UDC 547.972A study has been made of the phenolic compounds of Geranium sanguineum. One tannin of the hydrolyzable series has been isolated from the epigeal part, and for this the structure of 1,3-bis-O-digalloyl-2-O-galloyl-4, 6-(hexahydroxydiphenoyl) [13], and other types of activity [14][15][16][17][18][19][20][21][22][23]. All this accounts for the great interest in the study of the structure of this class of natural compounds.We have reported previously that flavanols, phenolic acids, and hydrolyzable tannins have been isolated from the epigeal part of Geranium sanguineum -blood-red geranium -and have been characterized; two of them -bis0aexahydroxy-diphenoyl)trigalloylglucose and 1,2,3-tri-O-gaUoyl-4,6-(hexahydroxydiphenoyl)-/~-D-glucose -proved to be new compounds, not previously described in the literature [24, 25].We have continued the study of the polyphenols of this plant. Using the procedure described in [24], the polyphenolic complex of the epigeal part of the plant was subjected to fractionation on a column of rawhide powder. The total polyphenols isolated from an aqueous acetone fraction were chromatographed on a column of silica gel using eluent systems 3 and 4. In the case of system 4, fractions were obtained containing a substance with Rf 0.43, contaminated with a substance having Ry 0.40 (system 1). After rechromatography on a column of silica gel, a substance was isolated that consisted of a f'mely disperse powder, light yellow with a greenish tinge, having mp 261~ UV spectrum of the substance (MeOH, kmax, nm): 226, 276 (log e 4.80, 4.34).The products of the complete acid hydrolysis of the substance obtained were gallic acid, glucose, and eUagic acid, in a ratio of 5:1:1, respectively. The gallic acid was determined colorimetrically [26], the ellagic acid gravimetrically, and the glucose by the semimicromethod of determining sugars [27]. Together with other compounds, 2-O-galloylglucose was detected among the products of mild acid hydrolysis. The rate of hydrolytic splitting out of the hexahydroxydiphenie acid showed that it esterified the hydroxy groups of the fourth and sixth atoms of glucose.In the IR spectrum of the substance we observed an absorption band in the 3500-3100 cm -1 region, showing the presence of free and bound hydroxy groups in the molecule. In the PMR spectrum (acetone-d6) there were overlapping signals of the protons of galloyl and hexahydroxydiphenoyl groups in the 7.20-6.65 ppm region. The signal of one of the glucose protons appeared at 6.60 ppm (1H) and those of the other six protons in the 5.60-4.21 ppm region. On the basis of the only slight change in the chemical shifts of the glucose protons and the considerable displacement of the signals of the aromatic protons of the acetylated substance into the weak-field region, it could be concluded that all the hydroxy groups of the glucose were substituted and only the phenolic hydroxyls were acetylated.A comparison of the results of chemical transformations and of spectral investigations of this compound with literature i...
