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In continuation of research on isoprenoids from plants of the genus Astragalus [1], we isolated from leaves of A. caucasicus Pall. (Leguminosae L.) compounds called cycloascaulosides A, B, and C. Herein the structure of cycloascauloside A is reported.The PMR spectrum of cycloascauloside A (1) contained two 1H doublets coupled in an AB-type system at 0.39-0.54 ppm with SSCC 2 J = 4.5 Hz in addition to signals for seven methyls at 0.80-1.78 ppm. This enabled 1 to be considered as a cycloartane triterpenoid [1][2][3]. This conclusion was confirmed by absorption bands in the IR spectrum at 3045 and 1452 cm -1 and the preparation of cyclogalegigenin (2) upon acid hydrolysis of 1 and its Smith decomposition [2][3][4]. The carbohydrate part of the hydrolysate contained D-glucose and L-rhamnose in a 1:1 ratio according to paper (PC) and gas chromatography [5]. 1: R = α-L-Rhap-(1→6)-β-D-(2-O-Ac)-Glcp 2: R = H 3: R = α-L-Rhap-(1→6)-β-D-Glcp 4: R = β-D-GlcpThe IR spectrum of 1 exhibited absorption bands at 1755 and 1240 cm -1 (ester); the PMR spectrum, a 3H singlet at 1.98 ppm belonging to an acetyl. As expected, the 13 C NMR spectrum of 1 contained signals for C atoms of one acetyl at 19.70 and 170.02 ppm.Glycoside 1 treated with dilute base solutions gave progenin 3, which underwent partial hydrolysis. The resulting products included cyclogalegigenin and glycoside 4, acid hydrolysis of which gave D-glucose and genin 2. Therefore, D-glucose was directly bound to cyclogalegigenin.

Astragalus galagiformis stems. The structure of the glycoside was established using chemical transformations and IR, PMR, and 13 C NMR spectral data.We have previously isolated from A. galegiformis L. stems and identified cycloartane glycosides cyclogaleginosides A, B, and E [2, 3]. In continuation of chemical research on isoprenoids from plants of the genus Astragalus (Leguminosae) [1], we isolated in addition to the aforementioned glycosides another two polar glycosides C and D. Herein the structure of cyclogaleginoside D (1) is examined.The PMR spectrum of 1 contained a 1H doublet for an AX system at 0.38 and 0.54 ppm with SSCC 2 J = 4.5 Hz in addition to signals for seven methyls in the range 0.91-1.41 ppm. This indicated that the compound was a triterpenoid cycloartane [1]. This was consistent with the isolation of cyclogalegigenin (3) as the genin from the acid-hydrolysis products of cyclogaleginoside D. Paper chromatography detected D-xylose and D-glucose in the carbohydrate part of the acid-hydrolysis products. The PMR and 13 C NMR spectra of 1 (Table 1) contained signals for two carbohydrate units and indicated that the studied glycoside was a bioside.A 3H singlet at 2.10 ppm in the PMR spectrum of 1 was consistent with one acetic acid moiety. As expected, the 13 C NMR spectrum of 1 contained signals for C atoms of one acetyl at 21.1 and 169.5 ppm.Alkaline hydrolysis of 1 gave glycoside 2, which was identified as cyclogaleginoside E [3]. Therefore, cyclogaleginoside D is cyclogaleginoside E monoacetate.The attachment site of the acetyl was found by comparing the 13 C NMR spectra of 1 and 2. Atoms C-6 and C-16 of 1 resonated in the 13 C NMR spectrum of 1 at 69.07 and 74.40 ppm, respectively. These values were practically the same as those in the 13 C NMR spectrum of 2. This means that the acetyl is not located on the genin of 1.

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Among the biologically active substances, the roots of Cephalaria gigantea mainly contain alkaloids, phenolic compounds and triterpene glycosides. Studies have shown that the total amount of saponins is less than 14 glycosides. Eleven individual compounds have been isolated, named giganteosides A,