Chalcone epoxide inter­mediates in the syntheses of lignin-related phenyl­coumarans

Compounds (2R*,3S*)-1-(3,4-dimethoxy­phen­yl)-3-{3-meth­oxy-2-[(2R*)-tetra­hydro­pyran-2-yl­oxy]phen­yl}-2,3-ep­oxy-1-propanone, C₂₃H₂₆O₇, (I), and trans-1-(3,4-dimethoxy­phen­yl)-3-[3-meth­oxy-2-(methoxy­methoxy)­phen­yl]-2,3-ep­oxy-1-propanone, C₂₀H₂₂O₇, (II), were obtained on epoxidation of chalcones. The stereochemistries of (I) and (II) were elucidated. In both compounds, the substituents on the oxirane ring are trans-oriented. Compound (I) was obtained together with a diastereometric form that differs from (I) with respect to the configuration of the asymmetric C atom in the tetra­hydro­pyran group. The geometries of the substituted oxirane rings of (I) and (II) are very similar. The hydrogen-bonding patterns, mediated via weak C-H...O inter­actions, differ considerably. The crystal structures of (I) and (II) are compared with those of related chalcone epoxides. The conversion of (I) and (II) into lignin-related phenyl­coumarans is discussed.

S1. Comment

Compounds (I) and (II) are obtained on epoxidation of chalcones (Li & Lundquist, 1997). Compound (I) (m.p. 401 K) and a diastereomer (m.p. 370–371 K) are obtained on epoxidation of the chalcone 1-(3,4-dimethoxyphenyl)-3-[3-methoxy-2-(tetrahydropyran-2-yloxy)phenyl] −2-propen-1-one. The epoxidation is accomplished with hydrogen peroxide using a method involving phase-transfer catalysis (Brunow & Lundquist, 1981, 1984). The epoxides can be converted to a lignin model of the phenylcoumaran type (III) in three reaction steps: BF₃-catalysed rearrangement, sodium borohydride reduction and acid-catalysed ring closure. The yield of (III) obtained from (II) was low (Li & Lundquist, 1997). Studies of the reactions involved have shown that the outcome of the rearrangement reaction is strongly dependent on the structure of the epoxide and the conditions prevailing during the reaction (Ralph et al., 1987; Li et al., 1993). It should be noted that reduction of the rearrangement product with sodium borohydride under alkaline conditions lowers the yield substantially (Li et al., 1993). The synthesis of the cis isomer corresponding to (III) using (I) as starting material has been described (Li et al., 1997). The lignin model (IV) has also been prepared via a chalcone epoxide (Brunow & Lundquist, 1984); the stereochemistry of (IV) has been established by a crystal structure determination (Stomberg & Lundquist, 1987). Compound (IV) has been used as starting material in the synthesis of neolignans of the phenylcoumaran type (Juhász et al., 2000, 2001). It is notable that a chalcone epoxide of the topical type is an intermediate in a synthesis of the flavonolignan silychristin (Tanaka et al., 1989).

Perspective drawings and the atom-numbering of (I) and (II) are shown in Figs. 1 and 2, respectively. Selected bond distances and bond angles for both compounds are given in Table 1. The crystal structures establish the stereochemistries of (I) and (II) and confirm their molecular structures. Comparison of the ¹H NMR spectra (Li & Lundquist, 1997) of (I) and its diastereomer of m.p. 370–371 K suggests that the diastereomers differ with respect to the configuration of the asymmetric carbon in the tetrahydropyranyl group. The substituents at the oxirane rings of (I) and (II) are trans-orientated. Chalcone epoxides described in the literature in general have the trans configuration but chalcone epoxides with the cis configuration are known (Wasserman & Aubrey, 1955; Matano, 1994).

Excepting the C10—C11 and O4—C11 bond lengths and bond angles involving the atoms of the oxirane rings (the C9—C10—C11 angles differ by 2.1º), the bond lengths and bond angles in the central parts of (I) and (II) are, within experimental error, the same (Table 1). The C1—C9—C10—C11 and C9—C10—C11—C12 torsion angles (denoted τ₂ and τ₃ in Table 2) differ just slightly, by 0.8 and 0.6º, respectively.

Comparison with the crystal structures of related chalcone epoxides was performed after a search of the Cambridge Structural Database (CSD; Version 5.27 of November 2005, plus two updates; Allen, 2002). The substituents at the oxirane ring are trans-orientated in the chalcone epoxides subjected to crystal structure determinations to date. Some pertinent structural data are tabulated in Table 2. It is apparent that torsion angle τ₃ is less flexible than torsion angle τ₂. The angles between the planes of the aromatic rings differ considerably.

There are weak C—H···O hydrogen bonds present in the crystal structures of both (I) and (II). (For geometrical details and notations of these hydrogen bonds see Tables 3 and 4.) The hydrogen-bonding patterns of (I) and (II) are quite different. For (I), on the first-level graph set, defined by Bernstein et al. (1995) and Grell et al. (1999), the following chains are formed: C(4) by hydrogen bond a, C(5) by f, C(6) by b, C(8) by d, and C(10) by c and e. On the second-level graph set, rings R²₂(10) (a, b), R²₂(27) (a, f) and R²₂(29) (b, f) and chains C²₁(8) (d, e), C²₂(8) (a, b), C²₂(10) (a, c; b, c), C²₂(14) (a, c), C²₂(15) (c, d), C²₂(16) (b, c), C²₂(17) (c, e), C²₂(18) (a, d; c, d; d, e), C²₂(19) (d, f; e, f), C²₂(20) (a, e; b, d; c, e), C²₂(22) (b, e), C²₂(24) (c, f) and C²₂(29) (b, f) were recognized. For (II), the hydrogen bonds can be descibed just on the first-level graph-set level, viz. chain C(8) for a, and intramolecular strings S(5) for b and S(6) for c. The assignments of graph-set descriptors were performed using PLUTO as described by Motherwell et al. (1999). All the examined chalcone epoxides (Table 2) have different hydrogen-bonding patterns.

