Cardenolides ofStrophanthus kombe III. 17α-Strophadogenin

17α-Strophadogenin, which is 3β,5,14,16β-tetrahydroxy-19-oxo-5β,14β-card-17βH-20(22)-enolide has been obtained in the pure form for the first time and has been studied.     

New semisynthetic cardiac glycosides and their biological activity

Digitoxigenin, digitoxin, D-xylose and L-rhamnose have been used as the starting materials for the synthesis of the new cardiac glycosides: digitoxigenin 3-O--D-xylopyranoside and digitoxin 4-O--L-rhamnopyranoside. It has been established that the compounds obtained possess comparatively high biological activities.All-Union Scientific-Research Institute of Drug Chemistry and Technology. Khar'kov Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 776–779, November–December, 1990.     

Unsteady flow around models in an electromagnetic shock tube

Results of experimental studies of the unsteady flow around models of a stream moving behind the front of a very strong shock wave excited in an electromagnetic shock tube are presented. The flow establishment time in the stagnation-point region of blunt bodies is found.     

Cardiac glycosides of Erysimum contractum. II

The structure of a new cardiac glycoside isolated from the seeds ofErysimum contractum has been established. The glycoside, which has been called nigrescigenin digilanidobioside is 3,5,11,14-tetrahydroxy-19-oxo-5,14-card-20(22)-enolide 3-O-(4-O--D-glucopyranosyl--D-digitoxopyranoside).All-Union Scientific-Research Institute of Drug Chemistry and Technology, Kharkov. G. S. Skovorod Kharkov State Pedagogic Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 693–695, September–October, 1991.     

10-chloro-19-norcardiosteroids

Substitution of the angular aldehyde by halogen in cardiosteroids in two steps was studied. The first step was oxidation of the aldehyde and production of the cooresponding 19-carboxylic acids; the second, decarboxylation of the 19-carboxylic acids using N-chlorosuccinimide or chloride salts. The 10-chloro-19norcardiosteroids: 10-chloro-19-norstrophanthidine (1), 10-chloro-19-norcymarin (2), 10-chloro-19norconvallatoxin (3), 10-chloro-19-norstrophalloside (4), and 10-chloro-19-norbovoside A (5) were prepared for the first time. The intermediates strophalloside-19-carboxylic acid and bovoside A-19-carboxylic acid were also prepared for the first time and characterized.     

Hydrophilic Interaction Chromatography on Silica: Group Analysis of Grape Anthocyanins

A group control procedure is developed, in which the anthocyanin complex of a grape extract is divided into six groups without differentiation by aglycons: 3-glucosides (Zone III); 3-glucosides acylated with p-coumaric acid (Zone I); 3-glucosides acylated with acetic acid (Zone II); 3,5-diglucosides (Zone IV); 3,5-diglucosides acylated with p-coumaric acid (Zone IV); and 3,5-diglucosides acylated with acetic acid (Zone V). The anthocyanins were separated by hydrophilic interaction chromatography in a column packed with a silica using the mobile phases of acetonitrile–water (20–8 vol %) containing 0.5 vol % of orthophosphoric acid. Due to the low viscosity of the mobile phase and the complete separation of anthocyanin groups, the procedure suitable for determining the inheritance of genetic traits in the selection of grapes is transferred to a format of microcolumn chromatography using MiLiChrome chromatographs.     

Cardiac glycosides ofAcokanthera venenata

Six cardenolides have been isolated from the leaves ofAcokanthera venenata G. Don: AV-1, mp 252–255°C, [] _D ²⁰ +39.4° (MeOH); AV-2, mp 199–208°C, [] _D ²⁰ -59.3° (MeOH); AV-3, mp 269–275°C/300–304°C, [] _D ²¹ –69.8° (MeOH); AV-4, mp 279–289°C; AV-5, mp 222–225°, [] _D ²⁰ -64.3° (MeOH); and AV-6, mp 193–196°C [] _D ²⁰ –23.8° (MeOH — CHCl₃). AV-5 has been identified as acovenoside A. AV-3 is a new cardiac glycoside: it is 1-acetoxy-3-(4-O--D-glucosyl-3-O-methyl--L-talomethylosyloxy)-14-hydroxy-5, 14-card-20(22)-enolide (glucoacovenoside B).Khar'kov State Pharmaceutical Institute. All-Union Scientific Research Institute of Drug, Chemistry and Technology, Khar'kov. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 372–376, May–June, 1987.