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ABSTRACT Controlled oxidation of methyl‐ketones to aryl glyoxals using Selenium dioxide and iodine is one of the useful transformation. Regardless the availability of many oxidation reagents, Iodine/DMSO system is very efficient and flexible. This system efficiently allows in situ formation of α‐halo ketones and subsequently transforming them directly to useful products. The Iodine/DMSO system allows the selective CI and CO bond formation, substantially useful for converting them to other bond forming reactions and heterocycles useful in the synthetic and medicinal chemistry. Iodine/DMSO system could be an important alternative strategy due to sustainability, metal‐free conditions, allowing multiple/linear domino reactions. This review will focus on heterocyclic systems smartly developed/manipulated by Wu group from methyl‐ketones. The scope and limitations of this method and selected examples of applications for the synthesis of interesting molecules are discussed herein. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to explore the possibility to perform an asymmetric reduction, utilising a CBS‐type catalyst, of prochiral aryl methyl ketones under electrochemical conditions to generate the needed BH3 upon oxidation of NaBH4 with in situ generated I2 in the anode compartment. Therefore, various electrochemical parameters were optimised to conduct the desired formation of the chiral secondary alcohols in high to quantitative yields with a high stereochemical induction, although the catalyst loading had to be chosen relatively high to concur with the racemic reduction of the ketones by the electrogenerated BH3. [ABSTRACT FROM AUTHOR]

Curcumin is a plant-derived secondary metabolite exhibiting antitumor, neuroprotective, antidiabetic activities, and so on. We previously isolated Escherichia coli as an enterobacterium exhibiting curcumin-converting activity from human feces, and discovered an enzyme showing this activity (CurA) and named it NADPH-dependent curcumin/dihydrocurcumin reductase. From soil, here, we isolated a curcumin-degrading microorganism (No. 34) using the screening medium containing curcumin as the sole carbon source and identified as Rhodococcus sp. A curcumin-degrading enzyme designated as CurH was purified from this strain and characterized, and compared with CurA. CurH catalyzed hydrolytic cleavage of a carbon-carbon bond in the β-diketone moiety of curcumin and its analogs, yielding two products bearing a methyl ketone terminus and a carboxylic acid terminus, respectively. These findings demonstrated that a curcumin degradation reaction catalyzed by CurH in the soil environment was completely different from the one catalyzed by CurA in the human microbiome. Of all the curcumin analogs tested, suitable substrates for the enzyme were curcuminoids (i.e., curcumin and bisdemethoxycurcumin) and tetrahydrocurcuminoids. Thus, we named this enzyme curcuminoid hydrolase. The deduced amino acid sequence of curH exhibited similarity to those of members of acetyl-CoA C-acetyltransferase family. Considering results of oxygen isotope analyses and a series of site-directed mutagenesis experiments on our enzyme, we propose a possible catalytic mechanism of CurH, which is unique and distinct from those of enzymes degrading β-diketone moieties such as β-diketone hydrolases known so far. [ABSTRACT FROM AUTHOR]

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The elimination of lactones is a crucial method for preparing corresponding cycloalkane derivatives, but the commonly used catalyst NaI is unstable and non-recyclable. In this work, reusable MgI2@SiO2 was prepared for heterogeneous catalytic lactone elimination. Cyclopropyl methyl ketone was synthesized from 2-acetyl-γ-butyrolactone using MgI2@SiO2 as a catalyst at 180 °C and 1 atm. The yield and selectivity were both over 99%. The activity of MgI2@SiO2 was estimated to be 11 times that of NaI. The high activity of MgI2@SiO2 is attributed to the Lewis hard acidity of Mg2+ and the soft basicity of I−. The high selectivity of Cyclopropyl methyl ketone comes from the faster reaction rate, and its good stability is due to the strong interactions between Mg2+ and I− with the carrier. This work provides a feasible scheme for the efficient and low-cost elimination synthesis of corresponding cycloalkanes from lactones. [ABSTRACT FROM AUTHOR]

Herein, it is demonstrated that a chemical waste from the silicon industry, namely polymethylhydrosiloxane (PMHS), is a suitable hydrosilane source for the challenging, selective aerobic oxidation of olefins into methyl ketones under cobalt catalysis: a first row, abundant in the Earth's crust and cheap metal with low toxicity. The catalytic system operates under unprecedented, stoichiometric amounts of hydrosilane while the cobalt catalyst loading is kept at a very low 1 mol% with the reactions being finished in less than 1 hour with very high turnover numbers (1,340) and record‐breaking turnover frequency values up to 530 h−1. Mechanistic studies highlight the key role of the porphyrin ligand for stabilizing the active cobalt species that does follow a radical‐based reaction pathway under these particular conditions. These results are relevant for replacing the expensive and scarce palladium catalyst, traditionally used for Wacker‐type oxidations, by first‐row, Earth‐abundant transition metals under green conditions including the efficient valorization of a chemical waste such as PMHS. [ABSTRACT FROM AUTHOR]