S2. Experimental

The syntheses of compounds (I) and (II) are described by Li & Lundquist (1997). Crystals of (I) (m.p. 401 K) and (II) (m.p. 381–382 K) were obtained from ethanol.

S3. Refinement

H atoms were refined isotropically and were constrained to the ideal geometry using an appropriate riding model. For methyl groups, the C—H distances (0.98 Å) and C–C–H angles (109.5°) were kept fixed, while the torsion angles were allowed to refine with the starting position based on the threefold averaged circular Fourier synthesis. For other H atoms, C—H = 0.95–1.00 Å. For (I), U_iso(H) values were fixed at 1.2 or 1.5 times U_eq(C). Please check added text.

Computing details

For both compounds, data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT and SADABS (Sheldrick, 2003); program(s) used to solve structure: SHELXTL (Bruker, 2003); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. A perspective drawing of (I), showing the atom numbering. The atomic displacement ellipsoids are shown at the 50% probability level.
	Fig. 2. A perspective drawing of (II), showing the atom numbering. The atomic displacement ellipsoids are shown at the 50% probability level.

(I) (2R*,3S*)-1-(3,4-dimethoxyphenyl)-3-{3-methoxy-2-[(2R*)-tetrahydropyran- 2-yloxy]phenyl}-2,3-epoxy-1-propanone

Crystal data

C23H26O7	F(000) = 880
Mr = 414.44	Dx = 1.365 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 7078 reflections
a = 14.4281 (5) Å	θ = 2.5–32.1°
b = 18.8386 (7) Å	µ = 0.10 mm^−1
c = 9.0887 (3) Å	T = 173 K
β = 125.285 (1)°	Prism, colourless
V = 2016.52 (12) Å^3	0.42 × 0.22 × 0.18 mm
Z = 4

Data collection

Siemens SMART CCD area-detector diffractometer	3639 independent reflections
Radiation source: fine-focus sealed tube	3193 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω scans	θmax = 33.2°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −21→21
Tmin = 0.608, Tmax = 0.982	k = −28→28
18037 measured reflections	l = −13→13

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.099	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.072P)^2 + 0.020P] where P = (Fo^2 + 2Fc^2)/3
3639 reflections	(Δ/σ)max < 0.001
274 parameters	Δρmax = 0.32 e Å^−3
2 restraints	Δρmin = −0.18 e Å^−3

Special details

Experimental. Data were collected at low temperature using a Siemens SMART CCD diffractometer equiped with a LT-2 device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal–to–detector distance of 3.97 cm, 30 s per frame. Preliminary orientation matrix was obtained from the first 100 frames using SMART (Bruker, 2003a). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement on the position of 7078 reflections with I>10σ(I) after integration of all the frames data using SAINT (Bruker, 2003b).

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.

