ChemInform Abstract: First Synthesis of the Antifungal Oidiolactone C from trans-Communic Acid: Cytotoxic and Antimicrobial Activity in Podolactone-Related Compounds (original) (raw)
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Organic Letters, 2002
A new route to podolactones functionalized in the A ring has been achieved. Two key steps were employed in this synthesis, the construction of the bicyclic skeleton via a Mn(III)-mediated radical cyclization and the transformation of this bicyclic intermediate into the tetracyclic podolactone skeleton through a Pd (II)-mediated bislactonization of the corresponding conjugate diene. The reported synthesis of 3 -hydroxy-13,14,15,-16-tetranorlabda-7,9(11)-dien-(19,6 ),(12,17)-diolide (1) let us reassign the structure of wentilactone B, for which structure 1 was wrongly reported.
Molecules, 2011
A series of new enantiomerically pure and racemic 1,3-dioxolanes 1-8 was synthesized in good yields and short reaction times by the reaction of salicylaldehyde with commercially available diols using a catalytic amount of Mont K10. Elemental analysis and spectroscopic characterization established the structure of all the newly synthesized compounds. These compounds were tested for their possible antibacterial and antifungal activity. Biological screening showed that all the tested compounds, except 1, show excellent antifungal activity against C. albicans, while most of the compounds have also shown significant antibacterial activity against S. aureus, S. epidermidis, E. faecalis and P. aeruginosa.
Diversity-Oriented Synthesis of a Library of Podocarpic Acid Derivatives
A variety of compounds, with a related structure to podocarpic acid, have been found to possess a wide variety of biological activities, including antileukemic activity, inhibition of plant cell growth, insect toxicity and antifungal properties. In the present study, a series of synthetic derivatives of podocarpic acid have been prepared by chemical synthesis for potential biological evaluation as useful compounds for use in medicine and agriculture.
Molecules, 2016
In this review the synthetic work in the field of aphidicolane, stemodane and stemarane diterpenoids, in which readily available (+)-podocarpic acid (4) was used as chiral template for the construction of their polycyclic structures, is described as it developed along the years. In the frame of this work (+)-podocarpic acid (4) was a very useful tool in a model study leading to the syntheses of tetracyclic ketones 7 and 8, models of key intermediates 5a and 6 in the syntheses of (+)-aphidicolin (1) and (+)-stemodin (2a), respectively. (+)-Podocarpic acid (4) was also converted into (+)-2-deoxystemodinone (2d), allowing confirmation of the stemodane diterpenoids absolute configuration, into (+)-aphidicol-15-ene (36) and into Stemodia chilensis tetracyclic diterpenoid (+)-19-acetoxystemodan-12-ol (2f), allowing confirmation of its structure. (+)-Podocarpic acid (4) was then extensively used in the work which led to the synthesis of (+)-stemar-13-ene (57) and (+)-18-deoxystemarin (3b). Finally, (+)-4 was converted into (+)-2-deoxyoryzalexin S (66), which made it possible to demonstrate that the structure of (+)-66 could not be attributed to a Chilean Calceolaria isolated diterpenoid to which this structure had been assigned.
World Journal of Microbiology and Biotechnology, 2005
The fungus Aspergillus terreus Thorn var. terreus isolated from an Ecuador soil sample was cultured in liquid and solid media and yielded three main metabolites identified as terreic acid (1), butyrolactone I (2) and lovastatin (3). The natural products as well as three synthetic butyrolactone I derivatives were assessed for antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi as well as for seed germination and seedling growth. Furthermore, the compounds were assessed as inhibitors towards the enzymes acetylcholinesterase, b-glucosidase, and b-glucuronidase. Terreic acid, butyrolactone I, butyrolactone 4¢,4¢¢-diacetate (2.1), and 3¢-(3-methylbutyl)butyrolactone II (2.2) were active towards the phytopathogenic bacteria Erwinia carotovora with IC 50 of 5 and 4-18 lg/ml, respectively. Under the same experimental conditions, the IC 50 of streptomycin was 1.9 lg/ml. 3¢-(3-Methylbutyl)-butyrolactone II was moderately active against Pseudomonas syringae and Botrytis cinerea with IC 50 of 21lg/ml and MIC of 15.6 lg/ml, respectively. Butyrolactone I also inhibited germination of the dicot Lactuca sativa with an IC 50 of 5 · 10 )5 M. The IC 50 of reference herbicide acetochlor was 1 · 10 )5 M. The effect of 2.2 and 2.3, known as butyrolactone III on Panicum millaceum germination and growth was stronger than that of 2 and 2.1. Reduction of the double bond in the isoprenyl side chain of butyrolactone I increased the antibacterial effect against E. carotovora as well as acetylation. To our best knowledge, this is the first report on the antibacterial effect of butyrolactone derivatives towards Erwinia carotovora and the phytopathogenic fungus Botrytis cinerea. The butyrolactone I derivative 2.2 presented a moderate inhibitory effect against the enzyme acetylcholinesterase with an IC 50 of 47 lg/ml. Under the same experimental conditions, the reference inhibitor galanthamine had an IC 50 of 3 lg/ml.
Journal of Natural Products, 1993
~STRACT.-A general strategy for a successful approach to labdanes of the type 3-5 is described. This methodology, which makes use of the known Eschenmoser fragmentation of 9, 1,3-oxidative rearrangement of allylic tertiary alcohol 14, and photochemical double bond isomerization ofallylic acetate 17 as key synthetic steps, is used to prepare optically pure labdane 5 from readily available (+)-podocarpenone 8. A very large number of diterpenoids possessing a labdane skeleton 1 occur in nature 1). Several of them (including some biologically active ones) possess a C-8 4-1 7 :xomethylene group and a P-oriented C-6 oxygenated function as common structural :-eatures. These are exemplified by compounds 2-5 (2-7). By far the most interesting compound of this type is scoparic acid A {2], a labdanetype diterpenoid isolated from the extract of "TypychB Kuratu" (8), a Paraguayan folk medicine used for the treatment of stomach disease and hepatosis (9). This compound, as recently demonstrated (lo), is characterized by an unusual syn stereochemical relationship between the H-9 and 10-Me substituents. As a part of our preliminary investigations directed toward the synthesis of scoparic acid A, initiated before the configuration of the side chain attached to C-9 was firmly established, we decided to explore the synthesis of 5, one of the less complex of these molecules (2). No biological activity has been reported for this compound, but the work m 1 2