organic compounds
rac-Dimethyl 2-(tert-butylamino)-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3,4-dicarboxylate
aPhysics Department, Sri Ram Engineering College, Chennai 602 024, India, bDepartment of Physics, RKM Vivekananda College (Autonomous), Chennai 600 004, India, and cOrganic Chemistry Division, Central Leather Research Institute, Adyar, Chennai 600020, India
*Correspondence e-mail: ksethusankar@yahoo.co.in
The title compound, C20H21NO7, is asymmetric with a chiral centre located in the pyran ring and crystallizes as a racemate. The molecular framework is somewhat bent; the coumarin moiety and the pyran ring are inclined by 7.85 (5)°. The molecular structure is characterized by an intramolecular N—H⋯O hydrogen bond, which generates an S(6) ring motif, and the crystal packing is stabilized by intermolecular C—H⋯O hydrogen bonds. The 3-carboxylate O atom is involved in both of them, having a bifurcated character.
Related literature
For the biological and pharmacological activity of coumarin and its derivatives, see: Borges et al. (2005); Gursoy & Karali (2003); Moffett (1964). For a related structure, see: Fun et al. (2011). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2008); cell SAINT (Bruker, 2008); 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: SHELXL97 and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536811041493/ld2028sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811041493/ld2028Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536811041493/ld2028Isup3.cml
To a stirred solution of 4-hydroxy coumarin (0.162 g, 1.0 mmol) and dimethyl acetylenedicarboxylate (0.142 g, 1.0 mmol) in CH3CN (10 ml), a solution of tert-butyl isocynaide (0.083 g, 1.0 mmol) was added at room temperature over 5 min. The mixture was then stirred for 24 h. After completion of the reaction, the solvent was removed under vacuum and the solid residue was washed with n-hexane and re-crystallized from CH2Cl2/n-hexane(1:2) to give product as colourless crystals (0.337 g, 87%).
The positions of the hydrogen atoms bound to the N and C atoms were identified from the difference electron density maps and their distances were geometrically optimized. The hydrogen atoms bound to the C and N atoms were treated as riding atoms, with d(N—H)=0.86 and Uiso(H) = 1.2Ueq(N) for amine group, d(C—H)=0.93 and Uiso(H) = 1.2Ueq(C) for aromatic, d(C—H)=0.98 and Uiso(H)=1.2Ueq(C) for methine and d(C—H)=0.96 and Uiso(H) =1.5Ueq(C) for methyl groups. Conformations of Me groups were rotationally optimized.
Data collection: APEX2 (Bruker, 2008); cell
SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).C20H21NO7 | F(000) = 816 |
Mr = 387.38 | Dx = 1.382 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 6688 reflections |
a = 10.0907 (2) Å | θ = 2.2–32.5° |
b = 16.3943 (4) Å | µ = 0.11 mm−1 |
c = 11.8266 (2) Å | T = 293 K |
