Crystal structures of mollugin and lucidin

Article abstract of DOI:10.1007/s10870-005-6159-8

Mollugin was isolated from the extract of Rubia tinctorum roots. Lucidin was obtained by semisynthesis from xanthopurpurin. Mollugin crystallises in space group P-1 (No. 2), a = 8.5857(7), b = 11.473(4), c = 15.024(1) A, α = 77.64(2)°, β = 89.36(1)°, γ = 89.71(2)°, and V = 1445.5(5) A³, lucidin crystallises in space group P2 ₁/c (No.14), a = 16.800(6), b = 9.637(2), c = 7.073(7) A, β = 98.01(5)°, and V = 1134(1) A³.

Full text of DOI:10.1007/s10870-005-6159-8

ꢀC
Journal of Chemical Crystallography, Vol. 35, No. 8, August 2005 ( 2005)
DOI: 10.1007/s10870-005-6159-8
Crystal structures of mollugin and lucidin
(2)
(3)
(3)
Alexandr Jegorov,(1)∗ Ladislav Cvak, Jan Cejka, Bohumil Kratochv´ıl,
ˇ
Petr Sedmera,(4) and Vladim´ır Havl´ıcˇek(4)
Received May 6, 2003
Mollugin was isolated from the extract of Rubia tinctorum roots. Lucidin was obtained
by semisynthesis from xanthopurpurin. Mollugin crystallises in space group P-1 (No.
◦
◦
˚
2), a = 8.5857(7), b = 11.473(4), c = 15.024(1) A, α = 77.64(2) , β = 89.36(1) , γ =
◦
3
˚
89.71(2) , and V = 1445.5(5) A , lucidin crystallises in space group P21/c (No.14), a =
◦
3
˚
˚
16.800(6), b = 9.637(2), c = 7.073(7) A, β = 98.01(5) , and V = 1134(1) A .
KEY WORDS: Madder root; mollugin; lucidin; Rubia tinctorum.
Introduction
Present work aims to provide primary analytical
standards of two mutagenic components of the
madder root.
Experimental
Plant material
Pigments extracted from the roots of Rubia
tinctorum belong to the oldest natural col-
orants (madder colour). In modern medicine they
have found use for the treatment of kidney
stones and as antimicrobial agents.1 Lucidin (1,3-
dihydroxy-2-hydroxymethyl-anthraquinone) and
lucidin primeveroside sometimes occurring in
Rubia tinctorum, are apparently responsible for
the potential mutagenic and genotoxic activity of
the madder root extracts.2–4 Recently, drosophila
wing spot test revealed that naphthoquinone mol-
lugin can also contribute to the mutagenity of
Rubia tinctorum extracts.5 However, the general
problem of madder colour analysis is the lack of
standards. The majority of pigments present in
Rubia tinctorum are not commercially available.
Rubia tinctorum roots from Iran were used
for preparative isolation of xanthopurpurin. Dried
plant roots (500 kg) were extracted with methanol
(12,000 L). The extract was concentrated on a
vacuum drier to 500 kg, conc. hydrochloric acid
was added (36%, 150 L) and hydrolysis of isolated
glycosides was carried out in 12 h, at 80◦C. Crude
pigments were isolated by filtration, rinsed with
water and dried (yield 33 kg).
A mixture of pigments (1 kg) was mixed with
diethyl ether (2:l) and stirred for 24 h. The soluble
part was separated by filtration and the insolu-
ble precipitate was rinsed with diethyl ether (1:l).
Pooled filtrates were mixed with n-hexane (1:1,
v/v), insoluble precipitate was removed (38 g),
and the solution was applied on silica gel (Silica
gel 60, Grace, 1.5 kg). Purified pigments were
obtained by subsequent elution with mixtures of
(1) IVAX Pharmaceuticals, Research Unit, Branisˇovska´, Ceske´
ˇ
Budeˇjovice, Czech Republic.
(2) IVAX Pharmaceuticals, Ostravska´, Opava, Czech Republic.