The Kröhnke Pyridine Synthesis has been discovered about six decades ago (1961), by Fritz Kröhnke and Wilfried Zecher at the University of Giessen. The original method involved the reaction of α‐pyridinium methyl ketone salts with α,β‐unsaturated carbonyl compounds in the presence of a nitrogen source, frequently ammonium acetate. Since its discovery, the Kröhnke methodology has been demonstrated to be suitable for the preparation of mono‐, di‐, tri‐ and tetra‐pyridines, with important applications in several research fields. Over the years, a number of modifications to the original approach have been developed and reported, enabling for the broad applicability of these methods even in modern days, also for the synthesis of non‐pyridine compounds. In this critical and tutorial review, we will thoroughly explore and discuss the potential of the original method, the refinements that have been made over the years, as well as some applications arising from each type of pyridine and/or non‐pyridine compounds produced by Kröhnke's approach. [ABSTRACT FROM AUTHOR]

A novel microwave-mediated synthesis method was developed for the rapid and eco-friendly production of pyrimido[1,2-a]benzimidazole in high yields utilizing simple and cost-effective starting materials. This reaction was facilitated by the green organocatalyst guanidine hydrochloride. This protocol offers a metal-free and organocatalysed technique to afford a library of highly fluorescent pyrimido[1,2-a]benzimidazole derivatives. Key features of this synthetic method include its broad compatibility with functional groups, operational simplicity, and scalability, making it a promising technique for various applications. [ABSTRACT FROM AUTHOR]

A characteristic feature of the three-component cyclization of ethyl trifluoropyruvate and methyl ketones with 1,3-diamino-2-propanol is the formation of 8a-alkyl(phenyl)-3,7-dihydroxy-7-(trifluoromethyl)hexahydropyrrolo[1,2-a]pyrimidin-6(2H)-ones as one, two, or three diastereomers, depending on the methyl ketone component. The structures of the new heterocycles were established using the data of X-ray diffraction and 1H and 13C NMR spectra, including 2D 1H—13C HSQC, HMBC, 1H—1H COSY, and NOESY experiments. [ABSTRACT FROM AUTHOR]

The chemical composition, antioxidant and antimicrobial activities of the essential oil from the aerial parts of Rumex obtusifolius L. were studied. To the best of the authors' knowledge, this essential oil has never been fully characterized. The component analysis of the essential oil was done by gas chromatography with flame ionization detector (GC-FID) and mass selective detector (GC-MS). A total of 104 compounds, representing 97.8% of the essential oil, were identified. Aliphatic compounds, mainly methyl ketones (74.2%) and monoterpene hydrocarbons (13.7%) were found to be the most abundant compounds. The major compounds were undecan-2-one (47.6%) and nonan-2-one (13.4%). The antioxidant activity of the essential oil, evaluated by DPPH (IC50 9.11 mg/mL) and ABTS (IC50 36.72 mg/mL) assays, exhibited a weak ability in scavenging radicals. The essential oil also showed a low ferric reducing activity. The essential oil exhibited very good activity against E. coli and S. aureus, but low activities against S. enterica serovar, P. aeruginosa and C. albicans. MIC values of the essential oil varied from 0.38-27.04 μL/mL, with the lowest for E. coli. [ABSTRACT FROM AUTHOR]

An iodine/DMSO‐promoted approach has been developed for the synthesis of indoloquinolines via a sequential sp3 C−H oxidation/intramolecular cyclization using 2‐(1H‐indol‐2‐yl)anilines and aryl methyl ketones. A wide range of aryl methyl ketones, including drugs and complex bioactive molecule‐derived substrates were compatible in the present reaction with yields in the range of 30–96%. This protocol proceeds through sp3 C−H oxidation of aryl methyl ketones to phenylglyoxals, subsequent imine formation, and cyclization to furnish the indoloquinolines. Further, the reaction is applicable for gram‐scale synthesis and is operationally simple. [ABSTRACT FROM AUTHOR]

The orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a significant wheat pest in the Prairie Provinces of Canada and northern regions of the USA. Wheat phenology plays a critical role in wheat midge oviposition. We hypothesized that S. mosellana oviposition behaviour is influenced by volatile organic compounds (VOCs) emitted by wheat at two adjacent wheat growth stages: preanthesis and postanthesis. A higher number of S. mosellana eggs laid on preanthesis than postanthesis spikes in an oviposition choice experiment using the susceptible spring wheat cultivar 'Roblin'. In preanthesis, wheat emitted higher amounts of Z-3-hexenyl acetate (Z3-06:OAc) than at the postanthesis stage. Higher amounts of methyl ketones such as 2-tridecanone, 2-pentadecanone, and 2-undecanone were emitted by wheat in the postanthesis stage and these VOCs were sensitive to S. mosellana antennae used in the Gas Chromatography-Electroantennographic Detection. Females were attracted to synthetic Z3-06:OAc but were deterred by 2-tridecanone relative to the solvent control in the vertical Y-tube olfactometer. 2-Undecanone and 2-pentadecanone did not show any attractiveness or deterrence. In a no-choice oviposition experiment, fewer eggs were laid in preanthesis wheat exposed to a synthetic VOC blend of Z3-06:OAc, 2-undecanone, 2-tridecanone, and 2-pentadecanone at the concentrations released by postanthesis spikes. This study shows that the reduction of Z3-06:OAc, in the VOC mix, and possibly the increase in 2-tridecanone, are likely responsible for the reduction in oviposition on postanthesis wheat. These results elucidate for the first time the role of specific VOCs mediating S. mosellana oviposition in preanthesis and postanthesis wheat. [ABSTRACT FROM AUTHOR]

