Table 2. Experimental details.

Crystal data
Chemical formula	C18H18O6
M r	330.32
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	105
a, b, c (Å)	28.5800 (14), 4.0632 (2), 14.4806 (7)
β (°)	115.100 (1)
V (Å3)	1522.78 (13)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.11
Crystal size (mm)	0.56 × 0.29 × 0.22
Data collection
Diffractometer	Bruker PHOTON CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2007 ▸)
T min, T max	0.602, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	17902, 2053, 1819
R int	0.037
(sin θ/λ)max (Å−1)	0.685
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.038, 0.109, 1.10
No. of reflections	2053
No. of parameters	111
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.41, −0.24

Computer programs: APEX2 and SAINT (Bruker, 2007 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2014 (Sheldrick, 2015 ▸), WinGX (Farrugia, 2012 ▸), DIAMOND (Brandenburg, 2004 ▸), ChemBioDraw (Cambridge Soft, 2009 ▸) and publCIF (Westrip, 2010 ▸).