Showing papers in "Heterocycles in 2000"

Synthesis of indolylpyrimidines VIA cross-coupling of indolylboronic acid with chloropyrimidines: facile synthesis of meridlanin D

Abstract: Palladium catalyzed cross-coupling reaction of 3-indolylboronic acid with 2,4-dichloropyrimidines proceeded regioselectively to yield indolylor bis(indolyl)pyrimidines in high yield, depending on the projection of 3-indolylboronic acid. The marine indole alkaloid meridianin D and an analogue were synthesised via the palladium catalyzed cross-coupling reaction as a key step.

Synthesis of Methylenebis(4-hydroxy-2-pyrone)or Methylenebis(4-hydroxycoumarin)Derivatives by Organic Solid State Reaction

Abstract: The methylene bridged biscoumarins namely dicoumarol (1) and coumetarol (2) find application as oral anticoagulants in the treatment of thromboemblic disorders, besides retaining their role as reagents for biochemical use. Some literature precedents do offer methods to synthesize these compounds, for example, methylenebis(4-hydroxy-2-coumarin) derivatives (5) was prepared by condensation of 4hydroxycoumarin (3) with aqueous formaldehyde under basic condition. Similarly, the electrochemical oxidation and the treatment of 6 under Knoevenagel reaction conditions are the other alternative procedure described for the preparation of these bis compounds. However, the first method lacks generality as it involves aqueous reaction media and the second procedure is useful to obtain only the methylene bridged bispyrone derivatives (11a).