7-Hy­droxy­hexa­cyclo­[7.5.1.01,7.06,13.08,12.010,14]penta­decan-15-one-11-spiro­cyclo­penta­ne

Kotha, S.; Cheekatla, S.R.; Gunta, R.

doi:10.1107/S2414314618000901

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 3| Part 1| January 2018| x180090

https://doi.org/10.1107/S2414314618000901

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access

7-Hydroxyhexacyclo[7.5.1.0^1,7.0^6,13.0^8,12.0^10,14]pentadecan-15-one-11-spirocyclopentane

Sambasivarao Kotha,^a ^* Subba Rao Cheekatla ^a and Rama Gunta ^a

^aDepartment of Chemistry, Indian Institute of Technology – Bombay, Powai, Mumbai 400 076, India
^*Correspondence e-mail: srk@chem.iitb.ac.in

Edited by S. Bernès, Benemérita Universidad Autónoma de Puebla, México (Received 12 December 2017; accepted 15 January 2018; online 26 January 2018)

The reorganization of the carbon skeleton in a spiro cage dione to an unusual cage system, C₁₉H₂₄O₂, using acid-promoted rearrangement with the aid of zinc dust as a reducing agent in the reaction medium is reported. The resulting trishomocubane hydroxyketone derivative includes five-membered rings having an envelope conformation and one seven-membered ring with a twist-chair conformation.

Keywords: crystal structure; propellane; cage system; ring rearrangement; ring-closing metathesis.

CCDC reference: 1586760

Structure description

Cage molecules act as useful precursors for the synthesis of diverse natural and non-natural products (Marchand et al., 1999 ). Many of these compounds are found to be key synthons in material chemistry (Eaton et al., 2002 ; Lal et al., 2015 ), in medicinal chemistry, and pharmaceutical drug design (Chalmers et al., 2016 ). Some of the functionalized cage systems are important templates for the design of supramolecules. As a result of the rigid architecture and considerable strain energy of cage moieties, they are involved in unusual skeletal rearrangements, generating intricate polycycles that are often difficult to design by other synthetic protocols (Kotha et al., 2017 ).

As part of our ongoing research efforts in this field, we present herein the synthesis and the structure of the title compound (Fig. 1). The title compound II was synthesized (Fig. 2) from inexpensive commercially available starting materials such as 1,4-hydroquinone, using our earlier reported strategy, via a Claisen rearrangement, Diels–Alder reaction, [2 + 2] photocycloaddition and ring-closing metathesis (RCM), followed by catalytic hydrogenation (Kotha & Dipak, 2006 ).

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

Figure 2
Reduction of cage propellane dione I with Zn/AcOH.

The molecule consists of eight fused rings of which one seven-membered, one six-membered and six five-membered rings are fused into a caged carbon skeleton. All five-membered rings are in envelope conformations, whereas the seven-membered ring is in a twist-chair conformation.

Synthesis and crystallization

A mixture of heptacyclic cage propellanedione I (100 mg, 0.35 mmol) and activated zinc dust (300 mg, 4.55 mmol) in 5 ml of glacial acetic acid was stirred at room temperature overnight. Insoluble zinc metal and salts were removed by filtration. The resulting filtrate was concentrated, diluted with cold water, and extracted with dichloromethane. The combined organic layers were washed with aqueous NaHCO₃, brine, and dried over anhydrous Na₂SO₄. The organic layer was concentrated under reduced pressure to give the crude rearranged cage hydroxyketone, which was purified by crystallization from mixed solvents of petroleum ether and ethyl acetate (4:1) to afford the title compound II (87 mg, 86%) as a colourless crystalline solid, m.p. 395–397 K.

IR (neat, cm⁻¹): 3440, 2935, 2861, 1756, 1451, 1308, 1244, 1158; ¹H NMR (500 MHz, CDCl₃, p.p.m.): 2.41–2.39 (m, 1H), 2.26–2.16 (m, 5H), 2.14–2.06 (m, 2H), 1.99 (s, 1H), 1.82–1.71 (m, 2H), 1.68–1.62 (m, 4H), 1.52–1.34 (m, 7H), 1.31–1.17 (m, 2H); ¹³C NMR (125 MHz, CDCl₃, p.p.m.): 217.7, 85.8, 58.3, 56.6, 56.4, 53.2, 50.2, 50.1, 49.6, 48.7, 47.2, 33.0, 31.2, 28.9, 26.2, 26.1, 26.0, 24.85, 24.81; HRMS (ESI) m/z calculated for C₁₉H₂₄NaO₂ [M + Na]⁺ 307.1669; found: 307.1670.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The molecule crystallizes in a centrosymmetric space group, with a racemic mixture of enantiomers. The relative configuration of the nine chiral centres was assigned as S-C2, S-C7, R-C8, S-C9, R-C10, R-C11, R-C12, S-C13 and R-C14.