Ruta angustifolia, a wild plant which largely grows in Morocco, is commonly used in folk medicine and is believed to possess several therapeutic properties. In the present work, we aimed to determine the chemical composition, antioxidant, and antimicrobial properties of the essential oil obtained from the aerial parts of Ruta angustifolia collected from the Rif region in Morocco. The employment of gas chromatography coupled to flame ionization detector and mass spectrometry detection led to the identification of five major components, representing 91.69 % of the total volatile fraction with a dominance of nonyl methyl ketone (accounting for % 86.97 % of the whole sample). The tested essential oil displayed moderate antioxidant activity and a strong antifungal effect against Fusarium oxysporum and Botrytis cinerea with MIC values equal to 7 µL/mL and 0.81 µL/mL respectively. However, no antibacterial effect was revealed against Gram-negative or Gram-positive bacterial strains. [ABSTRACT FROM AUTHOR]

The haloform reaction from methyl ketones to carboxylic acids is one of the oldest known synthetic organic reactions, which has been used in myriad applications over the decades. The corresponding reaction to produce esters is, however, less developed, as the reaction is generally limited to simple, primary alcohols that are used in solvent‐level quantities, thereby restricting the complexity of esters that can be directly formed. Herein, we detail the development of a general ester‐forming haloform coupling reaction using one equivalent of alcohol. Mechanistic and kinetic modelling studies demonstrated that the key intermediates are formed under equilibrium, which facilitated the development of conditions that are amenable to secondary alcohols. [ABSTRACT FROM AUTHOR]

Ruthenium(II) complexes [RuL(CO)Cl(PPh3)2], 1a–4a, have been synthesized using ligands PhN＝NC(Ar)NOH, HL 1–4, respectively, by varying the pendant aryl (Ar) groups. The single crystal X-ray diffraction studies of complexes reveal that there are certain changes in Ru–Nazo and Ru–Noxime bond lengths that may be explained primarily on the basis of electronic effects of pendant aryl groups. In 4a, all Ru–N bond lengths are longer and this is attributed to oximato–O⋯O (hydroxyphenyl) interactions. Furthermore, there are weak intramolecular F⋯π interactions in 3a. The complexes display multiple reductive responses ascribable to electron acceptance within the azo-oxime framework of the coordinated ligand and the corresponding one-electron reduced metastable anion radical complexes of type [Ru(L˙−)(CO)Cl(PPh3)2]−[1]˙− have been generated. This property of the complexes has been exploited in electron transfer catalysis via trapping of electrons in the azo-oxime skeleton in two types of reactions: (1) α-alkylation of ketones with primary alcohols and (ii) synthesis of 2-substituted quinoline derivatives from 2-aminobenzyl alcohols and substituted acetophenones/alkyl methyl ketones. The scope of catalysis has been studied and the probable catalytic pathway has been established from experimental results. The catalytic pathway is ligand-centric and redox-driven for the dehydrogenation process and the initial step involves formation of a coordinated anion radical. This leads to conversion of the starting 1° alcohol to the corresponding carbonyl via the HAT pathway, with the ruthenium(II) centre practically behaving as a template and remaining redox inactive. The catalytic reactions have been proven to be affected by the nature of pendant aryl (Ar) groups within the coordinated ligand. [ABSTRACT FROM AUTHOR]

Chalcone and triazole scaffolds have demonstrated a crucial role in the advancement of science and technology. Due to their significance, research has proceeded on the design and development of novel benzooxepine connected to 1,2,3‐triazolyl chalcone structures. The new chalcone derivatives produced by benzooxepine triazole methyl ketone and different aromatic carbonyl compounds. Product structures were established by various spectral techniques such as IR, 1H NMR, 13C NMR, and mass specrometric analysis. Among the tested compounds, two compounds exhibited exceptional antibacterial susceptibilities with MIC (Minimum inhibitory concentration) range of 3.59–10.30 μM against the tested S. aureus strain. Few of the compounds displayed superior antifungal activity against F. oxysporum with MIC value range from 3.25‐4.89 μM, when compared to fluconazole (MIC=3.83 μM). In addition, few derivatives demonstrated equivalent antitubercular action against H37Rv strain with MIC range of 2.16–4.90 μM. The capacity of one of the ligand to form a stable compound on the active site of CYP51 from M. tuberculosis (1EA1) was confirmed by docking studies. Additionally, the chalcone‐1,2,3‐triazole hybrids ADME (absorption, distribution, metabolism, and excretion), molecular characteristics, estimation of toxicity, and bioactivity scores were assessed. [ABSTRACT FROM AUTHOR]

A practical metal-free and additive-free approach for the synthesis of 6/7/8-membered oxacyclic ketone-fused isoxazoles/isoxazolines tetracyclic or tricyclic structures is reported through Csp3–H bond radical nitrile oxidation and the intramolecular cycloaddition of alkenyl/alkynyl-substituted aryl methyl ketones. This convenient approach enables the simultaneous formation of isoxazole/isoxazoline and 6/7/8-membered oxacyclic ketones to form polycyclic architectures by using tert-butyl nitrite (TBN) as a non-metallic radical initiator and N–O fragment donor. [ABSTRACT FROM AUTHOR]

We present here a phosphine-free, quinoline-based pincer Mn catalyst for α-alkylation of methyl ketones using primary alcohols as alkyl surrogates. The C–C bond formation reaction proceeds via a hydrogen auto-transfer methodology. The sole by-product formed is water, rendering the protocol atom efficient. Electronic structure theory studies corroborated the proposed mechanism. [ABSTRACT FROM AUTHOR]

