3-Butyl-1-(5-nitro­benzo­[c][1,2]­thia­zol-3-yl)-3-phenyl­triazene

The mol­ecule of the title compound, C₁₇H₁₇N₅O₂S, consists of three [pi] systems, viz. two aromatic rings and the triazene moiety, which are mutually deconjugated although coplanar. The n-butyl chain is roughly perpendicular to the molecular plane, with the terminal methyl­ene and methyl groups disordered between two equally populated positions. The mol­ecules in the crystal associate in an antiparallel fashion, forming dimers across the centre of symmetry, the principal intradimer interaction being stacking of the [pi]-electron portions of the mol­ecules.

S1. Comment

1,3-Diaryltriazenes, Ar—N=N—N(R)—Ar, represent a well known class of antitumour agents which act by non-covalent interaction with B-DNA, viz. either by intercalation between the base pairs of the DNA duplex or by binding to the DNA minor groove (Vaughan, 1990; Kimball & Haley, 2002). The third type of drugs in this class exhibits the so called `mixed binding' mode in which a planar part of the drug molecule is involved in the intercalative interaction, whereas a non-planar portion(s) protrudes out of the helix interior, where it interacts with minor groove functionalities. Thus, as a part of our program aimed at developing novel anticancer drugs, we have prepared a series of derivatives, (I), in which R is an alkyl, alkoxy or hydroxyalkyl group. As detailed knowledge of the molecular structure is of central value in drug design, it is of interest to examine the extent of conjugation (i.e. planarity) in these molecules by a combined use of theoretical and experimental methods. In this communication, we report on the crystal structure of the n-butyl derivative, (Ia).

The molecular structure along with the atom-numbering scheme is shown in Fig. 1. The terminal atoms, C18 and C19, of the n-butyl chain are disordered between two positions (C18/C18' and C19/C19') with approximately equal occupancies; the disorder results from concerted rotations about the C16—C17 and C17—C18 bonds (Table 1) and gives rise to two conformers, differing mainly in the orientation (gauche and trans) of the C19 and C19' sites, respectively (Fig. 1).

As noted above, the main purpose of this work was to establish the extent of π-electron delocalization and hence the overall planarity of the molecule. As shown in Table 1, the sum of the valence angles around atom N5 is close to 120°, i.e. the formally amine N atom is sp²-hybridized, with the lone-pair electrons available for π bonding. Furthermore, the N3=N4 and N4—N5 bonds, although non-equivalent, are intermediate between a double and single bond, assuming bond lengths of 1.23 and 1.41 Å for pure N=N double and N—N single bonds, respectively (Burke-Laing & Laing, 1976). These data indicate the π-electron delocalization within the triazene linkage. That the N3=N4 double bond is delocalized through conjugation with the lone-pair electrons on atom N5 rather than the adjacent heterocyclic ring is also evidenced by (i) the C3—N3 bond distance [1.390 (4) Å], which is only slightly, though significantly, shortened relative to the value [1.425 (3) Å] found for a pure Csp²—Nsp² single bond (Adler et al., 1976) and (ii) the pattern of bond lengths and angles within the heterocyclic ring, which is almost identical with other benzo[c]-1,2-thiazole derivatives containing substituents not involved in conjugation with the aromatic system, as revealed by a search of the Cambridge Structural Database (Allen et al., 1983). Similarly, the N5—C10 distance [1.426 (4) Å] is even identical, within experimental error, to the above value of 1.425 Å and comparable to the N5—C16 bond length [1.459 (4) Å], which is definitely deconjugated with the triazene moiety. Even though the conjugation of the triazene π system with the aromatic rings is very small, if any, both rings are aproximately coplanar with the plane of the triazene grouping; the dihedral angle between the mean planes through the 5-nitrobenzo[c]-1,2-thiazole and the triazene groups is 4.0 (3))°; the corresponding dihedral angle for the phenyl ring/triazene group is 11.9 (3)°. Thus, based on the present crystallographic data, molecule (Ia) is approximately planar as a whole, except for the n-butyl group, which is roughly perpendicular to the rest of the molecule (Table 1). However, a rather low barrier to rotation around the C—N bond linking the heterocyclic ring and the triazene group is predicted, while almost free rotation of the phenyl ring around the triazene is expected.

