rac-(6S)-6-Hy-droxy-6-{2-[2-(propan-2-yl-idene)hydrazinyl-idene]prop-yl}indolo[2,1-b]quinazolin-12(6H)-one.

The chiral title compound, C(21)H(20)N(4)O(2), crystallizes as a racemic mixture. In the crystal, mol-ecules form centrosymmetric π-overlapping dimers [inter-planar distance = 3.338 (6) Å], which are further connected along the a axis forming centrosymmetric dimers via O-H⋯N hydrogen bonds. C-H⋯O inter-actions are also observed. The indolo[2,1-b]quinazoline group is somewhat bent, with a small dihedral angle of 6.3 (4)° between the plane of the quinazoline system and the plane of the benzene ring of the indole moiety. The C=N-N=C atoms of the azine group is oriented almost perpendicular [84.1 (2)°] to the mean plane of the quinazoline system.

Related literature

The title compound is a derivative of the natural product tryptanthrin (indolo[2,1-b]quinazoline-6,12-dione). For reactions occurring at the 6-keto group of tryptanthrin with nucleophiles including CH-acidic compounds, see: Grandolini et al. (1997 ▶); Bergman & Tilstam (1985 ▶); Jao et al. (2008 ▶); Zou & Huang (1985 ▶). For related strutures, see: Brufani et al. (1971 ▶); Bergman et al. (1987 ▶); Jao et al. (2008 ▶); Grundt et al. (2010 ▶). For the Chebychev weighting scheme, see: Prince (1982 ▶); Watkin (1994 ▶).

Experimental

Crystal data

C21H20N4O2

M = 360.42

Monoclinic,

a = 8.6788 (17) Å

b = 15.117 (3) Å

c = 13.283 (3) Å

β = 99.58 (3)°

V = 1718.4 (6) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 100 K

0.20 × 0.20 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID II image-plate diffractometer

Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T min = 0.98, T max = 0.98

11165 measured reflections

2914 independent reflections

1850 reflections with I > 2σ(I)

R int = 0.096

Refinement

R[F 2 > 2σ(F 2)] = 0.062

wR(F 2) = 0.161

S = 1.01

2899 reflections

244 parameters

Only H-atom displacement parameters refined

Δρmax = 0.59 e Å−3

Δρmin = −0.48 e Å−3

Data collection: CrystalClear (Rigaku Americas, 2009 ▶); cell refinement: HKL-2000 (Otwinowski & Minor, 1997 ▶); data reduction: CrystalClear; program(s) used to solve structure: CrystalStructure (Rigaku Americas, 2009 ▶) and SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ▶); molecular graphics: CAMERON (Watkin et al., 1996 ▶); software used to prepare material for publication: CRYSTALS.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811037408/ld2027sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811037408/ld2027Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811037408/ld2027Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C21H20N4O2	F(000) = 760
Mr = 360.42	Dx = 1.393 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1820 reflections
a = 8.6788 (17) Å	θ = 25–2°
b = 15.117 (3) Å	µ = 0.09 mm−1
c = 13.283 (3) Å	T = 100 K
β = 99.58 (3)°	Block, colourless
V = 1718.4 (6) Å3	0.20 × 0.20 × 0.20 mm
Z = 4

Rigaku R-AXIS RAPID II image-plate diffractometer	2914 independent reflections
Radiation source: Mo Sealed tube tube	1850 reflections with I > 2σ(I)
graphite	Rint = 0.096
Detector resolution: 10 pixels mm-1	θmax = 24.7°, θmin = 3.1°
ω/2θ scans	h = −10→9
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −17→17
Tmin = 0.98, Tmax = 0.98	l = −14→15
11165 measured reflections

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)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.161	Only H-atom displacement parameters refined
S = 1.01	Method, part 1, Chebychev polynomial,(Watkin, 1994; Prince, 1982) [weight] = 1.0/[A0*T0(x) + A1*T1(x) ··· + An-1]*Tn-1(x)] where Ai are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] * [1-(deltaF/6*sigmaF)2]2 Ai are: 5.56 6.74 1.72
2899 reflections	(Δ/σ)max = 0.0001471
244 parameters	Δρmax = 0.59 e Å−3
0 restraints	Δρmin = −0.48 e Å−3
13 constraints

Experimental. 1H NMR (DMSO-d6, 500 MHz): δ 0.82 (s, 3H), 1.63 (s, 6H), 3.38 (d, J 16.6, 1H), 3.44 (d, J 16.5, 1H), 6.88 (s, 1H), 7.35 (t, J 7.3, 1H), 7.46 (t, J 7.7, 1H), 7.59 (t, J 7.2, 1H), 7.62 (d, J 6.7, 1H), 7.78 (d, J 8.0, 1H), 7.87 (t, J 8.3, 1H), 8.28 (d, J 7.8, 1H), 8.39 (d, J 7.7, 1H). 13C NMR (DMSO-d6, 125 MHz): δ 16.5, 17.3, 24.3, 45.5, 75.3, 115.9, 121.2, 123.4, 126.2, 126.3, 127.0, 127.3, 129.2, 134.4, 134.6, 139.2, 147.2, 157.6, 158.9, 159.0, 161.2.

