26 research outputs found
Crystal Structure and Spectroscopic Properties of (2-oxo-2<i>H</i>-chromen-3-yl)phosphonic Acid Monoethyl Ester Trihydrate
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Synthesis and Chemical Properties of 3-Phosphono-coumarins and 1,2-Benzoxaphosphorins as Precursors for Bioactive Compounds
No full textCoumarins are an important class of natural heterocyclic compounds that have attracted considerable synthetic and pharmacological interest due to their various biological activities. This review emphasizes on the synthetic methods for the preparation of dialkyl 2-oxo-2H-1-benzo- pyran-3-phosphonates and alkyl 1,2-benzoxaphosphorin-3-carboxylates. Their chemical properties as acceptors in conjugate addition reactions, [2+2] and [3+2] cycloaddition reactions are discussed
ChemInform Abstract: Reaction of 3-Bromobenzyl and 3-Bromoacetyl Coumarin with Phosphites. Synthesis of Some New Phosphonates and Phosphates in the Coumarin Series.
No full textUltrasound-Assisted Metal-Mediated Method for the Formation of Tetrahydro-3,3′-Disubstituted Biscoumarins
No full textA new method for faster and simple preparation of 3,3′,4,4′-tetrahydro-3,3′-disubstituted-4,4′-biscoumarins with participation of an organozinc reagent is reported. The reaction is promoted by ultrasound irradiation and it offers a simple experimental setup and excellent reproducibility of the results. Moreover, homodimers were isolated in yields of 45⁻92%. The dimerization conditions are applicable to coumarins with electron-withdrawing groups at third position
Regio- and Stereoselective [2+2] Photodimerization of 3-Substituted 2-Alkoxy-2-oxo-2H-1,2-benzoxaphosphorines
No full textDiethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the centrosymmetric stereoisomer 6 predominates over the non symmetric P-epimer 7
A New and Efficient Method for the Synthesis of 3,4-Disubstituted Pyrrolidine-2,5-diones
No full textA newly found reaction for the synthesis of 3,4-disubstituted 1-hydroxy-pyrrolidine-2,5-diones from 3-substituted coumarins and nitromethane has been elaborated. The reaction involved a simple and convenient experimental procedure. The applicability of the rearrangement reaction is determined
Current attempt on the transformations of coumarinyl-1,2-epoxyphosphonates
No full textBromohydrins were prepared by ring opening of coumarinyl-1,2-epoxy phosphonate esters under acidic conditions. The chemical behavior of bromohydrins was examined under Michaelis–Becker reaction conditions using dialkylphosphites.</p
A New and Efficient Method for Conjugate Addition of Trialkylphosphites to 3‐Acylsubstituted Coumarins.
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