Di-tert-butyl N,N′-(octa­hydro­penta­lene-2,5-di­yl)dicarbamate

Kendhale, A.M.; Gonnade, R.G.; Sanjayan, G.J.

doi:10.1107/S1600536808014876

organic compounds

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ISSN: 2056-9890

Volume 64| Part 6| June 2008| Page o1149

doi:10.1107/S1600536808014876

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Di-tert-butyl N,N′-(octahydropentalene-2,5-diyl)dicarbamate

Amol M. Kendhale,^a Rajesh G. Gonnade ^b ^* and Gangadhar J. Sanjayan ^a

^aDivision of Organic Chemistry, National Chemical Laboratory, Pashan Road, Pune 411 008, India, and ^bCenter for Materials Characterization, National Chemical Laboratory, Pashan Road, Pune 411 008, India
^*Correspondence e-mail: rg.gonnade@ncl.res.in

(Received 8 May 2008; accepted 16 May 2008; online 24 May 2008)

In the molecule of the title compound, C₁₈H₃₂N₂O₄, the central bicyclo[3.3.0]octane (octahydropentalene) has a rigid ring junction. Both rings of the bicyclo[3.3.0]octane unit adopt an envelope conformation, and the flexible tert-butylcarbamoyl side chains each have an extended conformation. Such a constrained bicyclo[3.3.0]octane aliphatic template is of interest with respect to the design of novel self-assembling motifs. Molecules related by c-glide symmetry are linked via intermolecular N—H⋯O hydrogen bonds, forming a two-dimensional layer structure. Neighboring layers are weakly associated along the a axis due to the close approach of the tert-butylcarbamoyl groups (2.55 Å).

Related literature

For related literature, see: Bertz et al. (1982 ); Kendhale et al. (2008 ); Yates et al. (1960 ); Yeo et al. (2006 ).

Experimental

Crystal data

C₁₈H₃₂N₂O₄
M_r = 340.46
Monoclinic, P 2/c
a = 33.161 (17) Å
b = 6.060 (3) Å
c = 9.926 (5) Å
β = 95.594 (9)°
V = 1985.2 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 297 (2) K
0.64 × 0.13 × 0.08 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ) T_min = 0.951, T_max = 0.994
9395 measured reflections
3479 independent reflections
2863 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.056
wR(F²) = 0.133
S = 1.08
3479 reflections
271 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.14 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯O3ⁱ	0.86	2.11	2.954 (3)	167
N1—H1⋯O1ⁱⁱ	0.86	2.19	3.022 (3)	162
Symmetry codes: (i) $[x, -y+1, z+{\script{1\over 2}}]$ ; (ii) $[x, -y+2, z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808014876/wk2086sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808014876/wk2086Isup2.hkl

checkCIF report

Comment top

The skeleton of bicyclo[3.3.0]octane is interesting because it has a rigid ring junction as well as conformationally flexible side groups (Bertz et al., 1982; Yates et al., 1960). Depending on the substituents, it can adopt one of three different conformations in a given circumstance (Yeo et al., 2006). In the context of our interest in extending the applicability of bicyclo[3.3.0]octane as a self-assembling motif (Kendhale et al., 2008), the title compound (I) has been synthesized and here we report its crystal structure.

The two five-membered rings of the bicyclo[3.3.0]octane subunit adopt an exo/endo envelope conformation, while the flexible tert-Butylcarbamoyl group takes an extended conformation (Fig. 1).

In the crystal, molecules related by c-glide symmetry are linked via intermolecular N—H···O hydrogen bonds (Table 1) forming a layered arrangement (Fig.2). These layers are weakly associated along the a axis due to the close approach of the bulkier tert-butylcarbamoy group (2.55 Å).

Related literature top

For related literature, see: Bertz et al. (1982); Kendhale et al. (2008); Yates et al. (1960); Yeo et al. (2006).