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

	x	y	z	Uiso*/Ueq
O1	0.05273 (12)	0.98417 (7)	0.28979 (18)	0.0336 (3)
O2	0.18225 (12)	0.91853 (7)	0.59272 (16)	0.0340 (3)
O3	0.35467 (12)	0.71243 (6)	0.46411 (18)	0.0336 (3)
O4	0.39322 (12)	0.67530 (6)	0.21211 (19)	0.0327 (3)
O5	0.72969 (10)	0.88301 (7)	0.24914 (16)	0.0293 (2)
O6	0.62968 (10)	0.83612 (6)	0.42010 (14)	0.0239 (2)
O7	0.56041 (10)	0.95177 (6)	0.31418 (15)	0.0276 (2)
C1	0.24632 (12)	0.81536 (8)	0.3156 (2)	0.0227 (3)
C2	0.18137 (13)	0.85382 (8)	0.1563 (2)	0.0252 (3)
H2	0.1821	0.8411	0.0558	0.030*
C3	0.11515 (14)	0.91087 (9)	0.1425 (2)	0.0277 (3)
H3	0.0700	0.9363	0.0324	0.033*
C4	0.11537 (13)	0.93045 (8)	0.2897 (2)	0.0257 (3)
C5	0.18502 (13)	0.89333 (8)	0.4551 (2)	0.0250 (3)
C6	0.24838 (13)	0.83617 (8)	0.4662 (2)	0.0241 (3)
H6	0.2937	0.8107	0.5761	0.029*
C7	−0.02777 (16)	1.01764 (10)	0.1194 (3)	0.0355 (4)
H7A	0.0126	1.0397	0.0738	0.053*
H7B	−0.0698	1.0541	0.1351	0.053*
H7C	−0.0809	0.9820	0.0330	0.053*
C8	0.24673 (18)	0.88047 (11)	0.7592 (2)	0.0375 (4)
H8A	0.2203	0.8312	0.7392	0.056*
H8B	0.2369	0.9028	0.8467	0.056*
H8C	0.3272	0.8814	0.8058	0.056*
C9	0.31515 (14)	0.75263 (8)	0.3367 (2)	0.0246 (3)
C10	0.34295 (13)	0.74188 (8)	0.2022 (2)	0.0247 (3)
H10	0.2917	0.7643	0.0808	0.030*
C11	0.46590 (13)	0.73650 (8)	0.2785 (2)	0.0243 (3)
H11	0.5192	0.7405	0.4126	0.029*
C12	0.51144 (13)	0.76015 (8)	0.1763 (2)	0.0235 (3)
C13	0.47217 (14)	0.73067 (9)	0.0081 (2)	0.0285 (3)
H13	0.4147	0.6953	−0.0436	0.034*
C14	0.51799 (15)	0.75361 (10)	−0.0817 (2)	0.0308 (3)
H14	0.4911	0.7343	−0.1965	0.037*
C15	0.60361 (14)	0.80494 (9)	−0.0048 (2)	0.0291 (3)
H15	0.6348	0.8199	−0.0674	0.035*
C16	0.64375 (13)	0.83445 (8)	0.1628 (2)	0.0249 (3)
C17	0.59533 (12)	0.81245 (8)	0.25264 (19)	0.0223 (3)
C18	0.77905 (17)	0.90537 (10)	0.1583 (3)	0.0332 (3)
H18A	0.8079	0.8639	0.1315	0.050*
H18B	0.8417	0.9382	0.2356	0.050*
H18C	0.7214	0.9293	0.0456	0.050*
C19	0.64536 (13)	0.91141 (8)	0.4610 (2)	0.0242 (3)
H19	0.7209	0.9260	0.4901	0.029*
C20	0.64751 (13)	0.91913 (8)	0.62880 (19)	0.0254 (3)
H20A	0.7009	0.8840	0.7198	0.030*
H20B	0.6754	0.9671	0.6803	0.030*
C21	0.53056 (15)	0.90814 (8)	0.5887 (2)	0.0265 (3)
H21A	0.5328	0.9190	0.6974	0.032*
H21B	0.5068	0.8581	0.5548	0.032*
C22	0.44625 (14)	0.95694 (9)	0.4349 (2)	0.0272 (3)
H22A	0.3689	0.9484	0.4028	0.033*
