	1799.50 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.31 × 0.15 × 0.05

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.973, 0.996
No. of measured, independent and observed [I > 2σ(I)] reflections	20077, 5309, 3542
R_int	0.046
(sin θ/λ)_max (Å⁻¹)	0.706

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.147, 1.02
No. of reflections	5309
No. of parameters	231
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.26

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.84	2.15	2.9684 (18)	166

Symmetry code: (i) x, y−1, z.

Footnotes

‡Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

HKF and WCL thank Universiti Sains Malaysia (USM) for a Research University Golden Goose grant (No. 1001/PFIZIK/811012). WCL thanks USM for a Research Fellowship. VV is grateful to DST–India for funding through the Young Scientist Scheme (Fast Track Proposal).

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