Mammeigin

Single crystals of the phenyl­coumarin named mammeigin (or mammea A/AA cycle D) [systematic name: 5-hydroxy-8,8-dimethyl-6-(3-methyl­butanoyl)-4-phenyl-2H,8H-pyrano[2,3-f]chromen-2-one], C₂₅H₂₄O₅, were obtained in the course of a chemotaxonomic study of the Guttiferae family. Mammeigin was extracted from the fruits of Kilmeyera pumila. The structure reveals an infinite three-dimensional network stabilized by non-classical inter­molecular hydrogen bonds.

S1. Comment

In the course of our chemical studies of plants belonging to the family Guttiferae, we have investigated the lipophilic extract of the fruits of Kilmeyera pumila Pohl and this led to the isolation of two phenylcoumarins, (I) and (II) (see scheme). The title compound, (I), named mammeigin (or mammea A/AA cycle D, or 5-hydroxy-8,8-dimethyl-6-(3-methylbutanoyl)-4-phenyl-2H,8H-pyrano[2,3-f]chromen-2-one (9CI), has already been isolated from Guttiferae species (Lopez-Perez et al., 2005; Reutrakul et al., 2003; Gramacho et al., 1999; Dennis & Akshaya Kumar, 1998; Castellano et al., 1988; Crombie et al., 1987, 1967; Carpenter et al., 1971; Chakraborty & Chatterji, 1969; Finnegan & Mueller, 1964), and its structure has been established based on spectroscopic evidence and chemical correlation (Finnegan & Mueller, 1965). The structure of (II), a phenylcoumarin from Guttiferae species, was proposed for a new natural product named isomammeigin from IR and NMR data (de Abreu e Silva, 1987). Later, its structure was unambiguously determined by X-ray diffraction by Castellano et al. (1988).

Some phenylcoumarins described previously have shown cytotoxic (Reutrakul et al., 2003; Scio et al., 2003) and anti-HIV (Ishikawa, 2000; Spino et al., 1998) activities. Chemopreventive activity against cancer in vitro without cytotoxicity has also been reported for some of these derivatives (Itoigawa et al., 2001; Ito et al., 2003).

The crystal structure of (I), reported here, was part of a chemotaxonomic study of the Guttiferae family. X-ray analysis is important in this case, since from spectroscopic data alone, structures (I) and (II) are possible alternatives. In this way, we have identified (I) by spectroscopic methods (UV, EI—MS, and ¹H and ¹³C NMR) and its structure was unambiguously confirmed by the X-ray data.

Fig. 1 is an ORTEP-3 (Farrugia, 1997) view of the title compound. The main geometrical parameters are given in Table 1. The intramolecular conformation was analyzed using Mogul (Bruno et al., 2004). This study showed that all bond lengths and angles are in agreement with the expected values. As expected, aromatic ring A is planar and shows nearly equal C—C distances and C—C—C angles. The molecular moiety, considering only the atoms of rings B, C and D, is also almost planar. All atoms in rings B, C and D, except for atom C18, which is an sp³ C atom, lie within ±0.152 (3) Å of the least-squares plane through the three-ring system. Ring D presents an envelope conformation, with atom C18, which deviates by 0.488 (4) Å from the least-squares plane through the three-ring system, at the flip point. The weighted average absolute torsion angle (Domenicano et al., 1975) in ring D is 24.2 (1)°. Rings B and C are also individually almost planar, including the first-neighbour atoms linked to them. The largest deviations from the individual least-squares planes are 0.059 (2) Å (C9) and 0.033 (2) Å (C12) for rings B and C, respectively. The least-squares planes of rings B and C form an angle of 5.5 (1)° and those of rings C and D form an angle of 1.9 (2)°. Phenyl ring A and the least-squares plane through ring B form an angle of 51.9 (1)°. This appreciable deviation from 90° can be viewed as a cooperative consequence of the non-classical intermolecular hydrogen-bond interactions [C4—H4···O5ⁱ and C20—H20A···Cgⁱⁱⁱ, where Cg is the centroid of ring A; symmetry code as in Table 2] (Figs. 2 and 3; Table 2).

Compound (I) exhibits a strong classical intramolecular hydrogen bond, O1—H1···O2 (Fig. 1, Table 2). An interesting structural feature is that the crystal packing of (I) is formed by an infinite three-dimensional network involving non-classical hydrogen bonds. The intermolecular hydrogen bond between phenyl ring A and the adjacent carboxyl atom O5 (C4—H4···O5) gives rise to a chain, in a zigzag molecular fashion, parallel to the [101] direction (Fig. 2). Networks parallel to the [101] direction are themselves hydrogen-bonded via two other non-classical associations, forming infinite chains along the [001] and [101] directions. The chain along [001] is stabilized by C19—H19B···O5 interactions, whereas that along [101] is stabilized by intermolecular bonds of the type H···π-aryl (Fig. 3). The result is an extended three-dimensional supramolecular assembly mediated by non-classical C—H··· bonding. Details of all hydrogen-bond contacts involved in these networks are given in Table 2.

