Pyranone Derivatives Research Articles

Nitidon, a new bioactive metabolite from the basidiomycete Junghuhnia nitida (Pers.: Fr.) Ryv.

Nitidon, a highly oxidised pyranone derivative produced by the basidiomycete Junghuhnia nitida, has been isolated and its biological activities evaluated. The structure was determined by spectroscopic methods. Nitidon exhibits antibiotic and cytotoxic activities and induces morphological and physiological differentiation of tumor cells at nanomolar concentrations.

Synthesis and hybridization properties of the conjugates of oligonucleotides and stabilization agents—II

New pyranone derivatives having tri- or pentamethylenamine linker functions were synthesized. These derivatives were covalently attached through the 5′-phosphoramide linkage to heptanucleotide pd(CCAAACA). Complementary complexes of the octanucleotide pd(TGTTTGGC) and above oligonucleotide conjugates were tested for their thermodynamic response. The Tm data and thermodynamic parameters for complex formation have demonstrated the ability of chromone (γ-pyrone) and coumarin (α-pyrone) derivatives to stabilize strongly 7-mer/8-mer complementary complex, most likely through the stacking interaction of the pyran aromatic system with the neighboring nucleotide bases. The effect of chromone (or coumarin) derivatives on the stability of the oligonucleotide complexes (AAG at 37 °C ranged from −1.0 to −1.7 kcal/mol) was shown to be comparable to the effect of one nucleotide base pair and similar to the effect (ΔΔG at 37 °C ranged from −1.5 to −2.0 kcal/mol) found for acridineoligonucleotide conjugates served in this study as a reference.

Stereoselective synthesis of plant-growth-regulating steroids: brassinolide, castasterone, and their 24,25-substituted analogues

Brassinosteroids and their congeners, brassinolide 1, castasterone 2, 25-methylbrassinolide 3, 25-methylcastasterone 4 and (24R)-24-phenylbrassinone 5, have been stereoselectively synthesized by employing the pyranone derivative 19 as a versatile intermediate for the construction of the side chain.

An enantiocontrolled synthesis of (–)-malyngolide

Enantioselective synthesis of (–)-malyngolide (1) was accomplished by employing diastereo-selective addition of nonylmagnesium bromide to the 2-acylfuran derivative (4), followed by a ring transformation of the resulting optically active 2-furylalcohol (5) to give the pyranone derivative (7) as key steps.

A concise stereoselective synthesis of castasterone

A stereoselective synthesis of a brassinosteroid, castasterone, has been achieved by employing a pyranone derivative as a side-chain precursor.

ChemInform Abstract: Organocuprate Conjugate Addition to 2,3‐Dihydro‐4H‐pyran‐4‐ones.

AbstractReaction of isophorone (I) and the pyranone derivative (VI) with vinylmagnesium bromide (II) or vinyllithium (III) in the presence of copper compounds leads to the formation of the 1,4‐adducts (IV) and (VII), together with minor amounts of the 1,2‐adducts (V) and (VIII).

Stereocontrolled synthesis of the brassinolide side chain via a pyranone derivative

A new method for assembling the brassinolide side chain from 20-carboxaldehyde 2 was developed via the stereoselective construction of the pyranone moiety as key steps.

ChemInform Abstract: Polarized Ketene Dithioacetals. Part 53. A Facile Synthesis of 2‐Aryl‐ 6‐methylthio‐4H‐pyran‐4‐ones and a Novel Cycloaromatization Reaction.

AbstractThe pyranone derivatives (IV) are obtained by coupling the 3‐acyl ketene dithioacetal (II) with the methyl benzoates (I) in refluxing benzene followed by acid catalyzed cyclization.

Thermal Rearrangement of 2,5-Bis(allyloxy)tropone, Revisited. Formation of Four Thermolysates under the Claisen Rearrangement Conditions and Structure Revision of the Major Thermolysate

Abstract A reinvestigation of the Claisen rearrangement of 2,5-bis(allyloxy)tropone led to the isolation of three diallyl-5-hydroxytropolones along with an intermediary thermolysate, 3-allyl-5-allyloxytropolone. The structure of the formerly identified product was revised from 3,6-diallyl-5-hydroxytropolone to 4,6-diallyl-5-hydroxytropolone. The involvement of no cleavage-recombination process was established by cross-over deuterium labelling experiments. These derivatives were respectively converted to p-tropoquinones, one of which was further converted to a cyclohepta[b]pyranone derivative by an electrochemical reaction.

β-Elimination in aldonolactones. the conversion of l-rhamnono-1-5-lactone into 3-benzoyloxy-6-methylpyran-2-one

Benzoylation of l-rhamnono-1,5-lactone ( 1) for 90 min at room temperature afforded 2,3,4-tri- O-benzoyl- l-rhamnono-I,5-Iactone ( 2). When an excess of benzoyl chloride and pyridine was used for 20 h, with subsequent sublimation of benzoic acid from the mixture at 120° in vacua, a double elimination took place and 3-benzoyloxy-6-methylpyran-2-one ( 4) was isolated as the main product. The conversion of 1, 2, and 2,4.-di- O-benzoyl-3,6-dideoxy- l- erythro-hex-2-enono-l,5-lactone ( 3) into the pyran-one derivative 4 under different conditions was monitored chromatographically.