β = 107.941 (1)° | Block, colourless |
V = 1861.34 (7) Å3 | 0.30 × 0.25 × 0.20 mm |
Z = 4 |
Bruker Kappa APEXII CCD diffractometer | 6688 independent reflections |
Radiation source: fine-focus sealed tube | 4069 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ω and ϕ scans | θmax = 32.5°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −15→15 |
Tmin = 0.969, Tmax = 0.979 | k = −24→24 |
27295 measured reflections | l = −17→17 |
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)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.158 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0737P)2 + 0.294P] where P = (Fo2 + 2Fc2)/3 |
6688 reflections | (Δ/σ)max < 0.001 |
258 parameters | Δρmax = 0.26 e Å−3 |
0 restraints | Δρmin = −0.21 e Å−3 |
C20H21NO7 | V = 1861.34 (7) Å3 |
Mr = 387.38 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.0907 (2) Å | µ = 0.11 mm−1 |
b = 16.3943 (4) Å | T = 293 K |
c = 11.8266 (2) Å | 0.30 × 0.25 × 0.20 mm |
β = 107.941 (1)° |
Bruker Kappa APEXII CCD diffractometer | 6688 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 4069 reflections with I > 2σ(I) |
Tmin = 0.969, Tmax = 0.979 | Rint = 0.030 |
27295 measured reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.158 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.26 e Å−3 |
6688 reflections | Δρmin = −0.21 e Å−3 |
258 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.60272 (14) | 0.10657 (9) | 0.40846 (13) | 0.0459 (3) | |
C2 | 0.68858 (16) | 0.12542 (11) | 0.52188 (14) | 0.0574 (4) | |
H2 | 0.7055 | 0.1794 | 0.5462 | 0.069* | |
C3 | 0.74773 (16) | 0.06267 (13) | 0.59709 (15) | 0.0632 (5) | |
H3 | 0.8049 | 0.0745 | 0.6735 | 0.076* | |
C4 | 0.72413 (16) | −0.01784 (12) | 0.56175 (14) | 0.0593 (4) | |
H4 | 0.7647 | −0.0595 | 0.6143 | 0.071* | |
C5 | 0.64022 (15) | −0.03630 (10) | 0.44824 (13) | 0.0489 (3) | |
H5 | 0.6253 | −0.0904 | 0.4241 | 0.059* | |
C6 | 0.57782 (13) | 0.02628 (8) | 0.36981 (12) | 0.0405 (3) | |
C7 | 0.48651 (12) | 0.01446 (7) | 0.25070 (11) | 0.0371 (3) | |
C8 | 0.42265 (13) | 0.07696 (7) | 0.18224 (11) | 0.0373 (3) | |
C9 | 0.44864 (15) | 0.15958 (8) | 0.22674 (13) | 0.0458 (3) | |
C10 | 0.32265 (12) | 0.06565 (7) | 0.06042 (11) | 0.0364 (2) | |
H10 | 0.3468 | 0.1037 | 0.0060 | 0.044* | |
C11 | 0.33327 (13) | −0.02048 (7) | 0.01863 (11) | 0.0364 (3) | |
C12 | 0.40362 (13) | −0.08012 (7) | 0.09507 (11) | 0.0376 (3) | |
C13 | 0.17418 (13) | 0.08403 (7) | 0.06189 (12) | 0.0385 (3) | |
C14 | −0.03365 (16) | 0.15297 (11) | −0.03895 (17) | 0.0615 (4) | |
H14A | −0.0825 | 0.1019 | −0.0530 | 0.092* | |
H14B | −0.0695 | 0.1878 | −0.1067 | 0.092* | |
H14C | −0.0464 | 0.1786 | 0.0299 | 0.092* | |
C15 | 0.26488 (14) | −0.04112 (8) | −0.10362 (12) | 0.0416 (3) | |
C16 | 0.11252 (17) | 0.00960 (12) | −0.28374 (14) | 0.0625 (4) | |
H16A | 0.1604 | −0.0203 | −0.3291 | 0.094* | |
H16B | 0.0811 | 0.0608 | −0.3221 | 0.094* | |