Experimental top

Tetramethylbicyclo[3.3.0]octane-3,7-dione-2,4,6,8-tetracarboxylate, bicyclo[3.3.0]octane-3,7-dione and 2, 5-dihydroxy-bicyclo[3.3.0]octane were prepared according to the literature procedure (Bertz et al., 1982; Yeo et al., 2006). The 2, 5-dihydroxy-bicyclo[3.3.0]octane (3.86 g, 27.183 mmol) was treated with methanesulfonyl chloride (6.31 ml, 9.34 g, 81.549 mmol) and triethyl amine (11.36 ml, 8.25 g, 81.549 mmol) in DCM (50 ml) at room temperature for 12 h to obtain 2,5-dimethanesulfonyloxy bicyclo[3.3.0]octane. Nucleophilic displacement of 2,5-dimethanesulfonyloxy bicyclo[3.3.0]octane (6 g, 20.134 mmol) by sodium azide (13.08 g, 201.34 mmol) in DMF (40 ml) at 343 K for 24 h, delivered 2,5-diazido-bicyclo[3.3.0]octane. The 2,5-diazido-bicyclo[3.3.0]octane (0.5 g, 2.6041 mmol) was hydrogenated in the presence of Pd/c-methanol (20 ml) system, and in situ protection with tert-Butyl Dicarbonate (Boc)2O, (1.7 g, 7.812 mmol), afforded the required 5-tert-Butoxycarbonylamino-octahydro-pentalen-2-yl)-carbamic acid tert-butyl ester (0.61 g, 69%). Colourless needles suitable for X-ray diffraction were obtained by slow evaporation of a solution in methanol-ethyl acetate (1:4) mixture at room temperature.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms.
	Fig. 2. Molecular packing viewed down the b axis, showing the layered arrangement of the molecules linked via N—H···O hydrogen bonds.

Di-tert-butyl N,N'-(octahydropentalene-2,5-diyl)dicarbamate top

Crystal data top

C₁₈H₃₂N₂O₄	F(000) = 744
M_r = 340.46	D_x = 1.139 Mg m⁻³
Monoclinic, P2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 3113 reflections
a = 33.161 (17) Å	θ = 2.5–25.4°
b = 6.060 (3) Å	µ = 0.08 mm⁻¹
c = 9.926 (5) Å	T = 297 K
β = 95.594 (9)°	Needle, colourless
V = 1985.2 (18) Å³	0.64 × 0.13 × 0.08 mm
Z = 4

Data collection top

Bruker SMART APEX diffractometer	3479 independent reflections
Radiation source: fine-focus sealed tube	2863 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.2°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −39→29
T_min = 0.951, T_max = 0.994	k = −7→7
9395 measured reflections	l = −10→11

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)] = 0.056	Hydrogen site location: geom, difmap for bicyclo unit
wR(F²) = 0.133	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ²(F_o²) + (0.0452P)² + 0.984P] where P = (F_o² + 2F_c²)/3
3479 reflections	(Δ/σ)_max < 0.001
271 parameters	Δρ_max = 0.17 e Å⁻³
0 restraints	Δρ_min = −0.14 e Å⁻³

Crystal data top

C₁₈H₃₂N₂O₄	V = 1985.2 (18) Å³
M_r = 340.46	Z = 4
Monoclinic, P2/c	Mo Kα radiation
a = 33.161 (17) Å	µ = 0.08 mm⁻¹
b = 6.060 (3) Å	T = 297 K
c = 9.926 (5) Å	0.64 × 0.13 × 0.08 mm
β = 95.594 (9)°

Data collection top

Bruker SMART APEX diffractometer	3479 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2003)	2863 reflections with I > 2σ(I)
T_min = 0.951, T_max = 0.994	R_int = 0.026
9395 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	0 restraints
wR(F²) = 0.133	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	Δρ_max = 0.17 e Å⁻³
3479 reflections	Δρ_min = −0.14 e Å⁻³
271 parameters

