Alloevodionol methyl ether

The crystal structure determination of one of the substituted α-chromene components isolated in the hexane extraction of the fruit of the indigenous Australian tree Melicope ellyrana, the methyl ether of the known compound alloevodionol, is reported. In this compound, 1-(5,7-di­methoxy-2,2-di­methyl-2H-1-benzo­pyran-8-yl)­ethanone, C₁₅H₁₈O₄, the methoxy groups are approximately coplanar with the aromatic ring, while the acetyl group is normal to the ring.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.063
• wR factor = 0.224
• Data-to-parameter ratio = 14.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

The hexane-extracted components of the fruit of the indiginous Australian tree Melicope ellyrana (Hartley, 1981) resulted in the isolation of a number of flavonoids, and the crystal structures of two of these, i.e. pachypodol [4',5-dihydroxy-3,3',7-trimethoxyflavone; Smith, Wang et al., 2001] and 4',5-dihydroxy-3,3',8-trimethoxy-7-(3-methylbut-2-enyloxy)flavone (Smith, Bartley et al., 2001), have been reported. In addition to these, several substituted α-chromenes have been isolated, including the title compound, 1-(5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran-8-yl)ethanone, (I) (alloevodionol methyl ether: CA Registry No. 31367–55-2). This compound was first isolated from Evodia elleryana (Jones & Wright, 1946) and from Medicosma cunninghamii, its trivial name being given, along with the parent alloevodionol by Sutherland (1949). It was also isolated from Melicope simplex (Briggs & Locker, 1950), while more recently, a total of 18 variants of 2,2-dimethyl-substituted α-chromenes, including (I), were identified in the leaves of M. ptelefolia Kamperdick et al. (1997). Interest in the chromenes, such as (I) and its variants, has also resulted in a number of patent applications for synthetic procedures, e.g. Nakayama et al. (1979).

The crystal structure of (I) (Fig. 1) shows the 2,2-dimethyl-2H-1-benzopyran moiety with the methoxy substituents at C5 and C7 being close to coplanarity with the aromatic ring [torsion angles C6—C5—O5—C51 - 1.8 (6)° and C6—C7—O7—C71 - 6.2 (6)°]. In contrast, the acetyl group is almost perpendicular to the ring [torsion angle C7—C8—C81—C82 94.2 (5)°]. As might be expected for this type of compound, there are no significant intermolecular associations involved in the packing in the unit cell.

S2. Experimental

The hexane extract of the fresh fruit of Melicope ellyrana, after concentration (Smith, Wang et al., 2001) gave a precipitate of crystals of the title compound suitable for single-crystal structural analysis.

S3. Refinement

H atoms were included at calculated positions and were constrained in the refinement.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999a); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1999b); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON for Windows (Spek, 1999); software used to prepare material for publication: TEXSAN for Windows.

Figures

Fig. 1. The molecular configuration and atom-naming scheme for the title compound. Atoms are shown as the 30% probability ellipsoids (Spek, 1999).

1-(5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran-8-yl)-ethanone

Crystal data

C15H18O4	Dx = 1.238 Mg m^−3
Mr = 262.29	Melting point: 380 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 7.2233 (19) Å	Cell parameters from 25 reflections
b = 10.354 (3) Å	θ = 12–18°
c = 18.825 (2) Å	µ = 0.09 mm^−1
β = 91.334 (19)°	T = 293 K
V = 1407.5 (6) Å^3	Plate, colourless
Z = 4	0.40 × 0.35 × 0.15 mm
F(000) = 560

Data collection

Rigaku AFC-7R diffractometer	Rint = 0.050
Radiation source: Rigaku rotating anode	θmax = 25.0°, θmin = 2.8°
Graphite monochromator	h = 0→8
ω–2θ scans	k = 0→12
2698 measured reflections	l = −22→22
2486 independent reflections	3 standard reflections every 150 reflections
1106 reflections with I > 2σ(I)	intensity decay: 2.2%

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)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.224	H-atom parameters not refined
S = 1.39	w = 1/[σ^2(Fo^2) + (0.1P)^2] where P = (Fo^2 + 2Fc^2)/3
2486 reflections	(Δ/σ)max < 0.001
173 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.31 e Å^−3

