organic compounds
2-Butyl-11-phenyl-5,10-dihydro-1H-benzo[e]imidazo[1,5-a][1,4]diazepine-1,3(2H)-dione
aDepartment of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Boulevard, Tucson, AZ 85721, USA, and bSouthwest Center for Drug Discovery and Development, College of Pharmacy, BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA
*Correspondence e-mail: gsnichol@email.arizona.edu
The title compound, C21H21N3O2, was obtained following a five-step synthetic procedure yielding weakly diffracting rod and needle-shaped crystals which crystallized concomitantly. Structural analysis of a rod-shaped crystal showed that the central seven-membered heterocyclic ring adopts a conformation that is perhaps best described as a distorted boat, with the H-bearing (CH2 and NH) atoms lying well out of the least-squares mean plane fitted through the other five atoms in the ring (r.m.s. deviation 0.075 Å). In the crystal, the compound packs as a twisted chain, which propagates along the b axis by means of an R12(6) motif formed by one of the carbonyl O atoms acting as a bifurcated acceptor in an N—H⋯O and C—H⋯O interaction. No diffraction was observed from the needle-shaped crystals.
Related literature
For background to the synthetic procedure, see: Hulme & Gore (2003); Hulme et al. (2000). For graph-set analysis of hydrogen-bond networks, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL and local programs.
Supporting information
10.1107/S1600536810005477/bh2272sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810005477/bh2272Isup2.hkl
Ugi reaction (For R1, R2=H, R3= n-butyl)
CO2 gas was bubbled through a stirring solution of MeOH for 25 minutes to generate methyl carbonic acid. In a separate 25 ml flask, phenyl glyoxal 2 (226 mg, 1.687 mmol) was added to BOC-2-aminobenyzlamine 1 (250 mg, 1.125 mmol). Methyl carbonic acid (10 ml) and N-butyl isonitrile (0.237 ml, 2.252 mmol) were then added to the latter flask. The reaction was stirred at room temperature under an atmosphere of CO2 for 16 h. The solvent was evaporated in vacuo and the crude product purified with a Biotage Isolera4TM system (hexane/EtOAc 10-30%) to afford the Ugi product 3 (218 mg, 0.438 mmol, 39%) as a yellow oil.
De-BOC and Cyclization
3 (0.180 g, 0.362 mmol) was treated with a 5 ml 10% TFA solution in 1,2-dichloroethane which was irradiated in a Biotage InitiatorTM at 80°C for 20 min. The resulting orange solution was washed with 1M NaHCO3 (4 × 2.5 ml) and the organic layer dried (Na2SO4), filtered and evaporated in vacuo. MeOH (1.5 ml), THF (0.75 ml), H2O (0.5 ml) were added to the crude product 4 (0.102 g, 0.269 mmol) followed by a 1 g/1 ml solution of KOH in H2O (0.03 ml). The solution was irradiated at 100°C for 20 min and resultant orange solution partitioned between EtOAc (5 ml) and 1M NaHCO3 (5 ml). The organic layer was dried (Na2SO4), filtered and evaporated in vacuo. Final crude product was purified with a Biotage Isolera4TM (hexane/EtOAc 30%) to afford the final product 5 (0.074 g, 0.214 mmol, 80%) as a yellow solid. FT-ICR calculated for C21H22N3O2 [M+H]+: 348.1707, found: 348.1707.
A resolution cutoff of 0.87 Å was applied to the dataset due to unobserved diffraction beyond this point. Nevertheless the N—H hydrogen atom was located in a difference Fourier map and the N—H distance freely refined to 0.86 (4) Å with Uiso(H) = 1.2 Ueq(N). C—H atoms were refined with Uiso(H) = 1.5 Ueq(C) (methyl) or Uiso(H) = 1.2 Ueq(C) (all others) with constrained C—H distances in the range 0.95–0.99 Å. The largest residual peak, 0.7 e.Å-3, is approximately 1.53 Å from C21.
