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The title compounds, namely 6-meth­oxy-3,3-dimethyl-3H-benzo[f]chromene, C16H16O2, (III), and racemic 3-bromo-2,2,6,6-tetra­methyl-3,4-dihydro-2H,6H-1,5-dioxatriphenyl­ene, C20H21BrO2, (IV), were both synthesized in one-step regioselective Wittig reactions from substituted 1,2-naphthoquinones. The new ring in both compounds adopts a screw-boat conformation. A single π–π stacking inter­action links the mol­ecules of (III) into centrosymmetric dimeric aggregates, and a single C—H...π(arene) hydrogen bond links the mol­ecules of (IV) into centrosymmetric dimers.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107039194/gg3118sup1.cif
Contains datablocks global, III, IV

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107039194/gg3118IIIsup2.hkl
Contains datablock III

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107039194/gg3118IVsup3.hkl
Contains datablock IV

CCDC references: 665498; 665499

Comment top

Chromenes are of considerable interest, both because of their biological activity (Hepworth, 1984) and because of their useful applications in modern optics (Zhang et al., 2001; Ahmed et al., 2003). We have developed a one-pot synthesis of chromenes which involves the reaction of a 1,2-naphthoquinone, (A) (see scheme), with the allylic Wittig precursor [Me2CHCHCH2PPh3]+Br in the presence of concentrated aqueous sodium hydroxide solution to give the intermediate, (B), which undergoes spontaneous cyclization to the chromene, (C), in a hetero Diels–Alder reaction. The Wittig reaction is fully regioselective for the 1-position, with no evidence for any reaction at the 2-position. Thus, reaction of 4-methoxy-1,2,naphthoqinone, (I), yields 9-methoxy-2,2-dimethyl-2H-benzo[d]chromene, (III), while racemic 3-bromo-β-lapachone, (II), yields racemic 3-bromo-2,2,6,6-tetramethyl-3,4-dihydro-2H,6H,1,5-dioxatriphenylene, (IV). Here, we report the structures of compounds (III) and (IV) (Figs. 1 and 2), which we compare briefly with that of the precursor, (II) (De Simone et al., 2002).

Compounds (II) and (IV) each contain a stereogenic centre, at atom C3, but since the precursor, (II), is racemic (De Simone et al., 2002), so also is the product, (IV). Compounds (II) and (IV) both crystallize in centrosymmetric space groups. The reference molecule in the structure of (IV) was selected to have an (S) configuration at C3, just as for compound (II). In each of compounds (III) and (IV), the newly-formed ring adopts a screw-boat conformation. In (III), the ring-puckering parameters (Cremer & Pople, 1975) for the atom sequence O1/C2/C3/C4/C4a/C10a are θ = 113.6 (2)° and ϕ = 215.8 (2)°, while in (IV), the parameters for the atom-sequence O5/C4b/C8a/C8/C7/C6 are θ = 63.2 (4)° and ϕ = 328.4 (4). For the ideal screw-boat conformer, the values are θ = 675 [67.5 ?] or 112.5°, and ϕ = (60n + 30)°, where n represents zero or an integer.

The brominated ring in compound (IV) adopts a half-chair conformation, with the Br substituent occupying an equatorial site and with ring-puckering parameters θ = 128.3 (2)° and ϕ = 262.2 (3) for the atom sequence O1/C2/C3/C4/C4a/C12b. The ideal values are θ = 50.8 or 129.2° and ϕ = (60n + 30)°, where n represents zero or an integer. This conformation was also found for the heterocyclic ring in compound (I) (De Simone et al., 2002).

In each of compounds (III) and (IV), the carbocyclic portion of the molecule shows the marked bond fixation typical of naphthalenes (Tables 1 and 2), while the bonds C3—C4 in compound (III) and C7—C8 in compound (IV) are effectively isolated double bonds. The remaining bond distances show no unusual features. The methoxy C atom in compound (III) is almost coplanar with the adjacent carbocyclic ring, as shown by the relevant torsion angles, and the exocyclic O—C—C angles differ by ca 10°.

While there are no hydrogen bonds of any kind in the structure of compound (III), pairs of molecules are weakly linked into centrosymmetric dimeric aggregates by means of a single aromatic ππ stacking interaction. The unsubstituted aryl rings of the molecules at (x, y, z) and (1 − x, 1 − y, 1 − z) are strictly parallel, with an interplanar spacing of 3.463 (2) Å; the ring centroid separation is 3.853 (2) Å, corresponding to a ring offset of 1.739 (2) Å. The molecules of compound (IV) are also weakly linked into centrosymmetric dimers, this time by a C—H···π(arene) hydrogen bond (Table 3), in which atom C4 in the molecule at (x, y, z) acts as hydrogen-bond donor, via its equatorial H atom H4A, to the aryl ring C4a/C4b/C8a/C8b/C12a/C12b in the molecule at (1 − x, 1 − y, 1 − z) (Fig. 3).