H16C | 0.0339 | −0.0214 | −0.2785 | 0.094* | |
C17 | 0.48307 (18) | −0.22850 (8) | 0.13618 (14) | 0.0519 (4) | |
C18 | 0.4116 (3) | −0.24776 (12) | 0.2283 (2) | 0.0821 (6) | |
H18A | 0.4305 | −0.2051 | 0.2867 | 0.123* | |
H18B | 0.4460 | −0.2986 | 0.2662 | 0.123* | |
H18C | 0.3129 | −0.2517 | 0.1904 | 0.123* | |
C19 | 0.6380 (2) | −0.21543 (11) | 0.19263 (19) | 0.0730 (5) | |
H19A | 0.6809 | −0.2064 | 0.1316 | 0.109* | |
H19B | 0.6783 | −0.2628 | 0.2380 | 0.109* | |
H19C | 0.6532 | −0.1688 | 0.2441 | 0.109* | |
C20 | 0.4601 (3) | −0.29789 (10) | 0.04631 (19) | 0.0820 (6) | |
H20A | 0.3621 | −0.3074 | 0.0117 | 0.123* | |
H20B | 0.5041 | −0.3465 | 0.0857 | 0.123* | |
H20C | 0.4998 | −0.2834 | −0.0150 | 0.123* | |
O1 | 0.54122 (11) | 0.17100 (6) | 0.33794 (10) | 0.0537 (3) | |
O2 | 0.39422 (14) | 0.21939 (6) | 0.17376 (11) | 0.0651 (3) | |
O3 | 0.12113 (11) | 0.05152 (7) | 0.12744 (10) | 0.0568 (3) | |
O4 | 0.11235 (10) | 0.13887 (6) | −0.01951 (10) | 0.0539 (3) | |
O5 | 0.25835 (12) | −0.10881 (7) | −0.14909 (9) | 0.0559 (3) | |
O6 | 0.20492 (12) | 0.02410 (6) | −0.16718 (9) | 0.0545 (3) | |
O7 | 0.47008 (10) | −0.06485 (5) | 0.21316 (8) | 0.0433 (2) | |
N1 | 0.41676 (14) | −0.15701 (7) | 0.06458 (11) | 0.0503 (3) | |
H1 | 0.3803 | −0.1670 | −0.0100 | 0.060* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0359 (6) | 0.0521 (8) | 0.0470 (7) | −0.0020 (5) | 0.0088 (5) | −0.0071 (6) |
C2 | 0.0439 (7) | 0.0686 (10) | 0.0542 (9) | −0.0058 (7) | 0.0069 (7) | −0.0172 (8) |
C3 | 0.0413 (7) | 0.0934 (13) | 0.0470 (8) | 0.0027 (8) | 0.0019 (6) | −0.0133 (9) |
C4 | 0.0445 (8) | 0.0835 (12) | 0.0447 (8) | 0.0112 (8) | 0.0060 (6) | 0.0050 (8) |
C5 | 0.0423 (7) | 0.0580 (8) | 0.0429 (7) | 0.0057 (6) | 0.0080 (6) | 0.0036 (6) |
C6 | 0.0318 (5) | 0.0473 (7) | 0.0406 (7) | 0.0012 (5) | 0.0087 (5) | 0.0000 (5) |
C7 | 0.0345 (6) | 0.0359 (6) | 0.0396 (6) | −0.0013 (5) | 0.0094 (5) | −0.0007 (5) |
C8 | 0.0356 (6) | 0.0333 (6) | 0.0412 (6) | −0.0016 (5) | 0.0090 (5) | −0.0004 (5) |
C9 | 0.0456 (7) | 0.0386 (6) | 0.0497 (8) | −0.0015 (5) | 0.0096 (6) | −0.0031 (6) |
C10 | 0.0377 (6) | 0.0314 (5) | 0.0384 (6) | −0.0020 (4) | 0.0092 (5) | 0.0047 (5) |
C11 | 0.0375 (6) | 0.0330 (5) | 0.0381 (6) | −0.0017 (4) | 0.0108 (5) | 0.0002 (5) |
C12 | 0.0398 (6) | 0.0333 (6) | 0.0400 (6) | −0.0025 (5) | 0.0127 (5) | 0.0004 (5) |
C13 | 0.0383 (6) | 0.0323 (6) | 0.0417 (7) | −0.0004 (5) | 0.0074 (5) | 0.0020 (5) |
C14 | 0.0401 (7) | 0.0598 (9) | 0.0757 (11) | 0.0082 (7) | 0.0047 (7) | 0.0113 (8) |
C15 | 0.0404 (6) | 0.0427 (7) | 0.0416 (7) | −0.0055 (5) | 0.0126 (5) | 0.0008 (5) |
C16 | 0.0517 (8) | 0.0845 (12) | 0.0422 (8) | −0.0023 (8) | 0.0013 (6) | 0.0040 (8) |
C17 | 0.0706 (9) | 0.0321 (6) | 0.0569 (9) | 0.0052 (6) | 0.0255 (7) | 0.0088 (6) |
C18 | 0.1131 (17) | 0.0600 (10) | 0.0932 (15) | 0.0014 (11) | 0.0612 (14) | 0.0179 (10) |
