J Chem Crystallogr (2009) 39:500–503
DOI 10.1007/s10870-008-9505-9
ORIGINAL PAPER
Microwave Assisted Synthesis and Crystal Structure of 3,3,6,6-
Tetramethyl-9-(phenyl)-1,8-dioxo-2,3,4,5,6,7-hexahydroxanthene
Xiao-Ping Rao Æ Yong Wu Æ Zhan-Qian Song Æ
Shi-Bin Shang
Received: 1 October 2008 / Accepted: 13 November 2008 / Published online: 19 December 2008
Ó Springer Science+Business Media, LLC 2008
Abstract The title compound (C23H26O3, Mr = 350.44)
has been synthesized under microwave irradiation. Its
pharmacological and biological activities [4–6], such as
antibacterial activity, antitumor activity, hypotensive
effect, antiproliferation effect, etc. In continuing efforts
dimedone derivatives often used to construct new xanthene
heterocycles with biological activities [7, 8].
1
structure was characterized by IR, H NMR spectroscopy
and single-crystal X-ray diffraction. The title crystal is in
the monoclinic system, space group C with cell dimensions
˚
˚
of a = 6.0500(12) A, b = 19.693(4) A, c = 16.386(3) A,
˚
In previous studies, InCl3 ꢀ 4H2O [9], Dowex-50 W
3
2-
˚
b = 97.85(3)8, V = 1,934.0(7) A , Z = 4, Dc = 1.204
[10], NaHSO4/SiO2 [11], PPA/SiO2 [12], TiO2/SO4
g/cm , k = 0.71073 A, l = 0.08 mm-1, F(000) = 752, the
[13], Amberlyst-15 [14], NH2SO3/SDS [15] and Nafion-H
[16] are reported as efficient catalysts for the synthesis of
xanthene derivatives. However, these methodologies have
some disadvantages, such as prolonged reaction time and
the requirement of catalysts [17]. Microwave irradiation
to synthesis of xanthene derivatives can avoid these
disadvantages [18, 19]. Although the title compound has
been synthesized by Jin et al. [15] through complex
catalysts of NH2SO3/SDS under aqueous media, the
microwave assisted synthesis and crystal structure of
the title compound have not yet been dealt with. Herein,
we report the microwave assisted synthesis and crys-
tal structure of 3,3,6,6-tetramethyl-9-(phenyl)-1,8-dioxo-
2,3,4,5,6,7-hexahydroxanthene.
3
˚
final R = 0.065 and wR = 0.165 for 1,992 observed
reflections with I [ 2r(I). In the molecular structure, the
pyran ring is of boat conformation, and the two-six-mem-
bered rings fused with it adopt envelope conformations.
Keywords Microwave irradiation ꢀ Synthesis ꢀ
Crystal structure
Introduction
Microwave-assisted organic synthesis has been a topic of
continuing interest since its application to the organic
synthesis in 1986 [1, 2]. As a non-conventional energy
source, microwave has become a very popular and useful
technology in organic chemistry because of its high
yield, short time span, and eco-friendly conditions [3].
Xanthene as well as its derivatives exhibit extensive
Experimental
Materials and Apparatuses
All chemicals used were of analytical grades. Microwave
irradiation was carried out on a microwave reactor (CEM,
Discover) at the atmospheric pressure. Infrared spectrum
was recorded as KBr pellets on a Bio-Rad FTS-185 IR
spectrophotometer. Melting point was determined by a
XT5 melting point apparatus. 1H NMR spectrum was
recorded on a DPX-300 Bruker AVANCE 300 spectrom-
eter (CDCl3 as solvent).
X.-P. Rao (&) ꢀ Y. Wu ꢀ Z.-Q. Song ꢀ S.-B. Shang
Institute of Chemical Industry of Forest Products, Chinese
Academy of Forestry, 210042 Nanjing, China
e-mail: rxping2001@163.com
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