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ent-Eudesmane-type terpenoids constitute a large class of natural products derived from plants, animals, and bacteria. We describe a synthetic approach to two ent-eudesmane-type terpenoids, sinupol and eutyscoparin A, that relies on a key π-facial- and endo/exo-selective intramolecular Diels–Alder reaction to set the C-5–C-10 stereotriads. Further key transformations of trans-fused decalin include conversion to methyl ketone via a versatile thioester intermediate and appropriate functionalization toward target compounds.

The preparation of heterocyclic compounds has attracted great attention in organic chemistry because of their extensive application in the field of bioactive molecules, materials science, and natural products. Accordingly, the straightforward design and synthesis of heterocycles using readily accessible starting materials and reagents are among the main targets of synthetic chemists. In this context, reactions involving aryl methyl ketone and molecular iodine are recognized as powerful approaches for one-pot synthesis of heterocyclic compounds. This review focuses on the approaches developed for one-pot synthesis of N,O,S,Se-heterocyclic compounds through reactions involving aryl methyl ketone and molecular iodine over the past ten years.

The peculiarities of the three-component cyclization of ethyl 4,4,4-trifluoroacetoacetate and 1,2-ethanediamines with 3-methylbutan-2-one into hexahydroimidazo[1,2-a]pyridin-5-ones were studied. The reactions proceeded under mild conditions. The use of methyl ketone with a bulky isopropyl substituent increased the stereoselectivity of the transformations, but the reaction with 1,2-diaminopropane was accompanied by the formation 4-[(1-ammoniopropan-2-yl)amino]-1,1,1-trifluoro-4-oxobut-2-en-2-olate as a by-product.

Using some spectral methods and density functional theory calculations, a complete structural, vibrational, thermodynamic, electronic, nonlinear optical properties of 3-pyridyl methyl ketone have been evaluated. The Fourier transform infrared spectrum was obtained for the title molecule at room temperature. In the theoretical calculations, the Becke three Lee-Yang-Parr functional with 6-311++G(d,p) basis set was applied to carry out the quantum mechanical calculations. The infrared spectra were interpreted by using of normal coordinate analysis based on the scaled quantum mechanical force field. In addition, molecular electrostatic potential map, some thermodynamic parameters at different temperatures of compound were investigated. © 2020, © 2020 Taylor & Francis Group, LLC.

A series containing twelve substituted 4′-piperidinophenyl chalcones were synthesized from crossed-aldol condensation between 4-piperidionphenyl methyl ketone and substituted benzaldehydes using solid Cu2+/Zeolite catalyzed microwave assisted method. This condensation gave more than 85% yield. The structures of chalcones were analyzed by physico-chemical properties and spectroscopic data. The influence of the catalyst was investigated by observed quantity of yields.

This review emphasizes the recent developments in the Wacker oxidation process from its conventional form to more efficient, economical, and greener methods established in the last five years (2015–2020). The Wacker oxidation process involves the synthesis of aldehyde or methyl ketone from terminal olefins following the Markovnikov or anti-Markonikov addition of water using palladium-based catalysts. The development of catalysts from Pd to other metals and the choice of more eco-friendly and economical oxidants has been investigated recently, which promises a new avenue for the synthesis of more functionalized ketones and aldehydes. The extension to aza-Wacker-type oxidation is a new dimension in this field. The effect of substituents on the regioselectivity of the reaction has been well illustrated. The choice of various secondary oxidants has been focused on in this review. The wide applicability of newer modes along with the conventional conditions of the Wacker oxidation process for the synthesis of natural products and valuable compounds is another recent dimension that has been covered to validate the potential of this well-known reaction.

From acetone and the orthoamide of phenylpropiolic acid (21b) N,N-dimethyl-phenylpropiolic acid amide (24) is formed. In contrast, the reaction of chloroacetone (28) with 21b results in the vinylogous guanidinium chloride 29. Unexpectedly, the Birckenbach-analogoue ethyl methyl ketone (34) reacts with the orthoamide 21b to give the push-pull-substituted butadiene 36. In contrast to this observation, the reaction of the Birckenbach-analogous acetophenones 30 with the orthoamides 21a – c delivers the push-pull-substituted 1,3,5-hexatrienes 31a – j.

