Angewandte
Chemie
5 (22 mg, 17%), 6 (42 mg, 33%), and 7 (38 mg, 30%) as colorless
solids.[15]
305 – 324; e) M. Tanaka, C. Mukaiyama, H. Mitsuhashi, M.
Maruno, T. Wakamatsu, J. Org. Chem. 1995, 60, 4339 – 4352.
[8] a) J. Chiarello, M. M. JoulliØ, Tetrahedron 1988, 44, 41 – 48; b) T.
Sala, M. V. Sargent, J. Chem. Soc. Perkin Trans. 1 1981, 855 – 869.
[9] a) R. G. F. Giles, M. V. Sargent, Aust. J. Chem. 1986, 39, 2177 –
2181; b) G. Billen, U. Karl, T. Scholl, K. D. Stroech, W. Steglich
in Natural Products III (Eds.: Atta-ur-Rahman, P. W. Le
Quesne), Springer, Berlin, 1988, p. 305 – 315; c) F. M. Hauser,
P. J. F. Gauuan, Org. Lett. 1999, 1, 671 – 672.
[10] The tetramethoxy derivative of the unsymmetrical dimer 7 was
obtained as a minor side product by Ullmann reaction of the 3,5-
diiodo orsellinate: U. Karl, PhD thesis, Rheinische Friedrich-
Wilhelms-Universität Bonn, 1988.
[11] a) E. Keinan, Y. Mazur, J. Org. Chem. 1978, 43, 1020 – 1022;
b) T. C. Jempty, L. L. Miller, Y. Mazur, J. Org. Chem. 1980, 45,
749 – 751; c) M. R. Parthasarathy, S. Gupta, Indian J. Chem. Sect.
B 1984, 23, 227 – 230; d) F. Toda, K. Tanaka, S. Iwata, J. Org.
Chem. 1989, 54, 3007 – 3009; e) H.-Y. Li, T. Nehira, M. Hagi-
wara, N. Harada, J. Org. Chem. 1997, 62, 7222 – 7227.
[12] a) R. Pummerer, H. Puttfarcken, P. Schopflocher, Ber. Dtsch.
Chem. Ges. 1925, 58, 1808 – 1820; b) J. D. Edwards, J. L. Cashaw,
J. Chem. Soc. 1954, 6141 – 6143.
5: Rf = 0.22 (isohexane/ethyl acetate, 2:1); M.p. 2468C; 1H NMR
(300 MHz, CDCl3): d = 11.81 (s, 2H, 2 OH), 6.41 (s, 2H, 2 Ar-H),
3.91 (s, 6H, 2 OCH3), 3.77 (s, 6H, 2 OCH3), 2.59 ppm (s, 6H, 2
13
¼
CH3); C NMR (75.5 MHz, CDCl3): d = 172.37 (2 C O), 161.90
(2 Cq), 161.50 (2 Cq), 143.10 (2 Cq), 107.84 (2 Cq), 106.69 (2
CH), 105.97 (2 Cq), 55.82 (2 OCH3), 51.85 (2 OCH3), 24.96 ppm
(2 CH3); MS: m/z (%): 390 (67) [M+], 358 (70) [C19H18O7+], 327 (65)
[C18H15O6+], 295 (100) [C17H11O5+]; HRMS: calcd for C20H22O8
390.1315; found 390.1311.
6: Rf = 0.33 (isohexane/ethyl acetate, 2:1); M.p. 1838C; 1H NMR
(300 MHz, CDCl3): d = 11.77 (s, 2H, 2 OH), 6.41 (s, 2H, 2 Ar-H),
3.91 (s, 6H, 2 OCH3), 3.67 (s, 6H, 2 OCH3), 2.10 ppm (s, 6H, 2
13
¼
CH3); C NMR (75.5 MHz, CDCl3): d = 172.49 (2 C O), 164.47
(2 Cq), 162.25 (2 Cq), 141.41 (2 Cq), 119.15 (2 Cq), 105.55 (2
Cq), 97.29 (2 CH), 55.69 (2 OCH3), 51.83 (2 OCH3), 19.36 ppm
(2 CH3); MS: m/z (%): 390 (47) [M+], 358 (31) [C19H18O7+], 327
(100) [C18H15O6+], 295 (100) [C17H11O5+]; HRMS: calcd for C20H22O8
390.1315; found 390.1314.
