Month: November 2022

On June 13, 2022, Puentener, Kurt; Bigler, Raphael; Stier, Kenta; Checinski, Marek P. published an article.Related Products of 3976-69-0 The title of the article was New Mechanistic Insights into the Ru-Catalyzed Asymmetric Hydrogenation of β-Ketoesters. And the article contained the following:

We describe the results of our quantum mech. investigation of the asym. hydrogenation of β-ketoesters catalyzed by [RuCl2(MeOH)2((R)-MeOBIPHEP)] (7a), which is generated in situ from [Ru(OAc)2((R)-MeOBIPHEP)] (4a) and HCl in methanol. Interestingly, HCl not only acts as an activator for 4 a as it has a dramatic effect on the reaction itself: While HCl/4 a=2 leads to rather poor results (36% ee and 13% conv. after 4 h at at a substrate-to-catalyst ratio (S/C)=50’000), HCl/4 a=20 results in high efficiency (>99.9% conv.) and enantioselectivity (99% ee favoring the opposite enantiomer) under otherwise identical conditions. The origin for this sweeping change in performance has remained a mystery for two decades. Here, we show for the first time that a highly selective HCl pathway becomes operational under acidic conditions, which outcompetes moderately selective pathways dominating under neutral conditions. Furthermore, we explain the effects of common phosphorus substituents on the activity of the catalyst. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Related Products of 3976-69-0

The Article related to ketoester ruthenium catalyst stereoselective hydrogenation mechanism, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.Related Products of 3976-69-0

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Noe, Marco; Perosa, Alvise; Selva, Maurizio published an article in 2013, the title of the article was A flexible Pinner preparation of ortho esters: the model case of trimethyl orthobenzoate.Quality Control of (Trimethoxymethyl)benzene And the article contains the following content:

In the absence of addnl. solvents, a novel procedure was implemented for the synthesis of tri-Me orthoesters through the Pinner reaction. At 5 °C, the reaction of both aliphatic and aromatic nitriles (RCN; R = Et, Bu, Ph) with a moderate excess of MeOH and gaseous HCl gave the corresponding imidate hydrochlorides [RC(:NH)OR’·HCl] in excellent yields (>90%). At 25-65 °C, the methanolysis of alkyl imidate salts provided tri-Me ortho-propionate and valerate, while only traces of tri-Me orthobenzoate (TMOB) were observed However, the aromatic hydrochloride could be readily converted into the hydrogen phosphate salt [PhC(:NH)OR’·H3PO4] which, in turn, underwent a selective (>80%) reaction with MeOH to produce TMOB in a 62% isolated yield. This allowed for an unprecedented Pinner-type synthesis of TMOB starting from benzonitrile, rather than from the highly toxic trichloromethylbenzene. Overall, remarkable improvements in safety and process intensification were achieved. The experimental process involved the reaction of (Trimethoxymethyl)benzene(cas: 707-07-3).Quality Control of (Trimethoxymethyl)benzene

The Article related to flexible pinner preparation ortho ester trimethyl orthobenzoate safety, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.Quality Control of (Trimethoxymethyl)benzene

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On December 16, 2011, Kurono, Nobuhito; Ohtsuga, Kentaro; Wakabayashi, Masanori; Kondo, Tadahiro; Ooka, Hirohito; Ohkuma, Takeshi published an article.Category: esters-buliding-blocks The title of the article was Kinetic resolution of racemic α-tert-alkyl-α-hydroxy esters by enantiomer-selective carbamoylation. And the article contained the following:

Kinetic resolution of sterically hindered racemic α-tert-alkyl-α-hydroxy esters is performed by enantiomer-selective carbamoylation with the t-Bu-Box-Cu(II) catalyst (Box = bis(oxazoline)). The reaction with 0.5 equiv of n-C3H7NCO is carried out with a substrate-to-catalyst molar ratio of 500-5000 at -20 to 25 °C. The high enantiomer-discrimination ability of the catalyst achieves an excellent stereoselectivity factor (s = kfast/kslow) of 261 in the best case. A catalytic cycle for this reaction is proposed. The experimental process involved the reaction of Methyl 2-hydroxy-3,3-dimethylbutanoate(cas: 121129-31-5).Category: esters-buliding-blocks

The Article related to kinetic resolution enantioselective carbamoylation racemic hydroxy ester, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.Category: esters-buliding-blocks

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Zhao, Baoli published an article in 2012, the title of the article was Pd-Catalyzed C-3 functionalization of indolizines via C-H bond cleavage.Product Details of 93476-46-1 And the article contains the following content:

New transition metal-catalyzed methods for the arylation of indolizines by the direct cleavage of C-H bonds have been developed. A wide range of aryltrifluoroborate salts react with indolizines in the presence of Pd(OAc)2 catalyst and AgOAc oxidant to give the arylated indolizines in high yields. Both electron-donating and electron-withdrawing groups perform smoothly while bromide and chlorine substituents are tolerated. In addition, the indolizines display similar reactivities in the Pd-catalyzed reaction with 3-phenylpropiolic acid to afford the corresponding C-3 alkynylated indolizines. These methods allow the direct functionalization of indolizines in one step. The experimental process involved the reaction of Ethyl indolizine-1-carboxylate(cas: 93476-46-1).Product Details of 93476-46-1