(3) Department of Solid State Chemistry, Institute of Chemical Tech-
nology, Prague, Technicka´, Prague, Czech Republic.
(4) Institute of Microbiology, Academy of Sciences of the Czech
Republic, V´ıdenˇska´, Prague, Czech Republic.
∗To whom correspondence should be addressed; e-mail: alexandr
jegorov@ivax-cz.com.
621
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1074-1542/05/0800-0621/0 2005 Springer Science+Business Media, Inc.

ˇ
622
Jegorov, Cvak, Cejka, Kratochv´ıl, Sedmera, and Havl´ıcˇek
Spectral data
diethyl ether/hexane = 3:7 v/v (175 g, xanthop-
urpurin, mollugin, 3,4-dihydromollugin), 2:3 v/v
(35 g, xanthopurpurin, alizarin), and 1:1 v/v (19 g,
2-methyl-1,3,6-trihydroxy-9,10-anthraquinone).
NMR spectra were measured with a Varian
INOVA-400 spectrometer (399.90 MHz for H,
1
100.57 MHz for 13C) at 30◦C in the solvents
stated. Chemical shifts are given on the δ-scale
(ppm) and coupling constants in Hz. Signal as-
signment is based on COSY, HMQC, and HMBC
experiments. Numbering of atoms according to
chemical nomenclature is used for the NMR
data (Fig. 1). Since this chemical numbering is
not applicable for substituents and symmetry in-
dependent molecules, consecutive numbering of
atoms is used for the X-ray data (Figs. 2 and 3).
Electrospray ionisation (ESI) mass spectra were
recorded on a Finnigan LCQ-DECA quadrupole
ion trap mass spectrometer (ThermoQuest, San
Jose, U.S.A.). The high-resolution mass spec-
trum of lucidin was measured on a Finnigan
MAT 95 (double-focusing, BE geometry)
instrument.
Isolation of xanthopurpurin and mollugin
Naphthoquinones mollugin and dihydromol-
lugin were isolated from the fraction diethyl
ether/hexane: 3:7 containing a mixture of xan-
thopurpurin, mollugin, and 3,4-dihydromollugin.
Crude pigments (30 g) were heated under reflux
with n-heptane (250 mL) for 1 h. The insoluble
fraction containing xanthopurpurin was separated
by filtration, rinsed with n-heptane (100 mL) and
dried (yield 15 g). Pure xanthopurpurin was ob-
tained by repeated crystallisation from diethyl
ether. Pooled filtrates containing mollugin and
3,4-dihydromollugin were evaporated and mol-
lugin was separated from 3,4-dihydromollugin by
repeated crystallisation from hot acetone. Alter-
natively, mollugin and 3,4-dihydromollugin were
separated by preparative HPLC on a reversed
phase column (Column 250 × 25 mm I.D., C-18,
7 µm, isocratic elution with an aqueous acetoni-
trile (72:28, v/v), flow 5 mL min−1, detection at
320 nm.
Synthesis and characterization of lucidin
Lucidin was synthesised according to a
modified procedure.6 Xanthopurpurin (180 mg)
was dissolved in methanol (80 mL) and aque-
ous sodium hydroxide (650 mg in 3 mL) and
formaldehyde (30%, 5 mL) were subsequently
added with stirring. After 5 h of stirring at ambient
temperature, distilled water was added (160 mL)
and the pH was adjusted with aqueous H3PO4
(10%) using lucidin itself as an indicator (sharp
transition from deep violet to orange). Fine micro
crystals of lucidin were separated by filtration,
washed with a methanol/water mixture (1:2, v/v)
in order to remove trace impurities of other an-
thraquinones present already in the original xan-
thopurpurin (particularly alizarin), and dried in
vacuo.
Fig. 1. Structure of mollugin (top) and lucidin (bottom).