This work examines the reactive extraction of propionic acid, a promising liquid–liquid extraction technique, using tri-n-octylphosphine oxide (TOPO) or dioctylamine (DOA) diluted with eight different solvents (n-octane, methyl isobutyl ketone (MIBK), 1-octanol, ethyl methyl ketone, diisobutyl ketone, n-decane, diethyl sabecate, 1-decanol) at 298.15 K to determine the most efficient mixture for the extraction processes. A phosphorous-based extractant, TOPO, has been chosen for the extraction tests since it has low water solvency and is more ecologically agreeable than the amine-type extractants. Among the other amine extractants reported in reactive extraction studies, there is no study on propionic acid extraction using DOA in the literature. Physical extraction experiments with pure solvents were also performed to analyze the effect of TOPO and DOA on the extraction process. Distribution coefficients, loading factors, and extraction yields of the processes were determined for the explanation of the resu...

New substituted 5,6-dihydro[1,2,4]triazolo[4,3-a][1,3,5]triazines were synthesized by cyclocondensation of N-alkyl(aryl)-N′-(4H-1,2,4-triazol-3-yl)ethan- and -propanimidamides with benzaldehyde or ethyl methyl ketone in the presence of p-toluenesulfonic acid in 1,4-dioxane under reflux. The reaction tolerated a broad substrate scope and provided good yields (43–64%). The structure of the newly synthesized compounds was confirmed by elemental analyses and IR, 1H and 13C NMR, and mass spectra.

We report the synthesis of 9-CD3-9-cis-retinal via a six-step procedure from β-ionone. The steps involve an initial deuteration of the methyl ketone of β-ionone followed by two consecutive Horner-Wadsworth-Emmons (HWE) coupling reactions and their corresponding DIBAL reductions. A final oxidation of the allylic alcohol of the retinol leads to the target compound. This deuterium labeled retinoid is an important cofactor for studying protein-retinoid interactions in isorhodopsin.

A series of poly(acrylic acid-co-methylvinylketone–graft–sulfamethoxazole)(AVMDS) species was synthesized for drug carrier applications. The synthesis involved two steps: copolymerization o...

Ferrocenyl methyl ketone reacts with aromatic aldehydes yielding 1-ferrocenyl-3-aryl-propenones (chalcones), which upon treatment with Lawesson’s reagent (LR) are converted to the corresponding thiochalcones. The latter enter the thia-Diels–Alder reaction with acetylenic dienophiles (DMAD and methyl propiolate) to give ferrocenyl-substituted 4H-thiopyrans. In the case of methyl propiolate, the formation of the six-membered ring occurs with complete regioselectivity.

An expeditious one-step synthesis of the imidazopyridoindole scaffold was achieved through the C–H oxidation/two-fold cyclization reaction of methyl ketone and tryptamine derivatives. Mild oxidizing conditions were employed to realize the efficient oxidation of C(sp3)–H bonds, while suppressing overoxidation of the intermediate and ensuring the cross-trapping of two in situ generated acylimine intermediates.