The Article related to palladium catalyzed functionalization indolizine carbon hydrogen bond cleavage, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.Product Details of 93476-46-1

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On October 31, 2016, Bulygina, L. A.; Khrushcheva, N. S.; Peregudov, A. S.; Sokolov, V. I. published an article.SDS of cas: 227940-70-7 The title of the article was Cyclopalladate complex of 3-benzyl-7-methyl-3,7-diazabicyclo[3.3.1]nonane. And the article contained the following:

A new (C,N,N)-pincer cyclopalladate unsym. complex of 3-benzyl-7-methyl-3,7-diazabicyclo[3.3.1]nonane (3-benzyl-7-methylbispidine) was synthesized and characterized. Catalytic performance of this complex was examined in the Heck and Suzuki reactions and in the norbornene hydroarylation. The experimental process involved the reaction of tert-Butyl 7-benzyl-9-oxo-3,7-diazabicyclo[3.3.1]nonane-3-carboxylate(cas: 227940-70-7).SDS of cas: 227940-70-7

The Article related to benzylmethyldiazabicyclononane cyclopalladate complex preparation coupling catalyst, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.SDS of cas: 227940-70-7

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On February 20, 2004, Creary, Xavier; Burtch, Elizabeth A. published an article.COA of Formula: C7H14O3 The title of the article was Remarkably Facile Solvolyses of Triflates via Carbocationic Processes in Dimethyl Sulfoxide. And the article contained the following:

A number of triflates have been shown to undergo clean pseudo-first-order solvolysis reactions in DMSO-d6 to give products derived from carbocationic intermediates. Thus, t-BuCH(OTf)CO-t-Bu (5) and t-BuCH2OTf (9) react readily in DMSO-d6 at 25 °C to give a rearranged oxosulfonium salts, and subsequent alkene products where Me migration to the incipient cationic center occurs. t-BuCH(OTf)CO2CH3 (14) gives analogous rearranged products, and 1-methylcyclopropyl triflate (21) gives a ring-opened allylic oxosulfonium salt. These triflates react primarily via kΔ pathways. 6-Methylbicyclo[3.1.0]hex-6-yl triflate (23), bicyclo[2.2.1]hept-1-yl triflate (24), 1,6-methano[10]annulen-11-yl triflate (25), (CH3)2C(OTf)CO2CH3 (26), and (CH3)2CCN(OTf) (29) all react in DMSO-d6 to give carbocation-derived products. PhCH(OTf)CF3 (33) and substituted analogs also react readily in DMSO-d6, and the Hammett ρ+ value is -3.7. This suggests a “borderline” mechanism where the transition state has substantial charge development. The primary feature of these solvolyses is the high reactivity of all of these triflates in DMSO-d6. Thus, these triflates are all more reactive in DMSO-d6 than in HOAc, and for most, rates are faster than in CF3CH2OH. Triflates 5, 21, 29, and 33 are 108-109 times more reactive in DMSO-d6 than the corresponding mesylates. It is suggested that the decreased need for electrophilic solvation of triflate anion, and the high cation solvating ability of DMSO, are the reasons for the high triflate reactivity in DMSO-d6. The experimental process involved the reaction of Methyl 2-hydroxy-3,3-dimethylbutanoate(cas: 121129-31-5).COA of Formula: C7H14O3

The Article related to facile solvolysis triflate carbocation intermediate dimethyl sulfoxide solvent effect, Physical Organic Chemistry: Addition, Elimination, and Substitution Reactions and other aspects.COA of Formula: C7H14O3

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Maczka, Wanda; Winska, Katarzyna; Grabarczyk, Malgorzata; Zarowska, Barbara published an article in 2018, the title of the article was Biotransformation of α-acetylbutyrolactone in Rhodotorula strains.Quality Control of 3-Acetyldihydrofuran-2(3H)-one And the article contains the following content:

Due to its structural similarity, the α-1-hydroxyethyl-γ-butyrolactone obtained by reduction of (±)-α-acetyl-γ-butyrolactone may have a similar function in the body to γ-butyrolactone (GBL). In the work presented, biotransformation of α-acetyl-γ-butyrolactone by three Rhodotorula strains was performed obtaining enantiomerically enriched alc. The process was carried out in growing and resting cultures. We studied how both media composition and organic solvent volume affected stereoselectivity and effectiveness of biotransformation. After 2 h, the enantiomerically pure (3R, 1 S)-α-1-hydroxyethyl-γ-butyrolactone was obtained using the R. marina AM77 strain in YPG (Yeast extract-Peptone-Glucose) medium enriched with 5% glycerol. To our best knowledge there is no previous information in the literature about the (±)-α-acetyl-γ-butyrolactone biotransformation performed in medium with addition of organic and deep eutectic solvents. The experimental process involved the reaction of 3-Acetyldihydrofuran-2(3H)-one(cas: 517-23-7).Quality Control of 3-Acetyldihydrofuran-2(3H)-one