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and local programs.C21H21N3O2 | F(000) = 736 |
Mr = 347.41 | Dx = 1.345 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2525 reflections |
a = 12.192 (4) Å | θ = 2.2–24.8° |
b = 7.638 (2) Å | µ = 0.09 mm−1 |
c = 18.514 (6) Å | T = 100 K |
β = 95.494 (5)° | Rod, yellow |
V = 1716.1 (9) Å3 | 0.29 × 0.14 × 0.08 mm |
Z = 4 |
Bruker Kappa APEXII DUO CCD diffractometer | 2724 independent reflections |
Radiation source: fine-focus sealed tube with Miracol optics | 1908 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.067 |
ϕ and ω scans | θmax = 24.1°, θmin = 1.9° |
Absorption correction: numerical (SADABS; Sheldrick, 1996) | h = −14→14 |
Tmin = 0.975, Tmax = 0.993 | k = −8→5 |
14047 measured reflections | l = −21→21 |
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)] = 0.065 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.181 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.1146P)2 + 0.6555P] where P = (Fo2 + 2Fc2)/3 |
2724 reflections | (Δ/σ)max = 0.001 |
239 parameters | Δρmax = 0.71 e Å−3 |
0 restraints | Δρmin = −0.29 e Å−3 |
0 constraints |
C21H21N3O2 | V = 1716.1 (9) Å3 |
Mr = 347.41 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 12.192 (4) Å | µ = 0.09 mm−1 |
b = 7.638 (2) Å | T = 100 K |
c = 18.514 (6) Å | 0.29 × 0.14 × 0.08 mm |
β = 95.494 (5)° |
Bruker Kappa APEXII DUO CCD diffractometer | 2724 independent reflections |
Absorption correction: numerical (SADABS; Sheldrick, 1996) | 1908 reflections with I > 2σ(I) |
Tmin = 0.975, Tmax = 0.993 | Rint = 0.067 |
14047 measured reflections | θmax = 24.1° |
R[F2 > 2σ(F2)] = 0.065 | 0 restraints |
wR(F2) = 0.181 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.71 e Å−3 |
2724 reflections | Δρmin = −0.29 e Å−3 |
239 parameters |
Experimental. 1H NMR (300 MHz, CDCl3) δ ppm 0.89 (t, J = 7.2 Hz, 3H), 1.28 (m, 2H), 1.56 (m, 2H), 3.49 (t, J = 7.3 Hz, 2H), 4.98 (s, 2H), 5.95 (s, 1H), 6.89 (d, J = 7.8 Hz, 1H), 7.06 (t, J = 7.2 Hz, 1H), 7.28 (t, J = 7.7 Hz, 1H), 7.34 (d, J = 7.5 Hz, 1H), 7.52 (m, 5H). 13C NMR (75 MHz, CDCl3) δ ppm 14.1, 20.5, 30.7, 39.0, 45.7, 109.4, 120.7, 123.9, 126.4, 129.1, 129.6, 129.7, 130.5, 130.6, 134.6, 135.4, 142.5, 153.7, 161.9. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.88328 (17) | 0.0841 (3) | 0.87585 (11) | 0.0267 (6) | |
O2 | 0.61570 (19) | 0.1425 (3) | 1.03172 (11) | 0.0346 (6) | |
N1 | 0.7648 (2) | 0.0891 (4) | 0.96528 (13) | 0.0249 (6) | |
N2 | 0.62702 (19) | 0.2468 (3) | 0.91468 (13) | 0.0221 (6) | |
N3 | 0.6120 (2) | 0.4044 (4) | 0.76450 (14) | 0.0253 (7) | |
