Isoflavone glycosides from the bark of Amorpha fruticosa

Four known isoflavone glucosides have been isolated from the bark of Amorpha fruticosa, which is a traditional remedy plant, for the first time. They were elucidated as 3′-hydroxy-4′-methoxyisoflavone-7-O-β-D-glucopyranoside (1), 4′,6-dimethoxyisoflavone-7-O-β-D-glucopyranoside (2), 4′-methoxyisoflavone-7-O-β-D-glucopyranoside (3), and 3′,5-dihydroxy-4′-methoxyisoflavone-7-O-β-D-glucopyranoside (4), based on the UV, FT-IR, EIMS, FABMS, HREIMS, and NMR (¹H and ¹³C, DEPT, COSY, NOESY, HMQC, and HMBC) data. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 336–338, July–August, 2006.     

A novel compound from <Emphasis Type="Italic">Flos carthami</Emphasis> and its bioactivity

A novel compound, 4-{1′-hydroxy-1′-mercapto-1′-[1′′-2′′(N→O)-isoquinolyl]}yl-1-benzoic acid (1), together with six known compounds, 6-hydroxykaempferol-3-O-β-D-glucopyranoside (2), rutin (3), quercetin-3-O-β-D-glucopyranoside (4), kaempferol-3-O-β-D-glucopyranoside (5), cartormin (6), hydroxysafflor yellow A (7), were isolated by chromatography from the n-BuOH fraction of 50% ethanol extraction of Flos carthami. Their structures were elucidated on the basis of spectral analysis and comparison with published data. Among them, compound 1 was shown to possess a weak protective effect against cerebral ischemic damage in rats. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 339–341, May–June, 2009.     

A new example of reversal of the order of migration of enantiomers, as a function of cyclodextrin concentration and pH, by cyclodextrin-modified capillary zone electrophoresis: enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol

Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capillary zone electrophoresis (CD-CZE) was studied using the three native α, β, and γ cyclodextrins, the three hydroxypropylated cyclodextrins (2-hydroxypropyl-α, β, and γ), heptakis-2,6-di-O-methyl-β-CD (DM-β-CD), and heptakis-2,3,6-tri-O-methyl-β-cyclodextrin (TM-β-CD). First, the acidity constants of DBBD were determined using capillary electrophoresis, before performing enantioseparation. The influence of the concentrations of the studied cyclodextrins on the enantioseparation was explored and the experimental optimal concentrations were determined and compared to the theoretical optimal concentrations. Moreover, the apparent complexation constants between each studied cyclodextrin and the two DBBD enantiomers were evaluated using a non-linear curve fitting method and three linear plotting methods (x-reciprocal, y-reciprocal and double reciprocal). For TM-β-CD, the order of migration of the enantiomers of DBBD reversed as a function of TM-β-CD concentration. The influence of the nature of methylated cyclodextrin derivatives (methyl-β-CD (M-β-CD) and DM-β-CD) was then studied. Inversion of the order of migration of the enantiomers of DBBD was observed for DM-β-CD, whereas the S enantiomer of DBBD always migrated first for M-β-CD.     

Investigations on 2,3′-biquinolines. 18. New convenient one-pot synthesis of 1′-alkyl-1′,4′-dihydro-2,3′-biquinolyl-4′-thiones and their conversion into 1′-alkyl-1′,4′-dihydro-2,3′-biquinolyl-4′-ones

A method has been developed for the one pot synthesis of 1′-alkyl-1′,4′-dihydro-2.3′-biquinolyl-4′-thiones based on the reduction of 1-alkyl-3-(2-quinolyl)quinolinium halides with sodium borohydride and subsequent thiolation. 1′-Alkyl-1′,4′-dihydro-2,3′-biquinolyl-4′-ones were obtained in close to quantitative yield by the oxidation of 1′-alkyl-1′, 4′-dihydro-2,3′-biquinolyl-4′-thiones. For Part 17 see [1]. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 67–70, January, 2006.     

Investigations on 2,3′-Biquinoline. 17. Regioselectivity of the Halogenation of 2,3′-Biquinoline Derivatives

A method has been developed for the synthesis of bromo and chloro derivatives of 2,3′-biquinoline and 2,3′-biquinolones based on the bromination and chlorination in various media. It was found that the bromination of 2,3′-biquinoline in strongly acidic medium occurred on the 2-quinoline fragment and in weak acid on the 3-quinoline and that it takes place via a stage of formation of a dihydro derivative. 1′-Alkyl-1′, 4′-dihydro-2,3′-biquinolin-4′-ones and 1′-alkyl-1′,2′-dihydro-2,3′-biquinolin-2′-ones are halogenated at position 6′. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1372–1377, September, 2005.     

