Conversion of protopanaxadiol type saponins to ginsenoside Rg3 by lemon.

The ability of fresh lemon (Citrus limon) to convert protopanaxadiol-type saponins into ginsenoside Rg3 was investigated, and the structures of 20(S)-ginsenoside Rg3 (1) and 20(R)-ginsenoside Rg3 (2) were identified by 1H NMR and 13C NMR spectroscopy. The experiment showed that lemon possesses the strong ability to hydrolyze ginsenosides. When protopanaxadiol-type saponins (16 mg/mL) were hydrolyzed by fresh lemon juice at 80 degrees C for 3 hrs, the conversion ratios of ginsenoside Rb1, Rb2, Rc and Rd were 92.

3,3'-Diazenediyldiphthalic acid dihydrate.

In the crystal structure of the title compound, C(16)H(10)N(2)O(8)·2H(2)O, the organic mol-ecule is located on a centre of symmetry. The two benzene rings are parallel, but not coplanar, as indicated by N=N-C-C torsion angles involving the azo group of 12.1 (5) and -168.

μ-4,4'-Diazenediyldiphthalato-κO:O-bis-[penta-aqua-manganese(II)] tetra-hydrate.

The dinuclear complex in the title compound, [Mn(2)(C(16)H(6)N(2)O(8))(H(2)O)(10)]·4H(2)O, lies on an inversion center. Two delocalized carboxyl-ate groups are each connected in a monodentate fashion to two similar penta-aqua-manganese units, whereas the other two localized carboxyl-ate groups are uncoordinated. The metal ion has octa-hedral coordination, with the O atom of a carboxyl-ate group and three coordinated water mol-ecules forming the equatorial plane [Mn-O(COO) = 2.

A novel copper(II) coordination polymer with 2,2'-bipyridyl-3,3'-dicarboxylic acid.

A novel copper(II) coordination polymer, poly[[[aquacopper(II)]-mu3-2,2'-bipyridyl-3,3'-dicarboxylato-kappa4N,N':O:O'] dihydrate], {[Cu(C12H6N2O4)(H2O)].2H2O}n, was obtained by the reaction of CuCl2.2H2O and 2,2'-bipyridyl-3,3'-dicarboxylic acid (H2L) in water.