Modified Coumarins. 9. Synthesis of Amino-Acid Derivatives of 3-(2,3,5-Trimethyl-7-oxofuro[3,2-g]chromen-6-yl)propanoic Acid

Furocoumarins modified by amino acids were prepared by condensation of the N-hydroxysuccinimide ester of 3-(2,3,5-trimethyl-7-oxofuro[3,2-g]chromen-6-yl)propanoic acid with amino acids.     

The Behavior of Certain Coumarins and Furocoumarins Toward Sulfur Reagents

The behavior of 4-hydroxycoumarin (1), 7-hydroxycoumarin (2), 4-hydroxy-bergapten (3), and 4-hydroxyisopimpinellin (4) toward sulfur reagents, namely, thionyl chloride, phosphorus pentasulfide, thiolacetic acid, and Lawesson's reagent (5), was studied. The nature of products in each case depended upon the type of reactants and reaction conditions. Possible reaction mechanisms were considered, and structural elucidations of the new products were based upon compatible elementary and spectroscopic evidences.     

Modified coumarins. 20. Furocoumarin derivatives of cytisine

Cytisine derivatives modified by furocoumarins were synthesized using activated esters. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 230–232, May–June, 2006.     

Study of plant coumarins 1. Transformations of peucedanin

The structure of 2-bromooreoselon, which was prepared by bromination of peucedanin or oreoselon with molecular bromine, was established. The compositions and structures of the reaction products of this bromide with amines, such as pyridine, triethylamine, and morpholine, as well as with sodium acetate and potassium hydroxide were studied. The reaction of peucedanin with m-chloroperoxybenzoic acid affords peuruthenicin isobutyrate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 362—366, February, 2006.     

A Novel Method for One‐pot Synthesis of Furo[3,2‐c]coumarin Derivatives from 4‐Hydroxycoumarin and Arylglyoxal under Microwave Irradiation

A novel one‐pot synthesis of furo[3,2‐c]coumarins has been developed from readily available starting materials 4‐hydroxycoumarin and arylglyoxal. This method is simple, rapid and good yielding.     

Hypervalent Iodine in Synthesis XL: First Example of Palladium-Catalyzed Coupling Reaction of 1- Hydroxy-1,2-benziodoxol-3(1H)-One with Arylboronic Acids and Arylborates

Biaryl-2-carboxylic acids have been prepared by palladium-catalyzed coupling reaction of 1-hydroxy-1,2-benziodoxol-3(1H)-one with arylboronic acids and arylborates with good yields under mild conditions.     

Metabolic study of Angelica dahurica extracts using a reusable liver microsomal nanobioreactor by liquid chromatography–mass spectrometry

Highly active and recoverable nanobioreactors prepared by immobilizing rat liver microsomes on magnetic nanoparticles (LMMNPs) were utilized in metabolic study of Angelica dahurica extracts. Five metabolites were detected in the incubation solution of the extracts and LMMNPs, which were identified by means of HPLC‐MS as trans‐imperatorin hydroxylate (M1), cis‐imperatorin hydroxylate (M2), imperatorin epoxide (M3), trans‐isoimperatorin hydroxylate (M1′) and cis‐isoimperatorin hydroxylate (speculated M2′). Compared with the metabolisms of imperatorin and isoimperatorin, it was found that the five metabolites were all transformed from these two major compounds present in the plant. Since no study on isoimperatorin metabolism by liver microsomal enzyme system has been reported so far, its metabolites (M1′ and M3′) were isolated by preparative HPLC for structure elucidation by ¹H‐NMR and MS² analysis. M3′ was identified as isoimperatorin epoxide, which is a new compound as far as its chemical structure is concerned. However, interestingly, M3′ was not detected in the metabolism of the whole plant extract. In addition, a study with known chemical inhibitors on individual isozymes of the microsomal enzyme family revealed that CYP1A2 is involved in metabolisms of both isoimperatorin and imperatorin, and CYP3A4 only in that of isoimperatorin. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and Photooxygenation of Furo[3,2‐c]coumarin Derivatives as Antibacterial and DNA Intercalating Agent

Syntheses of 2,3‐dimethyl‐4H‐furo[3,2‐c]coumarin and 3‐phenyl‐4H‐furo[3,2‐c]coumarin as angular furocoumarins were carried out through Williamson reaction of 4‐hydroxycoumarin with α‐haloketones followed by cyclization. Photooxygenation of the synthesized furocoumarin derivatives was performed and the photoproducts were isolated and characterized. The affinity of 2,3‐dimethyl‐4H‐furo[3,2‐c]coumarin towards DNA and the antibacterial activity were evaluated and compared with 8‐methoxypsoralen (8‐MOP).     

Modified Coumarins. 4. Synthesis and Biological Properties of Cyclopentaneannelated Furocoumarins

Psoralen and allopsoralen analogs that contain an annelated cyclopentane were synthesized from 7-hydroxyand 9-hydroxy-1,2,3,4-tetrahydrocyclopenta[c]chromen-4-ones. 9-Phenyl-1,2,3,4-tetrahydrocyclopenta[c]furo[3,2-g]chromen-4-one exhibited low toxicity, acted as a CNS stimulant, and exhibited cardiotropic activity.