By contrast with the dimeric aggregates formed by compounds (III) and (IV), the molecules of compound (II) are linked into chains of edge-fused rings (Fig. 4) by three independent C—H···O hydrogen bonds [C3—H3···O2ii, C9—H9···O2iii and C10—H10···O3iii; symmetry codes: (ii) 1 − x, 1/2 + y, 1/2 − z; (iii) x, 1 + y, z]. This aggregation was not discussed in the original report on this compound, which was concerned with proof of structure and conformation (De Simone et al., 2002).

Experimental top

The 1,2-naphthoquinone precursor, (II), was prepared from commercially available lapachol by the method of Hooker (1892). This product has been shown to be a racemic mixture of enantiomers (De Simone et al., 2002). For the synthesis of compounds (III) and (IV), a mixture of the appropriate 1,2-naphthoquinone (see scheme) (0.02 mol), the Wittig precursor [Me2CH CHCH2PPh3]+Br (0.04 mol), CHCl3 (15 ml) and aqueous NaOH (15 ml of a solution 50% by mass) was vigorously stirred for 48 h at ambient temperature. The organic phase was then separated, washed with water (3 × 10 ml) and dried over magnesium sulfate, and the solvent was removed under reduced pressure. The crude products, (III) and (IV), were purified by chromatography on silica using hexane–dichloromethane (1:1 v/v) as eluent. Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of solutions in ethanol.

Refinement top

For compounds (III) and (IV), the space groups Pbca and P21/c, respectively, were uniquely assigned from the systematic absences. All H atoms were located in difference maps and then treated as riding atoms in geometrically idealized positions, with C—H distances 0.95 Å (aromatic and alkenic), 0.98 Å (CH3), 0.99 Å (CH2) and 1.00 Å (aliphatic CH), and with Uiso(H) = kUeq(C), where k = 1.5 for the methyl groups and 1.2 for all other H atoms.