C19 | 0.0713 (11) | 0.0536 (9) | 0.0914 (14) | 0.0189 (8) | 0.0212 (10) | 0.0255 (9) |
C20 | 0.1286 (19) | 0.0364 (8) | 0.0855 (14) | 0.0102 (10) | 0.0396 (13) | −0.0010 (8) |
O1 | 0.0546 (6) | 0.0424 (5) | 0.0553 (6) | −0.0035 (4) | 0.0039 (5) | −0.0106 (5) |
O2 | 0.0781 (8) | 0.0363 (5) | 0.0692 (8) | 0.0051 (5) | 0.0054 (6) | −0.0007 (5) |
O3 | 0.0503 (6) | 0.0632 (7) | 0.0625 (7) | 0.0087 (5) | 0.0255 (5) | 0.0193 (5) |
O4 | 0.0411 (5) | 0.0509 (6) | 0.0659 (7) | 0.0077 (4) | 0.0108 (5) | 0.0225 (5) |
O5 | 0.0677 (7) | 0.0489 (6) | 0.0474 (6) | −0.0022 (5) | 0.0121 (5) | −0.0104 (5) |
O6 | 0.0598 (6) | 0.0511 (6) | 0.0417 (5) | −0.0015 (5) | −0.0002 (5) | 0.0038 (4) |
O7 | 0.0514 (5) | 0.0332 (4) | 0.0405 (5) | 0.0023 (4) | 0.0074 (4) | 0.0026 (4) |
N1 | 0.0667 (8) | 0.0336 (5) | 0.0473 (7) | 0.0054 (5) | 0.0127 (6) | −0.0004 (5) |
C1—O1 | 1.3703 (18) | C13—O4 | 1.3245 (15) |
C1—C2 | 1.389 (2) | C14—O4 | 1.4380 (18) |
C1—C6 | 1.3905 (19) | C14—H14A | 0.9600 |
C2—C3 | 1.371 (3) | C14—H14B | 0.9600 |
C2—H2 | 0.9300 | C14—H14C | 0.9600 |
C3—C4 | 1.383 (3) | C15—O5 | 1.2261 (16) |
C3—H3 | 0.9300 | C15—O6 | 1.3395 (17) |
C4—C5 | 1.382 (2) | C16—O6 | 1.4262 (18) |
C4—H4 | 0.9300 | C16—H16A | 0.9600 |
C5—C6 | 1.3962 (19) | C16—H16B | 0.9600 |
C5—H5 | 0.9300 | C16—H16C | 0.9600 |
C6—C7 | 1.4392 (18) | C17—N1 | 1.4797 (18) |
C7—C8 | 1.3415 (17) | C17—C18 | 1.514 (2) |
C7—O7 | 1.3674 (15) | C17—C19 | 1.514 (3) |
C8—C9 | 1.4474 (18) | C17—C20 | 1.525 (2) |
C8—C10 | 1.4942 (17) | C18—H18A | 0.9600 |
C9—O2 | 1.2016 (17) | C18—H18B | 0.9600 |
C9—O1 | 1.3714 (18) | C18—H18C | 0.9600 |
C10—C11 | 1.5107 (17) | C19—H19A | 0.9600 |
C10—C13 | 1.5335 (17) | C19—H19B | 0.9600 |
C10—H10 | 0.9800 | C19—H19C | 0.9600 |
C11—C12 | 1.3719 (17) | C20—H20A | 0.9600 |
C11—C15 | 1.4375 (18) | C20—H20B | 0.9600 |
C12—N1 | 1.3288 (16) | C20—H20C | 0.9600 |
C12—O7 | 1.3733 (16) | N1—H1 | 0.8600 |
C13—O3 | 1.1948 (16) | ||
O1—C1—C2 | 116.55 (14) | H14A—C14—H14B | 109.5 |
O1—C1—C6 | 121.84 (12) | O4—C14—H14C | 109.5 |
C2—C1—C6 | 121.59 (14) | H14A—C14—H14C | 109.5 |
C3—C2—C1 | 118.49 (16) | H14B—C14—H14C | 109.5 |
C3—C2—H2 | 120.8 | O5—C15—O6 | 121.50 (13) |
C1—C2—H2 | 120.8 | O5—C15—C11 | 126.77 (13) |
C2—C3—C4 | 121.35 (15) | O6—C15—C11 | 111.74 (11) |
C2—C3—H3 | 119.3 | O6—C16—H16A | 109.5 |
C4—C3—H3 | 119.3 | O6—C16—H16B | 109.5 |
C5—C4—C3 | 119.97 (16) | H16A—C16—H16B | 109.5 |
C5—C4—H4 | 120.0 | O6—C16—H16C | 109.5 |
C3—C4—H4 | 120.0 | H16A—C16—H16C | 109.5 |
C4—C5—C6 | 120.02 (15) | H16B—C16—H16C | 109.5 |
C4—C5—H5 | 120.0 | N1—C17—C18 | 110.21 (14) |
C6—C5—H5 | 120.0 | N1—C17—C19 | 111.32 (12) |
C1—C6—C5 | 118.57 (13) | C18—C17—C19 | 111.62 (16) |
C1—C6—C7 | 116.46 (12) | N1—C17—C20 | 104.32 (13) |
C5—C6—C7 | 124.96 (13) | C18—C17—C20 | 110.02 (15) |
C8—C7—O7 | 122.87 (11) | C19—C17—C20 | 109.10 (16) |
C8—C7—C6 | 122.11 (12) | C17—C18—H18A | 109.5 |