The crystal packing is dominated by a π–π stacking interaction between the centrosymmetricaly related molecules, which leads to the formation of dimers across the centre of symmetry. The mean interplanar separation of the planar portion of the molecules within the dimer is 3.47 Å. The stacking geometry (Fig. 2) is such that the triazene linkage of one molecule superimposes the benzo ring of the heterocyclic moiety in the other molecule. The n-butyl chains are loosely packed by van der Waals interactions, as reflected by U_eq of the C atoms, which increases on approaching the methyl termini.

S2. Experimental

Compound (Ia) was synthesized by a two-step procedure, as described elsewhere (Přikryl et al., 2003). Briefly, in the first step, cooling and stirring of 96% sulfuric acid (25 ml, 0.45 mol) was followed by addition of NaNO₂ in small portions, so as to avoid evolution of nitrous gases. After continuous stirring and slow heating (to 343 K), the resulting solution of nitrosyl sulfuric acid was cooled to 300 K; 3-amino-5-nitrobenzo[c]-1,2-thiazole was added and the reaction mixture was stirred for 3 h. In the next step, a solution of N-butylaniline (7.82 g, 52.5 mmol) in 1 M aqueous HCl (60 ml) was treated with charcoal and kieselguhr (0.25 g each), and after 10 min of stirring the solution was filtered. The filtrate, the solution of N-butylanilinium chloride, was treated with an emulsifier and sodium acetate trihydrate (68 g, 0.5 mol) under stirring. The obtained emulsion of N-butyl aniline was mixed with finely crushed ice, and then the solution of the diazonium salt obtained in the previous step was added while stirring. The reaction mixture was stirred for 3 h, whereupon the separated orange–brown precipitate of the triazene was collected by suction. The raw product (12.6 g, 71% yield) was purified by repeated crystallization from acetone (m.p. 398–400 K).

S3. Refinement

The disorder in the n-butyl chain was modelled by resolving the positions of atoms C18 and C19 into two components (C18/C18' and C19/C19'), and using a total of 21 restraints on corresponding bond distances and anisotropic displacement parameters [a combination of DFIX and SIMU options in SHELXL97 (Sheldrick, 1997)]. The refined occupancy factors for the unprimed and primed sites were 0.53 (1) and 0.47 (1), respectively. H atoms were refined with fixed geometry, riding on their carrier atoms, with U_iso set to 1.2 (1.5 for the methyl H atoms) times U_eq of the parent atom.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction Ltd, 2001'; cell refinement: CrysAlis RED (Oxford Diffraction Ltd, 2003'; data reduction: CrysAlis RED'; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. Displacement ellipsoid plot of (Ia), with the labelling scheme for the non-H atoms, which are drawn as 35% probability ellipsoids. Both rotamers of the disordered butyl chain are shown.
	Fig. 2. A view of the dimer along the stacking axis.

3-Butyl-1-(5-nitrobenzo[c][1,2]thiazol-3-yl)-3-phenyltriazene

Crystal data

C17H17N5O2S	Z = 2
Mr = 355.42	F(000) = 372
Triclinic, P1	Dx = 1.316 Mg m^−3
Hall symbol: -P 1	Melting point: 399 K
a = 9.702 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.750 (5) Å	Cell parameters from 20 reflections
c = 10.106 (6) Å	θ = 7–20°
α = 83.24 (5)°	µ = 0.20 mm^−1
β = 79.72 (4)°	T = 293 K
γ = 72.92 (4)°	Needle, orange
V = 897.0 (9) Å^3	0.08 × 0.02 × 0.02 mm