Table 1
Experimental details

Crystal data
Chemical formula	C₁₉H₂₄O₂
M_r	284.38
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	6.3600 (2), 11.0807 (4), 11.5351 (4)
α, β, γ (°)	114.539 (4), 91.465 (3), 93.401 (3)
V (Å³)	737.07 (5)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.08
Crystal size (mm)	0.13 × 0.11 × 0.06

Data collection
Diffractometer	Rigaku Saturn724+
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2015 $[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
T_min, T_max	0.815, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	7967, 2593, 2255
R_int	0.044
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.114, 1.11
No. of reflections	2593
No. of parameters	191
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.25
Computer programs: CrysAlis PRO (Rigaku OD, 2015 $[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), SHELXT2014/5 (Sheldrick, 2015a ), SHELXL2014/7 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1586760

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314618000901/bh4032sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618000901/bh4032Isup2.hkl

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

7-Hydroxyhexacyclo[7.5.1.0^1,7.0^6,13.0^8,12.0^10,14]pentadecan-15-one-11-spirocyclopentane top

Crystal data top

C₁₉H₂₄O₂	F(000) = 308
M_r = 284.38	D_x = 1.281 Mg m⁻³
Triclinic, P1	Melting point = 395–397 K
a = 6.3600 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.0807 (4) Å	Cell parameters from 5950 reflections
c = 11.5351 (4) Å	θ = 1.9–31.2°
α = 114.539 (4)°	µ = 0.08 mm⁻¹
β = 91.465 (3)°	T = 293 K
γ = 93.401 (3)°	Block, colourless
V = 737.07 (5) Å³	0.13 × 0.11 × 0.06 mm
Z = 2

Data collection top

Rigaku Saturn724+ diffractometer	2593 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2255 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.044
Detector resolution: 28.5714 pixels mm^-1	θ_max = 25.0°, θ_min = 1.9°
ω scans	h = −7→7
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2015)	k = −13→13
T_min = 0.815, T_max = 1.000	l = −13→13
7967 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.114	H-atom parameters constrained
S = 1.11	w = 1/[σ²(F_o²) + (0.0532P)² + 0.2482P] where P = (F_o² + 2F_c²)/3
2593 reflections	(Δ/σ)_max < 0.001
191 parameters	Δρ_max = 0.33 e Å⁻³
0 restraints	Δρ_min = −0.25 e Å⁻³

Special details top

Refinement. 1. Fixed Uiso At 1.2 times of: All C(H) groups, All C(H,H) groups At 1.5 times of: All O(H) groups 2.a Ternary CH refined with riding coordinates: C7(H7), C13(H13), C10(H10), C14(H14), C9(H9), C11(H11), C12(H12) 2.b Secondary CH2 refined with riding coordinates: C6(H6A,H6B), C3(H3A,H3B), C5(H5A,H5B), C4(H4A,H4B), C17(H17A,H17B), C19(H19A, H19B), C16(H16A,H16B), C18(H18A,H18B) 2.c Idealised tetrahedral OH refined as rotating group: O1(H1)