Acylation reactions of CH acids have been studied, and an efficient approach to the synthesis of 1-adamantyl methyl ketone directly from 1-adamantylcarbonyl chlorides has been developed. The proposed method involves the reaction of carboxylic acid chlorides with diethyl malonate in the presence of sodium hydroxide followed by hydrolysis of intermediate keto diesters in an acidic medium and decarboxylation. [ABSTRACT FROM AUTHOR]

Over the past decade, multiple studies have suggested that the secondary metabolites produced by plants against herbivorous insects could be used as biopesticides. However, as the molecular mechanism of action of these compounds remains unknown, it is difficult to predict how they would affect non-target insects; thus, their innocuity needs to be clarified. Here, we investigate, from the molecular level to the organism, the responses of a useful parasitic insect Nasonia vitripennis (Walker, 1836) being exposed at the pupae stage for 48 h (up to 6 days) to sublethal doses (5 µg/L and 500 µg/L) of 2-Dodecanone. 2-Dodecanone altered the gene expression of genes related to ecdysone-related pathways, biotransformation, and cell homeostasis. A significant induction of ecdysone response-genes (EcR, usp, E78, Hr4, Hr38) was detected, despite no significant differences in ecdysteroid levels. Regarding the cell homeostasis processes, the gene l(2)efl was differentially altered in both experimental conditions, and a dose-dependent induction of hex81 was observed. 2-Dodecanone also triggered an induction of Cyp6aQ5 activity. Finally, 2-Dodecanone exposure had a significant effect on neither development time, energy reserves, nor egg-laying capacity; no potential genotoxicity was detected. For the first time, this study shows evidence that 2-Dodecanone can modulate gene expression and interfere with the ecdysone signalling pathway in N. vitripennis. This could lead to potential endocrine alterations and highlight the suitability of this organism to improve our general understanding of the molecular effects of plant defences in insects. Our findings provide new insights into the toxicity of 2-Dodecanone that could potentially be explored in other species and under field conditions for plant protection and pest management as a means to reduce reliance on synthetic pesticides. [ABSTRACT FROM AUTHOR]

An expeditious strategy has been developed for the synthesis of diverse quinolines, indenoquinolines and acridines using KOtBu‐mediated reaction conditions. The designed process utilizes 2‐aminoaryl carbaldehydes/2‐aminoaryl ketones and methyl/methylene group containing ketones as readily available feedstock. The chemical transformation was affected at room temperature within a short duration of time to obtain diverse N‐heterocycles yields up to 92 %. The established process also exhibits considerable functional group tolerance with an operational simplicity. [ABSTRACT FROM AUTHOR]

A highly enantioselective Mannich reaction of biphenyl‐bridged seven‐membered cyclic N‐sulfonylimines with methyl alkyl ketones is disclosed in this study. The reaction was performed under organocatalysis by using a quinine‐derived primary amine as the catalyst in combination with a Brønsted acid as the co‐catalyst. High yields (up to 89 %) and excellent enantioselectivities (up to 97 % ee) were observed. For methyl alkyl ketones containing a larger alkyl substituent, specific regioselective addition to the C=N bond is favored at the methyl group. On the contrary, ketones containing a smaller alkyl substituent or hydroxyacetone substrates gave major syn selective Mannich products at the methylene group. [ABSTRACT FROM AUTHOR]

The asymmetric formal [3 + 3] annulation process of (E)-2-(3-phenylacryloyl)pyridine N-oxide with benzyl methyl ketone was investigated. The possibility of a stereoselective outcome was checked using salts of natural amino acids, as well as chiral bifunctional derivatives containing amino groups and thiourea or squaramide fragments as organocatalysts. Different types of organocatalysts applied led to opposite enantiomers of 2-(3-oxo-4,5-diphenyl-cyclohex-1-en-yl)pyridine 1-oxide (up to 60% ee). Spectroscopic analysis of the isolated product and analysis of the reaction course was carried out, taking into account the obtained regio- and stereoselectivity. In order to verify the postulated results, calculations of the energy of the intermediate reaction products and the final product using the Kohn–Sham Density Functional Theory (KS-DFT) were made. [ABSTRACT FROM AUTHOR]

Flavor sensation is one of the most prevalent characteristics of food industries and an important consumer preference regulator of dairy products. So far, many volatile compounds have been identified, and their molecular mechanisms conferring overall flavor formation have been reported extensively. However, little is known about the critical flavor compound of a specific sensory experience in terms of oxidized off-flavor perception. Therefore, the present study aimed to compare the variation in sensory qualities and volatile flavors in full-fat UHT milk (FFM) and low-fat UHT milk (LFM) samples under different natural storage conditions (0, 4, 18, 25, 30, or 37°C for 15 and 30 d) and determine the main component causing flavor deterioration in the FFM and LFM samples using sensory evaluation, electronic nose, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). In addition, the Pearson correlation between the volatile flavor components and oxidative off-flavors was analyzed and validated by sensory reconstitution studies. Compared with the LFM samples, the FFM samples showed a higher degree of quality deterioration with increased storage temperature. Methyl ketones of odd carbon chains (i.e., 2-heptanone, 2-nonanone, 2-undecanone, 2-tridecanone, and 2-pentadecanone) reached a maximum content in the FFM37 samples over 30 d storage. The combined results of the Pearson correlation and sensory recombination study indicated that 2-heptanone, 2-nonanone, and 2-undecanone conferred off-flavor perception. Overall, the present study results provide potential target components for detecting and developing high-quality dairy products and lay a foundation for specific sensory flavor compound exploration in the food industry. [Display omitted] [ABSTRACT FROM AUTHOR]