Computing details top

For both compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures top
[Figure 1] Fig. 1. A molecule of compound (III), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. The (S)-enantiomer of compound (IV), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 3] Fig. 3. Part of the crystal structure of compound (IV), showing the formation of a centrosymmetric dimer built from C—H···π(arene) hydrogen bonds. For the sake of clarity, H atoms not involved in the motif shown have been omitted. Atoms marked with an asterisk (*) are at the symmetry position (1 − x, 1 − y, 1 − z).
[Figure 4] Fig. 4. A stereoview of part of the crystal structure of compound (II), showing the formation of a chain of edge-fused rings along [10[] [100]? generated by three independent C—H···O hydrogen bonds. The original atomic coordinates (De Simone et al., 2002) have been used. For the sake of clarity, H atoms not involved in the motif shown have been omitted.
(III) 6-methoxy-3,3-dimethyl-3H-benzo[f]chromene top
Crystal data top
C16H16O2F(000) = 1024
Mr = 240.29Dx = 1.280 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 2848 reflections
a = 6.3357 (9) Åθ = 3.6–27.5°
b = 15.5230 (2) ŵ = 0.08 mm1
c = 25.3654 (6) ÅT = 120 K
V = 2494.7 (4) Å3Lath, colourless
Z = 80.74 × 0.40 × 0.14 mm
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
2848 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode2033 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.045
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 3.6°
ϕ and ω scansh = 78
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 2012
Tmin = 0.957, Tmax = 0.989l = 3232
18107 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0647P)2]
where P = (Fo2 + 2Fc2)/3
2848 reflections(Δ/σ)max = 0.001
166 parametersΔρmax = 0.18 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C16H16O2V = 2494.7 (4) Å3
Mr = 240.29Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 6.3357 (9) ŵ = 0.08 mm1
b = 15.5230 (2) ÅT = 120 K
c = 25.3654 (6) Å0.74 × 0.40 × 0.14 mm
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
2848 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
2033 reflections with I > 2σ(I)
Tmin = 0.957, Tmax = 0.989Rint = 0.045
18107 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.108H-atom parameters constrained
S = 1.05Δρmax = 0.18 e Å3
2848 reflectionsΔρmin = 0.22 e Å3
166 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.70117 (12)0.37579 (5)0.68605 (3)0.0212 (2)
C20.82434 (18)0.30916 (8)0.65864 (4)0.0219 (3)
C210.6699 (2)0.25065 (8)0.62982 (5)0.0286 (3)
C220.9400 (2)0.26182 (8)0.70243 (5)0.0301 (3)
C30.97423 (19)0.35210 (8)0.62097 (5)0.0238 (3)
C40.91824 (18)0.42430 (8)0.59660 (4)0.0221 (3)
C4a0.71668 (18)0.46481 (7)0.60879 (4)0.0190 (3)
C4b0.62045 (17)0.53175 (7)0.57814 (4)0.0190 (3)
C50.7091 (2)0.56243 (8)0.53040 (5)0.0233 (3)
C60.6118 (2)0.62464 (8)0.50125 (5)0.0265 (3)
C70.4195 (2)0.66049 (8)0.51780 (5)0.0273 (3)
C80.32983 (19)0.63325 (8)0.56408 (5)0.0236 (3)
C8a0.42748 (18)0.56946 (7)0.59527 (4)0.0191 (3)
C90.33652 (17)0.54048 (7)0.64358 (4)0.0187 (3)
O90.15338 (12)0.58134 (5)0.65701 (3)0.0245 (2)
C910.05003 (19)0.55380 (8)0.70402 (5)0.0246 (3)
C100.42760 (17)0.47598 (7)0.67253 (4)0.0186 (3)
C10a0.61566 (17)0.43818 (7)0.65416 (4)0.0180 (3)
