Month: December 2022

Ha, Deok Chan published the artcileN-Trimethylsilylimines: applications to the syntheses of β-lactams, Formula: C8H16O2, the publication is Journal of the American Chemical Society (1984), 106(17), 4819-25, database is CAplus.

Ester enolates and N-trimethylsilylimines react to afford β-lactams. The stereochem. course of the reaction depends on the ester enolate geometry. Thus, (E)-enolates give mainly cis β-lactams while (Z)-enolates give ∼1:1 mixtures of cis and trans β-lactams. The use of HOCHMeCH₂CO₂Et as the ester component gives β-lactams of potential use in carbapenem synthesis. The differences in the behavior of N-trimethylsilyl and N-arylimines in the ester-imine condensations are also discussed.

Journal of the American Chemical Society published new progress about 5340-78-3. 5340-78-3 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is Ethyltert-butylacetate, and the molecular formula is C8H16O2, Formula: C8H16O2.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Tajuddin, Hazmi published the artcileIridium-catalyzed C-H borylation of quinolines and unsymmetrical 1,2-disubstituted benzenes: insights into steric and electronic effects on selectivity, Application of Methyl 2,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate, the publication is Chemical Science (2012), 3(12), 3505-3515, database is CAplus.

Borylation of quinolines provides an attractive method for the late-stage functionalization of this important heterocycle. The regiochem. of this reaction is dominated by sterptsic factors but, by undertaking reactions at room temperature, an underlying electronic selectivity becomes apparent, as exemplified by the comparative reactions of 7-halo-2-methylquinoline and 2,7-dimethylquinoline which afford variable amounts of the 5- and 4-borylated products. Similar electronic selectivities are observed for nonsym. 1,2-disubstituted benzenes. The site of borylation can be simply estimated by anal. of the ¹H NMR spectrum of the starting material with preferential borylation occurring at the site of the most deshielded sterically accessible H or C atom. Such effects can be linked with C-H acidity. While DFT calculations of the pK_a for the C-H bond show good correlation with the observed selectivity, small differences suggest that related alternative, but much more computationally demanding values, such as the M-C bond strength, may be better quant. predictors of selectivity.

Chemical Science published new progress about 1417036-37-3. 1417036-37-3 belongs to esters-buliding-blocks, auxiliary class Boronic acid and ester, name is Methyl 2,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate, and the molecular formula is C12H10F2Si, Application of Methyl 2,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Tang, Ting published the artcileExperimental evidence for the formation of cationic intermediates during iodine(III)-mediated oxidative dearomatization of phenols, Synthetic Route of 50670-76-3, the publication is Organic & Biomolecular Chemistry (2018), 16(37), 6871-6874, database is CAplus and MEDLINE.

Iodine(III)-based oxidants are commonly used reagents for the oxidative dearomatization of phenols. Having a better understanding of the mechanism through which these reactions proceed is important for designing new iodine(III)-based reagents, catalysts, and reactions. A Hammett anal. of the oxidative dearomatization of substituted 4-phenylphenols was performed. This study confirms that iodine(III)-mediated oxidative dearomatizations likely proceed through cationic phenoxenium ions and not the direct addition of a nucleophile to an iodine-bound phenol intermediate.

Organic & Biomolecular Chemistry published new progress about 50670-76-3. 50670-76-3 belongs to esters-buliding-blocks, auxiliary class Benzene,Phenol,Ester, name is Ethyl 4′-hydroxy-[1,1′-biphenyl]-4-carboxylate, and the molecular formula is C11H17BO3S, Synthetic Route of 50670-76-3.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Srinivasa, H. T. published the artcileSynthesis of novel aryloxysilylethers using hexamethyldisilazane and laponite RD catalyst, Recommanded Product: Ethyl 4′-hydroxy-[1,1′-biphenyl]-4-carboxylate, the publication is Organic Chemistry: An Indian Journal (2012), 8(4), 130-134, database is CAplus.

The synthesis and characterization of some novel aryloxysilylethers from structurally diversified phenols and biphenols bearing alkyl-, alkoxy-, benzyl-, and ketone substituents is reported. Laponite RD was found to be a simple versatile catalyst for the conversion.

Organic Chemistry: An Indian Journal published new progress about 50670-76-3. 50670-76-3 belongs to esters-buliding-blocks, auxiliary class Benzene,Phenol,Ester, name is Ethyl 4′-hydroxy-[1,1′-biphenyl]-4-carboxylate, and the molecular formula is C10H9ClN2O, Recommanded Product: Ethyl 4′-hydroxy-[1,1′-biphenyl]-4-carboxylate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Hay, Michael B. published the artcilePalladium-catalyzed synthesis of tetrahydrofurans from γ-hydroxy terminal alkenes: Scope, limitations, and stereoselectivity, Application of Ethyltert-butylacetate, the publication is Journal of Organic Chemistry (2005), 70(8), 3099-3107, database is CAplus and MEDLINE.