Refinement. Crystals for Windows program eliminates all reflections with [sinθ/λ]2 < 0.01 in order to eliminate reflections that may be poorly measured in the vicinity of the beam stop. Such filter eliminated 15 reflections, which resulted in difference between 2914 measured unique reflections and 2899 reflections used for refinement.

	x	y	z	Uiso*/Ueq
O19	0.8991 (3)	0.37375 (18)	0.4708 (2)	0.0293
C6	0.8330 (4)	0.4137 (3)	0.3753 (3)	0.0247
C14	0.7388 (4)	0.4957 (2)	0.3956 (3)	0.0236
N11	0.5809 (3)	0.4758 (2)	0.3731 (2)	0.0246
C16	0.5590 (4)	0.3890 (2)	0.3310 (3)	0.0244
C15	0.7034 (4)	0.3519 (3)	0.3277 (3)	0.0252
C7	0.7135 (5)	0.2688 (3)	0.2869 (3)	0.0333
C8	0.5753 (5)	0.2223 (3)	0.2529 (3)	0.0340
C9	0.4329 (5)	0.2595 (3)	0.2605 (3)	0.0344
C10	0.4209 (5)	0.3440 (3)	0.2997 (3)	0.0310
C12	0.4659 (4)	0.5369 (3)	0.3857 (3)	0.0259
O18	0.3266 (3)	0.51841 (19)	0.3656 (2)	0.0338
C17	0.5287 (4)	0.6229 (3)	0.4227 (3)	0.0252
C13	0.6913 (4)	0.6366 (3)	0.4431 (3)	0.0258
N5	0.7978 (3)	0.5697 (2)	0.4294 (2)	0.0260
C4	0.7479 (5)	0.7207 (3)	0.4739 (3)	0.0312
C3	0.6455 (5)	0.7880 (3)	0.4861 (3)	0.0356
C2	0.4848 (5)	0.7732 (3)	0.4689 (3)	0.0348
C1	0.4268 (4)	0.6917 (3)	0.4381 (3)	0.0294
C20	0.9621 (4)	0.4328 (3)	0.3137 (3)	0.0272
C21	0.9162 (4)	0.4779 (2)	0.2122 (3)	0.0258
N23	0.7732 (4)	0.4958 (2)	0.1820 (2)	0.0301
N24	0.7448 (4)	0.5367 (2)	0.0842 (3)	0.0341
C25	0.6178 (5)	0.5803 (3)	0.0657 (3)	0.0370
C27	0.5820 (5)	0.6268 (3)	−0.0346 (3)	0.0413
C26	0.5009 (6)	0.5914 (4)	0.1369 (4)	0.0487
C22	1.0477 (5)	0.4992 (3)	0.1570 (3)	0.0363
H5	0.8117	0.2442	0.2822	0.0396*
H6	0.5785	0.1667	0.2260	0.0411*
H7	0.3403	0.2271	0.2407	0.0409*
H8	0.3245	0.3690	0.3040	0.0364*
H4	0.8560	0.7312	0.4877	0.0372*
H3	0.6855	0.8437	0.5051	0.0417*
H2	0.4150	0.8196	0.4786	0.0419*
H1	0.3181	0.6816	0.4280	0.0349*
H10	1.0397	0.4707	0.3542	0.0334*
H11	1.0097	0.3759	0.3019	0.0321*
H20	0.4768	0.6120	−0.0675	0.0614*
H18	0.5915	0.6909	−0.0245	0.0623*
H19	0.6553	0.6078	−0.0779	0.0617*
H15	0.4565	0.6506	0.1315	0.0720*
H16	0.5516	0.5824	0.2069	0.0725*
H17	0.4179	0.5475	0.1194	0.0723*
H13	1.0232	0.4842	0.0867	0.0554*
H14	1.0673	0.5604	0.1619	0.0561*
H12	1.1415	0.4695	0.1848	0.0554*
H9	0.9793	0.4019	0.4925	0.0440*

