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Article
Secondary metabolites of the lichen Cladonia stellaris
The composition of slightly polar extracts of the lichen Cladonia stellaris (Opiz.) was studied. The major metabolites of the CHCl3 and Me2CO extracts were isolated. Lichen acids 6 and 7 in addition to 3–5, deriv...
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Article
Reaction of (+)-usninic acid and several of its derivatives with diazomethane
New derivatives of (+)-usninic acid including products of ring expansion, methylation of enol and phenol hydroxyls, and formation of an oxirane ring in addition to products with pyran and furan rings annelated...
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Article
Synthesis of chalcones derived from (+)- and (−)-usnic acids
A number of chalcones with the (+)- and (−)-usnic acid moieties were synthesized by the following sequence: the reaction of these acids with phenylhydrazine, reduction of the C(1)=O group with sodium borohydri...
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Article
LDLR up-regulatory activity of berberine and its bromo and iodo derivatives in human liver HepG2 cells
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Article
Reduction of (+)-usninic acid and its pyrazole derivative by sodium borohydride
The reaction of (+)-usninic acid and its pyrazole derivative with sodium borohydride was studied. The reduction occurred stereoselectively at the endocyclic carbonyl group. Novel (+)-usninic acid derivatives t...
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Article
Oxidation of usninic acid
Reactions of usninic acid with various oxidants were studied. The oxidation occurred at the resorcinol ring. New derivatives of usninic acid were obtained from reactions with per-acids.
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Article
Chemical modification of usnic acid: III.* Reaction of (+)-usnic acid with substituted phenylhydrazines
Reactions of (+)-usnic acid with a number of substituted (halo, alkyl, alkoxy, nitro) phenylhydrazines led to the formation of the corresponding benzofuro[3,2-f]indazole derivatives or hydrazones at the acetyl gr...
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Article
Amino-derivatives of usninic acid
Products from the reaction of usninic acid and 4-(3-aminopropyl)-2,6-di-t-butylphenol, 4-(2-aminoethyl)-2,6-di-t-butylphenol, antipyrine, N,N-diethylaminoethylamine, p-chloroaniline, and p-bromoaniline in additio...
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Article
Isolation and identification of 4′,6-dimethoxy-7-hydroxyisoflavone from roots of Hedysarum theinum cultivated in vitro
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Article
Schmidt reaction of usnic acid
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Article
Structure of oligomeric proanthocyanidines from Hedysarum thienum roots studied by thiolysis and MALDI-TOF MS
Oligomeric proanthocyanidines from Hedysarum theinum roots that were cleaved by benzylmercaptan were shown to be heterogeneous mixtures consisting of prodelphinine and procyanidine structural units with the fo...
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Article
Usnic acid is a promising synergist for biopreparations based on entomopathogenic microorganisms
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Article
Fatty-acid composition and secondary metabolites from slightly polar extracts of the aerial part of Primula macrocalyx
Flavones 2′,5′-dimethoxyflavone, 3′-methoxy-4′,5′-methylenedioxyflavone, 3′,4′-dimethoxyflavone, 5,6,2′,3′,6′-pentamethoxyflavone, and 5,6,2′,3′,5′,6′-hexamethoxyflavone; salicylates, methyl-4-methoxysalicylat...
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Article
Low-molecular-weight phenolic compounds from Hedysarum theinum roots
Isoflavonoids (−)-medicarpin, (−)-vestitol, formononetin, 8-hydroxydaidzein, and 6″-O-acetylononin were isolated for the first time in addition to (−)-catechin, (−)-epicatechin, protocatechoic acid, raspberry ket...
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Article
Riccardin C, a bisbibenzyl compound from Primula macrocalyx
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Article
Chemical modification of usnic acid 1. Reaction of (+)-usnic acid with perfluoroolefins
The reactions of the natural lichen metabolite, (+)-usnic acid, with a series of commercially available polyfluoroolefins (tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, perfluoro-2-methylpen...
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Article
Chemical modification of usnic acid 2. Reactions of (+)-usnic acid with amino acids
The condensation of amino acids with (+)-usnic acid involves the 2-positioned acetyl group of the latter and gives derivatives containing an enamine fragment.
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Article
Transformations of diepoxy derivatives of limonene in homogeneous acidic media
Transformations of diepoxy derivatives of limonene under conditions of homogeneous acid catalysis were studied, and their results were compared with those obtained over heterogeneous catalysts. A number of pre...
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Article
Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis
Transformations of isocaryophyllene diepoxide (an isomer of widely spread natural sesquiterpene) were studied in various acidic media under conditions of homogeneous and heterogeneous catalysis. A number of pr...
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Article
Reactions of caryophyllene, isocaryophyllene, and their epoxy derivatives with acetonitrile under ritter reaction conditions
Acid-catalyzed reactions between acetonitrile and caryophyllene, isocaryophyllene, caryophyllene 4β, 5α-epoxide, and isocaryophyllene 4β,5β-epoxide affording optically active amides with a tricyclic skeleton w...