S2. Experimental

The title compound was extracted from the fruit of Kilmeyera pumila Pohl (family Guttiferae) using conventional methods of extraction and chromatography on silica gel, eluting with what solvent? (de Abreu e Silva, 1987). The purified powder of compound (I) which was obtained was re-crystallized from a solution in acetone by slow evaporation at room temperature.

S3. Refinement

Since the most electron-rich atom is O, the absolute structure could not be determined using the diffraction data. Therefore, Friedel pairs were averaged before refinement. All H atoms were positioned stereochemically and were refined with fixed individual displacement parameters [U_iso(H) = 1.2U_eq(C or O) or 1.5U_eq(C_(aromatic)] using a riding model, with C—H = 0.93–0.97 Å and O—H = 0.82 Å.

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Bruno et al., 2002); software used to prepare material for publication: WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).

Figures

	Fig. 1. A view of (I), showing the ring- and atom-labelling. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radii.
	Fig. 2. The packing of (I), showing the infinite network along the [101] direction. [Symmetry codes: (i) x − 1/2, −y − 1/2, z + 1/2; (iv) x + 1/2, −y − 1/2, z − 1/2; (v) x + 1, y, z − 1.]
	Fig. 3. The packing of (1), showing the infinite networks along the [001] and [101] directions. [Symmetry codes: (ii) x, −y, z − 1/2; (iii) x + 1/2, y + 1/2, z; (vi) x, −y, z + 1/2; (vii) x, y, z − 1; (viii) x − 1/2, y − 1/2, z.]

5-hydroxy-8,8-dimethyl-6-(3-methylbutanoyl)-4-phenyl-2H,8H- pyrano[2,3-f]chromen-2-one

Crystal data

C25H24O5	F(000) = 856
Mr = 404.44	Dx = 1.302 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C -2yc	Cell parameters from 5698 reflections
a = 16.727 (1) Å	θ = 2.9–27.5°
b = 14.152 (1) Å	µ = 0.09 mm^−1
c = 8.718 (1) Å	T = 150 K
β = 90.79 (1)°	Prism, pale yellow
V = 2063.5 (3) Å^3	0.35 × 0.12 × 0.10 mm
Z = 4

Data collection

Nonius KappaCCD area-detector diffractometer	2350 independent reflections
Radiation source: fine-focus sealed tube	1799 reflections with I > 2σ(I)
Horizonally mounted graphite crystal monochromator	Rint = 0.065
Detector resolution: 9 pixels mm^-1	θmax = 27.4°, θmin = 3.7°
ϕ scans and ω scans with κ offsets	h = −21→21
Absorption correction: multi-scan (Blessing, 1995)	k = −16→18
Tmin = 0.950, Tmax = 0.985	l = −11→10
9028 measured reflections

Refinement

Refinement on F^2	2 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.044	w = 1/[σ^2(Fo^2) + (0.0542P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.105	(Δ/σ)max < 0.001
S = 1.02	Δρmax = 0.22 e Å^−3
2350 reflections	Δρmin = −0.24 e Å^−3
271 parameters

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.

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

	x	y	z	Uiso*/Ueq
C1	0.30704 (17)	−0.0962 (2)	0.9510 (3)	0.0254 (6)
C2	0.24896 (17)	−0.0427 (2)	0.8756 (3)	0.0283 (7)
H2	0.2628	−0.0056	0.792	0.034*
C3	0.17039 (19)	−0.0443 (2)	0.9248 (4)	0.0344 (7)
H3	0.132	−0.0077	0.8746	0.041*
C4	0.1488 (2)	−0.0999 (2)	1.0474 (4)	0.0360 (8)
H4	0.0961	−0.101	1.0796	0.043*
C5	0.20644 (19)	−0.1540 (2)	1.1224 (3)	0.0327 (7)
H5	0.1922	−0.1914	1.2054	0.039*
C6	0.28525 (18)	−0.1528 (2)	1.0742 (3)	0.0277 (6)
H6	0.3235	−0.1897	1.1242	0.033*
C7	0.38952 (17)	−0.0996 (2)	0.8893 (3)	0.0234 (6)
C8	0.42125 (18)	−0.1849 (2)	0.8550 (3)	0.0298 (7)
H8	0.3951	−0.239	0.8884	0.036*
C9	0.49349 (19)	−0.1960 (2)	0.7694 (3)	0.0323 (7)
C10	0.50012 (17)	−0.0261 (2)	0.7534 (3)	0.0245 (6)
C11	0.43399 (16)	−0.0156 (2)	0.8481 (3)	0.0234 (6)
C12	0.41675 (15)	0.0771 (2)	0.8968 (3)	0.0226 (6)
C13	0.45746 (16)	0.1581 (2)	0.8387 (3)	0.0227 (6)
C14	0.52295 (17)	0.1396 (2)	0.7400 (3)	0.0230 (6)
C15	0.54405 (17)	0.0491 (2)	0.6946 (3)	0.0247 (6)
C16	0.60621 (17)	0.0374 (2)	0.5814 (3)	0.0299 (7)
H16	0.6134	−0.0206	0.5335	0.036*
C17	0.65279 (18)	0.1102 (2)	0.5466 (3)	0.0347 (7)
H17	0.6887	0.1054	0.4666	0.042*
C18	0.64724 (17)	0.2000 (2)	0.6369 (3)	0.0307 (7)
C19	0.66477 (19)	0.2882 (3)	0.5444 (4)	0.0401 (8)
H19A	0.6602	0.3428	0.6089	0.06*
H19B	0.6272	0.2929	0.4605	0.06*
H19C	0.718	0.2846	0.5052	0.06*
C20	0.7011 (2)	0.1941 (3)	0.7785 (4)	0.0395 (8)
H20A	0.6975	0.2519	0.8356	0.059*
H20B	0.7554	0.1845	0.7477	0.059*
H20C	0.6845	0.1423	0.8415	0.059*
C21	0.42774 (17)	0.2520 (2)	0.8787 (3)	0.0261 (6)
C22	0.45446 (18)	0.3410 (2)	0.7984 (4)	0.0309 (7)
H22A	0.4612	0.3272	0.6904	0.037*
H22B	0.5062	0.3596	0.8399	0.037*
C23	0.39661 (19)	0.4244 (2)	0.8135 (4)	0.0355 (7)
H23	0.3808	0.4296	0.921	0.043*
C24	0.4393 (2)	0.5154 (3)	0.7681 (5)	0.0535 (10)
H24A	0.486	0.5238	0.8319	0.08*
H24B	0.4039	0.5682	0.7813	0.08*
H24C	0.4548	0.5116	0.6627	0.08*
C25	0.3222 (2)	0.4096 (3)	0.7157 (4)	0.0455 (9)
H25A	0.296	0.3525	0.7469	0.068*
H25B	0.3368	0.4046	0.6099	0.068*
H25C	0.2867	0.4622	0.7284	0.068*
O1	0.36031 (12)	0.08751 (15)	1.0027 (2)	0.0274 (5)
H1	0.355	0.1438	1.0228	0.041*
O2	0.37608 (12)	0.26023 (15)	0.9796 (2)	0.0336 (5)
O3	0.56437 (11)	0.21496 (16)	0.6873 (2)	0.0291 (5)
O4	0.52670 (12)	−0.11352 (14)	0.7105 (2)	0.0288 (5)
O5	0.52657 (14)	−0.26898 (16)	0.7374 (3)	0.0444 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0273 (15)	0.0222 (16)	0.0267 (14)	−0.0028 (12)	0.0008 (12)	−0.0003 (11)
C2	0.0248 (15)	0.0266 (16)	0.0335 (16)	−0.0030 (12)	0.0031 (12)	0.0058 (12)
C3	0.0255 (16)	0.0336 (18)	0.0439 (18)	−0.0008 (14)	−0.0006 (13)	−0.0012 (13)
C4	0.0302 (16)	0.040 (2)	0.0384 (16)	−0.0084 (15)	0.0099 (13)	−0.0079 (15)
C5	0.0391 (18)	0.0328 (18)	0.0265 (15)	−0.0119 (15)	0.0066 (13)	−0.0025 (12)
C6	0.0317 (16)	0.0282 (17)	0.0232 (13)	−0.0037 (13)	−0.0018 (12)	0.0015 (12)
C7	0.0267 (15)	0.0215 (16)	0.0221 (13)	0.0000 (12)	−0.0012 (11)	0.0009 (11)
C8	0.0293 (16)	0.0257 (17)	0.0344 (16)	−0.0014 (14)	−0.0014 (13)	−0.0004 (12)
C9	0.0319 (17)	0.0274 (18)	0.0377 (17)	0.0011 (14)	−0.0027 (13)	−0.0065 (13)
C10	0.0256 (15)	0.0257 (17)	0.0222 (14)	0.0031 (12)	−0.0026 (11)	−0.0053 (11)
C11	0.0234 (15)	0.0253 (17)	0.0214 (14)	0.0021 (12)	0.0004 (12)	0.0003 (11)
C12	0.0209 (15)	0.0281 (17)	0.0188 (13)	−0.0025 (12)	0.0028 (11)	0.0001 (11)
C13	0.0232 (15)	0.0239 (16)	0.0208 (13)	−0.0010 (12)	−0.0013 (11)	0.0020 (10)
C14	0.0194 (14)	0.0305 (16)	0.0191 (13)	−0.0044 (13)	−0.0012 (10)	0.0016 (11)
C15	0.0225 (14)	0.0290 (17)	0.0226 (13)	−0.0013 (12)	−0.0008 (11)	−0.0033 (11)
C16	0.0259 (16)	0.0382 (19)	0.0255 (14)	−0.0020 (13)	0.0048 (12)	−0.0070 (12)
C17	0.0284 (16)	0.048 (2)	0.0278 (14)	−0.0041 (15)	0.0091 (12)	−0.0044 (14)
C18	0.0246 (15)	0.0404 (19)	0.0274 (16)	−0.0076 (14)	0.0086 (12)	−0.0012 (13)
C19	0.0353 (19)	0.048 (2)	0.0370 (17)	−0.0111 (16)	0.0092 (14)	0.0036 (15)
C20	0.0339 (18)	0.045 (2)	0.0393 (17)	−0.0058 (15)	−0.0027 (14)	−0.0043 (14)
C21	0.0228 (14)	0.0265 (16)	0.0290 (15)	0.0001 (13)	0.0005 (12)	−0.0007 (12)
C22	0.0272 (15)	0.0283 (18)	0.0372 (16)	−0.0027 (14)	0.0017 (12)	0.0010 (13)
C23	0.0344 (18)	0.0269 (18)	0.0453 (19)	0.0008 (14)	0.0014 (15)	0.0027 (13)
C24	0.052 (2)	0.029 (2)	0.079 (3)	0.0004 (18)	−0.0005 (19)	0.0095 (18)
C25	0.039 (2)	0.037 (2)	0.060 (2)	0.0072 (16)	0.0006 (16)	0.0027 (16)
O1	0.0284 (11)	0.0258 (12)	0.0283 (10)	−0.0009 (9)	0.0092 (8)	−0.0031 (8)
O2	0.0332 (12)	0.0283 (13)	0.0396 (11)	0.0021 (10)	0.0116 (9)	−0.0010 (9)
O3	0.0241 (11)	0.0317 (12)	0.0317 (11)	−0.0054 (9)	0.0088 (8)	0.0023 (8)
O4	0.0249 (11)	0.0263 (12)	0.0353 (11)	0.0015 (9)	0.0029 (9)	−0.0059 (9)
O5	0.0387 (14)	0.0283 (14)	0.0664 (16)	0.0071 (12)	0.0065 (11)	−0.0104 (12)