	U11	U22	U33	U12	U13	U23
O19	0.0221 (13)	0.0337 (15)	0.0307 (15)	−0.0019 (12)	0.0004 (11)	0.0048 (12)
C6	0.0199 (18)	0.030 (2)	0.0239 (19)	0.0019 (16)	0.0029 (15)	0.0069 (16)
C14	0.0199 (18)	0.029 (2)	0.0214 (18)	−0.0007 (15)	0.0025 (14)	0.0016 (16)
N11	0.0198 (15)	0.0290 (17)	0.0247 (16)	−0.0018 (13)	0.0028 (12)	0.0013 (14)
C16	0.0276 (19)	0.025 (2)	0.0200 (18)	−0.0013 (16)	0.0023 (15)	0.0037 (15)
C15	0.0254 (19)	0.028 (2)	0.0224 (19)	−0.0033 (16)	0.0051 (15)	0.0065 (16)
C7	0.033 (2)	0.031 (2)	0.036 (2)	0.0001 (18)	0.0052 (17)	0.0031 (18)
C8	0.039 (2)	0.029 (2)	0.034 (2)	−0.0014 (18)	0.0058 (18)	−0.0013 (18)
C9	0.037 (2)	0.036 (2)	0.027 (2)	−0.0116 (19)	−0.0015 (17)	0.0008 (18)
C10	0.026 (2)	0.036 (2)	0.030 (2)	−0.0031 (17)	0.0006 (16)	0.0058 (18)
C12	0.023 (2)	0.033 (2)	0.0212 (19)	−0.0011 (16)	0.0028 (15)	0.0003 (16)
O18	0.0193 (14)	0.0423 (17)	0.0384 (16)	−0.0002 (12)	0.0011 (12)	−0.0022 (13)
C17	0.0224 (19)	0.034 (2)	0.0189 (18)	0.0002 (16)	0.0035 (14)	0.0042 (16)
C13	0.0230 (19)	0.030 (2)	0.0244 (19)	0.0033 (16)	0.0049 (15)	0.0058 (16)
N5	0.0210 (16)	0.0290 (18)	0.0278 (17)	−0.0004 (14)	0.0033 (13)	0.0038 (14)
C4	0.026 (2)	0.029 (2)	0.039 (2)	−0.0041 (17)	0.0069 (17)	0.0003 (18)
C3	0.038 (2)	0.028 (2)	0.040 (2)	−0.0015 (18)	0.0060 (19)	−0.0028 (18)
C2	0.034 (2)	0.035 (2)	0.036 (2)	0.0072 (19)	0.0065 (18)	0.0013 (19)
C1	0.0231 (19)	0.035 (2)	0.030 (2)	0.0068 (17)	0.0040 (16)	0.0073 (17)
C20	0.0226 (19)	0.028 (2)	0.031 (2)	0.0020 (16)	0.0040 (16)	0.0020 (16)
C21	0.028 (2)	0.025 (2)	0.0245 (19)	0.0039 (16)	0.0060 (16)	−0.0017 (16)
N23	0.0278 (18)	0.0352 (19)	0.0271 (17)	0.0024 (15)	0.0042 (14)	0.0050 (15)
N24	0.0301 (18)	0.039 (2)	0.0329 (19)	0.0024 (16)	0.0034 (15)	0.0086 (16)
C25	0.034 (2)	0.040 (2)	0.037 (2)	−0.004 (2)	0.0052 (18)	0.003 (2)
C27	0.037 (2)	0.048 (3)	0.037 (2)	0.004 (2)	0.0009 (19)	0.008 (2)
C26	0.044 (3)	0.058 (3)	0.044 (3)	0.011 (2)	0.007 (2)	0.004 (2)
C22	0.032 (2)	0.043 (3)	0.035 (2)	0.0011 (19)	0.0101 (18)	−0.001 (2)

