675-10-5Relevant academic research and scientific papers
Screening for enhanced triacetic acid lactone production by recombinant Escherichia coli expressing a designed triacetic acid lactone reporter
Tang, Shuang-Yan,Qian, Shuai,Akinterinwa, Olubolaji,Frei, Christopher S.,Gredell, Joseph A.,Cirino, Patrick C.
, p. 10099 - 10103 (2013)
Triacetic acid lactone (TAL) is a signature byproduct of polyketide synthases (PKSs) and a valuable synthetic precursor. We have developed an endogenous TAL reporter by engineering the Escherichia coli regulatory protein AraC to activate gene expression in response to TAL. The reporter enabled in vivo directed evolution of Gerbera hybrida 2-pyrone synthase activity in E. coli. Two rounds of mutagenesis and high-throughput screening yielded a variant conferring ～20-fold increased TAL production. The catalytic efficiency (kcat/Km) of the variant toward the substrate malonyl-CoA was improved 19-fold. This study broadens the utility of engineered AraC variants as customized molecular reporters. In addition, the TAL reporter can find applications in other basic PKS activity screens.
Activation of acyl condensation reaction of monomeric 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme, by free coenzyme A
Kurosaki, Fumiya,Mitsuma, Satoru,Arisawa, Munehisa
, p. 597 - 604 (2002)
6-Hydroxymellein (6HM) synthase is a multifunctional polyketide enzyme induced in carrot cells, whose fully active homodimer catalyzes condensation of acyl-CoAs and the NADPH-dependent ketoreduction of the enzyme-bound intermediate. 6HM-forming activity of the synthase was markedly decreased when the reaction mixture pH was adjusted from 7.5 to 6.0. However, under these slightly acidic conditions, the acyl condensation catalyzed by the dissociated monomer enzyme was appreciably stimulated by addition of free coenzyme A (CoA). In contrast, the condensation reaction at pH 6.0 was significantly inhibited in the presence of CoA when the reaction was carried out with the NADPH-omitted dimer synthase. Among the kinetic parameters of the acyl condensation, velocity of the monomer-catalyzing reaction at the acidic pH was appreciably increased upon addition of CoA while Kms did not show any significant change in the presence and absence of the compound. These results suggest that CoA associates with a specific site in the dissociated monomeric form of 6HM synthase, and the velocity of the acyl condensation reaction catalyzed by the CoA-synthase complex appreciably increases in acidic conditions.
The first example of the [4+2] cycloaddition reaction of silylketenes with 1,3-dienes: A convenient preparation of 2-pyranones and isochromenes
Ito, Tatsuya,Aoyama, Toyohiko,Shioiri, Takayuki
, p. 6583 - 6586 (1993)
Silylketenes easily undergo the [4+2] cycloaddition reaction with electron-rich 1,3-dienes and o-quinodimethanes to give the corresponding 2-pyranones and isochromenes, respectively.
Note on the Synthesis of 4-Hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one
Haeusler, Johannes
, p. 1213 - 1216 (1982)
Meldrum's acid (2) is acylated by diketen affording the acyl Meldrum's acid 3.In aqueous bicarbonate its 3-oxogroup is selectively reduced by sodium tetrahydroborate giving the alcohol 4, which readily undergoes cyclization in refluxing dioxane leading to the title pyrone 7.Under identical conditions 3 produces the pyrone 6 with the pyrone carboxylic acid 5 as intermediate. - Keywords: Acyl Meldrum's acid; Ring closure; Selective reduction
Synthesis, characterization and antimicrobial activity of some new azo dyes derived from 4-hydroxy-6-methyl-2H-pyran-2-one and its dihydro derivative
Ben Mohamed-Smati, Soumaya,Faraj, Fadhil Lafta,Becheker, Imène,Berredjem, Hadjira,Le Bideau, Franck,Hamdi, Maamar,Dumas, Fran?oise,Rachedi, Yahia
, (2021)
A series of new azo disperse dyes was synthesized by coupling 4-hydroxy-6-methyl-2H-pyran-2-one (triacetic acid lactone, TAL) or its hydrogenated derivative 4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one (dihydro triacetic acid lactone, DHTAL) with diazonium salts derived from aniline, 4-bromoaniline, 4-nitroaniline, 4-methoxyaniline, 2,4-dimethoxyaniline and 2,5-dimethoxyaniline. Spectroscopic data of these dyes dissolved in five organic solvents were measured. The effects of solvent polarity, nucleophilic component and substituent nature on the visible absorption spectra of the dyes are also reported. The structures of all compounds were confirmed by FT-IR, electronic absorption in UV and visible regions, 1H, 13C and 2D NMR and high resolution mass spectroscopy (HRMS). In addition, in vitro antibacterial activity of the synthesized derivatives against Gram positive and Gram negative bacteria, both reference and clinical strains, was evaluated qualitatively and quantitatively by agar diffusion method.