Crystal structures of mollugin and lucidin
623
(1 H, ddd, J = 8.3, 1.3, 0.7 Hz, H-10), 8.378 (1 H,
ddd, J = 8.3, 1.4, 0.7 Hz, H-7), 12.159 (1 H, s,
OH). 13C NMR (CDCl3, 30◦C): 26.86 q (2 C,
Me2), 52.21 q (OMe), 74.63 s (C-2), 102.23 s (C-
5), 112.54 s (C-4a), 121.90 d (C-10), 122.28 d
(C-4), 124.01 d (C-7), 125.09 s (C-6a), 126.25 d
(C-8), 128.81 d (C-3), 129.01 s (C-10a), 129.28 d
(C-9), 141.57 s (C-11), 15−6.46 s (C-6), 172.44 s
---
---
(C O). ESI MS: [M H] at m/z 283, the CID
---
of the deprotonated molecule revealed ions at m/z
269 (10%), 251 (100%), 224 (16%) and peak at
m/z 209 (35%). Proton NMR spectrum roughly
corresponds to that found in literature.7
Lucidin
1H NMR (d6-DMSO): 4.531 (2 H, s, CH2O),
7.228 (1 H, s, H-4), 7.875 (1 H, ddd, J = 7.4,
7.4, 1.7 Hz, H-6), 7.907 (1 H, ddd, J = 7.4, 7.4,
1.8 Hz, H-7), 8.124 (1 H, dd, J = 7.4, 1.8 Hz,
H-5), 8.189 (1 H, dd, J = 7.4, 1.7 Hz, H-8),
13.166 (1 H, s, 1-OH). 13C NMR (d6-DMSO):
51.41 t (CH2O), 107.96 d (C-4), 109.19 s (C-
9a), 120.40 s (C-2), 126.49 d (C-8), 126.86 d (C-
5), 132.95 s (C-10a), 133.13 s (C-8a), 133.43 s
(C-4a), 134.58 d (C-6), 137.74 d (C-7), 163.21 s
(C-1), 164.74 s (C-3), 181.89 s (C-10),−186.31
Fig. 2. ORTEP drawing of mollugin with the atom num-
bering scheme. Thermal ellipsoids are drawn at the 50%
probability level.
Mollugin
1H NMR (CDCl3, 30◦C): 1.505 (6 H, s,
CMe2), 4.002 (3 H, s, OMe), 5.675 (1 H, d,
J = 10.1 Hz, H-3), 7.116 (1 H, d, J = 10.1 Hz,
H-4), 7.512 (1 H, ddd, J = 8.3, 6.9, 1.3 Hz, H-8),
7.615 (1 H, ddd, J = 8.3, 6.9, 1.4 Hz, H-9), 8.183
---
s (C-9). APCI MS: 269 (100, [M H] ), −252
---
(96), 239 (48), 224 (15). ESI MS: [M H] at
m/z 269.0445, for C15H905 calculated 269.0450.
Crystallography
A summary of crystallographic data is given
in Table 1, bond lengths and angles are sum-
marised in Tables 2 and 3. The structures were
solved by direct methods and anisotropically re-
fined by full-matrix least squares. The following
programs were used for calculations and visual-
isations: CRYSTALS,8 PARST,9 SHELXS86,10
ORTEP-3,11 and Mercury.12
Mollugin
Needle crystals were obtained by cooling of
the mollugin solution in hot acetone. Hydrogen
Fig. 3. Packing scheme for mollugin. Projection along c-axis.

ˇ
624
Jegorov, Cvak, Cejka, Kratochv´ıl, Sedmera, and Havl´ıcˇek
Table 1. Crystal Data and Structure Refinement
Mollugin
Lucidin
CCDC no.
