PODOBLASTIN A, B AND C. NEW ANTIFUNGAL 3-ACYL-4-HYDROXY-5,6-DIHYDRO-2-PYRONES OBTAINED FROM PODOPHYLLUM PELTATUM L

Abstract

The potent antifungal constituent against Pyricularia oryzae Cav. obtained from Podophyllum peltatum L. has been disclosed to be a mixture of three new 3-acyl-4-hydroxy-5,6-dihydropyrones (podiblastin A, B and C). The absolute configuration at C-6 of podoblastins was determined to be (R).

Alternaric acid. Proof of biosynthesis via condensation of two polyketide chains. Complete assignment of the 1H and 13C magnetic resonance spectra by 2D techniques

“…It may be noted that the observed shieldings for C-1' , -1, -2, and -3 in l b are very similar to those found for the corresponding centres in podoblastin A (3) (14) and in 5,6-dihydrodehydroacetic acid (4). 4 The assignments shown in 4 were obtained by a 2D INADEQUATE experiment which provided the required double quantum frequencies.…”

“…In further attempts to obtain differential incorporation into 50ther recent cases are those of citreothiolactone and citreopyrone from Penicillium viride (18) and the podoblastins from the higher plant Podophyllum peltatum (14). fungal cultures together with unlabelled compounds which had some promise as possible competitors.…”

Synthesis and thermal studies of mixed ligand complexes of Cu(II), Co(II), Ni(II) and Cd(II) with mercaptotriazoles and dehydroacetic acid

“…Molar susceptibilities were corrected for diamagnetism of the component atoms by the use of Pascal's constants. The calibrant used was Hg[Co(SCN) 4 ]. The infrared spectra of the free ligands and the metal complexes were recorded on a shimadzu 470 infrared spectrophotometer (4000-400 cm -1 ) using KBr discs.…”

“…The importance of similar pyrones as potential fungicides is reinforced by the existence of several natural fungicides possessing structures analogous to 5, 6-dihydro dehydroacetic acid, like alternaric acid, the podoblastins and lachnelluloic acid [3][4][5], studies have shown that such compounds and their complexes have very interesting biological properties [6][7][8][9][10][11][12][13]. Like dehydroacetic acid, mercaptotriazoles and their complexes have been shown to posses enhanced biological activities [14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

Biosynthesis of Phytotoxins fromAlternaria solani

“…1). 5) Another strain of A. solani produces solanapyrones A (8), B (9), C (10), D (11), and E (12).6,7) Diastereomeric isomers, solanapyrones A and D, and Band E, were obtained in a ratio of 6 : 1 in an enantiomerically pure state. Solanapyrones A (8) and C (10) were also isolated from filtrates of stationary cultures of Ascochyta rabiei, the causal fungus of chickpea blight.…”