A one-pot, efficient oxidative-condensation process for constructing both 4-alkyl and 4-aryl-5-(arylthio) thiazol-2-amines using DMSO/I2 is introduced. In this procedure, methyl ketones, thiourea, DMSO, and thiols are reacted together in the presence of molecular I2 at 80 °C simply to produce 4-alkyl or aryl-5-(arylthio)thiazol-2-amines due to formation of a C–S bond between thiourea and methyl carbon linked to carbonyl group and the another C–S bond formation between thiol and thiazol ring. Under reaction conditions, both aryl and alkyl methyl ketones including acetophenone and substituted acetophenones also, 2-alkanones such as acetone, 2-butanone, 2-pentanone, and 2-heptanone yield those products successfully. [ABSTRACT FROM AUTHOR]

BACKGROUND: α‐Ketothioamides play a vital role in the fields of medicine and biology. There are many α‐ketothioamide synthesis pathways, but in general, most current methods involve either conventional heating in solvent conditions or using non‐recyclable catalysts. Thus, our work investigated the preparation of α‐ketothioamides under solvent‐free sonication using magnetic nanoparticle‐immobilized chlorozincate ionic liquid as a catalyst. The desired products were purified by chromatography columns and characterized using 1H NMR and 13C NMR. RESULTS: In this study, Lewis acidic ionic liquid grafted onto magnetic nanoparticles (Fe3O4@IL‐ZnCl2) was used as an effective heterogeneous catalyst for the generation of a variety of α‐ketothioamide derivatives. The optimized conditions were methyl ketone (1.0 mmol), amine (1.2 mmol), S8 (1.2 mmol) and Fe3O4@IL‐ZnCl2 (15 mg) under solvent‐free sonication at 80 °C for 5 h, and the crude products were obtained in a 34–94% isolated yield. Then, this procedure was successfully applied to a wide range of aryl and alkyl ketone compounds. Besides, there was only a slight loss in catalytic activity in three consecutive cycles, indicating the reusability and stability of the catalytic system. CONCLUSIONS: We have successfully designed a novel protocol for the generation of α‐ketothioamide derivatives from aryl/alkyl methyl ketones, amines, and elemental sulfur catalyzed by chlorozincate ionic liquid‐coated magnetic Fe3O4 nanoparticles. The reaction proceeded via a mild, efficient, solvent‐free sonication accompanied by a well‐reactive catalyst, which is easily separated and reusable. Besides, a feasible mechanism is presented. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

An efficient, simple and general protocol for the selective hydration of terminal alkynes into the corresponding methyl ketones has been developed by using a cheap, easy‐to‐synthesise and sustainable FeIII‐based eutectic mixture [FeCl3 ⋅ 6H2O/Gly (3 : 1)] as both promoter and solvent for the hydration reaction, working: i) under mild (45 °C) and bench‐type reaction conditions (air); and ii) in the absence of ligands, co‐catalysts, co‐solvents or toxic, non‐abundant and expensive noble transition metals (Au, Ru, Pd). When the final methyl ketones are solid/insoluble in the eutectic mixture, the hydration reaction takes place in 30 min, and the obtained methyl ketones can be isolated by simply decanting the liquid FeIII‐DES, allowing the direct isolation of the desired ketones without VOC solvents. By using this straightforward and simple isolation protocol, we have been able to recycle the FeIII‐based eutectic mixture system up to eight consecutive times. Furthermore, the FeIII‐eutectic mixture is able to promote the selective and efficient formal oxidation of internal alkynes into 1,2‐diketones, with the possibility of recycling this system up to three consecutive times. Preliminary investigations into a possible mechanism for the oxidation of the internal alkynes seem to indicate that it proceeds through the formation of the corresponding methyl ketones and α‐chloroketones. [ABSTRACT FROM AUTHOR]

We have discovered base‐mediated conversion of 3,3‐bis(methylthio)‐1‐arylprop‐2‐en‐1‐ones to versatile active methylene compounds (β‐keto esters). A series of products were isolated and characterized as a mixture of keto‐enol form. We have modified the method and synthesized the active methylene compounds (β‐keto esters) directly from aryl methyl ketone via ketene dithioacetal intermediate (not isolated) by stepwise reactions in one pot. Most of the one‐pot reactions also provided excellent yields. In addition to aryl methyl ketones, we also tested cyclopropyl methyl ketone as a source of an aliphatic ketone, and under similar reaction conditions, ethyl 3‐cyclopropyl‐3‐oxopropanoate was afforded. [ABSTRACT FROM AUTHOR]