H21A0.59520.28380.60270.043*
H21B0.56760.22720.65500.043*
H21C0.74730.20330.61310.043*
H22A0.83710.23570.72640.045*
H22B1.02850.30260.72200.045*
H22C1.02900.21670.68710.045*
H31.10920.32760.61460.029*
H41.00960.44950.57120.027*
H50.83930.53910.51840.028*
H60.67480.64390.46940.032*
H70.35190.70340.49710.033*
H80.20000.65770.57530.028*
H91A0.14260.56390.73430.037*
H91B0.01770.49220.70150.037*
H91C0.08130.58630.70850.037*
H100.36490.45700.70450.022*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0235 (5)0.0202 (4)0.0199 (4)0.0052 (4)0.0007 (3)0.0013 (3)
C20.0243 (6)0.0183 (6)0.0231 (6)0.0054 (5)0.0007 (5)0.0018 (5)
C210.0325 (7)0.0216 (6)0.0317 (7)0.0012 (6)0.0009 (6)0.0020 (6)
C220.0328 (7)0.0285 (7)0.0288 (7)0.0099 (6)0.0009 (6)0.0030 (6)
C30.0206 (7)0.0256 (7)0.0252 (6)0.0038 (5)0.0005 (5)0.0049 (5)
C40.0213 (6)0.0250 (7)0.0201 (6)0.0026 (5)0.0022 (5)0.0015 (5)
C4a0.0203 (6)0.0181 (6)0.0187 (6)0.0018 (5)0.0000 (5)0.0025 (5)
C4b0.0217 (6)0.0176 (6)0.0176 (6)0.0034 (5)0.0004 (5)0.0030 (5)
C50.0256 (7)0.0226 (6)0.0217 (6)0.0002 (5)0.0046 (5)0.0023 (5)
C60.0347 (8)0.0242 (7)0.0206 (6)0.0019 (6)0.0050 (5)0.0017 (6)
C70.0362 (8)0.0228 (7)0.0227 (6)0.0030 (6)0.0005 (6)0.0031 (5)
C80.0247 (7)0.0216 (6)0.0245 (6)0.0028 (5)0.0011 (5)0.0007 (5)
C8a0.0213 (6)0.0164 (6)0.0196 (6)0.0022 (5)0.0008 (5)0.0018 (5)
C90.0162 (6)0.0185 (6)0.0214 (6)0.0003 (5)0.0003 (5)0.0037 (5)
O90.0222 (5)0.0258 (5)0.0254 (5)0.0050 (4)0.0062 (4)0.0033 (4)
C910.0220 (7)0.0287 (7)0.0232 (6)0.0014 (5)0.0057 (5)0.0008 (5)
C100.0195 (6)0.0194 (6)0.0170 (6)0.0035 (5)0.0009 (5)0.0007 (5)
C10a0.0193 (6)0.0160 (6)0.0188 (6)0.0014 (5)0.0033 (5)0.0011 (5)
Geometric parameters (Å, º) top
O1—C10a1.3732 (13)C6—C71.4035 (18)
O1—C21.4704 (13)C7—C81.3710 (17)
C2—C31.5030 (17)C8—C8a1.4104 (16)
C2—C221.5201 (16)C8a—C91.4269 (16)
C2—C211.5223 (17)C9—C101.3692 (16)
C21—H21A0.98C10—C10a1.4075 (15)
C21—H21B0.98C10a—C4a1.3802 (15)
C21—H21C0.98C4b—C8a1.4234 (16)
C22—H22A0.98C5—H50.95
C22—H22B0.98C6—H60.95
C22—H22C0.98C7—H70.95
C3—C41.3282 (16)C8—H80.95
C3—H30.95C9—O91.3655 (13)
C4—C4a1.4566 (16)O9—C911.4259 (14)
C4—H40.95C91—H91A0.98
C4a—C4b1.4339 (16)C91—H91B0.98
C4b—C51.4174 (16)C91—H91C0.98
C5—C61.3637 (17)C10—H100.95
C10a—O1—C2115.28 (8)C6—C5—C4b121.46 (11)
O1—C2—C3108.90 (9)C6—C5—H5119.3
O1—C2—C22104.51 (9)C4b—C5—H5119.3
C3—C2—C22111.97 (10)C5—C6—C7120.74 (11)
O1—C2—C21107.79 (9)C5—C6—H6119.6
C3—C2—C21111.44 (10)C7—C6—H6119.6
C22—C2—C21111.86 (10)C8—C7—C6119.57 (11)
C2—C21—H21A109.5C8—C7—H7120.2
C2—C21—H21B109.5C6—C7—H7120.2
H21A—C21—H21B109.5C7—C8—C8a121.00 (11)
C2—C21—H21C109.5C7—C8—H8119.5
H21A—C21—H21C109.5C8a—C8—H8119.5
H21B—C21—H21C109.5C8—C8a—C4b119.62 (10)
C2—C22—H22A109.5C8—C8a—C9121.73 (11)
C2—C22—H22B109.5C4b—C8a—C9118.65 (10)
H22A—C22—H22B109.5O9—C9—C8a114.27 (10)
C2—C22—H22C109.5O9—C9—C10124.33 (10)
H22A—C22—H22C109.5C10—C9—C8a121.40 (11)
H22B—C22—H22C109.5C9—O9—C91117.36 (9)
C4—C3—C2120.09 (11)O9—C91—H91A109.5
C4—C3—H3120.0O9—C91—H91B109.5
C2—C3—H3120.0H91A—C91—H91B109.5
C3—C4—C4a119.98 (11)O9—C91—H91C109.5
C3—C4—H4120.0H91A—C91—H91C109.5
C4a—C4—H4120.0H91B—C91—H91C109.5
C10a—C4a—C4b118.16 (10)C9—C10—C10a118.95 (10)
C10a—C4a—C4117.01 (10)C9—C10—H10120.5
C4b—C4a—C4124.79 (10)C10a—C10—H10120.5
C5—C4b—C8a117.59 (11)O1—C10a—C4a121.29 (10)