Color/shape
Chemical formula
Formula weight
Crystal system
Space group
184039
Yellow/needles
C17H16O4
283.31
Triclinic
P-1
8.5857(7)
11.473(4)
15.024(1)
77.64(2)
89.36(1)
89.71(2)
1445.5(5)
4
1.302
184038
Yellow/needles
C15H10O5
270.24
Monoclinic
P21/c
16.800(6)
9.637(2)
7.073(7)
90
98.01(5)
90
˚
a (A)
˚
b (A)
˚
c (A)
α (◦)
β (◦)
γ (◦)
3
˚
V (A )
1134(1)
4
1.583
Z
Dcalc (g cm−3
)
Crystal dimensions (mm)
Diffractometer and radiation used
0.07 × 0.25 × 0.28
0.14 × 0.25 × 0.46
Enraf-Nonius CAD4, CuKα,
˚
λ = 1.54184 A
Scan technique
ω/2θ
Temperature
293 K
No. and θ range of reflections for
lattice parameter refinement
Range of h, k, and l
Standard reflections monitored in the interval; 60 min; 2.4%
intensity fluctuation
20; 38–40◦
−10 → 10, −13 → 13, −18 → 18 −20 → 20, −11 → 11, 0 → 8
60 min; −0.43%
Total number of reflections
measured; 2θ range
10,377; 5–136◦
4,366; 5–136◦
No. of observed reflections
Criterion for observed reflections
Function minimised
Weighting scheme
Parameters refined
4,052
1,076
I ≥ 1.96σ(I)
w(|Fo| − |Fc|)2
Chebychev polynomial13
181
379
Value of R, wR, and S
0.0644, 0.0643 and 1.086
0.0006
0.1212, 0.1205 and 1.1853
0.000061
Ratio of the maximum least-squares
shift to e.s.d. in the last cycle
Maximum and mininimum heights
in final ρ map
−3
−3
˚
˚
0.35, −0.48 eA
0.75, −0.64 eA
atoms were localised from ρ-maps and expected
expected geometry. Those hydrogen atoms of al-
geometry. The position of H801 was set to fol-
cohol groups were found in the ρ map.
---
low the O1 H801· · ·O2 intra-molecular hydro-
---
gen bond, according to the O51 H851· · ·O52,
Results and discussion
found from the ρ-map.
Mollugin and 3,4-dihydromollugin were iso-
lated taking advantage of their solubility in
aliphatic hydrocarbons, which makes it possi-
ble to separate them from Rubia tinctorum an-
thraquinones. Thus short boiling of the crude xan-
thopurpurin, mollugin, and 3,4-dihydromollugin
Lucidin
Needle crystals were obtained by slow evap-
oration of the solution containing lucidin (50 mg),
methanol (16 mL) and conc. aqueous ammonium
(4 mL). Hydrogen atoms were located from the

Crystal structures of mollugin and lucidin
625
◦
◦
˚
˚
Table 2. Bond Lengths (A) and Angles ( ) for Mollugin
Table 3. Bond Lengths (A) and Angles ( ) for Lucidin
˚
˚
Bond lengths (A)
Bond lengths (A)
----
----
O51 C51
O1 C1
1.352(2)
1.222(2)
1.322(2)
1.446(2)
1.356(2)
1.226(2)
1.318(2)
1.447(2)
1.3730(19)
1.461(2)
1.384(3)
1.426(3)
1.454(2)
1.472(2)
1.372(2)
1.467(2)
1.420(2)
1.369(3)
1.410(2)
1.401(3)
1.361(3)
1.410(3)
1.416(2)
1.330(3)
1.497(3)
1.515(3)
1.519(3)
----
----
1.347(8) C5 C6
O1 C1
1.386(9)
----
O2 C11
----
O52 C61
----
O2 C15
----
1.430(9) C5 C13
1.373(10)
1.388(12)
1.359(11)
1.407(8)
1.464(7)
1.48(1)
1.469(9)
1.510(8)
1.409(8)
1.393(9)
----
----
O53 C61
O3 C11
----
----
1.364(7) C6 C7
O3 C3
----
O3 C12
----
O53 C62
----
O4 C10
----
1.217(8) C7 C8
----
----
O4 C4
1.3657(19) O54 C54
----
----
1.232(7) C8 C14
O5 C9
----
O4 C15
----
1.4564(19) O54 C65