Plane tree belongs to Platanaceae family. There is a widespread belief that Platanus orientalis leaves (POLs) have beneficial effects on joint disorders. Therefore, many people consume POLs as tea. To our knowledge, as there is no study on volatile compounds (VCs) of POLs, we objected to determine the VCs in POLs obtained from Platanus orientalis trees grown in Hatay province, Turkey. The VCs were extracted using solid phase micro-extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 140 VCs were found in POLs. Aldehydes, alcohols, ketones, terpenes and alkenes were determined in POLs as major VCs groups, which accounted for 32.40 %, 23.51 %, 18.08 %, 10.24 % and 4.82 % of total VCs identified, respectively. Trans, trans-2,4-heptadienal (6.62 %), nonanal (6.46 %), benzaldehyde (6.42 %), cis-3-hexen-1-ol (6.32 %), benzenemethanol (6.13 %) were the most abundant VCs identified in POLs. Trans-2-hexenal (3.46 %), 3-phenyl-2-butanone (2.87 %), trans-3,5-dimethyl-1,6-octadiene (2.80 %), 6-methyl-5-hepten-2-one (2.56 %), octan-1-ol (2.43 %), trans-geranyl acetone (2.17 %), trans-4,8-dimethyl-1,3,7-nonatriene (1.98 %), phenyl methyl ketone (1.69 %), 6-methyl-3,5-heptadiene-2-one (1.57 %) were the second most plentiful compounds found in POLs. 11H-dibenzo[b,e][1,4]diazepin-11-one,5,10-dihydro-5-[3-(methylamino)propyl] (1.38 %), benzeneethanol (1.36 %) and β-ionone (1.02 %) were found as the third most abundant VCs. The above-mentioned VCs were accounted for about 57 % of total VCs identified in POLs. The remaining VCs were below 1.00 % that is, found at trace levels. According to the VCs profiles of POL, its beneficial effects on health may be due to aldehydes, alcohols, ketones and terpenes., Planetree belongs to Platanaceae family. There is a widespread belief that Platanus orientalis leaves (POLs) have beneficialeffects on joint disorders. Therefore, many people consume POLs as tea. To our knowledge,as there is no study on volatile compounds (VCs) of POLs, we objected to determinethe VCs in POLs obtained from Platanus orientalistrees grown in Hatay province, Turkey. The VCs were extracted using solid phasemicro-extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS).A total of 140 VCs were found in POLs. Aldehydes, alcohols, ketones, terpenes andalkenes were determined in POLs as major VCs groups, which accounted for 32.40 %,23.51 %, 18.08 %, 10.24 % and 4.82 % of total VCs identified, respectively. Trans, trans-2,4-heptadienal (6.62 %), nonanal (6.46 %), benzaldehyde (6.42%), cis-3-hexen-1-ol (6.32 %), benzenemethanol(6.13 %) were the most abundant VCs identified in POLs. Trans-2-hexenal (3.46 %), 3-phenyl-2-butanone (2.87 %), trans-3,5-dimethyl-1,6-octadiene (2.80 %),6-methyl-5-hepten-2-one (2.56 %), octan-1-ol (2.43 %), trans-geranyl acetone (2.17 %), trans-4,8-dimethyl-1,3,7-nonatriene(1.98 %), phenyl methyl ketone (1.69 %), 6-methyl-3,5-heptadiene-2-one (1.57 %)were the second most plentiful compounds found in POLs. 11H-dibenzo[b,e][1,4]diazepin-11-one,5,10-dihydro-5-[3-(methylamino)propyl](1.38 %), benzeneethanol (1.36 %) and β-ionone (1.02 %) were found as the thirdmost abundant VCs. The above-mentioned VCs were accounted for about 57 % of totalVCs identified in POLs. The remaining VCs were below 1.00 % that is, found at tracelevels. According to the VCs profiles of POL, its beneficial effects on health maybe due to aldehydes, alcohols, ketones and terpenes.

Potential furfural compounds were detected by reverse phase high performance liquid chromatography (HPLC)-diode array detector (DAD) in milk-based formula (MBF), ultra-high temperature milk (UHT) and pasteurised yoghurt (PY). The content of potential 5-hydroxylmethyl-2-furaldehyde (HMF) and 2-furaldehyde (F) are significantly different in MBF, UHT and PY. 2-Furyl methyl ketone (FMC) and 5-methyl-2-furaldehyde (MF) were not detected in MBF, UHT and PY. Stress testing selected high temperature and high humidity to study the evolution of furfural compounds in MBF, UHT and PY. The contents of potential HMF and F sharply increased under high temperature conditions, while they showed little change under high humidity conditions. Accelerated testing and long-term testing were also conducted. Finally, regression equations of temperature–time-furfural content relationships were derived, by which the contents of furfural compounds in these dairy products stored under certain conditions for a certain time could be predicted.