Data collection

Oxford Diffraction Xcalibur CCD diffractometer	2017 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.019
Graphite monochromator	θmax = 27.6°, θmin = 2.8°
Detector resolution: Sapphire CCD detector pixels mm^-1	h = −12→12
Rotation method data acquisition using ω and phi scans	k = −11→12
6600 measured reflections	l = −11→13
3993 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.067	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.163	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0613P)^2] where P = (Fo^2 + 2Fc^2)/3
3993 reflections	(Δ/σ)max = 0.001
249 parameters	Δρmax = 0.16 e Å^−3
21 restraints	Δρmin = −0.22 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
N1	0.3368 (3)	0.5051 (3)	0.3631 (3)	0.0598 (9)
S2	0.22366 (10)	0.45907 (11)	0.28394 (10)	0.0565 (3)
C3	0.0691 (3)	0.5813 (3)	0.3510 (3)	0.0407 (8)
C4	0.0161 (4)	0.7698 (4)	0.5196 (3)	0.0468 (9)
H4	−0.0842	0.8007	0.5200	0.056*
C5	0.0812 (4)	0.8285 (4)	0.5983 (3)	0.0492 (9)
C6	0.2333 (4)	0.7867 (4)	0.6005 (4)	0.0535 (10)
H6	0.2728	0.8331	0.6531	0.064*
C7	0.3199 (4)	0.6803 (4)	0.5268 (4)	0.0546 (10)
H7	0.4194	0.6498	0.5312	0.065*
C8	0.2599 (4)	0.6124 (4)	0.4404 (3)	0.0484 (9)
C9	0.1055 (3)	0.6613 (3)	0.4382 (3)	0.0401 (8)
N2	−0.0082 (4)	0.9397 (4)	0.6866 (3)	0.0667 (9)
O1	−0.1407 (4)	0.9619 (4)	0.7007 (3)	0.0989 (11)
O2	0.0523 (3)	1.0062 (3)	0.7411 (3)	0.0881 (10)
N3	−0.0715 (3)	0.6045 (3)	0.3234 (3)	0.0420 (7)
N4	−0.0740 (3)	0.5117 (3)	0.2430 (3)	0.0434 (7)
N5	−0.2047 (3)	0.5258 (3)	0.2118 (3)	0.0458 (7)
C10	−0.2098 (4)	0.4242 (4)	0.1233 (3)	0.0477 (9)
C11	−0.0832 (4)	0.3365 (4)	0.0587 (3)	0.0570 (10)
H11	0.0067	0.3460	0.0691	0.068*
C12	−0.0900 (4)	0.2347 (4)	−0.0214 (4)	0.0612 (11)
H12	−0.0038	0.1756	−0.0642	0.073*
C13	−0.2190 (5)	0.2185 (5)	−0.0393 (4)	0.0709 (12)
H13	−0.2226	0.1487	−0.0928	0.085*
C14	−0.3440 (5)	0.3079 (5)	0.0236 (4)	0.0759 (13)
H14	−0.4335	0.2993	0.0104	0.091*
C15	−0.3420 (4)	0.4105 (4)	0.1058 (4)	0.0628 (11)
H15	−0.4286	0.4692	0.1486	0.075*
C16	−0.3312 (4)	0.6387 (4)	0.2664 (4)	0.0580 (10)
H16A	−0.3220	0.6521	0.3577	0.070*
H16B	−0.4184	0.6081	0.2704	0.070*
C17	−0.3480 (4)	0.7801 (4)	0.1840 (5)	0.0844 (14)
H17A	−0.3426	0.7630	0.0904	0.101*	0.527 (9)
H17B	−0.2660	0.8157	0.1900	0.101*	0.527 (9)
H17C	−0.3883	0.7787	0.1032	0.101*	0.473 (9)
H17D	−0.2546	0.8010	0.1582	0.101*	0.473 (9)
C18	−0.4867 (9)	0.8959 (13)	0.2239 (12)	0.098 (4)	0.527 (9)
H18A	−0.5054	0.9665	0.1485	0.118*	0.527 (9)
H18B	−0.5676	0.8537	0.2457	0.118*	0.527 (9)