----
C1 C2
----
1.423(8) C9 C11
----
----
C1 C2
1.389(3)
1.425(2)
1.444(2)
1.473(2)
1.374(2)
1.472(2)
1.427(2)
1.365(3)
1.411(2)
1.398(3)
1.361(3)
1.411(2)
1.411(2)
1.326(3)
1.503(3)
1.513(3)
1.523(3)
C51 C52
----
----
1.393(9) C9 C14
C1 C11
----
C1 C9
----
C51 C59
----
C2 C3
----
1.384(10) C10 C12
----
----
C2 C3
C52 C53
----
----
1.512(9) C10 C13
C2 C15
----
C2 C11
----
C52 C61
----
C3 C4
----
1.384(10) C11 C12
----
----
C3 C4
C53 C54
----
----
1.396(8) C13 C14
C4 C12
----
C3 C13
----
C53 C63
Bond angles (◦)
O1 C1 C2
---- ----
O1 C1 C11
C2 C1 C11
---- ----
C1 C2 C3
C1 C2 C15
---- ----
C3 C2 C15
O3 C3 C2
---- ----
O3 C3 C4
C2 C3 C4
---- ----
C3 C4 C12
C6 C5 C13
C5 C6 C7
C6 C7 C8
C7 C8 C14
O5 C9 C11
----
----
C4 C10
C54 C60
---- ----
----
----
----
----
117.3(6)
121.1(5)
121.6(6)
116.6(6)
121.4(5)
122.0(5)
116.5(6)
120.3(6)
123.1(5)
119.6(6)
120.3(6)
119.4(7)
120.4(6)
121.2(6)
121.8(6)
120.6(5)
117.5(5)
O4 C10 C12 123.5(5)
----
C5 C6
----
C55 C56
O4 C10 C13 119.7(6)
---- ----
----
----
C5 C10
C55 C60
---- ----
C12 C10 C13 116.8(5)
---- ----
----
C6 C7
----
C56 C57
C1 C11 C9
---- ----
119.8(5)
----
----
C7 C8
C57 C58
---- ----
C1 C11 C12 119.4(5)
---- ----
----
C8 C9
----
C58 C59
C9 C11 C12 120.8(5)
---- ----
----
----
C9 C10
C59 C60
---- ----
C4 C12 C10 118.5(5)
---- ----
----
C13 C14
----
C63 C64
C4 C12 C11 119.5(6)
---- ----
----
----
C14 C15
C64 C65
---- ----
C10 C12 C11 122.0(5)
---- ----
----
C15 C16
----
C65 C66
C5 C13 C10 119.2(6)
---- ----
----
----
C15 C17
C65 C67
Bond angles (◦)
C11 O3 C12
C4 O4 C15
O1 C1 C2
O1 C1 C9
C2 C1 C9
C1 C2 C3
C1 C2 C11
---- ----
C3 C2 C11
C2 C3 C4
C2 C3 C13
C4 C3 C13
O4 C4 C3
---- ----
O4 C4 C10
C3 C4 C10
---- ----
C6 C5 C10
---- ----
---- ----
---- ----
---- ----
---- ----
---- ----
---- ----
C5 C13 C14 121.0(6)
---- ----
C10 C13 C14 119.7(6)
---- ----
---- ----
---- ----
---- ----
---- ----
---- ----
---- ----
---- ----
----
----
----
116.87(18)
116.19(12)
123.50(16)
115.31(15)
121.19(15)
119.61(15)
116.40(16)
123.84(16)
118.56(15)
125.85(16)
115.40(15)
122.41(14)
115.08(14)
122.39(14)
120.38(16)
120.61(17)
120.18(17)
120.86(16)
121.95(15)
119.18(15)
118.84(16)
122.25(14)
118.64(15)
119.10(15)
121.17(17)
123.82(18)
115.00(16)
119.30(17)
C61 O53 C62 116.72(18)
----
C8 C14 C9
---- ----
119.8(6)
C54 O54 C65 116.35(13)
---- ----
C8 C14 C13 117.7(6)
---- ----
O51 C51 C52 123.41(16)
---- ----
C9 C14 C13 122.5(5)
---- ----
O51 C51 C59 115.04(15)
---- ----
C52 C51 C59 121.53(15)
---- ----
O5 C9 C14
C11 C9 C14
O2 C15 C2
112.7(6)
C51 C52 C53 119.28(16)
---- ----
C51 C52 C61 116.93(16)
---- ----
C53 C52 C61 123.69(16)
---- ----
---- ----
---- ----
---- ----
---- ----
C52 C53 C54 118.32(15)
---- ----
C52 C53 C63 125.53(16)
---- ----
mixture with n-heptane provided pure insoluble
xanthopurpurin and a mixture of mollugin and
3,4-dihydromollugin in solution. The presence of
3,4-dihydromollugin was inferred from its mass
spectrum and several NMR signals observed in
spectrum of crude mollugin (singlets at 1.413