A stereoselective synthesis of substituted tetrahydrofurans, e.g., I, by Pd-catalyzed reactions of aryl and vinyl bromides with γ-hydroxy terminal alkenes is described. This transformation afforded trans-2,5- and trans-2,3-disubstituted tetrahydrofurans with good diastereomeric ratio. This methodol. also provided access to bicyclic and spirocyclic THF derivatives in good yield diastereomeric ratio. The scope and limitations of these transformations are discussed in detail, as are the effect of substrate sterics and electronics on yield and stereoselectivity. A proposed mechanism of these transformations is presented along with a model that rationalizes the stereochem. outcome of the reactions.

Journal of Organic Chemistry published new progress about 5340-78-3. 5340-78-3 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is Ethyltert-butylacetate, and the molecular formula is C8H16O2, Application of Ethyltert-butylacetate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Li, Chunmei published the artcileAroma components at various stages of litchi juice processing, Application of 3-Methylbut-2-en-1-yl benzoate, the publication is Journal of the Science of Food and Agriculture (2009), 89(14), 2405-2414, database is CAplus.

BACKGROUND: Considering the importance of flavor on the quality of litchi juice, a study was conducted on how processing and operating stages influence the aroma components of clear litchi juice during processing. RESULTS: The aroma fractions isolated by solid-phase micro-extraction were analyzed by capillary gas chromatog.-mass spectrometry. According to statistical analyses, the amount of total and 7 characteristic aroma compounds (geraniol, citronellol, phenylethyl alc., D-limonene, nonanal, geranial and linalool) increased significantly after enzyme hydrolysis, but decreased significantly during the process of enzyme inactivation, ultra-filtration and sterilization. CONCLUSION: The aromatic fraction of litchi juice decreased greatly during processing. The major losses in aromatic composition of clear litchi juice were related to the ultra-filtration and sterilization processes. With regard to the retention of aroma, an ultra-filtration membrane with a larger pore size is better than a membrane with a smaller pore size, and a high-voltage pulsed elec. field was better than thermal sterilization. Copyright © 2009 Society of Chem. Industry.

Journal of the Science of Food and Agriculture published new progress about 5205-11-8. 5205-11-8 belongs to esters-buliding-blocks, auxiliary class Alkenyl,Benzene,Ester, name is 3-Methylbut-2-en-1-yl benzoate, and the molecular formula is C12H14O2, Application of 3-Methylbut-2-en-1-yl benzoate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Wu, W. -Q. published the artcileElectrophysiological and behavioral evidence for a fourth sex pheromone component in the turnip moth, Agrotis segetum, COA of Formula: C14H26O2, the publication is Physiological Entomology (1995), 20(1), 81-92, database is CAplus.

In addition to the pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl, and (Z)-9-tetradecenyl acetate (Z5-10:OAc, Z7-12:OAc and Z9-14:OAc), it has previously been shown that the sex pheromone gland of the turnip moth, A. segetum contains 10:OAc, 12:OAc, Z5-12:OAc, Z9-12:OAc, 11-12:OAc, Z5-14:OAc, Z7-14:OAc, and Z11-16:OAc. To find out whether any of these addnl. compounds is involved in the sex pheromone communication in A. segetum, a comprehensive electrophysiol. and behavioral investigation was conducted. Single-sensillum recordings on male antennae revealed 3 subtypes of sensilla among the previously so-called Z5-10:OAc sensilla. One subtype was identified having 1 receptor neuron (A) that responded to Z5-10:OAc with a large spike amplitude and another neuron (B) that responded to (Z)-5-decenol (Z5-10:OH) with a small spike amplitude. In another subtype the B neuron responded to Z5-12:OAc and sometimes also to Z7-12:OAc and 10:OAc, in addition to responding to Z5-10:OH. In a 3rd subtype the A neuron responded to all acetates identified from the female pheromone gland, whereas the small spike amplitude neuron was tuned to Z5-10:OH. A flight tunnel assay showed that blends composed of 9, 8, or 7 compounds were equivalent to the previously identified 3-component pheromone blend in eliciting male behavioral responses. In field trapping tests, blends of 11, 9, or 7 compounds did, however, catch significantly more moths than the 3-component blend. Further assays showed that only Z5-12:OAc could significantly increase the catch numbers when added to the 3-component blend, and thus qualified as a 4th pheromone component in A.segetum. The behavioral significance of addnl. female-produced acetates – for which males possess antennal receptors – is suggested, but may be impossible to confirm because of diminishing returns when trying to refine a multicomponent pheromone further.

Physiological Entomology published new progress about 16974-11-1. 16974-11-1 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is (Z)-Dodec-9-en-1-yl acetate, and the molecular formula is C8H15NO, COA of Formula: C14H26O2.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Said, Ahmed M. published the artcileBinding cooperativity between a ligand carbonyl group and a hydrophobic side chain can be enhanced by additional H-bonds in a distance dependent manner: A case study with thrombin inhibitors, Application of (R)-tert-Butyl (3-methyl-1-oxobutan-2-yl)carbamate, the publication is European Journal of Medicinal Chemistry (2015), 405-424, database is CAplus and MEDLINE.