Investigations on 2,3′-Biquinolyl. 16. The Regioselectivity of Reduction of 1-Alkyl-3-(2-quinolyl)quinolinium and 1,1′-Dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-biquinolyl Iodides Using Metallic Zinc,Lithium and Potassium

The reaction of 1-alkyl-3-(2-quinolyl)quinolinium iodides with excess zinc in THF gives a diastereomeric mixture of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls. An excess of lithium in THF gives a mixture of 1′,2′-dihydro-2,3′-biquinolyl and 1′-alkyl-1′, 4′-dihydro-2,3′-biquinolyl with the former predominating. The reduction by lithium in THF of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls leads to analogous products. Reduction of 1-alkyl-3-(2-quinolyl)quinolinium iodides by metallic potassium gives 1-alkyl-1′,4′-dihydro-2,3′-biquinolyls. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1208–1212, August, 2005.     

Fatty-acid composition and secondary metabolites from slightly polar extracts of the aerial part of <Emphasis Type="Italic">Primula macrocalyx</Emphasis>

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-methoxysalicylate and peonol; and bisbibenzyl polyphenol riccardin C were isolated for the first time from the acetone extract of the aerial part of Primula macrocalyx Bge. The content of free and total fatty acids was determined by GC and GC—MS. Palmitic (16:0), octadecatetraenoic 18:4 (6,9,12,15), linoleic 18:2 (9,12), and α-linolenic 18:3 (9,12,15) were the principal acids from the aerial part of Primula macrocalyx. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 457–460, September-October, 2008.     

Synthesis of a Bifunctional 1,1′-Diphenyl-1,2,3,4-tetrahydroquinoline Derivative: 1,1′-Diphenyl-1,2,3,4,1′,2′,3′,4′-octahydro-6,6′-biquinolinyl-3,3′-diol

Summary. Intramolecular cyclization of N,N′-di(3-chloro-2-hydroxy)propyl-N,N′-diphenylbenzidine occurs to give bis-1,2,3,4-tetrahydroquinoline derivative 1,1′-diphenyl-1,2,3,4,1′,2′,3′,4′-octahydro-6,6′-biquinolinyl-3,3′-diol.     

Investigation on 2,3′-biquinolyl series. 21. Reactions of 1′-alkyl-4′-aryl-1′,4′-dihydro-2,3t′-biquinolyls and 1′-alkyl-2′-aryl-1′,2′-dihydro-2,3′-biquinolyls with sulfur

A method has been developed for the synthesis of 2′-and 4′-aryl-2,3′-biquinolyls based on the reaction of 1′-alkyl-2′-aryl-1′,2′-dihydro-2,3′-biquinolyls and 1′-alkyl-4′-aryl-1′,4′-dihydro-2,3′-biquinolyls with sulfur in DMF. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1517–1519, October, 2006.     

Pyridoxal-5′-phosphate-dependent catalytic antibodies

Cofactors—i.e., metal ions and coenzymes—extend the catalytic scope of enzymes and might have been among the first biological catalysts. They may be expected to efficiently extend the catalytic potential of antibodies. Monoclonal antibodies (MAbs) against N^α-phosphopyridoxyl-l-lysine were screened for 1) binding of 5′-phosphopyridoxyl amino acids, 2) binding of the planar Schiff base of pyridoxal-5′-phosphate (PLP) and amino acids, the first intermediate of all PLP-dependent reactions, and 3), catalysis of the PLP-dependent α, β-elimination reaction with β-chloro-D/L-alanine. Antibody 15A9 fulfilled all criteria and was also found to catalyze the cofactor-dependent transamination reaction of hydrophobic D-amino acids and oxo acids (k′ _cat=0.42 min⁻¹ with D-alanine at 25°C). No other reactions with either D- or L-amino acids were detected. PLP markedly contributes to catalytic effecacy—it is a 10⁴ times more efficient acceptor of the amino group than pyruvate. The antibody ensures reaction specificity, stereospecificity, and substrate specificity, and further accelerates the transamination reaction (k′ _cat(Ab)/k′ _cat(PLP)=5×10³). The successive screening steps simulate the selection criteria that might have been operative in the evolution of protein-assisted psyridoxal catalysis.