C5—C4b—C4a122.56 (11)O1—C10a—C10115.66 (10)
C8a—C4b—C4a119.85 (10)C4a—C10a—C10122.94 (11)
C10a—O1—C2—C347.66 (12)C5—C4b—C8a—C81.64 (16)
C10a—O1—C2—C22167.46 (9)C4a—C4b—C8a—C8177.89 (11)
C10a—O1—C2—C2173.39 (11)C5—C4b—C8a—C9179.17 (10)
O1—C2—C3—C434.13 (14)C4a—C4b—C8a—C91.30 (16)
C22—C2—C3—C4149.19 (11)C8—C8a—C9—O91.73 (16)
C21—C2—C3—C484.65 (14)C4b—C8a—C9—O9179.10 (9)
C2—C3—C4—C4a3.77 (17)C8—C8a—C9—C10177.22 (11)
C3—C4—C4a—C10a15.43 (17)C4b—C8a—C9—C101.95 (17)
C3—C4—C4a—C4b166.73 (11)C8a—C9—O9—C91178.09 (10)
C10a—C4a—C4b—C5178.68 (10)C10—C9—O9—C910.82 (17)
C4—C4a—C4b—C53.50 (18)O9—C9—C10—C10a179.26 (10)
C10a—C4a—C4b—C8a0.82 (16)C8a—C9—C10—C10a0.42 (17)
C4—C4a—C4b—C8a176.99 (10)C2—O1—C10a—C4a32.52 (14)
C8a—C4b—C5—C61.23 (17)C2—O1—C10a—C10151.18 (9)
C4a—C4b—C5—C6178.28 (11)C4b—C4a—C10a—O1178.49 (10)
C4b—C5—C6—C70.08 (19)C4—C4a—C10a—O10.50 (16)
C5—C6—C7—C80.68 (19)C4b—C4a—C10a—C102.47 (17)
C6—C7—C8—C8a0.23 (19)C4—C4a—C10a—C10175.52 (10)
C7—C8—C8a—C4b0.95 (18)C9—C10—C10a—O1178.10 (10)
C7—C8—C8a—C9179.89 (11)C9—C10—C10a—C4a1.88 (17)
(IV) rac-3-bromo-2,2,6,6-tetramethyl-3,4-dihydro-2H,6H-1,5-dioxatriphenylene top
Crystal data top
C20H21BrO2F(000) = 768
Mr = 373.28Dx = 1.455 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3910 reflections
a = 10.7350 (2) Åθ = 2.0–27.5°
b = 13.7043 (3) ŵ = 2.42 mm1
c = 12.0692 (2) ÅT = 120 K
β = 106.343 (1)°Block, colourless
V = 1703.83 (6) Å30.44 × 0.40 × 0.18 mm
Z = 4
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
3910 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode3289 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 2.0°
ϕ and ω scansh = 1313
Absorption correction: multi-scan
(SADABS;(Sheldrick, 2003)
k = 1717
Tmin = 0.378, Tmax = 0.647l = 1515
27068 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.026Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088H-atom parameters constrained
S = 1.18 w = 1/[σ2(Fo2) + (0.0463P)2 + 0.5898P]
where P = (Fo2 + 2Fc2)/3
3910 reflections(Δ/σ)max = 0.001
212 parametersΔρmax = 0.43 e Å3
0 restraintsΔρmin = 0.49 e Å3
Crystal data top
C20H21BrO2V = 1703.83 (6) Å3
Mr = 373.28Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.7350 (2) ŵ = 2.42 mm1
b = 13.7043 (3) ÅT = 120 K
c = 12.0692 (2) Å0.44 × 0.40 × 0.18 mm
β = 106.343 (1)°
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
3910 independent reflections
Absorption correction: multi-scan
(SADABS;(Sheldrick, 2003)
3289 reflections with I > 2σ(I)
Tmin = 0.378, Tmax = 0.647Rint = 0.035
27068 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0260 restraints
wR(F2) = 0.088H-atom parameters constrained
S = 1.18Δρmax = 0.43 e Å3
3910 reflectionsΔρmin = 0.49 e Å3
212 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.64783 (14)0.45972 (10)0.79319 (12)0.0198 (3)
C20.7502 (2)0.39238 (15)0.78461 (17)0.0203 (4)
C210.7205 (2)0.29086 (16)0.82207 (19)0.0265 (5)
C220.8722 (2)0.43516 (19)0.86688 (19)0.0311 (5)
C30.75145 (19)0.39838 (15)0.65806 (17)0.0195 (4)
Br30.89842 (2)0.326417 (16)0.630931 (18)0.02644 (9)
C40.62668 (19)0.36142 (15)0.57523 (17)0.0191 (4)
C4a0.5129 (2)0.40107 (14)0.61074 (16)0.0167 (4)
C4b0.3848 (2)0.38825 (13)0.53866 (16)0.0159 (4)
O50.37728 (14)0.34380 (10)0.43508 (12)0.0201 (3)
C60.2593 (2)0.28945 (15)0.37892 (17)0.0190 (4)