One of the underappreciated non-covalent binding factors, which can significantly affect ligand-protein binding affinity, is the cooperativity between ligand functional groups. Using four different series of thrombin inhibitors, we reveal a strong pos. cooperativity between an H-bond accepting carbonyl functionality and the adjacent P3 hydrophobic side chain. Adding an H-bond donating amine adjacent to the P3 hydrophobic side chain further increases this pos. cooperativity thereby improving the K_i by as much as 546-fold. In contrast, adding an amidine multiple H-bond/salt bridge group in the distal S1 pocket does not affect this cooperativity. An anal. of the crystallog. B-factors of the ligand groups inside the binding site indicates that the strong cooperativity is mainly due to a significant mutual reduction in the residual mobility of the hydrophobic side chain and the H-bonding functionalities that is absent when the separation distance is large. This type of cooperativity is important to encode in binding affinity prediction software, and to consider in SAR studies.

European Journal of Medicinal Chemistry published new progress about 106391-88-2. 106391-88-2 belongs to esters-buliding-blocks, auxiliary class Amine,Aliphatic hydrocarbon chain,Amide,Aldehyde, name is (R)-tert-Butyl (3-methyl-1-oxobutan-2-yl)carbamate, and the molecular formula is C10H19NO3, Application of (R)-tert-Butyl (3-methyl-1-oxobutan-2-yl)carbamate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Dittrich, Torsten published the artcileSynthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance, Application In Synthesis of 115314-17-5, the publication is Beilstein Journal of Organic Chemistry (2012), 1700-1704, database is CAplus and MEDLINE.

The inhibition of ABC (ATP binding cassette) transporters is considered a powerful tool to reverse multidrug resistance. (αR)-4-[(1Aα,6α,10bα)-1,1-Difluoro-1,1a,6,10b-tetrahydrodibenzo[a,e]cyclopropa[c]cyclohepten-6-yl]-α-[(5-quinolinyloxy)methyl]-1-piperazineethanol (Zosuquidar) featuring a difluorocyclopropyl-annulated dibenzosuberyl moiety has been found to be an inhibitor of the P-glycoprotein, one of the best-studied multidrug efflux pumps. Twelve 5-oxyisoquinoline derivatives, which are analogs of Zosuquidar wherein the dibenzosuberyl-piperazine moiety is replaced by either a diarylaminopiperidine or a piperidone-derived acetal or thioacetal group, have been synthesized as pure enantiomers. Their inhibitory power has been evaluated for the bacterial multidrug-resistance ABC transporter LmrCD and fungal Pdr5. Four of the newly synthesized compounds reduced the transport activity to a higher degree than Zosuquidar, being up to fourfold more efficient than the lead compound in the case of LmrCD and about two times better for Pdr5. The title compounds thus formed included a quinoline piperidineethanol derivative (I) and related substances. The synthesis of the target compounds was achieved using 5-[(2R)-2-oxiranylmethoxy]quinoline as a key intermediate.

Beilstein Journal of Organic Chemistry published new progress about 115314-17-5. 115314-17-5 belongs to esters-buliding-blocks, auxiliary class Epoxides,Chiral,Nitro Compound,Sulfonate,Benzene, name is (R)-Oxiran-2-ylmethyl 3-nitrobenzenesulfonate, and the molecular formula is C9H9NO6S, Application In Synthesis of 115314-17-5.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Jiang, Yu published the artcileSolvent extraction of Hulunbeier lignite and oxidation of coal extracted residue with hydrogen peroxide, Synthetic Route of 5340-78-3, the publication is Mei Huagong (2014), 42(2), 27-31, database is CAplus.

Hulunbeier lignite was extracted using CS₂, ethanol and acetone as solvent and the coal extract residues were analyzed with GC/MS. The results showed that CS₂ extracts mainly consisted of long chain aliphatic hydrocarbon and aromatic hydrocarbon. Aliphatic hydrocarbon existed in the three solvent extracts Coal extracted residue was oxidized for 4h at 40°C with hydrogen peroxide at a constant temperature in a water bath with magnetic stirrer and ultrasonic bath, resp. The reaction in ultrasonic bath was sharp. The chem. structure changes of raw coal, coal extracted residue and oxidized coal were analyzed using FTIR. The water soluble products were extracted using Et acetate. The GC/MS anal. of Et acetate extracts detected 30 compounds through oxidation in water bath with magnetic stirrer, among which esters were in higher abundance, while 14 compounds were identified in ultrasonic bath.

Mei Huagong published new progress about 5340-78-3. 5340-78-3 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is Ethyltert-butylacetate, and the molecular formula is C8H16O2, Synthetic Route of 5340-78-3.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics