(1R,3R,4R,6S)-4-(7-Meth­oxy-2-oxo-2H-chromen-6-yl)-1-methyl-3,6-dioxa­bicyclo­[3.1.0]hexan-2-yl acetate

Wong Phakhodee; Surat Laphookhieo; Timothy John Prior; Apinpus Rujiwatra

doi:10.1107/S1600536812047617

. 2012 Nov 24;68(Pt 12):o3421–o3422. doi: 10.1107/S1600536812047617

(1R,3R,4R,6S)-4-(7-Methoxy-2-oxo-2H-chromen-6-yl)-1-methyl-3,6-dioxabicyclo[3.1.0]hexan-2-yl acetate

Wong Phakhodee ^a, Surat Laphookhieo ^a, Timothy John Prior ^b, Apinpus Rujiwatra ^c,^*

PMCID: PMC3589005 PMID: 23476241

Abstract

In the title compound, C₁₇H₁₆O₇, which was isolated from the leaves of Micromelum integerrimum, the furan ring adopts an envelope conformation with the O atom as the flap. An intramolecular C—H⋯O hydrogen bond occurs. The carbonyl O atom is disordered in a 0.57 (8):0.43 (8) ratio. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds into a C(10) chain along [010].

Related literature

Micromelum integerrimum is a shrub in the Rutacae family containing the coumarin molecule, micromelin, as the major chemical constituent (Cassady et al., 1979 ▶). Many coumarins including micromelin have been extracted from Rutacae plants, and for some their cytotoxicity has been investigated (Sripisut et al., 2012 ▶; He et al., 2001 ▶). For previous reports on the isolation of micromelin (micromelumin) from a Northern Queensland collection, an Assamese collection, and a Northeast Thailand collection, see: Lamberton et al. (1967 ▶); Das et al. (1984 ▶); Siridechakorn et al. (2012 ▶). For detailed H¹ NMR spectroscopic data, see: Das et al. (1984 ▶); Siridechakorn et al. (2012 ▶). For a phytochemical investigation, see: Siridechakorn et al. (2012 ▶). For a closely related micromelin structure, C₁₅H₁₂O₆, see: Fun et al. (2011 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₇H₁₆O₇
M _r = 332.31
Monoclinic,
a = 10.4825 (16) Å
b = 6.9213 (9) Å
c = 11.0212 (18) Å
β = 95.970 (7)°
V = 795.3 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 298 K
0.64 × 0.32 × 0.24 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1997 ▶) T _min = 0.653, T _max = 0.746
4381 measured reflections
2123 independent reflections
1692 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.136
S = 1.06
2123 reflections
223 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 1997 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2007 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(17.8KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812047617/bx2427sup1.cif

e-68-o3421-sup1.cif^{(17.8KB, cif)}

Click here for additional data file.^{(102.2KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812047617/bx2427Isup2.hkl

e-68-o3421-Isup2.hkl^{(102.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O19A ⁱ	1.07 (3)	2.46 (2)	3.064 (8)	114 (1)
C5—H5⋯O13	1.01 (3)	2.58 (3)	3.403 (3)	139 (1)
C12—H12⋯O2ⁱⁱ	0.98	2.35	3.282 (5)	158
C16—H16B⋯O2ⁱⁱⁱ	0.96	2.54	3.419 (4)	153

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The Thailand Research Fund is acknowledged for a research grant.

supplementary crystallographic information

Comment

Micromelum integerrimum is a shrub in the Rutacae family containing the coumarin molecule, micromilin, as the major chemical constituent (Cassady et al., 1979). Many coumarins including micromilin have been extracted from Rutacae plants, and for some their cytotoxicity has been investigated (Sripisut et al., 2012; He et al., 2001). In the attempt to investigate the chemical constitutents of the extract of Micromelum integerrimum leaves collected from Chiang Rai province in the Northern part of Thailand (March 2012), the colourless crystals of the title compound have been isolated and examined.

The absolute configurations of the four chiral centres in the molecule, (I) (C11, C12, C13, and C14) were assigned from a previous report (Das et al., 1984) as R, R, R and S, respectively. The benzene and dihydropyran ring system (C2–C10/O1) and also the carboxyl O2 and the methoxy O3 atoms are co-planar with the r.m.s. 0.004 (3) Å (Spek, 2009). A deviation of atoms O2 and O3 from the benzene and dihydropyran ring system are 0.028 (2) Å and 0.040 (2) Å, respectively. The five-membered furan ring (C11–C14/O11) shows envelope conformation with the puckering atom O11 of 0.075 (2) Å, and forms an angle of 66.11 (9)° to the twelve-membered benzene–dihydropyran due to free rotation about the C6—C11 bond. The puckering parameters Q and φ of the furan ring are 0.116 (2) Å and 176.4 (12)°, respectively (Cremer & Pople, 1975). The orientation of the oxiran ring (C12–C13/O12) attached to the furan can be defined by the dihedral angle being 79.5 (2)° with atom O12 of the oxirane ring located 1.250 (2) Å away from the furan plane. Regarding the acetate group, atom O19 shows minor positional disorder over two sites. The acetate O13 is arranged at 64.19 (15)° in reference to the furan plane, and the torsion angle measured on C14–O13–C17–C18 is 171.6 (2)°.In the crystal of (I), the molecules are linked by weak C—H···O hydrogen-bonding interactions into a chain along [010] with set-graph notation C(10), (Bernstein, et al., 1995)

Experimental

The title compound was obtained from an acetone extract of Micromelum integerrimum leaves (0.55 kg), which are collected from Chiang Rai Province, Thailand. From seven fractions (A—G) yielded by column chromatography using hexanes-acetone, the title compound (295.9 mg) was isolated from fraction D by also column chromatography using 2% acetone-CH₂Cl₂. The crystals were then crystallized by slowly evaporation of the solvent.