The variation of volatile compounds during production of microencapsulated cream powder was investigated. First, maltodextrin (DE18) and sodium caseinate as wall materials were used to obtain microencapsulated cream as an oil-in-water emulsion, then it was spray-dried to produce the microencapsulated cream powder. Headspace solid-phase microextraction was used for isolation of volatiles and gas chromatography-mass spectrometry for identification. Results showed the volatile composition and amounts varied significantly during production of the microencapsulated cream powder. The microencapsulation of volatile acids and lactones in the cream was successfully performed. During spray drying, methyl ketones and limonene concentration decreased while the concentration of aldehydes (especially straight-chain aldehydes) significantly increased, indicating milk fat oxidation. Moreover, the concentration of a heat-treatment-related compound (furfural) increased and a methyl ketone degradation product (2-heptanol) was formed during spray drying.

Wacker-type reactions of terminal alkenes mainly lead to methyl ketones rather than aldehydes. The selective formation of aldehydes usually requires alkenes containing a suitable coordinating fragment. A few procedures however provide fair to high aldehyde/methyl ketone ratios in the absence of a directing group. This review, which is focused on the formation of aldehydes, summarizes the methods reported since 2007 and, with personal comments, the mechanisms and intermediates proposed to rationalize the regioselectivity.

Accurate classification of gases/odors is a classical challenge. Gas sensor arrays are generally used to enhance classification accuracy as they generate unique signature patterns for each individual gas/odor sample. However, instead of using these raw signatures directly, analyzing these signatures in certain hyperspaces also improves classification results. Most of the clusters created using existing transformations and normalization techniques are usually non-spherical and overlapping, leading to ambiguous classification results. In this paper, a new transformation called normalized difference sensor response transformation has been proposed. Here, virtual multi-sensor responses are generated from raw signature responses. These virtual responses show unambiguous association between data belonging to respective gases/odors. In addition, the signatures generated from virtual responses are grossly concentration independent, which further enhances the accuracy of classification. Experiments were conducted by using a thick-film four-element gas sensor array for four hazardous gases viz., acetone, carbon tetrachloride (CCl4), ethyl methyl ketone, and xylene. The results show cluster compaction by an average of 94.38% in terms of intra-cluster distance with respect to raw sensor responses. In addition, when compared with existing techniques, only the proposed transformation could generate non-overlapping clusters. Furthermore, minimum inter-cluster separation was 0.80 units.

Iodine-catalyzed the reaction of substituted methyl ketone N-tosylhydrazones with elemental sulfur has been developed. The cyclizations of the ester-substituted N-tosylhydrazone substrates proceeded smoothly under optimal reaction conditions, and the corresponding products 4-alkyl-1, 2, 3-thiadiazoles are obtained. For the reaction of 4-arylbutan-2-one of N-tosylhydrazone substrates, (E)-4-styryl-1, 2, 3-thiadiazole derivatives were obtained with high selectivity through the control of reaction conditions. In addition, gram-scale synthesis and further transformation of the product were also investigated.

The aim of this study was to develop a multi-analyte UHPLC method for furans and to apply it to commercial coffee samples as well as commercial roasting trials. Furans, as rising time–temperature indicators (TTIs), promised to be an alternative to unsatisfactory roasting temperature measurements. Consequently, a UHPLC–UV method for the determination of 5-hydroxymethyl-2-furfural (HMF), 5-hydroxymethyl-2-furoic acid (HMFA), 2-furfural (F), 5-methylfurfural (MF), 2-furyl methyl ketone (FMC), 2-furoic acid (FA), and for 3-caffeoylquinic acid (3-CQA) was developed and validated. Commercial roasted coffee beans contained 77.7–322 mg/kg HMF, 73.3–158 mg/kg HMFA, 109–200 mg/kg 2-F, 157–209 mg/kg MF, 12.3–32.8 mg/kg FMC, and 137–205 mg/kg FA. Roasting trial samples showed strong rising HMF contents (max.: Arabica: 769 mg/kg, Robusta: 364 mg/kg) followed by a distinct decline. Only MF and FA appeared as steady rising TTIs in the roasting process in Arabica and Robusta beans. 3-CQA fitted well as a decreasing TTI as expected.