H3N | 0.625 (3) | 0.466 (5) | 0.7271 (19) | 0.030* | |
C1 | 0.7968 (3) | 0.1375 (4) | 0.89869 (16) | 0.0243 (8) | |
C2 | 0.6618 (3) | 0.1580 (5) | 0.97655 (17) | 0.0282 (8) | |
C3 | 0.5292 (3) | 0.3561 (5) | 0.90814 (17) | 0.0290 (8) | |
H3A | 0.5519 | 0.4803 | 0.9130 | 0.035* | |
H3B | 0.4843 | 0.3285 | 0.9485 | 0.035* | |
C4 | 0.4598 (2) | 0.3329 (5) | 0.83796 (17) | 0.0272 (8) | |
C5 | 0.3498 (3) | 0.2811 (5) | 0.83711 (18) | 0.0308 (8) | |
H5 | 0.3222 | 0.2501 | 0.8816 | 0.037* | |
C6 | 0.2800 (3) | 0.2733 (5) | 0.77408 (18) | 0.0316 (8) | |
H6 | 0.2060 | 0.2351 | 0.7752 | 0.038* | |
C7 | 0.3188 (3) | 0.3216 (5) | 0.70925 (18) | 0.0295 (8) | |
H7 | 0.2707 | 0.3223 | 0.6658 | 0.035* | |
C8 | 0.4285 (3) | 0.3690 (4) | 0.70802 (17) | 0.0274 (8) | |
H8 | 0.4551 | 0.4017 | 0.6634 | 0.033* | |
C9 | 0.4995 (2) | 0.3694 (4) | 0.77089 (17) | 0.0241 (8) | |
C10 | 0.7038 (2) | 0.3312 (4) | 0.80057 (16) | 0.0239 (8) | |
C11 | 0.7095 (2) | 0.2491 (4) | 0.86567 (16) | 0.0215 (7) | |
C12 | 0.8299 (3) | −0.0207 (5) | 1.01778 (16) | 0.0291 (8) | |
H12A | 0.8060 | 0.0008 | 1.0666 | 0.035* | |
H12B | 0.9083 | 0.0136 | 1.0189 | 0.035* | |
C13 | 0.8194 (3) | −0.2160 (5) | 1.00075 (16) | 0.0290 (8) | |
H13A | 0.7411 | −0.2509 | 0.9997 | 0.035* | |
H13B | 0.8435 | −0.2381 | 0.9520 | 0.035* | |
C14 | 0.8874 (3) | −0.3268 (5) | 1.05583 (17) | 0.0297 (8) | |
H14A | 0.8702 | −0.2937 | 1.1052 | 0.036* | |
H14B | 0.9666 | −0.3032 | 1.0523 | 0.036* | |
C15 | 0.8653 (3) | −0.5210 (5) | 1.04422 (19) | 0.0377 (9) | |
H15A | 0.7890 | −0.5471 | 1.0531 | 0.057* | |
H15B | 0.9157 | −0.5887 | 1.0779 | 0.057* | |
H15C | 0.8768 | −0.5525 | 0.9942 | 0.057* | |
C16 | 0.8047 (2) | 0.3506 (4) | 0.76174 (16) | 0.0231 (7) | |
C17 | 0.8030 (2) | 0.2989 (5) | 0.68966 (16) | 0.0256 (8) | |
H17 | 0.7377 | 0.2506 | 0.6654 | 0.031* | |
C18 | 0.8963 (3) | 0.3177 (5) | 0.65308 (16) | 0.0279 (8) | |
H18 | 0.8943 | 0.2830 | 0.6037 | 0.033* | |
C19 | 0.9920 (3) | 0.3863 (5) | 0.68772 (17) | 0.0292 (8) | |
H19 | 1.0559 | 0.3979 | 0.6625 | 0.035* | |
C20 | 0.9944 (3) | 0.4382 (4) | 0.75934 (17) | 0.0272 (8) | |
H20 | 1.0601 | 0.4852 | 0.7835 | 0.033* | |
C21 | 0.9005 (2) | 0.4217 (4) | 0.79611 (17) | 0.0256 (8) | |
H21 | 0.9022 | 0.4594 | 0.8451 | 0.031* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0233 (12) | 0.0323 (14) | 0.0259 (12) | 0.0001 (10) | 0.0093 (9) | −0.0012 (10) |
O2 | 0.0315 (13) | 0.0513 (17) | 0.0230 (12) | −0.0006 (11) | 0.0132 (10) | 0.0038 (11) |
N1 | 0.0252 (14) | 0.0305 (17) | 0.0200 (13) | 0.0005 (12) | 0.0063 (11) | 0.0030 (11) |