All H atoms were placed in their geometrically calculated positions and refined using a riding model with C–H distances of 0.98 Å for all H atoms bound to tertiary C(sp³) atoms and 0.97 Å for all other H atoms bound to secondary C(sp³) atoms. The hydroxyl O—H bond length was fixed to 0.82 Å. Isotropic displacement parameters for H atoms were calculated as U_iso(H) = xU_eq(C/O), where x = 1.2 for all methine and methylene groups, and x = 1.5 for the hydroxyl group.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.36404 (17)	0.91284 (11)	0.24611 (11)	0.0252 (3)
H1	0.3257	0.9389	0.3193	0.038*
O2	0.75618 (16)	1.03470 (11)	0.50985 (10)	0.0259 (3)
C1	0.7323 (2)	0.92662 (15)	0.41932 (15)	0.0199 (3)
C2	0.7505 (2)	0.89395 (15)	0.27990 (15)	0.0198 (3)
C3	0.8338 (3)	1.01079 (16)	0.25321 (16)	0.0249 (4)
H3A	0.9865	1.0123	0.2544	0.030*
H3B	0.7976	1.0921	0.3226	0.030*
C4	0.7555 (3)	1.01269 (17)	0.12836 (16)	0.0284 (4)
H4A	0.6089	1.0331	0.1346	0.034*
H4B	0.8355	1.0834	0.1162	0.034*
C5	0.7737 (3)	0.88268 (17)	0.01230 (16)	0.0303 (4)
H5A	0.9016	0.8440	0.0231	0.036*
H5B	0.7855	0.9009	−0.0627	0.036*
C6	0.5864 (3)	0.78268 (17)	−0.00940 (16)	0.0279 (4)
H6A	0.6022	0.7070	−0.0897	0.033*
H6B	0.4604	0.8233	−0.0198	0.033*
C7	0.5474 (2)	0.72978 (15)	0.09132 (15)	0.0208 (4)
H7	0.4183	0.6701	0.0634	0.025*
C8	0.5245 (2)	0.82645 (15)	0.22937 (15)	0.0190 (3)
C9	0.5050 (2)	0.73109 (15)	0.30108 (14)	0.0193 (3)
H9	0.3623	0.7183	0.3262	0.023*
C10	0.5980 (2)	0.59946 (15)	0.20791 (14)	0.0195 (3)
H10	0.4939	0.5245	0.1620	0.023*
C11	0.7151 (2)	0.65541 (15)	0.12496 (14)	0.0196 (3)
H11	0.7830	0.5903	0.0524	0.024*
C12	0.8694 (2)	0.76285 (15)	0.23240 (14)	0.0188 (3)
H12	1.0116	0.7723	0.2050	0.023*
C13	0.8622 (2)	0.71750 (15)	0.34580 (14)	0.0197 (3)
H13	0.9938	0.7353	0.3983	0.024*
C14	0.6743 (2)	0.79265 (15)	0.41509 (14)	0.0206 (4)
H14	0.6398	0.7879	0.4955	0.025*
C15	0.7715 (2)	0.57240 (15)	0.28579 (15)	0.0214 (4)
C16	0.9272 (3)	0.47262 (16)	0.20525 (16)	0.0264 (4)
H16A	0.8594	0.4104	0.1244	0.032*
H16B	1.0491	0.5188	0.1887	0.032*
C17	0.9918 (3)	0.40057 (18)	0.28674 (17)	0.0354 (4)
H17A	1.0424	0.3147	0.2347	0.042*
H17B	1.1004	0.4532	0.3516	0.042*
C18	0.7878 (3)	0.38491 (17)	0.34615 (17)	0.0357 (5)
H18A	0.8147	0.3666	0.4202	0.043*
H18B	0.6931	0.3138	0.2851	0.043*
C19	0.6968 (3)	0.51950 (16)	0.38404 (16)	0.0272 (4)
H19A	0.7481	0.5803	0.4697	0.033*
H19B	0.5440	0.5097	0.3814	0.033*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0202 (6)	0.0262 (6)	0.0305 (7)	0.0069 (5)	0.0017 (5)	0.0125 (6)
O2	0.0223 (6)	0.0205 (6)	0.0259 (6)	0.0006 (5)	−0.0008 (5)	0.0008 (5)
C1	0.0121 (7)	0.0193 (8)	0.0229 (8)	0.0024 (6)	−0.0019 (6)	0.0035 (7)
C2	0.0185 (8)	0.0169 (8)	0.0211 (8)	0.0002 (6)	−0.0006 (6)	0.0053 (7)
C3	0.0228 (8)	0.0185 (8)	0.0314 (9)	−0.0008 (6)	0.0003 (7)	0.0089 (7)
C4	0.0289 (9)	0.0242 (9)	0.0373 (10)	−0.0007 (7)	0.0034 (7)	0.0182 (8)
C5	0.0361 (10)	0.0316 (10)	0.0286 (9)	0.0020 (8)	0.0049 (7)	0.0176 (8)
C6	0.0342 (9)	0.0272 (9)	0.0241 (9)	0.0017 (7)	−0.0016 (7)	0.0129 (8)
C7	0.0204 (8)	0.0195 (8)	0.0212 (8)	−0.0017 (6)	−0.0025 (6)	0.0078 (7)
C8	0.0152 (7)	0.0189 (8)	0.0229 (8)	0.0017 (6)	−0.0007 (6)	0.0087 (7)
C9	0.0168 (7)	0.0196 (8)	0.0203 (8)	−0.0001 (6)	−0.0005 (6)	0.0075 (7)
C10	0.0215 (8)	0.0156 (8)	0.0187 (8)	−0.0014 (6)	−0.0016 (6)	0.0050 (6)
C11	0.0226 (8)	0.0168 (8)	0.0162 (8)	0.0024 (6)	0.0002 (6)	0.0036 (6)
C12	0.0160 (7)	0.0188 (8)	0.0195 (8)	0.0016 (6)	0.0013 (6)	0.0058 (7)
C13	0.0186 (7)	0.0197 (8)	0.0177 (8)	0.0015 (6)	−0.0027 (6)	0.0049 (7)
C14	0.0216 (8)	0.0210 (8)	0.0165 (8)	0.0012 (6)	0.0000 (6)	0.0053 (7)
C15	0.0243 (8)	0.0192 (8)	0.0196 (8)	0.0028 (6)	−0.0008 (6)	0.0070 (7)
C16	0.0297 (9)	0.0209 (8)	0.0241 (9)	0.0057 (7)	−0.0024 (7)	0.0046 (7)
C17	0.0463 (11)	0.0264 (10)	0.0288 (10)	0.0133 (8)	−0.0061 (8)	0.0060 (8)
C18	0.0572 (12)	0.0227 (9)	0.0279 (9)	0.0032 (8)	−0.0057 (9)	0.0117 (8)
C19	0.0341 (9)	0.0243 (9)	0.0248 (9)	0.0015 (7)	−0.0017 (7)	0.0122 (7)