H22B	0.4664	1.0071	0.4728	0.033*
C23	0.44844 (14)	0.94287 (9)	0.2723 (2)	0.0269 (3)
H23A	0.4220	0.8938	0.2291	0.032*
H23B	0.3954	0.9758	0.1740	0.032*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0385 (6)	0.0346 (6)	0.0312 (6)	0.0122 (5)	0.0221 (5)	0.0050 (5)
O2	0.0454 (7)	0.0376 (6)	0.0264 (6)	0.0100 (5)	0.0250 (5)	0.0029 (5)
O3	0.0435 (7)	0.0277 (5)	0.0370 (6)	0.0059 (5)	0.0276 (6)	0.0062 (5)
O4	0.0409 (7)	0.0207 (5)	0.0454 (7)	−0.0031 (4)	0.0300 (6)	−0.0069 (5)
O5	0.0326 (6)	0.0352 (6)	0.0282 (5)	−0.0041 (5)	0.0222 (5)	−0.0029 (4)
O6	0.0293 (5)	0.0250 (5)	0.0199 (4)	0.0009 (4)	0.0157 (4)	−0.0010 (4)
O7	0.0343 (6)	0.0271 (5)	0.0266 (5)	0.0032 (4)	0.0207 (5)	0.0053 (4)
C1	0.0241 (6)	0.0226 (6)	0.0248 (6)	−0.0020 (5)	0.0162 (5)	−0.0015 (5)
C2	0.0271 (7)	0.0281 (7)	0.0226 (6)	−0.0009 (5)	0.0156 (5)	−0.0020 (5)
C3	0.0294 (7)	0.0302 (7)	0.0237 (7)	0.0043 (6)	0.0154 (6)	0.0028 (5)
C4	0.0260 (7)	0.0260 (7)	0.0268 (7)	0.0023 (5)	0.0162 (6)	0.0018 (5)
C5	0.0276 (7)	0.0280 (7)	0.0229 (6)	0.0001 (5)	0.0167 (6)	0.0000 (5)
C6	0.0258 (6)	0.0255 (6)	0.0223 (6)	−0.0004 (5)	0.0146 (5)	0.0011 (5)
C7	0.0332 (8)	0.0374 (8)	0.0388 (9)	0.0122 (7)	0.0224 (7)	0.0118 (7)
C8	0.0478 (10)	0.0424 (9)	0.0253 (7)	0.0047 (8)	0.0228 (7)	0.0012 (7)
C9	0.0267 (7)	0.0226 (6)	0.0274 (7)	−0.0029 (5)	0.0172 (6)	−0.0030 (5)
C10	0.0265 (7)	0.0227 (6)	0.0271 (7)	−0.0013 (5)	0.0167 (6)	−0.0040 (5)
C11	0.0262 (7)	0.0223 (6)	0.0268 (7)	0.0012 (5)	0.0166 (6)	−0.0011 (5)
C12	0.0232 (6)	0.0256 (6)	0.0221 (6)	0.0031 (5)	0.0133 (5)	−0.0008 (5)
C13	0.0275 (7)	0.0316 (7)	0.0248 (7)	0.0004 (6)	0.0142 (6)	−0.0055 (6)
C14	0.0329 (8)	0.0374 (8)	0.0219 (7)	0.0054 (6)	0.0158 (6)	−0.0032 (6)
C15	0.0334 (8)	0.0354 (8)	0.0234 (7)	0.0049 (6)	0.0191 (6)	0.0005 (6)
C16	0.0257 (7)	0.0289 (7)	0.0233 (6)	0.0044 (5)	0.0160 (6)	0.0008 (5)
C17	0.0231 (6)	0.0261 (6)	0.0199 (6)	0.0034 (5)	0.0136 (5)	−0.0005 (5)
C18	0.0386 (9)	0.0379 (8)	0.0354 (8)	−0.0035 (7)	0.0284 (7)	−0.0017 (7)
C19	0.0265 (7)	0.0253 (6)	0.0228 (6)	−0.0013 (5)	0.0154 (6)	−0.0024 (5)
C20	0.0289 (7)	0.0273 (7)	0.0190 (6)	0.0003 (5)	0.0133 (6)	−0.0018 (5)
C21	0.0355 (8)	0.0260 (7)	0.0251 (6)	0.0001 (5)	0.0217 (6)	0.0004 (5)
C22	0.0313 (8)	0.0279 (7)	0.0274 (7)	0.0019 (5)	0.0199 (6)	−0.0009 (5)
C23	0.0289 (7)	0.0295 (7)	0.0231 (6)	0.0041 (5)	0.0156 (6)	0.0022 (5)