The reactions of (3S,4RS)-1,3-dideoxy-3-[(2Z)-4-methoxy-3-methyl-4-oxobut-2-en1-yl]-4-C-methyl-4,5-O-(1-methylethylidene)pent-2-ulose with MCPBA and trifluoroperacetic acid were studied. It was shown that 60% MCPBA in CH2Cl2 at room temperature caused isomerization in the acetonide fragment of this compound, while no expected Baeyer—Villiger (B—V) reaction was observed at the methyl ketone. In the MCPBA—AcONa system, the epoxidation of the activated double bond followed the conjugate addition—elimination scheme. The oxidation with trifluoroperacetic acid occurred at the methyl ketone moiety with subsequent decomposition of the dioxolane protecting group and intramolecular lactonization. The introduction into the B—V reaction of the corresponding aldehyde-containing partner instead of the methyl ketone-containing ulose led to an abnormal product of furanization with the loss of the chiral center. [ABSTRACT FROM AUTHOR]

This study highlights the straight‐forward synthesis of substituted 1,2‐amino alcohols from simple and readily available aromatic methyl ketones. Starting from acetophenone derivatives, the straight‐forward synthesis strategy involved an initial bromination of the alpha‐positioned methyl group in the first step, followed by a simple hydrolysis to the hydroxyketone (2‐hydroxyacetophenone). The hydroxylated intermediate was subsequently converted from Silicibacter pomeroyi to the final 1,2‐amino alcohol by using the transaminase. The transaminase‐catalyzed reaction proceeded with yields up to 62 % and always excellent enantiomeric excess of >99 %. Interestingly, the keto‐enol‐tautomerism of the hydroxyl ketone yields an unexpected amino alcohol isomer. [ABSTRACT FROM AUTHOR]

A I2‐DMSO mediated approach to introduce −OCD3 into pyrroles in situ via multicomponent cascade cyclization reaction using methyl ketones, aniline, ethyl benzoylacetate and CD3OD as readily available substrates is reported. This process realizes introduction of −OCD3 into the Hantzsch pyrrole synthesis and synthesis of deuterated alkoxy‐substituted pyrroles with formation of one C−C bond, one C−O bond and two C−N bonds in one pot. Notably, this conversion has good substrate compatibility (62 examples) and eliminates of the need for anhydrous and anaerobic operation. [ABSTRACT FROM AUTHOR]

Dulce de leche flavoring is a new product and is accepted by a range of the population that enjoys this type of flavoring similar to condensed milk. That is why this work aimed to develop a dulce de leche flavoring. The flavoring obtained presented 16 components for a concentration of 5.34% m/m. The highest qualitative percentage was of carbonyl compounds and esters, with vanillin and δ-decalactone being the majority. The compounds with the greatest sensory contribution were ethyl butyrate, methyl amyl ketone, ethyl cinnamate and heliotropin. The evaluation of the sensory quality of the flavoring, applied in milk at a dose of 1%, obtained a good rating. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of 2,4,6-triaryl pyridines is disclosed. Singlet molecular oxygen generated from trans-5-hydroperoxy-3,5-dimethyl-1,2-dioxolane-3-yl ethaneperoxate has been explored as an effective oxidant for oxidative cleavage of C-N bond in the synthesis of 2,4,6-trisubstituted pyridines from benzylamines and aryl methyl ketones. The convenient preparation of the reagent, simple reaction procedures, avoidance of transition metal catalysts, good-to-excellent yields, short reaction times, and synthesis of asymmetric pyridine derivate are some of the advantages of this protocol. Thus, this protocol may serve as a potential synthetic method for the synthesis of 2,4,6-trisubstituted pyridines. Singlet molecular oxygen generated from trans-5-hydroperoxy-3,5-dimethyl-1,2-dioxolane-3-yl ethaneperoxate/n-Bu4NF has been explored as an effective oxidant for oxidative cleavage of C-N bond in the synthesis of 2,4,6-trisubstituted pyridines. The avoidance of transition metal catalysts, good-to-excellent yields, and synthesis of symmetric and asymmetric pyridine derivates are some of the advantages of this protocol. [ABSTRACT FROM AUTHOR]

Current medication therapy for leishmaniasis and trypanosomiasis remains a major challenge due to its limited efficacy, significant adverse effects, and inaccessibility. Consequently, locating affordable and effective medications is a pressing concern. Because of their easy-to-understand structure and high functionalization potential, chalcones are promising candidates for use as bioactive agents. Thirteen synthetic ligustrazine-containing chalcones were evaluated for their ability to inhibit the growth of leishmaniasis and trypanosomiasis in etiologic agents. The tetramethylpyrazine (TMP) analogue ligustrazine was chosen as the central moiety for the synthesis of these chalcone compounds. The most effective compound (EC50 = 2.59 µM) was the chalcone derivative 2c, which featured a pyrazin-2-yl amino on the ketone ring and a methyl substitution. Multiple actions were observed for certain derivatives, including 1c, 2a–c, 4b, and 5b, against all strains tested. Eflornithine served as a positive control, and three ligustrazine-based chalcone derivatives, including 1c, 2c, and 4b, had a higher relative potency. Compounds 1c and 2c are particularly efficacious; even more potent than the positive control, they are therefore promising candidates for the treatment of trypanosomiasis and leishmaniasis. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) is a common phenomenon in clinical oncology, whereby cancer cells become resistant to chemotherapeutic drugs. A common MDR mechanism is the overexpression of ATP-binding cassette efflux transporters in cancer cells, with P-glycoprotein (P-gp) being one of them. New 3,4-seco-lupane triterpenoids, and the products of their intramolecular cyclization with the removed 4,4-gem-dimethyl group, were synthesized by the selective transformations of the A-ring of dihydrobetulin. Among the semi-synthetic derivatives, the MT-assay-enabled methyl ketone 31 (MK), exhibiting the highest cytotoxicity (0.7–16.6 µM) against nine human cancer cell lines, including P-gp overexpressing subclone HBL-100/Dox, is identified. In silico, MK has been classified as a potential P-gp-inhibitor; however, the Rhodamine 123 efflux test, and the combined use of P-gp-inhibitor verapamil with MK in vitro, showed the latter to be neither an inhibitor nor a substrate of P-gp. As the studies have shown, the cytotoxic effect of MK against HBL-100/Dox cells is, arguably, induced through the activation of the ROS-mediated mitochondrial pathway, as evidenced by the positive Annexin V-FITC staining of apoptotic cells, the cell cycle arrest in the G0/G1 phase, mitochondrial dysfunction, cytochrome c release, and the activation of caspase-9 and -3. [ABSTRACT FROM AUTHOR]