and 4.015 ppm, triplets at 1.839 and 3.065 ppm,
J = 6.8 Hz) giving a good match to the literature
values.14
Mollugin (Figs. 1–3) crystallises as an an-
hydrate. There is an apparent pseudo-symmetry
manifested by two cell angles fairly close to
90◦. The merging of reflections for monoclinic
setting (a unique) provided R-merge values of
0.77 compared with 0.023 for triclinic setting
providing thus proof that the triclinic cell is
correct. There are two independent molecules
in the asymmetric unit, which differ in puck-
ering parameters of the 2,2-dimethyl-2H-pyrane
C54 C53 C63 115.99(16)
---- ----
O54 C54 C53 122.04(14)
---- ----
O54 C54 C60 114.74(14)
---- ----
---- ----
C53 C54 C60 123.04(15)
---- ----
C56 C55 C60 120.40(16)
---- ----
---- ----
C5 C6 C7
---- ----
C6 C7 C8
C7 C8 C9
---- ----
C1 C9 C8
C1 C9 C10
---- ----
C8 C9 C10
C55 C56 C57 120.61(18)
---- ----
C56 C57 C58 120.10(17)
---- ----
---- ----
C57 C58 C59 120.97(17)
---- ----
C51 C59 C58 121.89(16)
---- ----
---- ----
C51 C59 C60 119.14(15)
---- ----
C58 C59 C60 118.93(16)
---- ----
----
----
C4 C10 C5
---- ----
C54 C60 C55 122.71(15)
---- ----
C4 C10 C9
---- ----
C54 C60 C59 118.32(15)
---- ----
C5 C10 C9
---- ----
C55 C60 C59 118.97(15)
---- ----
O2 C11 O3
---- ----
O52 C61 O53 121.28(17)
---- ----
O2 C11 C2
---- ----
O52 C61 C52 123.18(18)
---- ----
O3 C11 C2
---- ----
O53 C61 C52 115.53(16)
---- ----
C3 C13 C14
---- ----
C53 C63 C64 119.39(17)
---- ----
C13 C14 C15 120.32(16)
C63 C64 C65 120.73(16)
---- ----
----
----
O4 C15 C14
107.37(15)
104.15(14)
O54 C65 C64 107.79(15)
---- ----
---- ----
O4 C15 C16
---- ----
O54 C65 C66 104.13(15)
---- ----
C14 C15 C16 113.14(17)
---- ----
C64 C65 C66 113.08(17)
---- ----
O4 C15 C17
---- ----
108.95(15)
O54 C65 C67 108.55(15)
---- ----
C14 C15 C17 111.53(16)
---- ----
C64 C65 C67 111.31(18)
---- ----
C16 C15 C17 111.28(17)
C66 C65 C67 111.57(18)

ˇ
Jegorov, Cvak, Cejka, Kratochv´ıl, Sedmera, and Havl´ıcˇek
626
ring. The existence of two possible conforma-
tions of 2,2-dimethyl-2H-pyrane results from the
presence of two sp3-hybridised atoms and both
conformers have been found in 2,2-dimethyl-
2H-pyrane-containing structures without any ap-
parent preference. However, the puckering pa-
rameters of the 2,2-dimethyl-2H-pyrane ring
in mollugin are unusually high (ϕ1 = −41.91◦,
tals influenced also the resulting R-factor. Since
the attempts of truncating the high angle data re-
sulted in insignificant lowering of the R-factor
only, all measured data were used for the refine-
ment. The structural study of lucidin (Figs. 1,
4 and 5) was carried out also in order to eluci-
date its striking insolubility in practically all sol-
vents. There are different types of packing found
in structures of natural anthraquinones reported
so far.15–20 The molecules are mostly bound to
each other by π–π interactions forming various
cross-linked motifs, frequently in columns involv-
ing various parts of the anthraquinone molecule