C19	−0.4770 (14)	0.9693 (14)	0.3436 (12)	0.138 (5)	0.527 (9)
H19A	−0.5112	0.9201	0.4251	0.208*	0.527 (9)
H19B	−0.5362	1.0672	0.3386	0.208*	0.527 (9)
H19C	−0.3774	0.9673	0.3433	0.208*	0.527 (9)
C18'	−0.4510 (16)	0.8901 (11)	0.2752 (12)	0.117 (5)	0.473 (9)
H18C	−0.5408	0.8626	0.3029	0.141*	0.473 (9)
H18D	−0.4081	0.8865	0.3556	0.141*	0.473 (9)
C19'	−0.4889 (14)	1.0431 (10)	0.2160 (15)	0.131 (5)	0.473 (9)
H19D	−0.4049	1.0788	0.2050	0.197*	0.473 (9)
H19E	−0.5669	1.1015	0.2753	0.197*	0.473 (9)
H19F	−0.5189	1.0467	0.1298	0.197*	0.473 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0381 (17)	0.076 (2)	0.066 (2)	−0.0117 (16)	−0.0037 (15)	−0.0231 (18)
S2	0.0393 (5)	0.0647 (7)	0.0648 (7)	−0.0070 (5)	−0.0056 (4)	−0.0244 (5)
C3	0.0335 (19)	0.046 (2)	0.040 (2)	−0.0093 (16)	−0.0029 (15)	−0.0013 (16)
C4	0.039 (2)	0.045 (2)	0.054 (2)	−0.0075 (17)	−0.0089 (17)	−0.0024 (18)
C5	0.054 (2)	0.043 (2)	0.048 (2)	−0.0072 (18)	−0.0077 (17)	−0.0091 (18)
C6	0.057 (2)	0.054 (2)	0.057 (2)	−0.021 (2)	−0.0134 (19)	−0.010 (2)
C7	0.042 (2)	0.068 (3)	0.059 (2)	−0.021 (2)	−0.0168 (18)	0.001 (2)
C8	0.036 (2)	0.059 (2)	0.051 (2)	−0.0147 (18)	−0.0061 (16)	−0.0024 (19)
C9	0.0338 (19)	0.045 (2)	0.042 (2)	−0.0120 (16)	−0.0052 (15)	−0.0007 (17)
N2	0.078 (3)	0.055 (2)	0.063 (2)	−0.007 (2)	−0.014 (2)	−0.0104 (18)
O1	0.078 (2)	0.100 (3)	0.110 (3)	−0.001 (2)	−0.0030 (19)	−0.050 (2)
O2	0.112 (3)	0.072 (2)	0.086 (2)	−0.0131 (18)	−0.0314 (18)	−0.0323 (17)
N3	0.0357 (16)	0.0470 (18)	0.0436 (16)	−0.0122 (13)	−0.0056 (12)	−0.0036 (14)
N4	0.0375 (16)	0.0489 (18)	0.0459 (17)	−0.0142 (13)	−0.0074 (13)	−0.0044 (14)
N5	0.0315 (16)	0.0578 (19)	0.0503 (17)	−0.0144 (14)	−0.0040 (13)	−0.0115 (15)
C10	0.043 (2)	0.060 (2)	0.044 (2)	−0.0168 (18)	−0.0093 (16)	−0.0086 (18)
C11	0.048 (2)	0.071 (3)	0.053 (2)	−0.021 (2)	0.0005 (18)	−0.014 (2)
C12	0.058 (3)	0.070 (3)	0.057 (2)	−0.019 (2)	0.0002 (19)	−0.020 (2)
C13	0.078 (3)	0.079 (3)	0.065 (3)	−0.029 (3)	−0.011 (2)	−0.024 (2)
C14	0.060 (3)	0.092 (3)	0.089 (3)	−0.026 (3)	−0.025 (2)	−0.027 (3)
C15	0.052 (2)	0.079 (3)	0.065 (3)	−0.020 (2)	−0.0111 (19)	−0.024 (2)
C16	0.038 (2)	0.070 (3)	0.070 (3)	−0.016 (2)	−0.0100 (19)	−0.015 (2)
C17	0.059 (3)	0.074 (3)	0.119 (4)	−0.011 (2)	−0.023 (3)	−0.007 (3)
C18	0.039 (5)	0.084 (6)	0.168 (10)	0.005 (4)	−0.037 (5)	−0.021 (7)
C19	0.129 (9)	0.099 (10)	0.180 (12)	−0.020 (8)	0.003 (10)	−0.055 (9)
C18'	0.064 (8)	0.096 (7)	0.176 (12)	0.004 (7)	−0.021 (8)	−0.006 (9)
C19'	0.134 (10)	0.068 (9)	0.166 (13)	−0.016 (7)	0.018 (10)	0.000 (8)