Geometric parameters (Å, º) top

O2—C1	1.2163 (19)	C10—C15	1.526 (2)
O1—H1	0.8200	C4—H4A	0.9700
O1—C8	1.4025 (18)	C4—H4B	0.9700
C1—C14	1.489 (2)	C14—H14	0.9800
C1—C2	1.504 (2)	C14—C9	1.565 (2)
C6—H6A	0.9700	C2—C12	1.572 (2)
C6—H6B	0.9700	C2—C8	1.560 (2)
C6—C7	1.522 (2)	C17—H17A	0.9700
C6—C5	1.519 (2)	C17—H17B	0.9700
C3—H3A	0.9700	C17—C16	1.527 (2)
C3—H3B	0.9700	C17—C18	1.516 (3)
C3—C4	1.521 (2)	C9—H9	0.9800
C3—C2	1.520 (2)	C9—C8	1.591 (2)
C7—H7	0.9800	C19—H19A	0.9700
C7—C11	1.522 (2)	C19—H19B	0.9700
C7—C8	1.523 (2)	C19—C15	1.549 (2)
C13—H13	0.9800	C19—C18	1.525 (2)
C13—C14	1.541 (2)	C16—H16A	0.9700
C13—C15	1.530 (2)	C16—H16B	0.9700
C13—C12	1.585 (2)	C16—C15	1.546 (2)
C5—H5A	0.9700	C11—H11	0.9800
C5—H5B	0.9700	C11—C12	1.578 (2)
C5—C4	1.519 (2)	C18—H18A	0.9700
C10—H10	0.9800	C18—H18B	0.9700
C10—C9	1.570 (2)	C12—H12	0.9800
C10—C11	1.526 (2)