Special details

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	0.1504 (4)	0.3078 (3)	0.39021 (14)	0.0636 (9)
O5	0.7121 (4)	0.0752 (3)	0.37529 (16)	0.0788 (11)
O7	0.5009 (4)	0.2447 (3)	0.59881 (15)	0.0738 (10)
O81	0.0737 (5)	0.3082 (4)	0.5677 (2)	0.1121 (15)
C2	0.1561 (6)	0.3408 (5)	0.3142 (2)	0.0680 (13)
C3	0.2608 (7)	0.2384 (6)	0.2749 (2)	0.0817 (15)
C4A	0.4368 (6)	0.1890 (4)	0.3815 (2)	0.0594 (12)
C4	0.3927 (7)	0.1706 (5)	0.3064 (2)	0.0773 (15)
C5	0.5929 (6)	0.1393 (4)	0.4174 (2)	0.0558 (11)
C6	0.6197 (5)	0.1544 (4)	0.4893 (2)	0.0580 (12)
C7	0.4873 (6)	0.2219 (4)	0.5274 (2)	0.0559 (11)
C8A	0.3105 (5)	0.2589 (4)	0.4215 (2)	0.0553 (11)
C8	0.3310 (5)	0.2750 (4)	0.4941 (2)	0.0522 (11)
C21	−0.0468 (7)	0.3462 (6)	0.2913 (3)	0.0949 (19)
C22	0.2447 (8)	0.4714 (6)	0.3081 (3)	0.0927 (18)
C51	0.8796 (7)	0.0234 (6)	0.4082 (3)	0.0902 (17)
C71	0.6490 (6)	0.1866 (5)	0.6387 (2)	0.0718 (14)
C81	0.1994 (6)	0.3563 (5)	0.5358 (2)	0.0635 (12)
C82	0.2338 (7)	0.4995 (6)	0.5330 (3)	0.0903 (17)
H3	0.2302	0.2219	0.2263	0.098*
H4	0.4604	0.1095	0.2798	0.093*
H6	0.7262	0.1195	0.5128	0.070*
H51	0.9797	0.0345	0.3777	0.108*
H52	0.8623	−0.0666	0.4175	0.108*
H53	0.9036	0.0667	0.4520	0.108*
H71	0.6254	0.1940	0.6881	0.088*
H72	0.6579	0.0979	0.6264	0.088*
H73	0.7617	0.2290	0.6286	0.088*
H82	0.2434	0.5319	0.5803	0.108*
H83	0.3451	0.5154	0.5092	0.108*
H84	0.1332	0.5399	0.5087	0.108*
H211	−0.0779	0.2713	0.2644	0.114*
H212	−0.0687	0.4209	0.2631	0.114*
H213	−0.1214	0.3496	0.3323	0.114*
H221	0.2703	0.5050	0.3544	0.111*
H222	0.1636	0.5282	0.2830	0.111*
H223	0.3576	0.4639	0.2833	0.111*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0519 (18)	0.081 (2)	0.0582 (19)	−0.0017 (16)	0.0017 (13)	0.0119 (15)
O5	0.075 (2)	0.094 (3)	0.067 (2)	0.0218 (19)	0.0099 (17)	−0.0093 (18)
O7	0.0664 (19)	0.104 (3)	0.0509 (19)	0.0198 (18)	−0.0007 (14)	−0.0036 (17)
O81	0.087 (3)	0.108 (3)	0.144 (4)	0.020 (2)	0.063 (2)	0.041 (3)
C2	0.068 (3)	0.080 (4)	0.056 (3)	−0.004 (3)	0.000 (2)	0.017 (2)
C3	0.082 (3)	0.108 (4)	0.055 (3)	0.001 (3)	−0.003 (3)	0.001 (3)
C4A	0.057 (3)	0.060 (3)	0.061 (3)	0.004 (2)	0.011 (2)	0.005 (2)
C4	0.086 (3)	0.095 (4)	0.052 (3)	0.012 (3)	0.007 (2)	−0.007 (3)
C5	0.054 (3)	0.051 (3)	0.062 (3)	0.005 (2)	0.014 (2)	−0.002 (2)
C6	0.049 (2)	0.058 (3)	0.067 (3)	0.008 (2)	0.003 (2)	0.007 (2)
C7	0.052 (2)	0.064 (3)	0.052 (3)	0.000 (2)	0.006 (2)	0.004 (2)
C8A	0.046 (2)	0.059 (3)	0.061 (3)	−0.003 (2)	0.004 (2)	0.010 (2)
C8	0.046 (2)	0.059 (3)	0.053 (3)	0.002 (2)	0.0070 (19)	0.0067 (19)
C21	0.081 (4)	0.132 (5)	0.071 (3)	−0.004 (4)	−0.017 (3)	0.019 (3)
C22	0.103 (4)	0.088 (4)	0.087 (4)	−0.020 (3)	−0.003 (3)	0.028 (3)
C51	0.071 (3)	0.107 (5)	0.092 (4)	0.033 (3)	0.012 (3)	−0.009 (3)
C71	0.066 (3)	0.093 (4)	0.056 (3)	0.010 (3)	−0.008 (2)	0.004 (3)
C81	0.051 (3)	0.078 (4)	0.062 (3)	0.011 (2)	0.006 (2)	0.009 (2)
C82	0.067 (3)	0.089 (4)	0.115 (4)	0.003 (3)	0.015 (3)	−0.025 (3)

Geometric parameters (Å, º)