The isolation and structural characterization of a unique Cu(II) isonicotinate (ina) material with 4-acetylpyridine (4-acpy) is provided. The formation of [Cu(ina)2(4-acpy)]n (1) is triggered by the Cu(II) aerobic oxidation of 4-acpy using O2. This gradual formation of ina led to its restrained incorporation and hindered the full displacement of 4-acpy. As a result, 1 is the first example of a 2D layer assembled by an ina ligand capped by a monodentate pyridine ligand. The Cu(II)-mediated aerobic oxidation with O2 was previously demonstrated for aryl methyl ketones, but we extend the applicability of this methodology to heteroaromatic rings, which has not been tested so far. The formation of ina has been identified by 1H NMR, thus demonstrating the feasible but strained formation of ina from 4-acpy in the mild conditions from which 1 was obtained. [ABSTRACT FROM AUTHOR]

Here we report the preparation of primary α‐ketoamides via a highly efficient molecular iodine‐mediated oxidative amidation of aryl methyl ketones with ammonium carbamodithioate. A self‐sequenced iodination/nucleophilic substitution/Kornblum oxidation/amidation mechanism was proposed. In this mechanism, α‐thiocyanatoacetophenone is the key intermediate. [ABSTRACT FROM AUTHOR]

Herein, we report a solvent‐ and transition‐metal‐free, iodine‐catalyzed formation of C−S (sulfone) bonds for the synthesis of β‐keto sulfones using readily accessible methyl ketones and sulfonyl hydrazides. This study also features the α‐functionalization of β‐keto sulfones to synthesize β‐keto thiosulfones and α‐iodo‐β‐keto sulfones via iodine‐catalyzed carbon‐sulfide (C−S) bond formation under solvent‐free conditions and iodine‐mediated C−I bond formation under aqueous conditions, respectively. The analytical studies and control experiments allow insights into a free‐radical coupling strategy. Overall, the presented protocol is operationally simple and scalable, has a broad range of functional group tolerance, and provides access to three functionalized organic scaffolds. [ABSTRACT FROM AUTHOR]

An easy metal‐free cascade cyclization of 4‐amino coumarin with aryl methyl ketone has been developed as a straightforward method for constructing coumarino‐fused [1,5]‐diazocines. This chemical transformation affords linearly fused structure of coumarin and 1,5‐diazocine with significant yield. Such complex hybrid diazocine skeletons can propose various bioactivities in drug design. The technique is highly appealing, sustainable, and economic since it is operationally simple and uses a catalytic quantity of iodine in presence of DMSO. In this protocol, DMSO functions both as a solvent and an oxidant. Again, the sustainability of this protocol is enhanced as it is devoid of any exogenous oxidant. Further functionalization of these diazocine moieties using metal catalyzed cross coupling techniques lead to several interesting scaffolds. Furthermore, these diazocine compounds can undergo a base‐controlled regioselective metal‐free Chan‐Lam type coupling reaction, yielding novel N‐arylated and O‐arylated products. Additionally, the formation of densely functionlized coumarin fused pyrrole scaffolds from 3‐aminocoumarin and aryl methyl ketone widens the practical applicabilty of this protocol. This pyrrolo‐coumarin frameworks are present in the bio‐active marine alkaloid, lamellarins. [ABSTRACT FROM AUTHOR]

The combination of gold(I) and enzyme catalysis has provided access to a series of nor(pseudo)ephedrine derivatives in a regio‐ and stereoselective manner. The approach involves developing IPrAuNTf2‐catalyzed hydration of 1‐phenylprop‐2‐yn‐1‐yl acetate or N‐(1‐phenylprop‐2‐yn‐1‐yl)acetamide, followed by (dynamic) asymmetric biotransamination or bioreduction of the corresponding keto ester or keto amide intermediates. Enzyme actions were completely selective towards the modification of the methyl ketones in a highly stereoselective manner, allowing the synthesis of enantio‐ and diastereomerically enriched products using either racemic or optically active starting materials. Thus, a series of amino alcohol, diol, and diamine derivatives were produced from propargyl esters or amides (57 to 86% isolated yield), the biocatalyst of choice determining the (stereo)selectivity of the overall cascade process (70–99% diastereomeric excess and >98% enantiomeric excess), and providing access to nor(pseudo)ephedrine compounds in a straightforward manner. [ABSTRACT FROM AUTHOR]