7: Rf = 0.24 (isohexane/ethyl acetate, 2:1); M.p. 1908C; 1H NMR
(300 MHz, CDCl3): d = 11.79 (s, 1H, OH), 11.74 (s, 1H, OH), 6.44 (s,
1H, Ar-H), 6.38 (s, 1H, Ar-H), 3.92 (s, 3H, OCH3), 3.90 (s, 3H,
OCH3), 3.75 (s, 3H, OCH3), 3.70 (s, 3H, OCH3), 2.60 (s, 3H, CH3),
[13] a) A. K. Gupta, H. Ila, H. Junjappa, Tetrahedron 1990, 46, 2561 –
2572; b) W. Basinski, Pol. J. Chem. 1995, 69, 376 – 384; c) the
resulting compounds presumably exist in an iminocoumarin- or
iminochromenone-like structure since the proton NMR spectra
reveal two vinyl protons but no methylene groups.
2.22 ppm (s, 3H, CH3); 13C NMR (75.5 MHz, CDCl3): d = 172.53 (C
¼
¼
O), 172.41 (C O), 164.74 (Cq), 162.34 (Cq), 161.90 (Cq), 161.35 (Cq),
142.80 (Cq), 141.64 (Cq), 115.71 (Cq), 111.16 (Cq), 106.45 (CH), 105.87
(Cq), 105.65 (Cq), 97.50 (CH), 55.81 (OCH3), 55.69 (OCH3), 51.91
(OCH3), 51.78 (OCH3), 24.94 (CH3), 19.67 ppm (CH3); MS: m/z (%):
390 (53) [M+], 358 (66) [C19H18O7+], 326 (100) [C18H14O6+]; HRMS:
calcd for C20H22O8 390.1315; found 390.1323.
[14] X-ray structure analysis of dimethyl (M)-(ꢀ)-2,2’-bis(campha-
nate)-6,6’-dimethoxy-4,4’-dimethyl-1,1’-biphenyldicarboxylate
(C40H46O14): colorless crystals, crystal dimension 0.30 0.35
0.40 mm3; M = 750.77; monoclinic, space group P21 (no. 4), a =
10.5732(2), b = 16.5829(3), c = 11.0339(2) , b = 105.317(1)8,
V= 1865.90(6) nm3,
Z = 2,
m(MoKa) = 0.101 mmꢀ1
,
T=
Received: August 16, 2002 [Z19985]
123(2) K, F(000) = 796. 20007 reflections up to 2qmax = 50.78
were measured on a Nonius Kappa-CCD diffractometer with
MoKa radiation, 6614 of which were independent and used for all
calculations (Rint = 0.035). The structure was solved by direct
methods and refined to F2 anisotropically, the H atoms were
refined with a riding model. The final quality coefficient wR2(F2)
was 0.113, with a conventional R(F) = 0.043 for 483 parameters
and 165 restraints. One carboxylate group is disordered. The
absolute structure cannot be determined reliably (Flack's
x parameter 0.2(8)). CCDC-197800 contains the supplementary
crystallographic data for this paper. These data can be obtained
from the Cambridge Crystallographic Data Centre, 12, Union
Road, Cambridge CB21EZ, UK; fax: (+ 44)1223-336-033; or
deposit@ccdc.cam.ac.uk).
[1] For leading references on both the synthesis and natural
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Sarkanen, N. G. Lewis, Science 1997, 275, 362 – 366.
[15] From fractions containing 5 and 7, the symmetric compound
crystallizes quantitatively to give after separation by centrifuga-
tion analytically pure (NMR) 5 and 7.
[3] G. Bringmann, C. Günther, E.-M. Peters, K. Peters, Tetrahedron
2001, 57, 1253 – 1259.
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