Geometric parameters (Å, º)

N1—C8	1.337 (4)	C13—C14	1.367 (5)
N1—S2	1.653 (3)	C13—H13	0.9300
S2—C3	1.705 (3)	C14—C15	1.381 (5)
C3—N3	1.390 (4)	C14—H14	0.9300
C3—C9	1.394 (4)	C15—H15	0.9300
C4—C5	1.363 (4)	C16—C17	1.506 (4)
C4—C9	1.400 (4)	C16—H16A	0.9700
C4—H4	0.9300	C16—H16B	0.9700
C5—C6	1.415 (5)	C17—C18	1.506 (4)
C5—N2	1.457 (5)	C17—C18'	1.508 (5)
C6—C7	1.335 (5)	C17—H17A	0.9700
C6—H6	0.9300	C17—H17B	0.9700
C7—C8	1.443 (5)	C17—H17C	0.9700
C7—H7	0.9300	C17—H17D	0.9700
C8—C9	1.436 (4)	C18—C19	1.505 (5)
N2—O2	1.221 (4)	C18—H18A	0.9700
N2—O1	1.224 (4)	C18—H18B	0.9700
N3—N4	1.293 (3)	C19—H19A	0.9600
N4—N5	1.325 (3)	C19—H19B	0.9600
N5—C10	1.426 (4)	C19—H19C	0.9600
N5—C16	1.459 (4)	C18'—C19'	1.505 (5)
C10—C15	1.372 (4)	C18'—H18C	0.9700
C10—C11	1.376 (5)	C18'—H18D	0.9700
C11—C12	1.374 (5)	C19'—H19D	0.9600
C11—H11	0.9300	C19'—H19E	0.9600
C12—C13	1.352 (5)	C19'—H19F	0.9600
C12—H12	0.9300
C8—N1—S2	108.5 (2)	C10—C15—C14	118.6 (4)
N1—S2—C3	96.41 (16)	C10—C15—H15	120.7
N3—C3—C9	123.7 (3)	C14—C15—H15	120.7
N3—C3—S2	127.3 (2)	N5—C16—C17	113.0 (3)
C9—C3—S2	108.9 (2)	N5—C16—H16A	109.0
C5—C4—C9	117.7 (3)	C17—C16—H16A	109.0
C5—C4—H4	121.2	N5—C16—H16B	109.0
C9—C4—H4	121.2	C17—C16—H16B	109.0
C4—C5—C6	123.5 (3)	H16A—C16—H16B	107.8
C4—C5—N2	119.5 (3)	C16—C17—C18	115.7 (7)
C6—C5—N2	117.0 (3)	C16—C17—C18'	104.9 (6)
C7—C6—C5	119.7 (3)	C16—C17—H17A	108.4
C7—C6—H6	120.2	C18—C17—H17A	108.4
C5—C6—H6	120.2	C18'—C17—H17A	133.0
C6—C7—C8	120.3 (3)	C16—C17—H17B	108.4
C6—C7—H7	119.8	C18—C17—H17B	108.4
C8—C7—H7	119.8	C18'—C17—H17B	92.1
N1—C8—C9	116.9 (3)	H17A—C17—H17B	107.4
N1—C8—C7	125.1 (3)	C16—C17—H17C	110.8
C9—C8—C7	118.0 (3)	C18—C17—H17C	85.4
C3—C9—C4	130.1 (3)	C18'—C17—H17C	110.8
C3—C9—C8	109.2 (3)	H17B—C17—H17C	126.7
C4—C9—C8	120.7 (3)	C16—C17—H17D	110.8
O2—N2—O1	123.7 (4)	C18—C17—H17D	121.9
O2—N2—C5	118.7 (4)	C18'—C17—H17D	110.8
O1—N2—C5	117.6 (3)	H17A—C17—H17D	87.2
N4—N3—C3	110.3 (3)	H17C—C17—H17D	108.8