Geometric parameters (Å, º)

C1—C9	1.483 (2)	C8—H8B	0.9800
O3—C9	1.215 (2)	C8—H8C	0.9800
C9—C10	1.504 (2)	C10—H10	1.0000
C10—C11	1.489 (2)	C11—H11	1.0000
O4—C10	1.4256 (19)	C12—C17	1.395 (2)
O4—C11	1.4359 (19)	C12—C13	1.401 (2)
C11—C12	1.483 (2)	C13—C14	1.384 (3)
O1—C4	1.3574 (19)	C13—H13	0.9500
O1—C7	1.438 (2)	C14—C15	1.397 (3)
O2—C5	1.3598 (18)	C14—H14	0.9500
O2—C8	1.429 (2)	C15—C16	1.395 (2)
O5—C16	1.366 (2)	C15—H15	0.9500
O5—C18	1.430 (2)	C16—C17	1.409 (2)
O6—C17	1.3746 (17)	C18—H18A	0.9800
O6—C19	1.4505 (18)	C18—H18B	0.9800
O7—C19	1.4042 (19)	C18—H18C	0.9800
O7—C23	1.440 (2)	C19—C20	1.514 (2)
C1—C2	1.390 (2)	C19—H19	1.0000
C1—C6	1.407 (2)	C20—C21	1.521 (2)
C2—C3	1.395 (2)	C20—H20A	0.9900
C2—H2	0.9500	C20—H20B	0.9900
C3—C4	1.386 (2)	C21—C22	1.522 (2)
C3—H3	0.9500	C21—H21A	0.9900
C4—C5	1.419 (2)	C21—H21B	0.9900
C5—C6	1.378 (2)	C22—C23	1.519 (2)
C6—H6	0.9500	C22—H22A	0.9900
C7—H7A	0.9800	C22—H22B	0.9900
C7—H7B	0.9800	C23—H23A	0.9900
C7—H7C	0.9800	C23—H23B	0.9900
C8—H8A	0.9800
C1—C9—C10	118.37 (13)	C13—C12—C11	121.18 (14)
O3—C9—C1	122.03 (14)	C14—C13—C12	119.32 (16)
O3—C9—C10	119.47 (14)	C14—C13—H13	120.3
O4—C10—C9	115.59 (13)	C12—C13—H13	120.3
O4—C10—C11	58.99 (10)	C13—C14—C15	120.44 (15)
O4—C11—C10	58.31 (10)	C13—C14—H14	119.8
O4—C11—C12	117.26 (13)	C15—C14—H14	119.8
C10—C11—C12	121.84 (14)	C14—C15—C16	120.77 (15)
C4—O1—C7	116.74 (14)	C14—C15—H15	119.6
C5—O2—C8	116.84 (13)	C16—C15—H15	119.6
C10—O4—C11	62.71 (10)	O5—C16—C15	124.13 (15)
C16—O5—C18	117.05 (13)	O5—C16—C17	116.94 (13)
C17—O6—C19	120.29 (12)	C15—C16—C17	118.91 (14)
C19—O7—C23	114.72 (12)	O6—C17—C12	115.74 (13)
C2—C1—C6	119.37 (14)	O6—C17—C16	124.33 (14)
C2—C1—C9	123.25 (13)	C12—C17—C16	119.82 (13)
C6—C1—C9	117.38 (13)	O5—C18—H18A	109.5
C1—C2—C3	120.67 (14)	O5—C18—H18B	109.5
C1—C2—H2	119.7	H18A—C18—H18B	109.5
C3—C2—H2	119.7	O5—C18—H18C	109.5
C4—C3—C2	119.92 (14)	H18A—C18—H18C	109.5
C4—C3—H3	120.0	H18B—C18—H18C	109.5
C2—C3—H3	120.0	O7—C19—O6	111.38 (12)
O1—C4—C3	124.68 (14)	O7—C19—C20	113.84 (13)
O1—C4—C5	115.52 (13)	O6—C19—C20	105.17 (12)
C3—C4—C5	119.80 (14)	O7—C19—H19	108.8
O2—C5—C6	125.19 (14)	O6—C19—H19	108.8
O2—C5—C4	115.06 (13)	C20—C19—H19	108.8
C6—C5—C4	119.75 (13)	C21—C20—C19	111.80 (12)
C5—C6—C1	120.41 (14)	C21—C20—H20A	109.3
C5—C6—H6	119.8	C19—C20—H20A	109.3
C1—C6—H6	119.8	C21—C20—H20B	109.3
O1—C7—H7A	109.5	C19—C20—H20B	109.3
O1—C7—H7B	109.5	H20A—C20—H20B	107.9
H7A—C7—H7B	109.5	C20—C21—C22	108.97 (12)
O1—C7—H7C	109.5	C20—C21—H21A	109.9
H7A—C7—H7C	109.5	C22—C21—H21A	109.9
H7B—C7—H7C	109.5	C20—C21—H21B	109.9
O2—C8—H8A	109.5	C22—C21—H21B	109.9
O2—C8—H8B	109.5	H21A—C21—H21B	108.3
H8A—C8—H8B	109.5	C23—C22—C21	109.50 (13)
O2—C8—H8C	109.5	C23—C22—H22A	109.8
H8A—C8—H8C	109.5	C21—C22—H22A	109.8
H8B—C8—H8C	109.5	C23—C22—H22B	109.8
C11—C10—C9	115.84 (14)	C21—C22—H22B	109.8
O4—C10—H10	117.8	H22A—C22—H22B	108.2
C11—C10—H10	117.8	O7—C23—C22	111.92 (13)
C9—C10—H10	117.8	O7—C23—H23A	109.2
O4—C11—H11	115.7	C22—C23—H23A	109.2
C10—C11—H11	115.7	O7—C23—H23B	109.2
C12—C11—H11	115.7	C22—C23—H23B	109.2
C17—C12—C13	120.69 (14)	H23A—C23—H23B	107.9
C17—C12—C11	118.13 (13)
C6—C1—C2—C3	−2.5 (2)	C10—C11—C12—C17	121.61 (16)