Special details top

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	0.14804 (5)	1.1114 (3)	0.46136 (15)	0.0640 (5)
O2	0.10387 (4)	1.1306 (3)	0.62262 (15)	0.0567 (4)
O3	0.35645 (5)	0.4521 (3)	0.36953 (14)	0.0614 (5)
O4	0.39622 (4)	0.3724 (3)	0.56279 (14)	0.0559 (4)
N1	0.16176 (5)	0.9541 (3)	0.66747 (17)	0.0496 (5)
H1	0.1525	0.9274	0.7438	0.060*
N2	0.34243 (5)	0.5850 (3)	0.57189 (16)	0.0460 (5)
H2	0.3496	0.5892	0.6575	0.055*
C1	0.20180 (6)	0.8722 (4)	0.6444 (2)	0.0421 (5)
C2	0.23645 (7)	0.9724 (4)	0.7371 (3)	0.0526 (6)
C3	0.27303 (6)	0.8282 (3)	0.7141 (2)	0.0395 (5)
C4	0.25453 (6)	0.6036 (3)	0.6631 (2)	0.0396 (5)
C5	0.20867 (7)	0.6266 (4)	0.6674 (3)	0.0485 (5)
C6	0.29869 (7)	0.9084 (4)	0.6030 (2)	0.0471 (5)
C7	0.30653 (6)	0.7070 (4)	0.5165 (2)	0.0439 (5)
C8	0.26760 (7)	0.5747 (4)	0.5201 (2)	0.0437 (5)
C9	0.13895 (6)	1.0694 (4)	0.5737 (2)	0.0450 (5)
C10	0.07445 (7)	1.2714 (4)	0.5428 (2)	0.0522 (6)
C11	0.05791 (8)	1.1566 (5)	0.4146 (3)	0.0763 (8)
H11A	0.0788	1.1449	0.3545	0.114*
H11B	0.0356	1.2399	0.3716	0.114*
H11C	0.0487	1.0116	0.4360	0.114*
C12	0.04103 (8)	1.2937 (6)	0.6378 (3)	0.0875 (10)
H12A	0.0302	1.1505	0.6547	0.131*
H12B	0.0198	1.3864	0.5965	0.131*
H12C	0.0521	1.3582	0.7218	0.131*
C13	0.09321 (10)	1.4901 (5)	0.5166 (4)	0.0927 (10)
H13A	0.1068	1.5463	0.5994	0.139*
H13B	0.0725	1.5917	0.4825	0.139*
H13C	0.1124	1.4724	0.4511	0.139*
C14	0.36414 (6)	0.4672 (4)	0.4910 (2)	0.0415 (5)
C15	0.42463 (7)	0.2332 (4)	0.4955 (2)	0.0554 (6)
C16	0.45595 (10)	0.1763 (7)	0.6134 (3)	0.1111 (14)
H16A	0.4667	0.3098	0.6547	0.167*
H16B	0.4775	0.0925	0.5806	0.167*
H16C	0.4433	0.0908	0.6791	0.167*
C17	0.40278 (10)	0.0335 (5)	0.4356 (4)	0.0995 (12)
H17A	0.3882	−0.0360	0.5030	0.149*
H17B	0.4221	−0.0686	0.4051	0.149*
H17C	0.3841	0.0775	0.3604	0.149*
C18	0.44483 (8)	0.3633 (5)	0.3914 (3)	0.0732 (8)
H18A	0.4255	0.3942	0.3153	0.110*
H18B	0.4668	0.2790	0.3618	0.110*
H18C	0.4550	0.4994	0.4306	0.110*
H3	0.2897 (6)	0.808 (3)	0.798 (2)	0.043 (6)*
H4	0.2652 (6)	0.486 (4)	0.720 (2)	0.050 (6)*
H7	0.3117 (6)	0.747 (3)	0.422 (2)	0.047 (6)*
H1A	0.2045 (6)	0.908 (3)	0.555 (2)	0.045 (6)*
H2A	0.2412 (8)	1.128 (5)	0.717 (3)	0.074 (8)*
H5A	0.1936 (8)	0.540 (5)	0.598 (3)	0.080 (9)*
H6A	0.3249 (8)	0.982 (4)	0.643 (3)	0.070 (7)*
H8A	0.2709 (6)	0.416 (4)	0.495 (2)	0.044 (6)*
H2B	0.2287 (8)	0.959 (4)	0.836 (3)	0.073 (8)*
H5B	0.2002 (7)	0.592 (4)	0.758 (2)	0.052 (6)*
H6B	0.2824 (7)	1.009 (4)	0.544 (2)	0.058 (7)*
H8B	0.2473 (6)	0.636 (3)	0.456 (2)	0.038 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0590 (10)	0.0951 (14)	0.0394 (9)	0.0194 (9)	0.0125 (7)	0.0133 (9)
O2	0.0453 (9)	0.0790 (12)	0.0467 (9)	0.0222 (8)	0.0095 (7)	0.0101 (8)
O3	0.0549 (10)	0.0956 (13)	0.0333 (9)	0.0147 (9)	0.0019 (7)	−0.0137 (8)
O4	0.0495 (9)	0.0773 (11)	0.0413 (8)	0.0235 (8)	0.0055 (7)	−0.0050 (8)
N1	0.0437 (10)	0.0693 (13)	0.0377 (9)	0.0157 (9)	0.0131 (8)	0.0096 (9)
N2	0.0442 (10)	0.0644 (12)	0.0296 (8)	0.0127 (9)	0.0051 (7)	−0.0014 (8)
C1	0.0410 (11)	0.0513 (13)	0.0353 (11)	0.0063 (10)	0.0095 (9)	0.0038 (10)
C2	0.0498 (13)	0.0465 (14)	0.0628 (15)	−0.0001 (11)	0.0122 (11)	−0.0151 (12)
C3	0.0394 (11)	0.0432 (12)	0.0356 (11)	−0.0004 (9)	0.0022 (9)	−0.0018 (9)
C4	0.0439 (12)	0.0335 (11)	0.0415 (11)	0.0030 (9)	0.0049 (9)	0.0040 (9)
C5	0.0428 (12)	0.0478 (13)	0.0559 (14)	−0.0051 (10)	0.0092 (11)	−0.0022 (11)
C6	0.0429 (12)	0.0424 (12)	0.0569 (14)	0.0003 (10)	0.0093 (10)	0.0061 (11)
C7	0.0412 (11)	0.0570 (14)	0.0341 (11)	0.0087 (10)	0.0072 (9)	0.0072 (10)
C8	0.0448 (12)	0.0450 (13)	0.0406 (12)	0.0084 (10)	0.0001 (9)	−0.0078 (10)
C9	0.0416 (12)	0.0544 (13)	0.0395 (12)	0.0069 (10)	0.0058 (9)	−0.0011 (10)
C10	0.0436 (12)	0.0594 (14)	0.0523 (13)	0.0136 (11)	−0.0024 (10)	0.0019 (11)
C11	0.0626 (16)	0.089 (2)	0.0735 (18)	0.0099 (15)	−0.0139 (14)	−0.0117 (16)
C12	0.0612 (17)	0.122 (3)	0.0797 (19)	0.0425 (18)	0.0100 (14)	0.0030 (19)
C13	0.079 (2)	0.0664 (19)	0.128 (3)	0.0028 (16)	−0.0131 (19)	0.0090 (19)
C14	0.0361 (11)	0.0540 (13)	0.0348 (11)	0.0010 (10)	0.0044 (8)	−0.0033 (9)
C15	0.0534 (14)	0.0604 (15)	0.0551 (13)	0.0157 (12)	0.0195 (11)	0.0013 (12)
C16	0.096 (2)	0.159 (4)	0.081 (2)	0.084 (2)	0.0219 (18)	0.025 (2)
C17	0.104 (2)	0.0595 (18)	0.145 (3)	−0.0050 (17)	0.063 (2)	−0.018 (2)
C18	0.0549 (15)	0.0820 (19)	0.0867 (19)	0.0037 (14)	0.0270 (14)	0.0087 (16)