Reactions of Cp2TiMe2, with the ester derivatives of organometallic sandwich compounds (ɳ5-RC5H4)Fe(ɳ5-C5H5) and (ɳ5-RC5H4)Co(ɳ4-C4Ph4) (R=ester groups) gave products having R=C(CH2)Me, instead of the expected vinyl ethers indicating conversion of the ester units by Cp2TiMe2 to methyl ketones followed by methylenation. A reaction of Cp2TiMe2 with the diester (ɳ5-RC5H4)Co(ɳ4-C4Ph3R)(R C(O)OMe) also gave similar results. The study has also been successfully extended to metal sandwich derived amides, thio and seleno esters. By controlling the amount of Cp2TiMe2, the reactions were also stopped at the methyl ketone stage and the methyl ketones were isolated in good yields and characterized. The method provides an easy and direct access to convert organometallic sandwich derived esters and related compounds to 1-methylvinyl derived products.

Three-component reactions of cotarnine chloride with silver acetylides and methyl propiolate or ethynyl methyl ketone in acetonitrile, as well as two-component reactions of 5-phenylethynyl-substituted tetrahydro[1,3]dioxolo[4,5-g]isoquinoline with alkynes in various solvents were studied. Performing them in 2,2,2-trifluoroethanol as the solvent, 10-phenylethynyl-substituted tetrahydro[1,3]dioxolo[4,5-i]-[3]benzazocines were obtained in good yields.

Some substituted styryl 2-benzimidazole ketones have been synthesised by fly-ash:H2SO4 catalysed aldol condensation of 2-benzimidazole methyl ketone and various substituted benzaldehydes in microwave oven. The yields of these chalcones are more than 70%. The purities of synthesised benzimidazole chalcones were checked by their physical constants and spectral data earlier published in the literature. The spectral frequencies of these chalcones have been correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses the effects of substituent on the group frequencies were discussed. The insect antifeedant activities of these chalcones have been studied using Dethler’s method.

A simple, convenient, and efficient oxidative cross-coupling reaction of oxindoles with ketones toward a variety of 3-(2-oxoalkyl)-3-hydroxyoxindoles in moderate to excellent yields has been developed. This transformation proceeds via a tandem oxidative cross-coupling by using 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) in air as an environmentally benign oxidant. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C3 position of oxindoles.

The development of tandem radical Csp3-H functionalization/cycloaddition of methyl ketone, tert-butyl nitrite, and maleimide has been reported herein. A variety of pyrrolo[3,4-d]isoxazolines have been successfully synthesized under metal-free conditions with excellent functional group compatibility. X-ray crystallography of the pyrrolo[3,4-d]isoxazoline was obtained and the reaction mechanism was proposed.

vi CHAPTER ONE: GENERAL INTRODUCTION 1 I. Dependence on Petroleum Products 1 II. Alternative Fuels from Biorenewable Sources 1 III. Alternative Chemicals from Biorenewable Sources 3 CHAPTER TWO: LITERATURE REVIEW 5 I. Fatty Acid Production Methods 6 II. Methyl Ketone Production 14 CHAPTER THREE: FERMENTATIVE PRODUCTION OF SHORT-CHAIN 16 FATTY ACIDS IN ESCHERICHIA COLI I. Abstract 16 I

A reliable three-step synthesis of ortho-substituted 4-pyrazolyl-2-ethylamines starting from a pyrazole methyl ketone and N-tert-butanesulfinylamine is described. Strongly dehydrating conditions were required to form the N-tert-butanesulfinyl ketimines, but these intermediates were stable to aqueous work-up and chromatography. Reduction of N-tert-butanesulfinyl ketimines with L-selectride®, or Super-hydride®, in THF afforded excellent yields and diastereoselectivities of the sulfinamides, which were converted into chiral amines with methanolic HCl. The 4-pyrazolyl-2-ethylamines from these investigations are attractive building blocks for medicinal chemists, as they exhibit low molecular weight, and low calculated octanol-water partition coefficient (c Log P values), while disrupting planarity with three-dimensional character. For example, the amine products were utilized in structure-activity studies of the human transient receptor potential vanilloid 1 (TRPV1/VR1).