N2 | 0.0193 (13) | 0.0305 (17) | 0.0179 (13) | 0.0017 (11) | 0.0093 (10) | 0.0011 (11) |
N3 | 0.0213 (14) | 0.0332 (18) | 0.0226 (14) | −0.0016 (12) | 0.0080 (11) | 0.0057 (12) |
C1 | 0.0251 (17) | 0.028 (2) | 0.0209 (16) | −0.0040 (14) | 0.0075 (13) | −0.0026 (14) |
C2 | 0.0274 (18) | 0.034 (2) | 0.0242 (18) | −0.0042 (15) | 0.0092 (14) | −0.0018 (15) |
C3 | 0.0250 (17) | 0.036 (2) | 0.0281 (17) | 0.0057 (14) | 0.0145 (14) | −0.0007 (15) |
C4 | 0.0240 (17) | 0.035 (2) | 0.0244 (17) | 0.0043 (14) | 0.0109 (13) | −0.0012 (14) |
C5 | 0.0239 (17) | 0.041 (2) | 0.0297 (18) | 0.0028 (15) | 0.0147 (14) | 0.0035 (15) |
C6 | 0.0176 (16) | 0.044 (2) | 0.0348 (19) | −0.0002 (15) | 0.0084 (14) | 0.0032 (16) |
C7 | 0.0222 (17) | 0.038 (2) | 0.0293 (18) | 0.0033 (15) | 0.0059 (13) | 0.0009 (15) |
C8 | 0.0256 (17) | 0.031 (2) | 0.0274 (17) | 0.0024 (14) | 0.0093 (14) | 0.0030 (14) |
C9 | 0.0223 (16) | 0.023 (2) | 0.0285 (17) | 0.0013 (13) | 0.0112 (13) | 0.0003 (14) |
C10 | 0.0216 (17) | 0.026 (2) | 0.0253 (17) | 0.0004 (13) | 0.0084 (13) | −0.0035 (14) |
C11 | 0.0197 (16) | 0.027 (2) | 0.0193 (15) | −0.0018 (13) | 0.0082 (12) | −0.0033 (13) |
C12 | 0.0282 (18) | 0.038 (2) | 0.0221 (16) | 0.0009 (15) | 0.0079 (13) | 0.0041 (15) |
C13 | 0.0294 (18) | 0.040 (2) | 0.0183 (16) | −0.0014 (15) | 0.0059 (13) | 0.0011 (14) |
C14 | 0.0256 (17) | 0.036 (2) | 0.0279 (17) | 0.0005 (15) | 0.0063 (14) | 0.0023 (15) |
C15 | 0.040 (2) | 0.038 (2) | 0.036 (2) | −0.0037 (17) | 0.0099 (16) | −0.0002 (17) |
C16 | 0.0218 (16) | 0.027 (2) | 0.0207 (16) | 0.0008 (13) | 0.0058 (12) | 0.0031 (13) |
C17 | 0.0219 (16) | 0.034 (2) | 0.0220 (16) | 0.0008 (14) | 0.0060 (13) | 0.0016 (14) |
C18 | 0.0276 (17) | 0.037 (2) | 0.0199 (16) | 0.0041 (15) | 0.0078 (13) | 0.0012 (15) |
C19 | 0.0289 (18) | 0.031 (2) | 0.0299 (18) | 0.0049 (15) | 0.0152 (14) | 0.0062 (15) |
C20 | 0.0238 (17) | 0.030 (2) | 0.0285 (17) | −0.0012 (14) | 0.0045 (13) | 0.0048 (14) |
C21 | 0.0266 (17) | 0.029 (2) | 0.0227 (16) | 0.0023 (14) | 0.0091 (13) | 0.0024 (14) |
O1—C1 | 1.241 (4) | C10—C11 | 1.355 (4) |
O2—C2 | 1.218 (4) | C10—C16 | 1.491 (4) |
N1—C1 | 1.379 (4) | C12—H12A | 0.990 |
N1—C2 | 1.396 (4) | C12—H12B | 0.990 |
N1—C12 | 1.459 (4) | C12—C13 | 1.528 (5) |
N2—C2 | 1.363 (4) | C13—H13A | 0.990 |
N2—C3 | 1.452 (4) | C13—H13B | 0.990 |
N2—C11 | 1.417 (4) | C13—C14 | 1.510 (5) |
N3—H3N | 0.86 (4) | C14—H14A | 0.990 |
N3—C9 | 1.413 (4) | C14—H14B | 0.990 |
N3—C10 | 1.367 (4) | C14—C15 | 1.519 (5) |
C1—C11 | 1.453 (5) | C15—H15A | 0.980 |
C3—H3A | 0.990 | C15—H15B | 0.980 |
C3—H3B | 0.990 | C15—H15C | 0.980 |
C3—C4 | 1.492 (5) | C16—C17 | 1.390 (4) |