Regioselective functionalization of pyrones: Facile synthesis of 6-styrylpyrones via KHMDS-mediated aldol condensation
Basu, Manas K.,Mukkanti, K.,Samala, Ramakrishna
, (2022/01/03)
Herein, we disclose our efforts directed toward the synthesis of the kavalactone-based natural product penstyrylpyrone and other related 4-OMe-2-pyrones possessing diverse substituents at the 3-, 5-, and 7-positions. Further, a facile approach to access 6-styrylpyrones via the KHMDS-mediated regioselective aldol condensation of 2-pyrones is described with moderate substrate scope and good to high yields (58–80%). The utility of this methodology was exemplified by the stereoselective construction of desmethoxyyangonin, asnipyrone A, and asnipyrone B.
Synthesis and Herbicidal Activity against Buffelgrass (Cenchrus ciliaris) of (±)-3-deoxyradicinin
Marsico, Giulia,Ciccone, Maria Sabrina,Masi, Marco,Freda, Fabrizio,Cristofaro, Massimo,Evidente, Antonio,Superchi, Stefano,Scafato, Patrizia
, (2019/09/09)
A novel synthetic strategy for obtainment of (±)-3-deoxyradicinin (2) is reported. This synthetic methodology is more efficient than those previously reported in the literature and also shows higher versatility towards the introduction of different side-chains at both C-7 and C-2. The obtained compound (±)-2 shows phytotoxicity against the grass-weed buffelgrass comparable to that of the natural phytotoxin radicinin (1). Therefore, (±)-2 can constitute a more practical synthetic alternative to 1 as bioherbicide for buffelgrass control.
The Generation of a Library of Bromodomain-Containing Protein Modulators Expedited by Continuous Flow Synthesis
Filipponi, Paolo,Baxendale, Ian R.
, p. 2000 - 2012 (2016/04/26)
A continuous flow process delivering key building blocks for a series of BCP modulator libraries is reported. A dynamically mixed flow reactor emerged as a pivotal technology in both synthesis and isolation phases enabling the processing of slurries and suspensions while maintaining high productivity and reliability. Accordingly, the synthesis of common intermediates in flow were employed to further build a pyridazone-based library (36 compounds) aimed at improving lead compound potency and selectivity while further enabling structure-activity relationship studies of a new BCP modulator family.
Easy and green synthesis of 6-(arylvinyl)-4-hydroxy-3-(phenylsulfanyl)-2H-pyran-2-ones in aqueous potassium hydroxide
Benferrah,Hammadi,Berthiol
, p. 2881 - 2886 (2017/03/22)
A convenient green procedure have been proposed for the synthesis of 6-(2-arylvinyl)-4-hydroxy-3-(phenylsulfanyl)-2H-pyran-2-ones by condensation of 6-(arylvinyl)-4-hydroxy-2H-pyran-2-ones with S-phenyl benzenesulfonothioate in aqueous potassium hydroxide at room temperature.
An Efficient Synthetic Access to Substituted Thiazolyl-pyrazolyl-chromene-2-ones from Dehydroacetic Acid and Coumarin Derivatives by a Multicomponent Approach
Ben Mohamed, Soumaya,Rachedi, Yahia,Hamdi, Maamar,Le Bideau, Franck,Dejean, Camille,Dumas, Fran?oise
, p. 2628 - 2636 (2016/06/08)
Two new series of pyran- or coumarin-substituted thiazolyl-pyrazole-chromen-2-one derivatives 10a-10d and 11a-11d were efficiently synthesized under environmentally friendly reaction conditions through a convenient one-pot multicomponent reaction of a heterocyclic bromoacetyl derivative 3 or 4 with thiosemicarbazide and a substituted 3-(acetoacetyl)coumarin derivative 5a-5d in anhydrous ethanol. The reaction proceeds through Hantzsch thiazole and Knorr pyrazole syntheses in refluxing ethanol. The key features of this approach are its operational simplicity, the quick access to the desired products, and the good to excellent yields. The structures of the newly synthesized compounds were established by IR spectroscopy, 1H, 13C, and 2D NMR spectroscopy, and mass spectrometry. Two new series of pyran- or coumarin-substituted (thiazolyl-pyrazole-chromen-2-ones) may be efficiently accessed from bromoacetyl derivatives of dehydroacetic acid or coumarin, thiosemicarbazide, and substituted 3-(acetoacetyl)coumarins by green multicomponent reactions. The newly synthesized structures were established by IR spectroscopy, 1H, 13C, and 2D NMR spectroscopy, and mass spectrometry.