C8—O1—H1	109.5	C3—C2—C8	120.48 (13)
O2—C1—C14	130.14 (14)	C8—C2—C12	97.08 (11)
O2—C1—C2	128.57 (14)	H17A—C17—H17B	109.1
C14—C1—C2	101.29 (12)	C16—C17—H17A	111.2
H6A—C6—H6B	107.1	C16—C17—H17B	111.2
C7—C6—H6A	107.7	C18—C17—H17A	111.2
C7—C6—H6B	107.7	C18—C17—H17B	111.2
C5—C6—H6A	107.7	C18—C17—C16	102.78 (14)
C5—C6—H6B	107.7	C10—C9—H9	114.2
C5—C6—C7	118.51 (14)	C10—C9—C8	104.35 (11)
H3A—C3—H3B	107.3	C14—C9—C10	103.93 (12)
C4—C3—H3A	108.1	C14—C9—H9	114.2
C4—C3—H3B	108.1	C14—C9—C8	104.67 (11)
C2—C3—H3A	108.1	C8—C9—H9	114.2
C2—C3—H3B	108.1	H19A—C19—H19B	108.7
C2—C3—C4	116.65 (14)	C15—C19—H19A	110.5
C6—C7—H7	107.2	C15—C19—H19B	110.5
C6—C7—C8	119.86 (13)	C18—C19—H19A	110.5
C11—C7—C6	119.97 (13)	C18—C19—H19B	110.5
C11—C7—H7	107.2	C18—C19—C15	106.10 (13)
C11—C7—C8	94.09 (11)	C17—C16—H16A	110.8
C8—C7—H7	107.2	C17—C16—H16B	110.8
C14—C13—H13	115.6	C17—C16—C15	104.70 (13)
C14—C13—C12	99.50 (11)	H16A—C16—H16B	108.9
C15—C13—H13	115.6	C15—C16—H16A	110.8
C15—C13—C14	102.84 (12)	C15—C16—H16B	110.8
C15—C13—C12	105.66 (12)	C7—C11—C10	102.41 (12)
C12—C13—H13	115.6	C7—C11—H11	115.6
C6—C5—H5A	109.0	C7—C11—C12	107.14 (12)
C6—C5—H5B	109.0	C10—C11—H11	115.6
H5A—C5—H5B	107.8	C10—C11—C12	98.33 (11)
C4—C5—C6	112.79 (14)	C12—C11—H11	115.6
C4—C5—H5A	109.0	C13—C15—C19	113.97 (13)
C4—C5—H5B	109.0	C13—C15—C16	114.25 (13)
C9—C10—H10	115.4	C10—C15—C13	93.32 (12)
C11—C10—H10	115.4	C10—C15—C19	116.05 (13)
C11—C10—C9	98.14 (11)	C10—C15—C16	114.56 (13)
C15—C10—H10	115.4	C16—C15—C19	104.95 (13)
C15—C10—C9	105.94 (12)	C17—C18—C19	103.31 (14)
C15—C10—C11	104.71 (12)	C17—C18—H18A	111.1
C3—C4—H4A	108.8	C17—C18—H18B	111.1
C3—C4—H4B	108.8	C19—C18—H18A	111.1
C5—C4—C3	113.87 (13)	C19—C18—H18B	111.1
C5—C4—H4A	108.8	H18A—C18—H18B	109.1
C5—C4—H4B	108.8	C13—C12—H12	114.1
H4A—C4—H4B	107.7	C2—C12—C13	105.03 (11)
C1—C14—C13	100.18 (12)	C2—C12—C11	104.64 (11)
C1—C14—H14	117.5	C2—C12—H12	114.1
C1—C14—C9	103.04 (12)	C11—C12—C13	103.68 (11)
C13—C14—H14	117.5	C11—C12—H12	114.1
C13—C14—C9	98.00 (11)	O1—C8—C7	114.29 (12)
C9—C14—H14	117.5	O1—C8—C2	115.98 (12)
C1—C2—C3	114.04 (13)	O1—C8—C9	116.75 (12)
C1—C2—C12	102.23 (12)	C7—C8—C2	105.24 (12)
C1—C2—C8	99.12 (11)	C7—C8—C9	102.90 (12)
C3—C2—C12	120.17 (13)	C2—C8—C9	99.74 (11)