C9—C1—C2—C3	177.72 (15)	O4—C11—C12—C13	9.1 (2)
C1—C2—C3—C4	1.2 (2)	C10—C11—C12—C13	−58.8 (2)
C7—O1—C4—C3	6.8 (2)	C17—C12—C13—C14	0.4 (2)
C7—O1—C4—C5	−173.40 (15)	C11—C12—C13—C14	−179.17 (15)
C2—C3—C4—O1	−178.78 (16)	C12—C13—C14—C15	0.9 (3)
C2—C3—C4—C5	1.4 (2)	C13—C14—C15—C16	−0.6 (3)
C8—O2—C5—C6	−2.8 (2)	C18—O5—C16—C15	1.3 (2)
C8—O2—C5—C4	176.94 (15)	C18—O5—C16—C17	179.94 (14)
O1—C4—C5—O2	−2.3 (2)	C14—C15—C16—O5	177.70 (15)
C3—C4—C5—O2	177.56 (16)	C14—C15—C16—C17	−0.9 (2)
O1—C4—C5—C6	177.49 (15)	C19—O6—C17—C12	−136.15 (14)
C3—C4—C5—C6	−2.7 (2)	C19—O6—C17—C16	47.8 (2)
O2—C5—C6—C1	−178.91 (15)	C13—C12—C17—O6	−178.22 (14)
C4—C5—C6—C1	1.4 (2)	C11—C12—C17—O6	1.37 (19)
C2—C1—C6—C5	1.2 (2)	C13—C12—C17—C16	−1.9 (2)
C9—C1—C6—C5	−179.00 (14)	C11—C12—C17—C16	177.65 (13)
C2—C1—C9—O3	−166.56 (16)	O5—C16—C17—O6	−0.6 (2)
C6—C1—C9—O3	13.6 (2)	C15—C16—C17—O6	178.13 (14)
C2—C1—C9—C10	17.7 (2)	O5—C16—C17—C12	−176.55 (13)
C6—C1—C9—C10	−162.10 (13)	C15—C16—C17—C12	2.2 (2)
C11—O4—C10—C9	−106.02 (15)	C23—O7—C19—O6	67.84 (16)
O3—C9—C10—O4	13.8 (2)	C23—O7—C19—C20	−50.85 (17)
C1—C9—C10—O4	−170.34 (13)	C17—O6—C19—O7	39.66 (18)
O3—C9—C10—C11	−52.4 (2)	C17—O6—C19—C20	163.43 (12)
C1—C9—C10—C11	123.41 (15)	O7—C19—C20—C21	50.31 (18)
C10—O4—C11—C12	−112.29 (15)	O6—C19—C20—C21	−71.88 (15)
C9—C10—C11—O4	105.60 (15)	C19—C20—C21—C22	−52.97 (17)
O4—C10—C11—C12	104.49 (16)	C20—C21—C22—C23	56.24 (17)
C9—C10—C11—C12	−149.91 (13)	C19—O7—C23—C22	54.54 (17)
O4—C11—C12—C17	−170.46 (13)	C21—C22—C23—O7	−57.01 (17)

(II) trans-1-(3,4-dimethoxyphenyl)-3-(3-methoxy-2-methoxymethoxyphenyl)-2,3- epoxy-1-propanone

Crystal data

C20H22O7	F(000) = 792
Mr = 374.38	Dx = 1.345 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3556 reflections
a = 12.7503 (10) Å	θ = 2.5–22.7°
b = 9.4201 (7) Å	µ = 0.10 mm^−1
c = 15.4409 (12) Å	T = 173 K
β = 94.706 (2)°	Needle with an arrow-head end, colorless
V = 1848.3 (2) Å^3	0.65 × 0.14 × 0.06 mm
Z = 4

Data collection

Siemens SMART CCD area-detector diffractometer	3280 independent reflections
Radiation source: fine-focus sealed tube	2257 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.057
ω scans	θmax = 25.1°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −15→15
Tmin = 0.805, Tmax = 0.994	k = −11→11
19850 measured reflections	l = −18→18

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.113	Only H-atom coordinates refined
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0524P)^2 + 0.460P] where P = (Fo^2 + 2Fc^2)/3
3280 reflections	(Δ/σ)max < 0.001
270 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.14 e Å^−3

Special details

Experimental. Data were collected at low temperature using a Siemens SMART CCD diffractometer equiped with a LT-2 device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal–to–detector distance of 3.97 cm, 30 s per frame. Preliminary orientation matrix was obtained from the first 100 frames using SMART (Bruker, 2003a). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement on the position of 3556 reflections with I>10σ(I) after integration of all the frames data using SAINT (Bruker, 2003b).

