M. G. Korochkina

Unfolded and macrocyclic ammonium derivatives of diterpenoids steviol and isosteviol having choline moieties. Synthesis and inhibitory activities toward acetylcholine- and butyrylcholinesterases

A series of unfolded and macrocyclic ammonium derivatives of diterpenoids isosteviol 2 and steviol 17 possessing choline moieties have been synthesized and assayed for inhibitory activities toward AchE and BchE. Compounds 5–8, 13, 16, 20, and 21 showed moderate activity within the range of IC50 values 8.0 × 10−4 to 2.2 × 10−6 mol L−1. Isosteviol derivative 16 exhibited the best inhibition selectivity against acetylcholinesterase among the compounds tested. It inhibited AchE of human erythrocytes at IC50 = 80 μM, whereas inhibition of BchE occurred at IC50 > 1000 μM.

Synthesis and antimicrobial and antifungal activity of derivatives of the diterpenoid isosteviol and the glycoside steviolbioside containing onium nitrogen atoms

Previously unknown derivatives of the diterpenoid isosteviol and the glycoside steviobioside containing onium nitrogen atoms were synthesized. The antimicrobial and antifungal activities of these compounds were studied.

Synthesis and antimicrobial activity of several bis-quaternized ammonium derivatives of the diterpenoid isosteviol

Previously unreported bis-quaternized ammonium derivatives of the diterpenoid isosteviol (16-oxo-entbeyeran-19-oic acid) were synthesized. The compound in which the two quaternized N atoms were joined by a dodecamethylene spacer had the greatest antimicrobial activity and was comparable in activity with ciprofloxacin and clotrimazole.

Chemistry and Structure of Diterpene Compounds of the Kaurane Series: VII. Chiral Complexes of Isosteviol with Aromatic Compounds

Abstract(4α,8β,13β)-13-Methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) forms with aniline, dimethylaniline, and toluene individual 2:1 molecular complexes whose crystals are isostructural. According to X-ray diffraction data, the supramolecular crystal structure of these complexes is formed by chiral double helices with a 43 screw axis, consisting of isosteviol molecules. The strands of the helices are linked together by intermolecular hydrogen bonds involving the carboxy and carbonyl groups of two isosteviol molecules of neighboring helices. In their turn, the two hydrogen-bonded isosteviol molecules form head-to-tail pseudocage dimers. The aromatic guests occupy fairly large cavities between the strands of isosteviol helices.

Alkylation of the isosteviol terpenoid and its oxime with dibromoalkanes in the KOH-DMSO system

The reaction of 16-hydroximinoisosteviol with dihaloalkanes in the KOH-DMSO results in coupling of two isosteviol carcasses by the carboxy groups. The same products were previously synthesized by hydroximination of isosteviol diesters.

Chemistry and Structure of Diterpene Compounds of the Kaurane Series: IV.1 Acylation of Reduction Products of the Isosteviol Keto Group

Acetylation with acetic anhydride of (4α,8β,13β)-16-hydroxy-13-methyl-17-norkaurane-18-carboxylic acid and its methyl ester, obtained by reduction of isosteviol and (4α,8β,13β)-18-methoxycarbonyl-13-methyl-16-oxo-17-norkaurane, respectively, gives rise to (4α,8β,13β)-16-acetoxy-13-methyl-17-norkaurane-18-carboxylic acid and (4α,8β,13β)-16-acetoxy-18-methoxycarbonyl-13-methyl-17-norkaurane. The molecular and crystal structures of the compounds were established by X-ray diffraction.

Chemistry and Structure of Diterpene Derivatives of the Kaurane Series: V. Isosteviol Anhydrides

Abstract(4α,8β,13β)-13-Methyl-16-oxo-17-norkaurane-18-carboxylic acid (isosteviol) anhydride is synthesized, which is a first representative of bisditerpene compounds of the kaurane series. The structures of the anhydride and isosteviol chloride were studies by X-ray diffraction and quantum chemistry (AM1).

Investigation of diterpenoid isosteviol ammonium derivatives by matrix-assisted laser desorption/ionization mass spectrometry

Matrix-assisted laser desorption/ionization (MALDI) mass spectra of diterpenoid isosteviol ammonium derivatives have been analyzed. The compounds were synthesized as antibacterial agents. It has been found that peaks of salt cations were detected in positive ion MALDI mass spectra of mono-quaternary derivatives. The fragmentation of bis-quaternary salts depended on the distance between the ammonium centers. Clusters containing dication and acidic matrix anion have been observed for compounds with two quaternized nitrogen atoms connected by a nonanomethylene or a longer spacer. Similar clusters did not form for compounds containing pentamethylene or a shorter spacer between two quaternized nitrogen atoms.