O7—C7—C6 | 115.02 (11) | C17—C18—H18B | 109.5 |
C7—C8—C9 | 119.72 (12) | H18A—C18—H18B | 109.5 |
C7—C8—C10 | 122.91 (11) | C17—C18—H18C | 109.5 |
C9—C8—C10 | 117.36 (11) | H18A—C18—H18C | 109.5 |
O2—C9—O1 | 117.10 (12) | H18B—C18—H18C | 109.5 |
O2—C9—C8 | 124.86 (13) | C17—C19—H19A | 109.5 |
O1—C9—C8 | 118.04 (12) | C17—C19—H19B | 109.5 |
C8—C10—C11 | 109.67 (10) | H19A—C19—H19B | 109.5 |
C8—C10—C13 | 109.67 (10) | C17—C19—H19C | 109.5 |
C11—C10—C13 | 110.81 (10) | H19A—C19—H19C | 109.5 |
C8—C10—H10 | 108.9 | H19B—C19—H19C | 109.5 |
C11—C10—H10 | 108.9 | C17—C20—H20A | 109.5 |
C13—C10—H10 | 108.9 | C17—C20—H20B | 109.5 |
C12—C11—C15 | 119.05 (11) | H20A—C20—H20B | 109.5 |
C12—C11—C10 | 121.68 (11) | C17—C20—H20C | 109.5 |
C15—C11—C10 | 119.25 (11) | H20A—C20—H20C | 109.5 |
N1—C12—C11 | 124.89 (12) | H20B—C20—H20C | 109.5 |
N1—C12—O7 | 112.99 (11) | C1—O1—C9 | 121.69 (11) |
C11—C12—O7 | 122.12 (11) | C13—O4—C14 | 117.09 (12) |
O3—C13—O4 | 124.71 (12) | C15—O6—C16 | 117.20 (12) |
O3—C13—C10 | 123.67 (11) | C7—O7—C12 | 118.42 (10) |
O4—C13—C10 | 111.61 (11) | C12—N1—C17 | 131.41 (13) |
O4—C14—H14A | 109.5 | C12—N1—H1 | 114.3 |
O4—C14—H14B | 109.5 | C17—N1—H1 | 114.3 |
O1—C1—C2—C3 | 177.39 (13) | C13—C10—C11—C15 | 69.62 (14) |
C6—C1—C2—C3 | −1.0 (2) | C15—C11—C12—N1 | 1.5 (2) |
C1—C2—C3—C4 | 0.4 (2) | C10—C11—C12—N1 | 179.80 (12) |
C2—C3—C4—C5 | 0.5 (3) | C15—C11—C12—O7 | −179.35 (11) |
C3—C4—C5—C6 | −0.8 (2) | C10—C11—C12—O7 | −1.03 (18) |
O1—C1—C6—C5 | −177.67 (12) | C8—C10—C13—O3 | −54.74 (16) |
C2—C1—C6—C5 | 0.6 (2) | C11—C10—C13—O3 | 66.48 (17) |
O1—C1—C6—C7 | 1.41 (19) | C8—C10—C13—O4 | 126.41 (12) |
C2—C1—C6—C7 | 179.72 (13) | C11—C10—C13—O4 | −112.38 (12) |
C4—C5—C6—C1 | 0.3 (2) | C12—C11—C15—O5 | 2.2 (2) |
C4—C5—C6—C7 | −178.70 (13) | C10—C11—C15—O5 | −176.18 (13) |
C1—C6—C7—C8 | −3.39 (18) | C12—C11—C15—O6 | −178.03 (11) |
C5—C6—C7—C8 | 175.63 (13) | C10—C11—C15—O6 | 3.61 (16) |
C1—C6—C7—O7 | 176.64 (11) | C2—C1—O1—C9 | −176.45 (13) |
C5—C6—C7—O7 | −4.34 (18) | C6—C1—O1—C9 | 1.9 (2) |
O7—C7—C8—C9 | −178.01 (11) | O2—C9—O1—C1 | 176.14 (13) |
C6—C7—C8—C9 | 2.02 (19) | C8—C9—O1—C1 | −3.3 (2) |
O7—C7—C8—C10 | 2.75 (19) | O3—C13—O4—C14 | −7.5 (2) |
C6—C7—C8—C10 | −177.22 (11) | C10—C13—O4—C14 | 171.38 (12) |
C7—C8—C9—O2 | −178.08 (14) | O5—C15—O6—C16 | 11.0 (2) |
C10—C8—C9—O2 | 1.2 (2) | C11—C15—O6—C16 | −168.79 (12) |
C7—C8—C9—O1 | 1.36 (19) | C8—C7—O7—C12 | 10.56 (18) |
C10—C8—C9—O1 | −179.36 (11) | C6—C7—O7—C12 | −169.47 (10) |
C7—C8—C10—C11 | −13.49 (16) | N1—C12—O7—C7 | 167.98 (11) |
C9—C8—C10—C11 | 167.26 (11) | C11—C12—O7—C7 | −11.28 (17) |
C7—C8—C10—C13 | 108.41 (13) | C11—C12—N1—C17 | −177.04 (14) |
C9—C8—C10—C13 | −70.84 (14) | O7—C12—N1—C17 | 3.7 (2) |
C8—C10—C11—C12 | 12.52 (16) | C18—C17—N1—C12 | 61.5 (2) |
C13—C10—C11—C12 | −108.70 (13) | C19—C17—N1—C12 | −62.9 (2) |