The tumorigenic activity of upregulated Mcl-1 is manifested by binding the BH3 α-helical death domains of opposing Bcl-2 family members, neutralizing them and preventing apoptosis. Accordingly, the development of Mcl-1 inhibitors largely focuses on synthetic BH3 mimicry. The condensation of α-pyridinium methyl ketone salts and α,β-unsaturated carbonyl compounds in the presence of a source of ammonia, or the Krohnke pyridine synthesis, is a simple approach to afford highly functionalized pyridines. We adapted this chemistry to rapidly generate low-micromolar inhibitors of Mcl-1 wherein the 2,4,6-substituents were predicted to mimic the i, i + 2 and i + 7 side chains of the BH3 α-helix.

n . The latter compounds were supposedly formed by free-radical reactions, followed by spontaneous benzilic acid rearrangement and esterification. Furthermore, extraction of M. perennis with aqueous Me2CO produced an aldol condensation product, the known alkaloid speranskatine A (9a), which was identified by NMR after chromatographic purification. In a similar manner, a CH2 homolog of speranskatine A (10a) was obtained as a novel compound when ethyl methyl ketone (¼ butan-2-one; EtCOMe) instead of Me2CO was used for extraction. Consequently, 1 easily undergoes artefact formation upon extraction of plant material with polar or slightly polar solvents.

The Willgerodt reaction under iron-catalyzed aerobic conditions was found to be an excellent tool for full α-heterofunctionalization of acetophenones with sulfur and amines. Via this break-and rebuild strategy, a wide range of thioglyoxamides was synthesized in a four-component, highly atom-, step- and redox-economical manner with water as the only by-product.

Alpha-morpholine substituted poly(vinyl methyl ketone) (PVMK) was determined to undergo rapid self-crosslinking by short-term vacuuming (i.e., 30–60 min) or curing at 70–100 °C. The chemical transformations involved were monitored by TGA, DSC, FT-IR, 1HNMR and solid-state 13C NMR techniques. These experiments revealed an “unzipping-like” mechanism yielding multi conjugated enone structure via consecutive deamination by β-hydrogen elimination and simultaneous Diels–Alder cyclization resulting in crosslinking. This chemistry was exploited for generating Michael acceptor thin film coatings on silica nanoparticles, in which the silica was impregnated with morpholine substituted poly(vinyl methyl ketone) and simply heated at 100 °C. The dense polyene functional films so formed were demonstrated to add amines and thiols at room temperature. The resulting silica nanoparticles were employed to form homogenous composite films using poly(butyl acrylate-stat-methylmethacrylate) as carrier matrix. Morpholine substituted poly(vinyl methyl ketone) (MSP) seems to be generally applicable for surface modification of different inorganic surfaces with organics.

An I2–DMSO promoted novel and efficient method is described for the synthesis of isatins from 2-aminoaryl methyl ketone. A series of alkyl or aryl isatin derivatives were successfully synthesized under the optimized reaction conditions.

A simple and an efficient procedure for the synthesis of 4,6-diarylpyrimidin-2(1H)-ones using atomized sodium/THF via a one-pot three-component Biginelli-like cyclocondensation of an aldehyde, a methyl ketone and urea under ultrasonic condition is developed. The method is mild and inexpensive; yields are high and the reactions go to completion within 10-15 min.

The chemical composition of the essential oil of Perilla frutescens (L.) Britt. aerial parts and its insecticidal activity against Tribolium castaneum and Lasioderma serricorne were investigated. The essential oil of P. frutescens was obtained by hydrodistillation and a total of 34 components in the essential oil were identified with GC–MS. It was found that the main compounds included 2-furyl methyl ketone (71.83 %), decahydro-1-methyl-2-methylene-naphthalene (10.47 %), limonene (5.16 %) and caryophyllene (1.66 %). With a further isolation, the two active constituents were obtained from the essential oil and identified as 2-furyl methyl ketone, limonene. In the progress of assay, it showed that the essential oil and 2-furyl methyl ketone exhibited stronger contact and fumigant activities against the two stored product insects than limonene. Moreover, the essential oil and its constituents exhibited the comparable repellency against the two stored product insects, relative to the positive control, DEET. The results indicate that the essential oil of P. frutescens aerial parts and its isolated compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.

