Modification of the titrimetric method of analyzing pectin substances

A potentiometric variant of the titrimetric method of analyzing pectin substances has been developed which is distinguished by adequate accuracy and good reproducibility. The modified method has been tested on methyl (methyl 2,3-di-O-methyl-,-galactopyranosid)uronate and has been used for determining the free (K_f) and esterified (K_e) carboxy groups of the pectin substances of mint. The methods of isolating, purifying, and fractionating the pectin substances and determining their K_f and K_e values are given. Formulas are presented for calculating the percentage values of K_f and K_e.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 428–431, July–August, 1984.     

Triterpene glycosides ofHedera helix II. Determination of the structure of glycoside L-6d from common ivy leaves

A new hederagenin pentaoside — glycoside L-6d — has been isolated from the leaves of common ivyHedera helix L., fam. Araliaceae, and its structure has been determined by using various NMR-spectroscopic methods. Glycoside L-6d is hederagenin 3-O-[O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside.     

Triterpene glycosides ofScheffleropsis angkae. II. Structure of glycosides L-E1, L-E2, L-K1, and L-K2

The structures of four triterpene glycosides from leaves ofScheffleropsis angkae (Araliaceae) are established using chemical and NMR methods. The structures 3-O--D-glucopyranosyl-(1-3)-O--L-arabinopyranosides of oleanic and ursolic acids and their 28-O--L-rhamnopyranosyl-(1-4)-O--gentiobiosyl ethers are proposed for L-E₁, L-E₂, L-K₁, and L-K₂, respectively. L-K₁ and L-K₂ are new triterpene glycosides.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 239–241, May–June, 2000.     

Synthesis of glycosidic analogues of N-acetylneuramoyl-L-alanyl-D-isoglutamine

β-Heptyl and β-hexadecyl glycosides of N-acetylglucosamine have been obtained by the oxazoline method followed by deacetylation. Via a benzylidenation stage, the glycosides have been converted into the corresponding N-acetylmuramic acid derivatives and from these compounds glycosidic analogues of N-acetylmuramoyl-L-alanyl-D-isoglutamine have been synthesized.     

Triterpene glycosies of Hedera taurica VIII. Taurosides F1, F2, and F3 and a triterpenoid sulfate

M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 860–861, November–December, 1991.     

Triterpene Glycosides of Fatsia japonica. IV. Structure of Glycosides D1 and D2 from Seeds

Seeds ofFatsia japonica(Araliaceae) afforded the known hederagenin 3-O--D-glucopyranosyl-(12)-O--L-arabinopyranoside and the new triterpene glycoside D ₂ , for which the structure hederagenin 3-O--D- galactopyranosyl-(12)-O--L-arabinopyranoside was proposed based on chemical methods and NMR spectroscopy     

Interaction of pectin substances with copper,mercury, zinc,and cadmium salts

The interaction of the sage, mint, apple, and ginseng pectins, isolated from tissue culture wastes and purified with copper, mercury, zinc, and cadmium salts, has been studied by the amperometric method with two metal indicator electrodes. The optimum conditions of titration have been determined: pH 3.5–5.0; concentration of pectin substances 5·10^–5-1·10^–3 g/ml of solution. It has been established by graphical and mathematical methods that the interaction is accompanied by the formation of compounds with a ratio of the carboxy groups of pectins to the metal cation of two. The IR spectra of sage pectin and of copper and mercury pectinates are given.M. V. Frunze, Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 171–175, March–April, 1988.     

Triterpene glycosides of Hedera taurica VI. Structures of hederosides G,H1, H2, and I from the berries of Crimean ivy

We have isolated from Crimean ivy berries in addition previously known triterpene glycosides — 3-O-α-L-arabinopyranosyl-28-O-[O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glycopyranosyl-(1 → 6)-β-D-glucopyranosyl]hederagenin, 3-O-[O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl]-28-O-[O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-β-D-glycopyranosyl]hederagenin, the new triterpene glycosides hederoside H₂-3-O-[O-β-D-glycopyranosyl-(1 → 2)-β-D-glycopyranosyl-(1 → 2)-β-D-glucopyranosyl]-28-O-[O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]oleanolic acid- and hederoside I-3-O-[O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosyl]-28-O-[O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]hederagenin. Details of their¹³C NMR spectra are given. M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 779–783, November–December, 1990.