Geometric parameters (Å, º) top

O1—C9	1.210 (3)	C7—C8	1.523 (3)
O2—C9	1.355 (2)	C7—H7	1.00 (2)
O2—C10	1.469 (3)	C8—H8A	1.00 (2)
O3—C14	1.211 (2)	C8—H8B	0.95 (2)
O4—C14	1.350 (2)	C10—C13	1.497 (4)
O4—C15	1.472 (3)	C10—C11	1.506 (3)
N1—C9	1.337 (3)	C10—C12	1.530 (3)
N1—C1	1.456 (3)	C11—H11A	0.9600
N1—H1	0.8600	C11—H11B	0.9600
N2—C14	1.336 (3)	C11—H11C	0.9600
N2—C7	1.462 (3)	C12—H12A	0.9600
N2—H2	0.8600	C12—H12B	0.9600
C1—C5	1.520 (3)	C12—H12C	0.9600
C1—C2	1.526 (3)	C13—H13A	0.9600
C1—H1A	0.92 (2)	C13—H13B	0.9600
C2—C3	1.530 (3)	C13—H13C	0.9600
C2—H2A	0.98 (3)	C15—C17	1.503 (4)
C2—H2B	1.04 (3)	C15—C18	1.508 (3)
C3—C6	1.536 (3)	C15—C16	1.527 (4)
C3—C4	1.557 (3)	C16—H16A	0.9600
C3—H3	0.96 (2)	C16—H16B	0.9600
C4—C5	1.532 (3)	C16—H16C	0.9600
C4—C8	1.534 (3)	C17—H17A	0.9600
C4—H4	0.96 (2)	C17—H17B	0.9600
C5—H5A	0.96 (3)	C17—H17C	0.9600
C5—H5B	0.99 (2)	C18—H18A	0.9600
C6—C7	1.529 (3)	C18—H18B	0.9600
C6—H6A	1.02 (3)	C18—H18C	0.9600
C6—H6B	0.97 (2)