C610.2711 (3)0.18812 (15)0.4329 (2)0.0286 (5)
C620.2602 (2)0.28442 (17)0.25302 (17)0.0246 (5)
C70.1421 (2)0.34131 (15)0.39436 (18)0.0207 (4)
C80.1504 (2)0.40043 (14)0.48396 (17)0.0178 (4)
C8a0.27603 (19)0.42038 (13)0.56644 (16)0.0157 (4)
C8b0.29330 (19)0.47272 (13)0.67280 (16)0.0157 (4)
C90.1878 (2)0.51017 (14)0.70886 (17)0.0195 (4)
C100.2084 (2)0.55897 (15)0.81183 (18)0.0230 (4)
C110.3345 (2)0.57284 (15)0.88449 (18)0.0231 (4)
C120.4388 (2)0.53802 (14)0.85254 (17)0.0201 (4)
C12a0.42136 (19)0.48714 (13)0.74691 (16)0.0162 (4)
C12b0.52830 (19)0.44786 (14)0.71427 (16)0.0167 (4)
H21A0.63610.26910.77290.040*
H21B0.71840.29290.90270.040*
H21C0.78810.24530.81470.040*
H22A0.85780.44580.94260.047*
H22B0.89280.49750.83620.047*
H22C0.94470.38970.87480.047*
H30.76140.46860.63960.023*
H4A0.62140.38280.49570.023*
H4B0.62520.28920.57640.023*
H61A0.27810.19390.51530.043*
H61B0.34880.15570.42330.043*
H61C0.19410.14950.39480.043*
H62A0.33950.25160.24780.037*
H62B0.25730.35070.22180.037*
H62C0.18420.24770.20840.037*
H70.06040.33180.33910.025*
H80.07410.42970.49410.021*
H90.10160.50130.66110.023*
H100.13630.58370.83420.028*
H110.34740.60630.95570.028*
H120.52400.54810.90180.024*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0149 (7)0.0229 (7)0.0190 (7)0.0007 (6)0.0008 (6)0.0050 (6)
C20.0146 (10)0.0242 (10)0.0209 (10)0.0027 (8)0.0031 (8)0.0005 (8)
C210.0323 (13)0.0259 (11)0.0225 (11)0.0057 (10)0.0098 (9)0.0049 (9)
C220.0205 (12)0.0426 (14)0.0252 (11)0.0014 (10)0.0018 (9)0.0071 (10)
C30.0142 (10)0.0220 (10)0.0225 (10)0.0010 (8)0.0057 (8)0.0012 (8)
Br30.01572 (13)0.03517 (15)0.02973 (14)0.00178 (8)0.00852 (9)0.00089 (9)
C40.0159 (10)0.0230 (10)0.0186 (9)0.0017 (8)0.0050 (8)0.0014 (8)
C4a0.0165 (10)0.0164 (9)0.0176 (9)0.0001 (7)0.0053 (8)0.0003 (7)
C4b0.0183 (10)0.0144 (9)0.0146 (9)0.0001 (7)0.0040 (7)0.0009 (7)
O50.0166 (7)0.0273 (7)0.0165 (7)0.0024 (6)0.0047 (6)0.0076 (5)
C60.0189 (10)0.0198 (9)0.0165 (9)0.0024 (8)0.0019 (8)0.0040 (8)
C610.0359 (14)0.0231 (11)0.0278 (11)0.0008 (9)0.0105 (10)0.0007 (9)
C620.0238 (11)0.0305 (12)0.0187 (10)0.0004 (9)0.0045 (8)0.0050 (8)
C70.0162 (10)0.0242 (11)0.0193 (10)0.0012 (8)0.0013 (8)0.0002 (8)
C80.0148 (10)0.0190 (9)0.0197 (9)0.0015 (8)0.0047 (8)0.0023 (7)
C8a0.0169 (10)0.0147 (9)0.0147 (9)0.0012 (7)0.0029 (7)0.0006 (7)
C8b0.0188 (10)0.0127 (9)0.0161 (9)0.0014 (7)0.0054 (7)0.0011 (7)
C90.0203 (10)0.0173 (9)0.0217 (10)0.0028 (8)0.0071 (8)0.0019 (8)
C100.0271 (12)0.0202 (10)0.0239 (10)0.0060 (9)0.0106 (9)0.0006 (8)
C110.0329 (12)0.0191 (10)0.0185 (10)0.0035 (9)0.0093 (9)0.0035 (8)
C120.0238 (11)0.0177 (9)0.0173 (9)0.0007 (8)0.0034 (8)0.0014 (7)
C12a0.0195 (10)0.0127 (9)0.0162 (9)0.0002 (7)0.0050 (7)0.0005 (7)
C12b0.0160 (10)0.0152 (9)0.0169 (9)0.0017 (7)0.0013 (8)0.0013 (7)
Geometric parameters (Å, º) top
O1—C12b1.376 (2)C11—C121.369 (3)
O1—C21.461 (2)C12—C12a1.419 (3)
C2—C221.521 (3)C12a—C12b1.420 (3)
C2—C211.524 (3)C12b—C4a1.372 (3)
C2—C31.533 (3)C8b—C12a1.427 (3)
C21—H21A0.98C4b—O51.372 (2)
C21—H21B0.98O5—C61.461 (2)
C21—H21C0.98C6—C71.501 (3)
C22—H22A0.98C6—C621.524 (3)
C22—H22B0.98C6—C611.524 (3)
C22—H22C0.98C61—H61A0.98
C3—C41.515 (3)C61—H61B0.98
C3—Br31.965 (2)C61—H61C0.98
C3—H31.00C62—H62A0.98
C4—C4a1.505 (3)C62—H62B0.98
C4—H4A0.99C62—H62C0.98
C4—H4B0.99C7—H70.95