O19—C6	1.436 (4)	C4—C3	1.379 (6)
O19—H9	0.826	C4—H4	0.939
C6—C14	1.532 (5)	C3—C2	1.393 (6)
C6—C15	1.518 (5)	C3—H3	0.929
C6—C20	1.520 (5)	C2—C1	1.367 (6)
C14—N11	1.386 (5)	C2—H2	0.950
C14—N5	1.281 (5)	C1—H1	0.942
N11—C16	1.426 (5)	C20—C21	1.505 (5)
N11—C12	1.391 (5)	C20—H10	0.975
C16—C15	1.380 (5)	C20—H11	0.979
C16—C10	1.381 (5)	C21—N23	1.268 (5)
C15—C7	1.377 (6)	C21—C22	1.491 (5)
C7—C8	1.399 (6)	N23—N24	1.423 (4)
C7—H5	0.941	N24—C25	1.272 (5)
C8—C9	1.377 (6)	C25—C27	1.493 (6)
C8—H6	0.916	C25—C26	1.507 (6)
C9—C10	1.390 (6)	C27—H20	0.971
C9—H7	0.941	C27—H18	0.979
C10—H8	0.928	C27—H19	0.969
C12—O18	1.226 (4)	C26—H15	0.973
C12—C17	1.463 (5)	C26—H16	0.970
C17—C13	1.408 (5)	C26—H17	0.979
C17—C1	1.402 (5)	C22—H13	0.950
C13—N5	1.401 (5)	C22—H14	0.942
C13—C4	1.399 (5)	C22—H12	0.948
C6—O19—H9	106.3	C3—C4—H4	119.7
O19—C6—C14	109.3 (3)	C4—C3—C2	120.6 (4)
O19—C6—C15	105.5 (3)	C4—C3—H3	118.8
C14—C6—C15	101.0 (3)	C2—C3—H3	120.6
O19—C6—C20	109.4 (3)	C3—C2—C1	120.2 (4)
C14—C6—C20	113.8 (3)	C3—C2—H2	120.2
C15—C6—C20	117.0 (3)	C1—C2—H2	119.6
C6—C14—N11	108.9 (3)	C17—C1—C2	120.1 (4)
C6—C14—N5	125.1 (3)	C17—C1—H1	120.0
N11—C14—N5	126.0 (3)	C2—C1—H1	119.9
C14—N11—C16	110.3 (3)	C6—C20—C21	117.3 (3)
C14—N11—C12	122.3 (3)	C6—C20—H10	108.6
C16—N11—C12	127.4 (3)	C21—C20—H10	106.4
N11—C16—C15	108.9 (3)	C6—C20—H11	106.8
N11—C16—C10	128.6 (4)	C21—C20—H11	108.1
C15—C16—C10	122.5 (4)	H10—C20—H11	109.6
C6—C15—C16	110.5 (3)	C20—C21—N23	118.6 (3)
C6—C15—C7	129.4 (4)	C20—C21—C22	115.4 (3)
C16—C15—C7	120.1 (4)	N23—C21—C22	126.0 (4)
C15—C7—C8	118.5 (4)	C21—N23—N24	113.2 (3)
C15—C7—H5	120.3	N23—N24—C25	114.4 (3)
C8—C7—H5	121.2	N24—C25—C27	117.4 (4)
C7—C8—C9	120.2 (4)	N24—C25—C26	126.1 (4)
C7—C8—H6	120.4	C27—C25—C26	116.5 (4)
C9—C8—H6	119.3	C25—C27—H20	109.5
C8—C9—C10	121.8 (4)	C25—C27—H18	110.1
C8—C9—H7	120.1	H20—C27—H18	109.9
C10—C9—H7	118.0	C25—C27—H19	109.3
C9—C10—C16	116.7 (4)	H20—C27—H19	109.0
C9—C10—H8	121.4	H18—C27—H19	109.0
C16—C10—H8	121.9	C25—C26—H15	110.9
N11—C12—O18	121.6 (4)	C25—C26—H16	109.9
N11—C12—C17	113.4 (3)	H15—C26—H16	108.1
O18—C12—C17	125.0 (4)	C25—C26—H17	108.7
C12—C17—C13	120.0 (3)	H15—C26—H17	109.8
C12—C17—C1	120.0 (3)	H16—C26—H17	109.4
C13—C17—C1	120.0 (4)	C21—C22—H13	111.6
C17—C13—N5	122.1 (4)	C21—C22—H14	108.7
C17—C13—C4	118.8 (3)	H13—C22—H14	108.1
N5—C13—C4	119.1 (3)	C21—C22—H12	112.6
C13—N5—C14	116.3 (3)	H13—C22—H12	107.9
C13—C4—C3	120.2 (4)	H14—C22—H12	107.8
C13—C4—H4	120.1

D—H···A	D—H	H···A	D···A	D—H···A
C20—H10···O18i	0.98	2.57	3.381 (6)	140.(1)
O19—H9···N5ii	0.83	2.08	2.872 (6)	160.(1)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C20—H10⋯O18i	0.98	2.57	3.381 (6)	140 (1)
O19—H9⋯N5ii	0.83	2.08	2.872 (6)	160 (1)

Symmetry codes: (i) ; (ii) .