A NOVEL METHOD FOR THE SYNTHESIS OF 4H-PYRAN-4-ONE DERIVATIVES

Erinaceolactones A to C, from the culture broth of Hericium erinaceus

Three novel compounds, erinaceolactones A to C (1-3), and a known compound (4) were isolated from the culture broth of Hericium erinaceus. The planar structures of 1-3 were determined by the interpretation of spectroscopic data. The absolute configuration of 3 was determined by X-ray crystallography. Although compound 4 had been synthesized, it was isolated from a natural source for the first time. In the bioassay examining plant-growth regulatory activity of these compounds (1-4) and other components of the fungus (5-8), compounds 1, 2, and 4-8 suppressed the growth of lettuce.

An efficient synthesis of carboxaldehyde derivatives of 4H-pyran-4-one

We developed a general method for the synthesis of various 2-mono- and 2,6-di-carboxaldehyde substituted derivatives of 3,5-diphenyl-4H-pyran-4-one and 4H-pyran-4-one. 3,5-Diphenyl-6-methyl-4-oxo-4H-pyran-2-carboxaldehyde (4a), 6-methyl-4-oxo-4H-pyran-2-carboxaldehyde (4b), 3,5-diphenyl-4-oxo-4H-pyran-2,6-dicarboxaldehyde (5a), 4-oxo-4H-pyran-2,6-dicarboxaldehyde (5b), 3,5-diphenyl-6-hydroxymethyl-4-oxo-4H-pyran-2-carboxaldehyde (10a), and 6-hydroxymethyl-4-oxo-4H-pyran-2-carboxaldehyde (10b) were obtained from the corresponding di-, tri-, and tetra-bromo derivatives of 2,6-dimethyl-3,5-diphenyl-4H-pyran-4-one (1a) and 2,6-dimethyl-4H-pyran-4-one (1b) by treatment with silver acetate followed by hydrolysis. Compounds 4a and 4b were also obtained by the oxidation of 10a and 10b with barium manganate.Key words: 4H-pyran-4-one, hydroxymethyl and carboxaldehyde derivatives, acetoxylation, hydrolysis, oxidation.

Synthesis of Some Aldoxime Derivatives of 4H-Pyran-4-ones

Aldoxime derivatives of 4H-pyran-4-ones 4-7a,b have been synthesized by the reaction of di(aminoxymethyl) pyranones 3a,b with aromatic aldehydes.