C7—C81.334 (3)C8—C8a1.459 (3)
C4a—C4b1.416 (3)C8—H80.95
C4b—C8a1.375 (3)C9—H90.95
C8a—C8b1.436 (3)C10—H100.95
C8b—C91.419 (3)C11—H110.95
C9—C101.373 (3)C12—H120.95
C10—C111.403 (3)
C12b—O1—C2116.74 (15)C62—C6—C61111.21 (17)
O1—C2—C22103.72 (16)C6—C61—H61A109.5
O1—C2—C21109.37 (17)C6—C61—H61B109.5
C22—C2—C21111.81 (18)H61A—C61—H61B109.5
O1—C2—C3104.73 (15)C6—C61—H61C109.5
C22—C2—C3112.47 (18)H61A—C61—H61C109.5
C21—C2—C3113.92 (17)H61B—C61—H61C109.5
C2—C21—H21A109.5C6—C62—H62A109.5
C2—C21—H21B109.5C6—C62—H62B109.5
H21A—C21—H21B109.5H62A—C62—H62B109.5
C2—C21—H21C109.5C6—C62—H62C109.5
H21A—C21—H21C109.5H62A—C62—H62C109.5
H21B—C21—H21C109.5H62B—C62—H62C109.5
C2—C22—H22A109.5C8—C7—C6121.41 (19)
C2—C22—H22B109.5C8—C7—H7119.3
H22A—C22—H22B109.5C6—C7—H7119.3
C2—C22—H22C109.5C7—C8—C8a120.31 (19)
H22A—C22—H22C109.5C7—C8—H8119.8
H22B—C22—H22C109.5C8a—C8—H8119.8
C4—C3—C2112.66 (17)C4b—C8a—C8b118.23 (17)
C4—C3—Br3108.94 (13)C4b—C8a—C8117.33 (17)
C2—C3—Br3111.82 (14)C8b—C8a—C8124.43 (18)
C4—C3—H3107.7C9—C8b—C12a117.97 (17)
C2—C3—H3107.7C9—C8b—C8a122.77 (18)
Br3—C3—H3107.7C12a—C8b—C8a119.25 (18)
C4a—C4—C3109.21 (16)C10—C9—C8b121.0 (2)
C4a—C4—H4A109.8C10—C9—H9119.5
C3—C4—H4A109.8C8b—C9—H9119.5
C4a—C4—H4B109.8C9—C10—C11120.8 (2)
C3—C4—H4B109.8C9—C10—H10119.6
H4A—C4—H4B108.3C11—C10—H10119.6
C12b—C4a—C4b117.69 (18)C12—C11—C10119.90 (19)
C12b—C4a—C4121.90 (18)C12—C11—H11120.0
C4b—C4a—C4120.38 (17)C10—C11—H11120.0
O5—C4b—C8a121.85 (17)C11—C12—C12a120.87 (19)
O5—C4b—C4a114.40 (17)C11—C12—H12119.6
C8a—C4b—C4a123.71 (17)C12a—C12—H12119.6
C4b—O5—C6118.05 (15)C12—C12a—C12b121.55 (18)
O5—C6—C7110.38 (16)C12—C12a—C8b119.43 (18)
O5—C6—C62103.78 (16)C12b—C12a—C8b119.00 (17)
C7—C6—C62112.67 (17)C4a—C12b—O1122.38 (18)
O5—C6—C61108.01 (17)C4a—C12b—C12a122.00 (18)
C7—C6—C61110.50 (18)O1—C12b—C12a115.62 (16)
C12b—O1—C2—C22170.25 (16)C4a—C4b—C8a—C8179.11 (18)
C12b—O1—C2—C2170.3 (2)C7—C8—C8a—C4b9.5 (3)
C12b—O1—C2—C352.1 (2)C7—C8—C8a—C8b171.85 (19)
O1—C2—C3—C464.6 (2)C4b—C8a—C8b—C9179.12 (18)
C22—C2—C3—C4176.56 (17)C8—C8a—C8b—C90.5 (3)
C21—C2—C3—C454.9 (2)C4b—C8a—C8b—C12a1.7 (3)
O1—C2—C3—Br3172.33 (12)C8—C8a—C8b—C12a179.62 (17)
C22—C2—C3—Br360.4 (2)C12a—C8b—C9—C100.1 (3)
C21—C2—C3—Br368.2 (2)C8a—C8b—C9—C10179.32 (18)
C2—C3—C4—C4a44.1 (2)C8b—C9—C10—C110.2 (3)
Br3—C3—C4—C4a168.73 (13)C9—C10—C11—C120.4 (3)
C3—C4—C4a—C12b10.5 (3)C10—C11—C12—C12a0.5 (3)
C3—C4—C4a—C4b171.45 (17)C11—C12—C12a—C12b177.96 (19)
C12b—C4a—C4b—O5177.96 (17)C11—C12—C12a—C8b0.4 (3)
C4—C4a—C4b—O53.9 (3)C9—C8b—C12a—C120.2 (3)
C12b—C4a—C4b—C8a0.3 (3)C8a—C8b—C12a—C12179.42 (17)
C4—C4a—C4b—C8a178.45 (18)C9—C8b—C12a—C12b178.19 (17)
C8a—C4b—O5—C628.9 (3)C8a—C8b—C12a—C12b1.0 (3)
C4a—C4b—O5—C6153.46 (17)C4b—C4a—C12b—O1176.64 (17)
C4b—O5—C6—C738.2 (2)C4—C4a—C12b—O11.4 (3)
C4b—O5—C6—C62159.17 (17)C4b—C4a—C12b—C12a3.3 (3)
C4b—O5—C6—C6182.7 (2)C4—C4a—C12b—C12a178.65 (18)
O5—C6—C7—C826.1 (3)C2—O1—C12b—C4a21.8 (3)
C62—C6—C7—C8141.6 (2)C2—O1—C12b—C12a158.14 (16)
C61—C6—C7—C893.3 (2)C12—C12a—C12b—C4a178.02 (18)
C6—C7—C8—C8a3.4 (3)C8b—C12a—C12b—C4a3.6 (3)
O5—C4b—C8a—C8b175.33 (16)C12—C12a—C12b—O12.1 (3)
C4a—C4b—C8a—C8b2.1 (3)C8b—C12a—C12b—O1176.29 (16)
O5—C4b—C8a—C83.4 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···Cgi0.992.953.765 (2)140
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