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.

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

	x	y	z	Uiso*/Ueq
O1	0.86916 (13)	0.22744 (16)	0.37251 (9)	0.0521 (4)
O2	0.97263 (12)	0.16958 (15)	0.51711 (9)	0.0473 (4)
O3	0.90694 (14)	0.58207 (17)	0.71809 (10)	0.0646 (5)
O4	0.86665 (13)	0.86795 (16)	0.70153 (11)	0.0588 (5)
O5	0.54610 (11)	0.81483 (15)	0.70368 (9)	0.0453 (4)
O6	0.52449 (15)	0.64410 (17)	0.59345 (10)	0.0656 (5)
O7	0.40794 (13)	1.01620 (17)	0.64405 (10)	0.0577 (5)
C1	0.87274 (16)	0.5238 (2)	0.57035 (13)	0.0377 (5)
C2	0.92472 (15)	0.3935 (2)	0.58090 (13)	0.0376 (5)
H2	0.9622	0.3713	0.6349	0.038 (5)*
C3	0.92223 (16)	0.2974 (2)	0.51417 (13)	0.0384 (5)
C4	0.86580 (16)	0.3292 (2)	0.43418 (13)	0.0401 (5)
C5	0.81294 (17)	0.4567 (2)	0.42385 (14)	0.0441 (5)
H5	0.7739	0.4780	0.3704	0.055 (6)*
C6	0.81693 (17)	0.5540 (2)	0.49191 (13)	0.0435 (5)
H6	0.7810	0.6421	0.4844	0.042 (6)*
C7	1.02743 (18)	0.1310 (2)	0.59851 (14)	0.0468 (6)
H7A	1.0810	0.2027	0.6151	0.050 (6)*
H7B	1.0613	0.0385	0.5928	0.043 (6)*
H7C	0.9774	0.1254	0.6433	0.051 (6)*
C8	0.8243 (2)	0.2591 (3)	0.28698 (14)	0.0561 (7)
H8A	0.7481	0.2717	0.2880	0.071 (8)*
H8B	0.8384	0.1808	0.2478	0.081 (8)*
H8C	0.8556	0.3467	0.2664	0.060 (7)*
C9	0.87822 (17)	0.6218 (2)	0.64538 (14)	0.0446 (5)
C10	0.84505 (17)	0.7733 (2)	0.63022 (15)	0.0460 (6)
H10	0.8505	0.8126	0.5706	0.046 (6)*
C11	0.76023 (16)	0.8292 (2)	0.67980 (13)	0.0414 (5)
H11	0.7303	0.7601	0.7203	0.053 (6)*
C12	0.68639 (17)	0.9407 (2)	0.64478 (12)	0.0383 (5)
C13	0.72199 (19)	1.0577 (2)	0.59966 (13)	0.0460 (6)
H13	0.7947	1.0671	0.5915	0.042 (6)*
C14	0.6521 (2)	1.1588 (2)	0.56717 (14)	0.0514 (6)
H14	0.6769	1.2372	0.5360	0.064 (7)*
C15	0.5461 (2)	1.1483 (2)	0.57917 (13)	0.0490 (6)
H15	0.4984	1.2186	0.5559	0.060 (7)*
C16	0.50976 (18)	1.0346 (2)	0.62536 (13)	0.0432 (5)
C17	0.58059 (17)	0.9289 (2)	0.65674 (12)	0.0380 (5)
C18	0.3332 (2)	1.1197 (3)	0.61232 (17)	0.0675 (8)
H18A	0.3530	1.2126	0.6372	0.072 (8)*
H18B	0.2633	1.0933	0.6291	0.092 (10)*
H18C	0.3318	1.1245	0.5488	0.074 (8)*
C19	0.4761 (2)	0.7200 (2)	0.65499 (15)	0.0534 (6)
H19A	0.4459	0.6528	0.6955	0.048 (6)*
H19B	0.4174	0.7754	0.6258	0.056 (7)*
C20	0.5818 (3)	0.5253 (3)	0.6265 (2)	0.0781 (9)
H20A	0.6380	0.5568	0.6693	0.119 (13)*
H20B	0.6128	0.4760	0.5788	0.098 (10)*
H20C	0.5346	0.4606	0.6543	0.095 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0728 (11)	0.0500 (9)	0.0337 (8)	0.0179 (8)	0.0056 (7)	0.0004 (7)
O2	0.0596 (10)	0.0448 (9)	0.0379 (8)	0.0217 (8)	0.0071 (7)	0.0040 (7)
O3	0.0931 (14)	0.0559 (10)	0.0424 (10)	0.0222 (9)	−0.0100 (9)	−0.0048 (8)
O4	0.0560 (11)	0.0495 (10)	0.0685 (11)	0.0028 (8)	−0.0093 (8)	−0.0140 (8)
O5	0.0534 (9)	0.0447 (9)	0.0383 (8)	0.0062 (8)	0.0078 (7)	0.0065 (7)
O6	0.1076 (15)	0.0419 (10)	0.0487 (10)	−0.0061 (10)	0.0158 (10)	0.0015 (8)
O7	0.0522 (10)	0.0650 (11)	0.0560 (10)	0.0233 (9)	0.0054 (8)	0.0003 (8)
C1	0.0363 (12)	0.0374 (12)	0.0400 (12)	0.0053 (10)	0.0060 (9)	0.0021 (9)
C2	0.0362 (12)	0.0417 (12)	0.0352 (11)	0.0080 (10)	0.0051 (9)	0.0060 (10)
C3	0.0417 (13)	0.0389 (12)	0.0360 (11)	0.0110 (10)	0.0105 (9)	0.0064 (10)
C4	0.0466 (13)	0.0414 (12)	0.0334 (11)	0.0079 (10)	0.0106 (10)	0.0033 (10)
C5	0.0478 (14)	0.0476 (13)	0.0367 (12)	0.0078 (11)	0.0014 (10)	0.0068 (10)
C6	0.0457 (13)	0.0390 (12)	0.0457 (13)	0.0133 (10)	0.0025 (10)	0.0037 (10)
C7	0.0498 (14)	0.0454 (14)	0.0448 (13)	0.0141 (12)	0.0023 (11)	0.0088 (11)
C8	0.0687 (18)	0.0666 (17)	0.0327 (12)	0.0125 (14)	0.0033 (11)	−0.0018 (12)
C9	0.0431 (13)	0.0448 (13)	0.0457 (14)	0.0075 (10)	0.0033 (10)	−0.0010 (11)
C10	0.0492 (14)	0.0452 (13)	0.0439 (13)	0.0023 (11)	0.0043 (10)	−0.0026 (11)
C11	0.0451 (13)	0.0409 (12)	0.0377 (12)	0.0026 (10)	0.0001 (10)	−0.0047 (10)
C12	0.0553 (14)	0.0302 (11)	0.0289 (11)	0.0053 (10)	0.0006 (10)	−0.0043 (9)
C13	0.0534 (15)	0.0390 (13)	0.0455 (13)	−0.0027 (11)	0.0027 (11)	−0.0070 (10)
C14	0.0741 (18)	0.0327 (12)	0.0466 (14)	0.0007 (12)	−0.0002 (12)	0.0026 (11)
C15	0.0733 (18)	0.0324 (12)	0.0395 (13)	0.0135 (12)	−0.0070 (12)	−0.0039 (10)
C16	0.0535 (15)	0.0395 (13)	0.0357 (12)	0.0124 (11)	−0.0014 (10)	−0.0083 (10)
C17	0.0496 (14)	0.0354 (12)	0.0291 (11)	0.0053 (10)	0.0040 (9)	−0.0028 (9)
C18	0.0658 (19)	0.0740 (19)	0.0603 (17)	0.0344 (15)	−0.0103 (14)	−0.0140 (14)
C19	0.0591 (16)	0.0463 (14)	0.0549 (14)	−0.0031 (13)	0.0053 (12)	0.0098 (12)
C20	0.112 (3)	0.0407 (15)	0.085 (2)	−0.0029 (16)	0.034 (2)	−0.0058 (15)