C4—C5 | 1.396 (5) | C16—C21 | 1.387 (5) |
C4—C9 | 1.403 (4) | C17—H17 | 0.950 |
C5—H5 | 0.950 | C17—C18 | 1.386 (4) |
C5—C6 | 1.379 (5) | C18—H18 | 0.950 |
C6—H6 | 0.950 | C18—C19 | 1.380 (5) |
C6—C7 | 1.382 (5) | C19—H19 | 0.950 |
C7—H7 | 0.950 | C19—C20 | 1.381 (5) |
C7—C8 | 1.387 (4) | C20—H20 | 0.950 |
C8—H8 | 0.950 | C20—C21 | 1.392 (4) |
C8—C9 | 1.383 (5) | C21—H21 | 0.950 |
C1—N1—C2 | 111.6 (3) | C1—C11—C10 | 128.3 (3) |
C1—N1—C12 | 124.5 (3) | N1—C12—H12A | 108.9 |
C2—N1—C12 | 123.8 (2) | N1—C12—H12B | 108.9 |
C2—N2—C3 | 122.9 (2) | N1—C12—C13 | 113.2 (3) |
C2—N2—C11 | 111.2 (2) | H12A—C12—H12B | 107.7 |
C3—N2—C11 | 124.5 (3) | H12A—C12—C13 | 108.9 |
H3N—N3—C9 | 115 (2) | H12B—C12—C13 | 108.9 |
H3N—N3—C10 | 115 (2) | C12—C13—H13A | 109.2 |
C9—N3—C10 | 129.6 (3) | C12—C13—H13B | 109.2 |
O1—C1—N1 | 122.6 (3) | C12—C13—C14 | 112.2 (3) |
O1—C1—C11 | 131.4 (3) | H13A—C13—H13B | 107.9 |
N1—C1—C11 | 105.9 (3) | H13A—C13—C14 | 109.2 |
O2—C2—N1 | 125.6 (3) | H13B—C13—C14 | 109.2 |
O2—C2—N2 | 128.5 (3) | C13—C14—H14A | 109.2 |
N1—C2—N2 | 105.9 (2) | C13—C14—H14B | 109.2 |
N2—C3—H3A | 108.9 | C13—C14—C15 | 111.9 (3) |
N2—C3—H3B | 108.9 | H14A—C14—H14B | 107.9 |
N2—C3—C4 | 113.4 (3) | H14A—C14—C15 | 109.2 |
H3A—C3—H3B | 107.7 | H14B—C14—C15 | 109.2 |
H3A—C3—C4 | 108.9 | C14—C15—H15A | 109.5 |
H3B—C3—C4 | 108.9 | C14—C15—H15B | 109.5 |
C3—C4—C5 | 120.5 (3) | C14—C15—H15C | 109.5 |
C3—C4—C9 | 122.2 (3) | H15A—C15—H15B | 109.5 |
C5—C4—C9 | 117.3 (3) | H15A—C15—H15C | 109.5 |
C4—C5—H5 | 118.8 | H15B—C15—H15C | 109.5 |
C4—C5—C6 | 122.5 (3) | C10—C16—C17 | 119.8 (3) |
H5—C5—C6 | 118.8 | C10—C16—C21 | 121.0 (3) |
C5—C6—H6 | 120.4 | C17—C16—C21 | 119.1 (3) |
C5—C6—C7 | 119.2 (3) | C16—C17—H17 | 119.9 |
H6—C6—C7 | 120.4 | C16—C17—C18 | 120.1 (3) |
C6—C7—H7 | 120.2 | H17—C17—C18 | 119.9 |
C6—C7—C8 | 119.7 (3) | C17—C18—H18 | 119.7 |
H7—C7—C8 | 120.2 | C17—C18—C19 | 120.6 (3) |
C7—C8—H8 | 119.6 | H18—C18—C19 | 119.7 |
C7—C8—C9 | 120.9 (3) | C18—C19—H19 | 120.2 |
H8—C8—C9 | 119.6 | C18—C19—C20 | 119.6 (3) |
N3—C9—C4 | 122.1 (3) | H19—C19—C20 | 120.2 |
N3—C9—C8 | 117.7 (3) | C19—C20—H20 | 120.0 |
C4—C9—C8 | 120.2 (3) | C19—C20—C21 | 120.1 (3) |
N3—C10—C11 | 126.4 (3) | H20—C20—C21 | 120.0 |
N3—C10—C16 | 113.5 (3) | C16—C21—C20 | 120.5 (3) |
C11—C10—C16 | 120.1 (3) | C16—C21—H21 | 119.8 |
N2—C11—C1 | 105.0 (2) | C20—C21—H21 | 119.8 |
N2—C11—C10 | 126.6 (3) | ||
C2—N1—C1—O1 | −176.4 (3) | C9—N3—C10—C16 | 158.5 (3) |
C2—N1—C1—C11 | 1.5 (4) | N3—C10—C11—N2 | −10.9 (6) |
C12—N1—C1—O1 | 3.5 (5) | N3—C10—C11—C1 | 165.3 (3) |
C12—N1—C1—C11 | −178.5 (3) | C16—C10—C11—N2 | 168.2 (3) |