C9—O2—C10	120.93 (17)	H8A—C8—H8B	107.1 (17)
C14—O4—C15	120.70 (16)	O1—C9—N1	125.17 (19)
C9—N1—C1	122.09 (17)	O1—C9—O2	124.89 (19)
C9—N1—H1	119.0	N1—C9—O2	109.93 (18)
C1—N1—H1	119.0	O2—C10—C13	110.0 (2)
C14—N2—C7	120.73 (17)	O2—C10—C11	110.8 (2)
C14—N2—H2	119.6	C13—C10—C11	112.7 (2)
C7—N2—H2	119.6	O2—C10—C12	101.63 (18)
N1—C1—C5	115.83 (18)	C13—C10—C12	111.5 (2)
N1—C1—C2	114.47 (18)	C11—C10—C12	109.6 (2)
C5—C1—C2	101.90 (19)	C10—C11—H11A	109.5
N1—C1—H1A	104.2 (13)	C10—C11—H11B	109.5
C5—C1—H1A	110.1 (13)	H11A—C11—H11B	109.5
C2—C1—H1A	110.4 (13)	C10—C11—H11C	109.5
C1—C2—C3	104.11 (18)	H11A—C11—H11C	109.5
C1—C2—H2A	112.7 (16)	H11B—C11—H11C	109.5
C3—C2—H2A	111.8 (16)	C10—C12—H12A	109.5
C1—C2—H2B	107.3 (14)	C10—C12—H12B	109.5
C3—C2—H2B	111.8 (14)	H12A—C12—H12B	109.5
H2A—C2—H2B	109 (2)	C10—C12—H12C	109.5
C2—C3—C6	115.44 (19)	H12A—C12—H12C	109.5
C2—C3—C4	104.78 (17)	H12B—C12—H12C	109.5
C6—C3—C4	105.77 (17)	C10—C13—H13A	109.5
C2—C3—H3	110.0 (12)	C10—C13—H13B	109.5
C6—C3—H3	110.2 (12)	H13A—C13—H13B	109.5
C4—C3—H3	110.3 (13)	C10—C13—H13C	109.5
C5—C4—C8	113.99 (19)	H13A—C13—H13C	109.5
C5—C4—C3	105.79 (17)	H13B—C13—H13C	109.5
C8—C4—C3	105.21 (17)	O3—C14—N2	124.39 (19)
C5—C4—H4	111.3 (13)	O3—C14—O4	124.89 (19)
C8—C4—H4	109.9 (13)	N2—C14—O4	110.70 (17)
C3—C4—H4	110.4 (13)	O4—C15—C17	109.6 (2)
C1—C5—C4	102.69 (17)	O4—C15—C18	111.0 (2)
C1—C5—H5A	111.6 (17)	C17—C15—C18	112.3 (2)
C4—C5—H5A	112.2 (16)	O4—C15—C16	101.48 (19)
C1—C5—H5B	106.9 (13)	C17—C15—C16	112.8 (3)
C4—C5—H5B	112.0 (13)	C18—C15—C16	109.2 (2)
H5A—C5—H5B	111 (2)	C15—C16—H16A	109.5
C7—C6—C3	106.68 (18)	C15—C16—H16B	109.5
C7—C6—H6A	112.4 (14)	H16A—C16—H16B	109.5
C3—C6—H6A	111.9 (14)	C15—C16—H16C	109.5
C7—C6—H6B	105.8 (14)	H16A—C16—H16C	109.5
C3—C6—H6B	108.6 (14)	H16B—C16—H16C	109.5
H6A—C6—H6B	111 (2)	C15—C17—H17A	109.5
N2—C7—C8	112.69 (19)	C15—C17—H17B	109.5
N2—C7—C6	111.67 (18)	H17A—C17—H17B	109.5
C8—C7—C6	102.47 (17)	C15—C17—H17C	109.5
N2—C7—H7	105.5 (12)	H17A—C17—H17C	109.5
C8—C7—H7	111.8 (12)	H17B—C17—H17C	109.5
C6—C7—H7	112.9 (12)	C15—C18—H18A	109.5
C7—C8—C4	106.16 (17)	C15—C18—H18B	109.5
C7—C8—H8A	112.7 (12)	H18A—C18—H18B	109.5
C4—C8—H8A	112.7 (12)	C15—C18—H18C	109.5
C7—C8—H8B	109.0 (12)	H18A—C18—H18C	109.5
C4—C8—H8B	109.2 (12)	H18B—C18—H18C	109.5