O2—C1—C14—C13	−123.78 (16)	C14—C9—C8—C7	128.39 (12)
O2—C1—C14—C9	135.46 (16)	C14—C9—C8—C2	20.15 (14)
O2—C1—C2—C3	7.6 (2)	C2—C1—C14—C13	57.20 (13)
O2—C1—C2—C12	138.86 (15)	C2—C1—C14—C9	−43.56 (13)
O2—C1—C2—C8	−121.79 (16)	C2—C3—C4—C5	−49.74 (19)
C1—C14—C9—C10	122.62 (12)	C17—C16—C15—C13	106.45 (16)
C1—C14—C9—C8	13.42 (14)	C17—C16—C15—C10	−147.55 (14)
C1—C2—C12—C13	12.06 (14)	C17—C16—C15—C19	−19.11 (17)
C1—C2—C12—C11	120.91 (12)	C9—C10—C11—C7	−49.50 (13)
C1—C2—C8—O1	80.03 (15)	C9—C10—C11—C12	60.21 (12)
C1—C2—C8—C7	−152.60 (12)	C9—C10—C15—C13	−44.32 (13)
C1—C2—C8—C9	−46.25 (13)	C9—C10—C15—C19	74.45 (16)
C6—C7—C11—C10	−169.91 (14)	C9—C10—C15—C16	−162.93 (13)
C6—C7—C11—C12	87.20 (16)	C16—C17—C18—C19	−42.56 (17)
C6—C7—C8—O1	56.73 (18)	C11—C7—C8—O1	−175.07 (12)
C6—C7—C8—C2	−71.66 (16)	C11—C7—C8—C2	56.54 (13)
C6—C7—C8—C9	−175.68 (13)	C11—C7—C8—C9	−47.48 (12)
C6—C5—C4—C3	84.99 (18)	C11—C10—C9—C14	−92.20 (12)
C3—C2—C12—C13	139.52 (14)	C11—C10—C9—C8	17.24 (14)
C3—C2—C12—C11	−111.63 (15)	C11—C10—C15—C13	58.82 (13)
C3—C2—C8—O1	−44.95 (19)	C11—C10—C15—C19	177.59 (13)
C3—C2—C8—C7	82.42 (16)	C11—C10—C15—C16	−59.79 (16)
C3—C2—C8—C9	−171.23 (13)	C15—C13—C14—C1	−155.62 (12)
C7—C6—C5—C4	−63.8 (2)	C15—C13—C14—C9	−50.74 (13)
C7—C11—C12—C13	123.26 (12)	C15—C13—C12—C2	127.24 (12)
C7—C11—C12—C2	13.41 (15)	C15—C13—C12—C11	17.69 (14)
C13—C14—C9—C10	20.16 (14)	C15—C10—C9—C14	15.71 (15)
C13—C14—C9—C8	−89.05 (13)	C15—C10—C9—C8	125.15 (12)
C5—C6—C7—C11	−59.9 (2)	C15—C10—C11—C7	−158.42 (12)
C5—C6—C7—C8	55.3 (2)	C15—C10—C11—C12	−48.72 (14)
C10—C9—C8—O1	145.51 (13)	C15—C19—C18—C17	30.67 (17)
C10—C9—C8—C7	19.49 (14)	C18—C17—C16—C15	38.27 (17)
C10—C9—C8—C2	−88.75 (13)	C18—C19—C15—C13	−132.77 (14)
C10—C11—C12—C13	17.45 (13)	C18—C19—C15—C10	120.51 (15)
C10—C11—C12—C2	−92.39 (12)	C18—C19—C15—C16	−7.03 (17)
C4—C3—C2—C1	−149.20 (14)	C12—C13—C14—C1	−47.02 (13)
C4—C3—C2—C12	88.96 (17)	C12—C13—C14—C9	57.85 (13)
C4—C3—C2—C8	−31.6 (2)	C12—C13—C15—C10	−44.42 (13)
C14—C1—C2—C3	−173.38 (12)	C12—C13—C15—C19	−164.89 (12)
C14—C1—C2—C12	−42.10 (13)	C12—C13—C15—C16	74.44 (15)
C14—C1—C2—C8	57.26 (13)	C12—C2—C8—O1	−176.31 (12)
C14—C13—C15—C10	59.45 (13)	C12—C2—C8—C7	−48.94 (13)
C14—C13—C15—C19	−61.02 (16)	C12—C2—C8—C9	57.41 (12)
C14—C13—C15—C16	178.31 (12)	C8—C7—C11—C10	61.96 (13)
C14—C13—C12—C2	20.92 (14)	C8—C7—C11—C12	−40.92 (13)
C14—C13—C12—C11	−88.63 (13)	C8—C2—C12—C13	−88.92 (12)
C14—C9—C8—O1	−105.59 (14)	C8—C2—C12—C11	19.94 (13)

Acknowledgements

The authors thank Darshan Mhatre for helping in collecting the X-ray data.

Funding information

We thank the Defence Research and Development Organization (DRDO, No. ARDB/01/1041849/M/1), New Delhi for financial assistance. SK thanks the Department of Science and Technology (DST, No. SR/S2/JCB-33/2010) for the award of a J. C. Bose fellowship and Praj Industries for a Chair Professorship (Green Chemistry). SRC and RG thank the University Grants Commission (UGC), New Delhi, for the award of a research fellowship.

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