C8—C10—C11—C15 | −169.16 (10) | C20—C17—N1—C12 | 179.60 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O5 | 0.86 | 1.97 | 2.6602 (16) | 136 |
C19—H19B···O5i | 0.96 | 2.49 | 3.4469 (19) | 174 |
Symmetry code: (i) x+1/2, −y−1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C20H21NO7 |
Mr | 387.38 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 10.0907 (2), 16.3943 (4), 11.8266 (2) |
β (°) | 107.941 (1) |
V (Å3) | 1861.34 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.30 × 0.25 × 0.20 |
Data collection | |
Diffractometer | Bruker Kappa APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.969, 0.979 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 27295, 6688, 4069 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.756 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.158, 1.00 |
No. of reflections | 6688 |
No. of parameters | 258 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.26, −0.21 |
Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O5 | 0.86 | 1.97 | 2.6602 (16) | 136 |
C19—H19B···O5i | 0.96 | 2.49 | 3.4469 (19) | 174.2 |
Symmetry code: (i) x+1/2, −y−1/2, z+1/2. |
Acknowledgements
SAIB and KS thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the
data collection and Dr V. Murugan, Head of the Physics Department, for providing facilities in the department to carry out this work.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.
The coumarin and its derivatives, comprising many of the plant-derived compounds, display a wide range of biological activities such as antiviral, anti-inflammatory, anti-bacterial (Gursoy & Karali et al., 2003), anti-fungal (Moffett et al. 1964), anticoagulant, and anti-proliferative. Some coumarin derivatives have been shown to be potential anti-HIV agents, antibiotics and antioxidants as well as flavour compounds(Borges et al., 2005).
The title compound C20H21NO7 consists of a coumarin ring system fused with a pyran ring. The coumarin ring system is almost planar, with the C9 atom having a maximum deviation of only 0.0495 (15) Å. The coumarin ring system (O1/C1—C9) makes dihedral angles of 81.43 (7)° and 7.67 (5)° with the methyl carboxylates(C13/O3/O4/C14) and (C15/C16/O5/O6), respectively. The pyran ring forms dihedral angles of 88.77 (7)° and 2.95 (6)° with these two methyl carboxylates.
The X-ray crystal structure determination shows that the compound crystallizes as a racemate - the molecule has an asymmetric carbon atom C10. The title compound exhibits structural similarities with a previously reported related structure (Fun et al., 2011).
The molecular structure is stabilized by an intramolecular N—H···O (Table 1) hydrogen bond which generates an S(6) ring motif (Bernstein et al., 1995). The crystal packing is stabilized by intermolecular C—H···O hydrogen bonds. The carboxylate atom O5 is a bifurcated hydrogen acceptor - from the neighbouring tert-butyl group and from the amino group.