C9—N1—C1—C5	−126.3 (2)	C3—C6—C7—C8	34.0 (2)
C9—N1—C1—C2	115.6 (2)	N2—C7—C8—C4	83.2 (2)
N1—C1—C2—C3	168.58 (18)	C6—C7—C8—C4	−36.9 (2)
C5—C1—C2—C3	42.8 (2)	C5—C4—C8—C7	141.38 (19)
C1—C2—C3—C6	91.7 (2)	C3—C4—C8—C7	25.9 (2)
C1—C2—C3—C4	−24.2 (2)	C1—N1—C9—O1	2.5 (4)
C2—C3—C4—C5	−3.1 (2)	C1—N1—C9—O2	−178.18 (19)
C6—C3—C4—C5	−125.53 (19)	C10—O2—C9—O1	−4.6 (4)
C2—C3—C4—C8	117.87 (19)	C10—O2—C9—N1	176.08 (19)
C6—C3—C4—C8	−4.6 (2)	C9—O2—C10—C13	−61.7 (3)
N1—C1—C5—C4	−169.18 (18)	C9—O2—C10—C11	63.6 (3)
C2—C1—C5—C4	−44.3 (2)	C9—O2—C10—C12	180.0 (2)
C8—C4—C5—C1	−85.8 (2)	C7—N2—C14—O3	0.3 (3)
C3—C4—C5—C1	29.3 (2)	C7—N2—C14—O4	178.76 (18)
C2—C3—C6—C7	−133.66 (19)	C15—O4—C14—O3	−1.7 (3)
C4—C3—C6—C7	−18.3 (2)	C15—O4—C14—N2	179.80 (19)
C14—N2—C7—C8	93.1 (2)	C14—O4—C15—C17	−63.5 (3)
C14—N2—C7—C6	−152.15 (19)	C14—O4—C15—C18	61.1 (3)
C3—C6—C7—N2	−86.9 (2)	C14—O4—C15—C16	177.1 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O3ⁱ	0.86	2.11	2.954 (3)	167
N1—H1···O1ⁱⁱ	0.86	2.19	3.022 (3)	162

Symmetry codes: (i) x, −y+1, z+1/2; (ii) x, −y+2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₁₈H₃₂N₂O₄
M_r	340.46
Crystal system, space group	Monoclinic, P2/c
Temperature (K)	297
a, b, c (Å)	33.161 (17), 6.060 (3), 9.926 (5)
β (°)	95.594 (9)
V (Å³)	1985.2 (18)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.64 × 0.13 × 0.08

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2003)
T_min, T_max	0.951, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	9395, 3479, 2863
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.133, 1.08
No. of reflections	3479
No. of parameters	271
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.14

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O3ⁱ	0.86	2.11	2.954 (3)	167.0
N1—H1···O1ⁱⁱ	0.86	2.19	3.022 (3)	162.2

Symmetry codes: (i) x, −y+1, z+1/2; (ii) x, −y+2, z+1/2.

Acknowledgements

AMK is the recipient of a Senior Research Fellowship from the Council of Scientific and Industrial Research (CSIR), New Delhi, India.

References

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