in the π–π stacking. Lucidin molecules are
close packed in L-shape pillars in the c-axis, all
ring oxygen atoms are involved in the stacking
(Fig. 5). There are two intramolecular hydro-
◦
◦
˚
θ1 = 69.14 , Q1 = 0.419 A; ϕ2 = −135.55 ,
◦
˚
θ2 = 110.21 , Q2 = 0.435 A). Two independent
molecules in the asymmetric unit with such high
puckering parameters have been found appar-
ently with 3,12-dihydro-3,3,6,12-tetramethyl-7H-
pyrano(2,3-c)acridin-7-one only. In the crystal,
molecules are packed into pillars along the a-axis,
and each molecule is bound to its centrosym-
metric neighbour giving a broad double-pillar
(Fig. 3). An intramolecular hydrogen bond in-
---
---
gen bonds O1 H· · ·O5 and O3 H· · ·O2. The
---
volving O1 H· · ·O2 was found.
packing is stabilised by two bifurcated hydrogen
---
---
Lucidin tends to crystallise in a form of fi-
brous needles, which are far from to be suit-
able for X-ray crystal structure determination.
The use of a trick consisting in the crystalli-
sation of lucidin from its ammonium phenolate
solution was only manner providing few measur-
able lucidin crystals. The poor quality of crys-
bonds O2 H· · ·O4 (x, y + 1, z), d(O2 O4) =
◦
˚
---
3.392(6) A, angle O2 H· · ·O4=130(7) and
---
O2 H· · ·O3 (−x + 1, +y + 1/2, −z + 1/2),
˚
---
---
d(O2 O3) = 2.654(6) A, angle O2 H· · ·O3 =
119(6)◦. The complex hydrogen bonding system
seems likely to explain the insolubility of lucidin.
It is also worth to mention that the close packing is
Fig. 4. ORTEP drawing of lucidin with the atom numbering scheme. Thermal ellipsoids
are drawn at the 50% probability level.

Crystal structures of mollugin and lucidin
627
Fig. 5. Packing scheme for lucidin. Projection along c-axis.
7. Itokawa, H.; Mihara, K.; Takeya, K. Phytochemistry 1983, 31,
2352.
most probably responsible also for a remarkably
high density of lucidin.
8. Watkin, D.J.; Carruthers, R.J.; Betteridge, P. Crystals; Chemical
Crystallography Laboratory: Oxford, UK 1998; Issue 10.
9. Nardelli, M. PARST, a system of computer routines for calcu-
lating molecular parameters from results of crystal structure
analysis; University of Parma, 1998.
10. Sheldrick, G.M. SHELXS86, Program for Crystal Structure So-
lution; University of Go¨ttingen 1986.
11. Farrugia, L.J. J. Appl. Cryst. 1997, 30, 565.
12. Bruno, I.J.; Cole, J.C.; Edgington, P.R.; Kessler, M.K.; Macrae,
C.F.; McCabe, P.; Pearson, J.; Taylor, R. Acta Crystallogr. B
2002, 58, 389.
Supplementary material
CCDC 184038 (lucidin) and
184039 (mollugin) contain the supplementary crystallographic
data for this paper. These data can be obtained free of
charge via www.ccdc.cam.ac.uk/data request/cif, by e-mailing
data request@ccdc.cam.ac.uk, or by contacting The Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: +44(0)1223-336033.
13. Carruthers, J.R.; Watkin, D.J. Acta Crystallogr. A 1979, 35,
698.
14. Ho, L.K.; Don, M.J.; Chen, H.C.; Yeh, S.F.; Chen, J.M. J. Nat.
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