Geometric parameters (Å, º)

C1—C2	1.390 (4)	C16—C17	1.329 (4)
C1—C6	1.392 (4)	C16—H16	0.93
C1—C7	1.488 (4)	C17—C18	1.499 (5)
C2—C3	1.388 (4)	C17—H17	0.93
C2—H2	0.93	C18—O3	1.475 (3)
C3—C4	1.379 (5)	C18—C19	1.516 (5)
C3—H3	0.93	C18—C20	1.520 (4)
C4—C5	1.388 (5)	C19—H19A	0.96
C4—H4	0.93	C19—H19B	0.96
C5—C6	1.389 (4)	C19—H19C	0.96
C5—H5	0.93	C20—H20A	0.96
C6—H6	0.93	C20—H20B	0.96
C7—C8	1.354 (4)	C20—H20C	0.96
C7—C11	1.451 (4)	C21—O2	1.247 (3)
C8—C9	1.438 (4)	C21—C22	1.512 (4)
C8—H8	0.93	C22—C23	1.533 (4)
C9—O5	1.207 (4)	C22—H22A	0.97
C9—O4	1.393 (4)	C22—H22B	0.97
C10—O4	1.368 (3)	C23—C25	1.513 (5)
C10—C15	1.394 (4)	C23—C24	1.528 (5)
C10—C11	1.397 (4)	C23—H23	0.98
C11—C12	1.410 (4)	C24—H24A	0.96
C12—O1	1.338 (3)	C24—H24B	0.96
C12—C13	1.429 (4)	C24—H24C	0.96
C13—C14	1.426 (4)	C25—H25A	0.96
C13—C21	1.463 (4)	C25—H25B	0.96
C14—O3	1.356 (3)	C25—H25C	0.96
C14—C15	1.388 (4)	O1—H1	0.82
C15—C16	1.453 (4)
C2—C1—C6	119.3 (2)	C18—C17—H17	120.1
C2—C1—C7	119.5 (2)	O3—C18—C17	110.1 (2)
C6—C1—C7	120.9 (3)	O3—C18—C19	103.3 (3)
C3—C2—C1	120.2 (3)	C17—C18—C19	113.9 (2)
C3—C2—H2	119.9	O3—C18—C20	108.4 (2)
C1—C2—H2	119.9	C17—C18—C20	109.8 (3)
C4—C3—C2	120.5 (3)	C19—C18—C20	111.1 (3)
C4—C3—H3	119.8	C18—C19—H19A	109.5
C2—C3—H3	119.8	C18—C19—H19B	109.5
C3—C4—C5	119.5 (3)	H19A—C19—H19B	109.5
C3—C4—H4	120.2	C18—C19—H19C	109.5
C5—C4—H4	120.2	H19A—C19—H19C	109.5
C4—C5—C6	120.4 (3)	H19B—C19—H19C	109.5
C4—C5—H5	119.8	C18—C20—H20A	109.5
C6—C5—H5	119.8	C18—C20—H20B	109.5
C5—C6—C1	120.0 (3)	H20A—C20—H20B	109.5
C5—C6—H6	120	C18—C20—H20C	109.5
C1—C6—H6	120	H20A—C20—H20C	109.5
C8—C7—C11	118.2 (2)	H20B—C20—H20C	109.5
C8—C7—C1	118.5 (3)	O2—C21—C13	119.6 (3)
C11—C7—C1	122.9 (3)	O2—C21—C22	117.4 (3)
C7—C8—C9	123.1 (3)	C13—C21—C22	122.9 (2)
C7—C8—H8	118.4	C21—C22—C23	114.3 (2)
C9—C8—H8	118.4	C21—C22—H22A	108.7
O5—C9—O4	116.4 (3)	C23—C22—H22A	108.7
O5—C9—C8	127.2 (3)	C21—C22—H22B	108.7
O4—C9—C8	116.3 (3)	C23—C22—H22B	108.7
O4—C10—C15	114.5 (2)	H22A—C22—H22B	107.6
O4—C10—C11	121.4 (3)	C25—C23—C24	110.8 (3)
C15—C10—C11	124.1 (3)	C25—C23—C22	111.1 (3)
C10—C11—C12	116.4 (3)	C24—C23—C22	109.2 (3)
C10—C11—C7	118.2 (3)	C25—C23—H23	108.6
C12—C11—C7	125.5 (2)	C24—C23—H23	108.6
O1—C12—C11	117.3 (2)	C22—C23—H23	108.6
O1—C12—C13	120.1 (3)	C23—C24—H24A	109.5
C11—C12—C13	122.6 (2)	C23—C24—H24B	109.5
C14—C13—C12	116.1 (3)	H24A—C24—H24B	109.5
C14—C13—C21	125.2 (3)	C23—C24—H24C	109.5
C12—C13—C21	118.6 (2)	H24A—C24—H24C	109.5
O3—C14—C15	119.8 (2)	H24B—C24—H24C	109.5
O3—C14—C13	117.4 (3)	C23—C25—H25A	109.5
C15—C14—C13	122.8 (3)	C23—C25—H25B	109.5
C14—C15—C10	117.5 (2)	H25A—C25—H25B	109.5
C14—C15—C16	119.1 (3)	C23—C25—H25C	109.5
C10—C15—C16	123.3 (3)	H25A—C25—H25C	109.5
C17—C16—C15	119.6 (3)	H25B—C25—H25C	109.5
C17—C16—H16	120.2	C12—O1—H1	109.5
C15—C16—H16	120.2	C14—O3—C18	118.4 (2)
C16—C17—C18	119.8 (3)	C10—O4—C9	121.6 (2)
C16—C17—H17	120.1

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2	0.82	1.73	2.467 (3)	149
C4—H4···O5^i	0.93	2.58	3.234 (4)	128
C19—H19B···O5^ii	0.96	2.58	3.523 (4)	168
C20—H20A···Cg^iii	0.96	2.60	3.534 (3)	165

Symmetry codes: (i) x−1/2, −y−1/2, z+1/2; (ii) x, −y, z−1/2; (iii) x+1/2, y+1/2, z.