C3—N2—C2—O2 | 6.5 (5) | C16—C10—C11—C1 | −15.6 (5) |
C3—N2—C2—N1 | −172.0 (3) | C2—N2—C11—C1 | 5.7 (4) |
C11—N2—C2—O2 | 173.7 (3) | C2—N2—C11—C10 | −177.3 (3) |
C11—N2—C2—N1 | −4.8 (4) | C3—N2—C11—C1 | 172.7 (3) |
C1—N1—C2—O2 | −176.7 (3) | C3—N2—C11—C10 | −10.4 (5) |
C1—N1—C2—N2 | 2.0 (4) | O1—C1—C11—N2 | 173.5 (3) |
C12—N1—C2—O2 | 3.4 (5) | O1—C1—C11—C10 | −3.4 (6) |
C12—N1—C2—N2 | −178.0 (3) | N1—C1—C11—N2 | −4.2 (3) |
C2—N2—C3—C4 | −136.8 (3) | N1—C1—C11—C10 | 178.9 (3) |
C11—N2—C3—C4 | 57.7 (4) | C1—N1—C12—C13 | −80.8 (4) |
N2—C3—C4—C5 | 121.8 (3) | C2—N1—C12—C13 | 99.1 (3) |
N2—C3—C4—C9 | −61.3 (4) | N1—C12—C13—C14 | −180.0 (2) |
C3—C4—C5—C6 | 174.0 (3) | C12—C13—C14—C15 | 172.6 (3) |
C9—C4—C5—C6 | −3.1 (5) | N3—C10—C16—C17 | −52.2 (4) |
C4—C5—C6—C7 | −1.3 (5) | N3—C10—C16—C21 | 127.0 (3) |
C5—C6—C7—C8 | 3.1 (5) | C11—C10—C16—C17 | 128.6 (3) |
C6—C7—C8—C9 | −0.3 (5) | C11—C10—C16—C21 | −52.2 (5) |
C7—C8—C9—N3 | 174.6 (3) | C10—C16—C17—C18 | 179.6 (3) |
C7—C8—C9—C4 | −4.3 (5) | C21—C16—C17—C18 | 0.3 (5) |
C3—C4—C9—N3 | 9.9 (5) | C16—C17—C18—C19 | 0.5 (5) |
C3—C4—C9—C8 | −171.2 (3) | C17—C18—C19—C20 | −0.6 (5) |
C5—C4—C9—N3 | −173.1 (3) | C18—C19—C20—C21 | −0.2 (5) |
C5—C4—C9—C8 | 5.8 (5) | C10—C16—C21—C20 | 179.7 (3) |
C10—N3—C9—C4 | 37.7 (5) | C17—C16—C21—C20 | −1.1 (5) |
C10—N3—C9—C8 | −141.3 (3) | C19—C20—C21—C16 | 1.1 (5) |
C9—N3—C10—C11 | −22.3 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3N···O1i | 0.86 (4) | 2.10 (4) | 2.944 (3) | 165 (3) |
C8—H8···O1i | 0.95 | 2.57 | 3.326 (4) | 136 |
Symmetry code: (i) −x+3/2, y+1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C21H21N3O2 |
Mr | 347.41 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 100 |
a, b, c (Å) | 12.192 (4), 7.638 (2), 18.514 (6) |
β (°) | 95.494 (5) |
V (Å3) | 1716.1 (9) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.29 × 0.14 × 0.08 |
Data collection | |
Diffractometer | Bruker Kappa APEXII DUO CCD diffractometer |
Absorption correction | Numerical (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.975, 0.993 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14047, 2724, 1908 |
Rint | 0.067 |
θmax (°) | 24.1 |
(sin θ/λ)max (Å−1) | 0.575 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.065, 0.181, 1.03 |
No. of reflections | 2724 |
No. of parameters | 239 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.71, −0.29 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXTL (Sheldrick, 2008) and local programs.
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3N···O1i | 0.86 (4) | 2.10 (4) | 2.944 (3) | 165 (3) |