O1—C8A	1.382 (5)	C7—C8	1.392 (6)
O1—C2	1.472 (5)	C8A—C8	1.381 (6)
O5—C5	1.357 (5)	C8—C81	1.504 (6)
O5—C51	1.450 (6)	C21—H211	0.95
O7—C7	1.365 (5)	C21—H212	0.95
O7—C71	1.426 (5)	C21—H213	0.95
O81—C81	1.207 (5)	C22—H221	0.95
C2—C22	1.501 (7)	C22—H222	0.95
C2—C3	1.507 (7)	C22—H223	0.95
C2—C21	1.519 (7)	C51—H51	0.94
C3—C4	1.314 (7)	C51—H52	0.96
C3—H3	0.95	C51—H53	0.95
C4A—C8A	1.399 (6)	C71—H71	0.95
C4A—C5	1.400 (6)	C71—H72	0.95
C4A—C4	1.454 (6)	C71—H73	0.95
C4—H4	0.95	C81—C82	1.504 (7)
C5—C6	1.372 (6)	C82—H82	0.95
C6—C7	1.396 (6)	C82—H83	0.94
C6—H6	0.95	C82—H84	0.95
C8A—O1—C2	117.2 (3)	C2—C21—H211	110
C5—O5—C51	117.8 (4)	C2—C21—H212	110
C7—O7—C71	118.8 (3)	H211—C21—H212	110
O1—C2—C22	107.8 (4)	C2—C21—H213	109
O1—C2—C3	109.9 (4)	H211—C21—H213	109
C22—C2—C3	112.1 (4)	H212—C21—H213	109
O1—C2—C21	103.6 (4)	C2—C22—H221	109
C22—C2—C21	110.8 (5)	C2—C22—H222	110
C3—C2—C21	112.2 (5)	H221—C22—H222	109
C4—C3—C2	121.4 (4)	C2—C22—H223	110
C4—C3—H3	119	H221—C22—H223	109
C2—C3—H3	119	H222—C22—H223	110
C8A—C4A—C5	117.2 (4)	O5—C51—H51	110
C8A—C4A—C4	117.5 (4)	O5—C51—H52	109
C5—C4A—C4	125.3 (4)	H51—C51—H52	110
C3—C4—C4A	120.5 (4)	O5—C51—H53	109
C3—C4—H4	120	H51—C51—H53	110
C4A—C4—H4	120	H52—C51—H53	109
O5—C5—C6	123.7 (4)	O7—C71—H71	109
O5—C5—C4A	114.3 (4)	O7—C71—H72	110
C6—C5—C4A	121.9 (4)	H71—C71—H72	109
C5—C6—C7	118.8 (4)	O7—C71—H73	110
C5—C6—H6	121	H71—C71—H73	110
C7—C6—H6	121	H72—C71—H73	110
O7—C7—C8	114.5 (4)	O81—C81—C8	121.3 (5)
O7—C7—C6	123.9 (4)	O81—C81—C82	123.4 (5)
C8—C7—C6	121.6 (4)	C8—C81—C82	115.2 (4)
C8—C8A—O1	116.6 (4)	C81—C82—H82	109
C8—C8A—C4A	122.7 (4)	C81—C82—H83	109
O1—C8A—C4A	120.6 (4)	H82—C82—H83	110
C8A—C8—C7	117.7 (4)	C81—C82—H84	109
C8A—C8—C81	121.9 (4)	H82—C82—H84	110
C7—C8—C81	120.1 (4)	H83—C82—H84	110
C8A—O1—C2—C22	−81.1 (5)	C5—C6—C7—C8	−0.8 (7)
C8A—O1—C2—C3	41.3 (5)	C2—O1—C8A—C8	155.5 (4)
C8A—O1—C2—C21	161.4 (4)	C2—O1—C8A—C4A	−28.8 (6)
O1—C2—C3—C4	−28.8 (7)	C5—C4A—C8A—C8	−2.8 (6)
C22—C2—C3—C4	91.1 (6)	C4—C4A—C8A—C8	175.4 (4)
C21—C2—C3—C4	−143.5 (5)	C5—C4A—C8A—O1	−178.1 (4)
C2—C3—C4—C4A	2.4 (8)	C4—C4A—C8A—O1	0.1 (6)
C8A—C4A—C4—C3	13.5 (7)	O1—C8A—C8—C7	177.4 (4)
C5—C4A—C4—C3	−168.5 (5)	C4A—C8A—C8—C7	1.9 (6)
C51—O5—C5—C6	−1.8 (6)	O1—C8A—C8—C81	−7.8 (6)
C51—O5—C5—C4A	178.6 (4)	C4A—C8A—C8—C81	176.7 (4)
C8A—C4A—C5—O5	−178.5 (4)	O7—C7—C8—C8A	178.2 (4)
C4—C4A—C5—O5	3.5 (7)	C6—C7—C8—C8A	0.0 (6)
C8A—C4A—C5—C6	1.9 (6)	O7—C7—C8—C81	3.3 (6)
C4—C4A—C5—C6	−176.1 (4)	C6—C7—C8—C81	−174.9 (4)
O5—C5—C6—C7	−179.8 (4)	C8A—C8—C81—O81	98.2 (6)
C4A—C5—C6—C7	−0.2 (6)	C7—C8—C81—O81	−87.2 (6)
C71—O7—C7—C8	175.6 (4)	C8A—C8—C81—C82	−80.5 (5)
C71—O7—C7—C6	−6.2 (6)	C7—C8—C81—C82	94.2 (5)
C5—C6—C7—O7	−178.9 (4)