Iridium‐catalyzed α‐alkylation of methyl ketones with primary carbohydrate alcohols proceeded via borrowing hydrogen strategy. Protected sugar derivatives having one free primary hydroxyl group reacted with methyl ketones to give the α‐alkylation products or alkylated 4,5‐unsaturated sugars along with the elimination of an alkoxy group. [ABSTRACT FROM AUTHOR]

Herein we report the development of deacylative thiolation of diverse methyl ketones. The reaction is redox‐neutral, and heavy‐metal‐free, which provides a new way to introduce thioether groups site‐specifically to unactivated aliphatic positions. It also features excellent functional group tolerance and broad substrate scope, thus allowing late‐stage derivatization. The process benefits from efficient condensation between the activation reagent and ketone substrates, which triggers aromatization‐driven C−C fragmentation and rapid radical coupling with thiosulfonates. Experimental and computational mechanistic studies suggest the involvement of a radical chain pathway. [ABSTRACT FROM AUTHOR]

A series of new Morita–Baylis–Hillman acetates were prepared and reacted with methanesulfonamide (K2CO3, DMF, 23 °C) to produce tertiary dihydroquinoline sulfonamides in high yields. Subsequent efforts to eliminate the methylsulfonyl group from these derivatives (K2CO3, DMF, 90 °C) as a route to quinolines were met with mixed results. Although dihydroquinoline sulfonamides prepared from ethyl acrylate and acrylonitrile generally underwent elimination to give excellent yields of quinolines, those generated from 3-buten-2-one failed to undergo elimination and instead decomposed. The failure of these ketone substrates to aromatize presumably derives from the enolizable methyl ketone at C-3. Finally, the attempted aromatization of the acrylate-derived 6,7-difluoro-1,2-dihydroquinoline sulfonamide demonstrated that other interesting processes could occur in preference to the desired elimination. [ABSTRACT FROM AUTHOR]

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Rationale: Methyl ketones are of interest for the application as biofuels. The fatty acid metabolism of different microbes has been rearranged to achieve a sustainable production of methyl ketones. The biofuel properties and possible further chemical modifications of these methyl ketones are influenced by their chain length, as well as their degree of saturation and the corresponding double bond position. Methods: A method based on gas chromatography–electron ionization; mass spectrometry (GC‐EI‐MS) was used to determine the double bond position of methyl ketones. Derivatization using dimethyl disulfide (DMDS) and an iodine catalyst enabled the activation of the double bonds for selective fragmentation during electron ionization. The cleavage led to key fragments in the Orbitrap high‐resolution mass spectrum and allowed the unequivocal localization of the double bond position of the respective monounsaturated methyl ketone. Results: The double bond position of several medium chain length methyl ketones originating from the gram‐negative bacterium Pseudomonas taiwanensis (P. taiwanensis) VLB120 was determined. The DMDS derivatives of methyl ketones can yield isobaric fragment ions for different possible double bond positions, which can be distinguished only using high‐resolution MS. The double bond position of all methyl ketones deriving from P. taiwanensis VLB120 was the same, counting from the end of the aliphatic chain, and was determined as ω‐7. Conclusions: The derivatization of medium chain length monounsaturated methyl ketones with DMDS allowed the determination of the corresponding double bond position via GC‐EI‐MS. High‐resolution MS is needed to differentiate possible double bond positions that yield isobaric fragment ions. [ABSTRACT FROM AUTHOR]

The Wacker process, which is widely used to convert monosubstituted alkenes into the corresponding methyl ketones, is thought to proceed through a PdII/Pd0 catalytic cycle involving a b-hydride elimination step. This mechanistic scenario is inapplicable to the synthesis of ketones from the 1,1-disubstituted alkenes. Current approaches based on semi-pinacol rearrangement of PdII intermediates are limited to the ring expansion of highly strained methylene cyclobutane derivatives. Herein, we report a solution to this synthetic challenge by designing a PdII/PdIV catalytic cycle incorporating a 1,2-alkyl/PdIV dyotropic rearrangement as a key step. This reaction, compatible with a broad range of functional groups, is applicable to both linear olefins and methylene cycloalkanes, including macrocycles. Regioselectivity favors the migration of the more substituted carbon, and a strong directing effect of the b-carboxyl group was also observed. [ABSTRACT FROM AUTHOR]

Pyrroloquinoline quinone (PQQ) is an important cofactor of methanol dehydrogenases and glycose dehydrogenases. In addition, isolated PQQ is used as a central component in sensors and biomimetic complexes. The synthesis of PQQ derivatives is of interest for developing new alcohol oxidation catalysts and redox sensors. This work describes a modular synthesis for derivatives of PQQ bearing methyl and ketone groups instead of carboxylic acid moieties. These modifications reduce the possible coordination sites of PQQ for metal ions outside the protein environment. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reactions of 2-amino-1,3-benzothiazole with aliphatic, aromatic and heteroaromatic α-iodoketones in the absence of bases or catalysts have been studied. The reaction proceeds by N-alkylation of the endocyclic nitrogen atom followed by intramolecular dehydrative cyclization. The regioselectivity is explained and the mechanism of the reaction is proposed. A number of new linear and cyclic iodide and triiodide benzothiazolium salts have been obtained and their structure proved by NMR and UV spectroscopy. [ABSTRACT FROM AUTHOR]