Candibrin A

 Candibrin A

 A furanocoumarin dimer from

Candibrin A

Paper Doi, M., Nakamori, T., Shibano, M., Taniguchi, M. Wang, N-.H. and Baba, K. (2004). Acta Cryst. C60, o833-o835.
Candibirin A, a furanocoumarin dimer isolated from Heracleum candicans WALL.

Copyright © International Union of Crystallography
ABSTRACT: Candibirin A (I), a new furanocoumarin dimer, was isolated from Heracleum candicans WALL. 1H NMR and MS spectra indicated that (I) was a dimer of heraclenin or heraclenol, but the linkage structure and its chirality have been unknown. The dioxane linkage having (R,R)-configurations was elucidated from dimethylsulfoxide-solvated crystals. Therefore, it was supported that (I) was a dimerization product from heraclenin by reaction of epoxy group. Moreover, the dimethylformamide solution gave the different crystal form. Its folded structure was different from the extended structure of the former, but the puckering of dioxane linkage were very similar to each other. This showed that the rotation of ether bonds, which was a linker between furanocoumarin and dioxane moieties, caused the conformational flexibility of (I).

DMSO form
One of two DMSO molecules are disordered to
two sites. Inset shows the disrodering state.

DMF form
The DMF molecule is sandwiched in
between two furanocoumarin rings.

X-Ray summary for Candibrin A

 DMSO form
    Formula         C32H28O10,2(C2H6OS)
    Mr              728.8
    System          orthorhombic
    Space group     P212121
    a               10.903(2)
    b               13.068(2) 
    c               24.400(4)
    β               90.0
    V               3476.5(11)
    Z               4
    T, K            200.0(2)
    Dx              1.392
    F(0 0 0)        1536
    Wavelength      0.7107
    μ               0.218
    NREF (obs)      30564
    Rint            0.0255
    NREF (used)     7659
    θmax            27.1
    Flack param.    0.04(6) for 3379 Friedels
    R               0.0370
    wR              0.0951
    (Δ/σ)max        0.003 
    Fraction θmax   0.999 
    Δρmax           0.397 
    Δρmin          -0.191 

    PDB coord.      kde3dmf.pdb
The absolute structure was determined from anomalous dispersion effects from the sulfur atoms of dimethylsulfoxide (DMSO).

 DMF form
    Formula         C32H28O10,C3H7NO
    Mr              645.6
    System          monoclinic
    Space group     P21
    a               8.2000(7)
    b               16.213(1)
    c               11.671(1) 
    β               97.244(1)
    V               1539.2(2)
    Z               2
    T, K            200.0(2)
    Dx              1.393
    F(0 0 0)        680
    Wavelength      0.7107
    μ               0.104
    NREF (obs)      13520
    Rint            0.0174
    NREF (used)     3516
    θ max           27.1

    R               0.0419
    wR              0.1144
    (Δ/σ)max        < 0.001 
    Fraction θmax   0.998 
    Δρmax           0.666 
    Δρmin          -0.376 

    PDB coord.      kde3dmso.pdb

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