C8—H8···O1i | 0.95 | 2.57 | 3.326 (4) | 136.3 |
Symmetry code: (i) −x+3/2, y+1/2, −z+3/2. |
Acknowledgements
The diffractometer was purchased with funding from NSF grant No. CHE-0741837.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
We recently investigated a three step solution phase protocol for the synthesis of arrays of tricyclic fused hydantoin-benzodiazepines as part of broader research on multi-component reactions (Figure 1). Interestingly, the major product of this unique synthetic route was the tautomer 5 derived from the originally desired product 4, the structure being confirmed by X-ray crystallography. The methodology employs ortho-N-Boc benzylamines 1 and phenylglyoxaldehydes 2 in the rarely used five component Ugi reaction with CO2 to assemble desired diversity in product 3 (Hulme et al., 2000). Acid treatment unmasks an internal amino nucleophile and promotes rapid formation of the diazepine ring of generic structure 4. Subsequent base treatment employs the amidic NH of the Ugi scaffold as a second internal nucleophile promoting hydantoin formation and an unexpected 1,3-H shift to give 5. As such the methodology represents an example of a post-condensation Ugi modification (Hulme & Gore, 2003) that employs two internal nucleophiles in distinct operations, generating a novel scaffold of high complexity in three succinct functional operations.
Two types of crystals were formed: very fine yellow needles together with a few slightly larger rod-shaped pale yellow crystals. The needles did not give any measurable diffraction and the rod crystals showed weak diffraction with 60 second exposure times; a resolution cutoff of 0.87Å was applied to the dataset. The identity of the needle crystals was not established. The molecular structure of 5 is shown in Figure 2. Molecular dimensions are unexceptional. The amine hydrogen atom was located in a difference Fourier map and its presence is confirmed by participation in hydrogen bonding discussed below. The central 7-membered heterocyclic ring adopts a conformation that is perhaps best described as a distorted boat with the H-bearing (C3 and N3) atoms lying well out of a least squares mean plane fitted through the other five atoms in the ring [r.m.s. deviation 0.075 Å; C3 deviates by 0.679 (5) Å and N3 deviates by 0.301 (4) Å]. The compound packs as a twisted chain which propagates along the b axis by means of an R12(6) motif (Bernstein et al., 1995) formed by one of the carbonyl oxygen atoms acting as bifurcated acceptor in an N–H···O and C–H···O interaction (Figure 3).