(III)(IV)
Crystal data
Chemical formulaC16H16O2C20H21BrO2
Mr240.29373.28
Crystal system, space groupOrthorhombic, PbcaMonoclinic, P21/c
Temperature (K)120120
a, b, c (Å)6.3357 (9), 15.5230 (2), 25.3654 (6)10.7350 (2), 13.7043 (3), 12.0692 (2)
α, β, γ (°)90, 90, 9090, 106.343 (1), 90
V3)2494.7 (4)1703.83 (6)
Z84
Radiation typeMo KαMo Kα
µ (mm1)0.082.42
Crystal size (mm)0.74 × 0.40 × 0.140.44 × 0.40 × 0.18
Data collection
DiffractometerBruker Nonius KappaCCD area-detector
diffractometer
Bruker Nonius KappaCCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Multi-scan
(SADABS;(Sheldrick, 2003)
Tmin, Tmax0.957, 0.9890.378, 0.647
No. of measured, independent and
observed [I > 2σ(I)] reflections
18107, 2848, 2033 27068, 3910, 3289
Rint0.0450.035
(sin θ/λ)max1)0.6490.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.108, 1.05 0.026, 0.088, 1.18
No. of reflections28483910
No. of parameters166212
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.18, 0.220.43, 0.49

Computer programs: COLLECT (Nonius, 1999), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997), OSCAIL and SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97 and PRPKAPPA (Ferguson, 1999).

Selected geometric parameters (Å, º) for (III) top
C3—C41.3282 (16)C8—C8a1.4104 (16)
C4a—C4b1.4339 (16)C8a—C91.4269 (16)
C4b—C51.4174 (16)C9—C101.3692 (16)
C5—C61.3637 (17)C10—C10a1.4075 (15)
C6—C71.4035 (18)C10a—C4a1.3802 (15)
C7—C81.3710 (17)C4b—C8a1.4234 (16)
O9—C9—C8a114.27 (10)O9—C9—C10124.33 (10)
C8a—C9—O9—C91178.09 (10)C10—C9—O9—C910.82 (17)
Selected bond lengths (Å) for (IV) top
C7—C81.334 (3)C10—C111.403 (3)
C4a—C4b1.416 (3)C11—C121.369 (3)
C4b—C8a1.375 (3)C12—C12a1.419 (3)
C8a—C8b1.436 (3)C12a—C12b1.420 (3)
C8b—C91.419 (3)C12b—C4a1.372 (3)
C9—C101.373 (3)C8b—C12a1.427 (3)
Hydrogen-bond geometry (Å, º) for (IV) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···Cgi0.992.953.765 (2)140
Symmetry code: (i) x+1, y+1, z+1.
 

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