Dielectric constant of binary mixtures of ethyl methyl ketone (EMK) with some carboxylic acid, namely, acetic acid, propionic acid, and butyric acid, is measured at 303.16 K and 455 kHz. The data are used to compute the mutual correlation factor, gab, excess molar polarization, ΔP, and excess Gibbs free energy, ΔG, of mixing to study the molecular interaction. The study reveals that interaction is maximum in EMK + butyric acid system and microheterogeneous β-clusters with antiparallel orientation of dissimilar molecules predominate in it.

A series of β-disubstituted N-sulfinyl β-amino isoxazolyl ketones has been prepared by addition of tert-butanesulfinyl ketimines with the n-BuLi-generated enolates of isoxazolyl methyl ketones.

Humic acids (HAs), mixture of several complex-structured aromatic and aliphatic compounds, are ubiquitous in the terrestrial environment. In this study, HAs were fractionated on the basis of their polarity (degree of humification). The fractions namely 200P, 300P and 400P were comparatively more humified than fractions like 800P and 800S. The application of organic amendments significantly increased concentrations of HA fractions especially the more humified fractions in rice paddy soils. Among the different fractions, 300P fraction was the most abundant in rice paddy soils and its concentration was significantly increased due to compost application. The compounds like methyl ketone and 3-phenylprop-2-enal contributed almost 90% of 300P fraction.

A novel mode of achieving site selectivity between C-2 and C-4 positions in the indole framework by altering the property of the ketone directing group is disclosed. Methyl ketone, as directing group, furnishes exclusively C-2 alkenylated product, whereas trifluoromethyl ketone changes the selectivity to C-4, indicating that the electronic nature of the directing group controls the unusual choice between a 5-membered and a 6-membered metallacycle. The screening of other carbonyl-derived directing groups reveals that strong and weak directing groups exhibit opposite selectivity. Experimental controls and deuteration experiments lend support to the proposed mechanism.

Glioblastoma—a type of aggressive, invasive brain tumor—is almost always fatal. Although treatments exist, there is no cure. Now, researchers have taken a fresh look at a drug used to treat glioblastoma, temozolomide (TMZ), and made it a better cancer killer with potential for fewer side effects (ACS Chem. Biol. 2018, DOI:10.1021/acschembio.8b00864). Because only 17% of TMZ gets through the blood-brain barrier, Paul J. Hergenrother of the University of Illinois, Urbana-Champaign, and colleagues wanted to see if they could tweak the molecule’s structure to help it pass into the brain without compromising its anticancer properties. The team swapped out TMZ’s amide group for a series of chemical groups hypothesized to improve brain penetration and then tested the compounds, first in cancer cells and then in mice. The best-performing compound, K-TMZ, contains a methyl ketone group instead of the amide and showed greatly increased brain permeability, with 69% entering the brain compared

A formal asymmetric synthesis of the marine natural product apratoxin D, a highly potent inhibitor of H-460 human lung cancer cell growth (IC 50 value of 2.6 nM), is described. The key feature of the synthesis is an advanced-stage asymmetric ACC α,α-bisalkylation of a chiral nonracemic methyl ketone to provide access to an advanced intermediate as a single diastereomer that has previously been advanced to apratoxin D.

The aldol addition of an enol(ate) to a carbonyl compound is one of the most powerful and versatile C–C bond forming reactions. In complex target synthesis the coupling of two chiral partners may complicate the stereochemical outcome by multiple stereoinductions. Here, we report studies on pivotal aldol couplings employed in the rhizopodin synthesis, detailing the various directing effects exerted by the stereogenic centers present in this sterically hindered connection.

A highly stereocontrolled total synthesis of the cytotoxic marine macrolide aplyronine C is described. The route exploits aldol methodology to install the requisite stereochemistry and features a crucial boron-mediated aldol coupling of an N-vinylformamide-bearing methyl ketone with a macrocyclic aldehyde to introduce the full side chain. The synthesis of two novel C21–C34 side chain analogs is also reported.