Geometric parameters (Å, º)

C1—C9	1.478 (3)	C7—H7A	0.9800
O3—C9	1.211 (2)	C7—H7B	0.9800
C9—C10	1.502 (3)	C7—H7C	0.9800
O4—C10	1.426 (3)	C8—H8A	0.9800
O4—C11	1.418 (3)	C8—H8B	0.9800
C10—C11	1.473 (3)	C8—H8C	0.9800
C11—C12	1.483 (3)	C10—H10	1.0000
O1—C4	1.354 (2)	C11—H11	1.0000
O1—C8	1.427 (2)	C12—C17	1.381 (3)
O2—C3	1.363 (2)	C12—C13	1.400 (3)
O2—C7	1.434 (2)	C13—C14	1.371 (3)
O5—C17	1.388 (2)	C13—H13	0.9500
O5—C19	1.432 (3)	C14—C15	1.383 (3)
O6—C19	1.375 (3)	C14—H14	0.9500
O6—C20	1.409 (3)	C15—C16	1.387 (3)
O7—C16	1.364 (3)	C15—H15	0.9500
O7—C18	1.422 (3)	C16—C17	1.404 (3)
C1—C6	1.383 (3)	C18—H18A	0.9800
C1—C2	1.398 (3)	C18—H18B	0.9800
C2—C3	1.370 (3)	C18—H18C	0.9800
C2—H2	0.9500	C19—H19A	0.9900
C3—C4	1.410 (3)	C19—H19B	0.9900
C4—C5	1.380 (3)	C20—H20A	0.9800
C5—C6	1.393 (3)	C20—H20B	0.9800
C5—H5	0.9500	C20—H20C	0.9800
C6—H6	0.9500
C1—C9—C10	118.46 (19)	O4—C10—H10	117.1
O3—C9—C1	121.7 (2)	C11—C10—H10	117.1
O3—C9—C10	119.9 (2)	C9—C10—H10	117.1
O4—C10—C9	116.10 (18)	O4—C11—C10	59.07 (13)
O4—C10—C11	58.57 (13)	O4—C11—H11	115.2
C11—C10—C9	117.93 (19)	C12—C11—H11	115.2
C11—O4—C10	62.36 (13)	C10—C11—H11	115.2
O4—C11—C12	118.07 (18)	C17—C12—C13	119.33 (19)
C12—C11—C10	122.35 (19)	C17—C12—C11	119.52 (19)
C4—O1—C8	117.99 (17)	C13—C12—C11	121.1 (2)
C3—O2—C7	116.57 (16)	C14—C13—C12	120.1 (2)
C17—O5—C19	114.82 (15)	C14—C13—H13	119.9
C19—O6—C20	114.30 (19)	C12—C13—H13	119.9
C16—O7—C18	117.5 (2)	C13—C14—C15	120.9 (2)
C6—C1—C2	119.19 (19)	C13—C14—H14	119.5
C6—C1—C9	123.06 (19)	C15—C14—H14	119.5
C2—C1—C9	117.73 (18)	C16—C15—C14	119.7 (2)
C3—C2—C1	120.74 (19)	C16—C15—H15	120.1
C3—C2—H2	119.6	C14—C15—H15	120.1
C1—C2—H2	119.6	C15—C16—O7	124.8 (2)
C2—C3—O2	125.21 (18)	C15—C16—C17	119.5 (2)
C2—C3—C4	119.81 (18)	O7—C16—C17	115.67 (19)
O2—C3—C4	114.97 (17)	O5—C17—C12	119.12 (18)
O1—C4—C3	114.98 (18)	O5—C17—C16	120.48 (19)
O1—C4—C5	125.31 (19)	C12—C17—C16	120.3 (2)
C3—C4—C5	119.71 (19)	O7—C18—H18A	109.5
C6—C5—C4	119.9 (2)	O7—C18—H18B	109.5
C6—C5—H5	120.0	H18A—C18—H18B	109.5
C4—C5—H5	120.0	O7—C18—H18C	109.5
C5—C6—C1	120.63 (19)	H18A—C18—H18C	109.5
C5—C6—H6	119.7	H18B—C18—H18C	109.5
C1—C6—H6	119.7	O6—C19—O5	113.1 (2)
O2—C7—H7A	109.5	O6—C19—H19A	109.0
O2—C7—H7B	109.5	O5—C19—H19A	109.0
H7A—C7—H7B	109.5	O6—C19—H19B	109.0
O2—C7—H7C	109.5	O5—C19—H19B	109.0
H7A—C7—H7C	109.5	H19A—C19—H19B	107.8
H7B—C7—H7C	109.5	O6—C20—H20A	109.5
O1—C8—H8A	109.5	O6—C20—H20B	109.5
O1—C8—H8B	109.5	H20A—C20—H20B	109.5
H8A—C8—H8B	109.5	O6—C20—H20C	109.5
O1—C8—H8C	109.5	H20A—C20—H20C	109.5
H8A—C8—H8C	109.5	H20B—C20—H20C	109.5
H8B—C8—H8C	109.5
C6—C1—C2—C3	1.1 (3)	C9—C10—C11—O4	105.0 (2)
C9—C1—C2—C3	179.57 (19)	O4—C10—C11—C12	105.7 (2)
C1—C2—C3—O2	178.04 (19)	C9—C10—C11—C12	−149.3 (2)
C1—C2—C3—C4	−0.7 (3)	O4—C11—C12—C17	−152.82 (18)
C7—O2—C3—C2	3.6 (3)	C10—C11—C12—C17	137.8 (2)
C7—O2—C3—C4	−177.60 (18)	O4—C11—C12—C13	27.2 (3)
C8—O1—C4—C3	−172.81 (19)	C10—C11—C12—C13	−42.2 (3)
C8—O1—C4—C5	7.1 (3)	C17—C12—C13—C14	−0.5 (3)
C2—C3—C4—O1	179.50 (18)	C11—C12—C13—C14	179.40 (19)
O2—C3—C4—O1	0.7 (3)	C12—C13—C14—C15	0.8 (3)
C2—C3—C4—C5	−0.4 (3)	C13—C14—C15—C16	0.6 (3)
O2—C3—C4—C5	−179.21 (18)	C14—C15—C16—O7	177.36 (19)
O1—C4—C5—C6	−178.9 (2)	C14—C15—C16—C17	−2.3 (3)
C3—C4—C5—C6	1.0 (3)	C18—O7—C16—C15	1.3 (3)
C4—C5—C6—C1	−0.6 (3)	C18—O7—C16—C17	−179.05 (18)
C2—C1—C6—C5	−0.5 (3)	C19—O5—C17—C12	−116.1 (2)
C9—C1—C6—C5	−178.9 (2)	C19—O5—C17—C16	66.9 (2)
C6—C1—C9—O3	163.4 (2)	C13—C12—C17—O5	−178.16 (16)
C2—C1—C9—O3	−15.0 (3)	C11—C12—C17—O5	1.9 (3)
C6—C1—C9—C10	−15.4 (3)	C13—C12—C17—C16	−1.2 (3)
C2—C1—C9—C10	166.20 (19)	C11—C12—C17—C16	178.90 (17)
C11—O4—C10—C9	−108.2 (2)	C15—C16—C17—O5	179.52 (17)
O3—C9—C10—O4	10.3 (3)	O7—C16—C17—O5	−0.1 (3)
C1—C9—C10—O4	−170.88 (18)	C15—C16—C17—C12	2.6 (3)
O3—C9—C10—C11	−56.3 (3)	O7—C16—C17—C12	−177.09 (18)
C1—C9—C10—C11	122.6 (2)	C20—O6—C19—O5	80.5 (3)
C10—O4—C11—C12	−112.8 (2)	C17—O5—C19—O6	68.8 (2)