N3—N4—N5	114.3 (3)	C19—C18—C17	111.4 (7)
N4—N5—C10	115.1 (3)	C19—C18—H18A	109.3
N4—N5—C16	120.6 (3)	C17—C18—H18A	109.3
C10—N5—C16	124.2 (3)	C19—C18—H18B	109.3
C15—C10—C11	119.6 (3)	C17—C18—H18B	109.3
C15—C10—N5	119.7 (3)	H18A—C18—H18B	108.0
C11—C10—N5	120.7 (3)	C19'—C18'—C17	116.0 (9)
C12—C11—C10	120.0 (3)	C19'—C18'—H18C	108.3
C12—C11—H11	120.0	C17—C18'—H18C	108.3
C10—C11—H11	120.0	C19'—C18'—H18D	108.3
C13—C12—C11	121.5 (4)	C17—C18'—H18D	108.3
C13—C12—H12	119.2	H18C—C18'—H18D	107.4
C11—C12—H12	119.2	C18'—C19'—H19D	109.5
C12—C13—C14	118.0 (4)	C18'—C19'—H19E	109.5
C12—C13—H13	121.0	H19D—C19'—H19E	109.5
C14—C13—H13	121.0	C18'—C19'—H19F	109.5
C13—C14—C15	122.3 (4)	H19D—C19'—H19F	109.5
C13—C14—H14	118.9	H19E—C19'—H19F	109.5
C15—C14—H14	118.9
C8—N1—S2—C3	0.0 (3)	C9—C3—N3—N4	−177.8 (3)
N1—S2—C3—N3	178.1 (3)	S2—C3—N3—N4	4.3 (4)
N1—S2—C3—C9	0.0 (3)	C3—N3—N4—N5	179.7 (2)
C9—C4—C5—C6	0.7 (5)	N3—N4—N5—C10	−179.9 (3)
C9—C4—C5—N2	−178.7 (3)	N3—N4—N5—C16	0.1 (4)
C4—C5—C6—C7	−2.8 (5)	N4—N5—C10—C15	167.1 (3)
N2—C5—C6—C7	176.6 (3)	C16—N5—C10—C15	−12.9 (5)
C5—C6—C7—C8	2.8 (5)	N4—N5—C10—C11	−10.8 (5)
S2—N1—C8—C9	0.0 (4)	C16—N5—C10—C11	169.3 (3)
S2—N1—C8—C7	178.9 (3)	C15—C10—C11—C12	−0.8 (5)
C6—C7—C8—N1	−179.8 (4)	N5—C10—C11—C12	177.0 (3)
C6—C7—C8—C9	−0.9 (5)	C10—C11—C12—C13	0.4 (6)
N3—C3—C9—C4	4.2 (5)	C11—C12—C13—C14	0.7 (6)
S2—C3—C9—C4	−177.6 (3)	C12—C13—C14—C15	−1.4 (7)
N3—C3—C9—C8	−178.2 (3)	C11—C10—C15—C14	0.2 (6)
S2—C3—C9—C8	0.0 (3)	N5—C10—C15—C14	−177.7 (3)
C5—C4—C9—C3	178.6 (3)	C13—C14—C15—C10	0.9 (6)
C5—C4—C9—C8	1.2 (5)	N4—N5—C16—C17	85.5 (4)
N1—C8—C9—C3	−0.1 (4)	C10—N5—C16—C17	−94.6 (4)
C7—C8—C9—C3	−179.0 (3)	N5—C16—C17—C18	172.3 (5)
N1—C8—C9—C4	177.8 (3)	N5—C16—C17—C18'	−163.2 (8)
C7—C8—C9—C4	−1.2 (5)	C16—C17—C18—C19	80.5 (13)
C4—C5—N2—O2	−169.3 (3)	C18'—C17—C18—C19	10.9 (17)
C6—C5—N2—O2	11.3 (5)	C16—C17—C18'—C19'	−179.1 (13)
C4—C5—N2—O1	10.0 (5)	C18—C17—C18'—C19'	−60.0 (19)
C6—C5—N2—O1	−169.5 (3)