The Article related to rhodotorula biotransformation alpha acetyl gamma butyrolactone, des, biotransformation, glycerol, lactone, yeast, Microbial, Algal, and Fungal Biochemistry: Metabolism and Microbial Nutrition and other aspects.Quality Control of 3-Acetyldihydrofuran-2(3H)-one

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Boehnlein-Mauss, Jutta; Kroeber, Hartmut published an article in 2017, the title of the article was The REACH Impact on Gun Propellant Formulations.Safety of Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate And the article contains the following content:

REACH is the abbreviation for Registration, Evaluation, Authorisation, and Restriction of Chems. It is a regulation of the European Union, adopted to improve the protection of human health and the environment from the risks that can be posed by chems., while enhancing the competitiveness of the EU chems. industry. Current gun propellant formulations employ environmentally unfriendly materials, like dibutyl-phthalate (DBP). In this contribution a study was conducted, which aims to evaluate the environmental friendliness of common gun propellant ingredients and to propose environmentally acceptable substitutes for harmful substances. In the first step a simplified assessment matrix based on the REACH relevant properties of chems. was developed. The matrix consists of the main criteria of the new European regulation, their legal limit values, and their evaluation by REACH. For a selected number of ingredients of commonly used gun propellants the toxicol. and eco-toxicol. data were collected in order to carry out an initial assessment under the REACH regulation. In this context some substances show remarkable and critical properties and it was started to find suitable substitutes, which were first assessed with regard to the REACH regulation. As an example potential substitutes for nitroglycerin were exptl. introduced in gun propellant formulations and their main properties were determined and compared with the standard formulation. The experimental process involved the reaction of Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate(cas: 3319-31-1).Safety of Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate

The Article related to registration evaluation authorisation restriction chem gun propellant formulation, Propellants and Explosives: Incendiaries, Pyrotechnics, Smoke Generators, etc. and other aspects.Safety of Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Cui, Y. H.; Wei, P.; Peng, F.; Zong, M. H.; Lou, W. Y. published an article in 2018, the title of the article was Efficient biocatalytic stereoselective reduction of methyl acetoacetate catalyzed by whole cells of engineered E. coli.Application In Synthesis of (R)-Methyl 3-hydroxybutanoate And the article contains the following content:

Asym. synthesis of chiral β-hydroxy esters, the key building blocks for many functional materials, is currently of great interest. In this study, the biocatalytic anti-Prelog reduction of Me acetoacetate (MAA) to methyl-(R)-3-hydroxybutyrate ((R)-HBME) was successfully carried out with high enantioselectivity using the whole cell of engineered E. coli, which harbored an AcCR (carbonyl reductase) gene from Acetobacter sp. CCTCC M209061 and a GDH (glucose dehydrogenase) gene from Bacillus subtilis 168 for the in situ regeneration of the coenzyme. Compared with the corresponding wild strain, the engineered E. coli cells were proved to be more effective for the bio-reduction of MAA, and afforded much higher productivity. Under the optimized conditions, the product e.e. was >99.9% and the maximum yield was 85.3% after a reaction time of 10 h, which were much higher than those reported previously. In addition, the production of (R)-HBME increased significantly by using a fed-batch strategy of tuning pH, with a space-time yield of approx. 265 g L-1 d-1, thus the issue in previous research of relatively low substrate concentrations appears to be solved. Besides, the established bio-catalytic system was proved to be feasible up to a 150 mL scale with a large-scale relatively high substrate concentration and selectivity. For further industrial application, these results open a way to use of whole cells of engineered E. coli for challenging higher substrate concentrations of β-ketone esters enantioselective reduction reactions. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Application In Synthesis of (R)-Methyl 3-hydroxybutanoate

The Article related to methyl acetoacetate escherichia coli, Fermentation and Bioindustrial Chemistry: Pharmaceuticals (Including Nutrients) and other aspects.Application In Synthesis of (R)-Methyl 3-hydroxybutanoate

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Kalachandra, S.; Kusy, R. P. published an article in 1991, the title of the article was Comparison of water sorption by methacrylate and dimethacrylate monomers and their corresponding polymers.Product Details of 1985-51-9 And the article contains the following content:

Water sorption of some glycol dimethacrylates (GDM) and alkyl methacrylates (AM) was determined by Karl-Fischer anal. After γ-irradiation, the corresponding polymers were characterized in terms of percentage water uptake (gravimetrically), diffusion coefficient (D), and contact angle (θ) measurements. Water sorption of the polymers approximated Fick’s law. Ignoring the double bond contribution, the weight per cent O content (WPO), which was indicative of hydrophilic character of these materials, was calculated and correlated with the total O content present in each monomer mol. A linear relationship between the WPO and percentage water uptake was observed in a series of 4 GDM’s and 8 linear AM’s. Their corresponding polymers conformed to a linear correlation between the WPO and θ. On the basis of its WPO, bisphenol A-bis(2-hydroxypropyl) methacrylate sorbed less water than expected because an intramol. H bond was present. The rapid initial rates observed in soft Me methacrylate polymers were attributed to the water soluble impurities present in the matrix. The D values of the networks based on difunctional methacrylates were generally lower than Me methacrylates presumably because of the highly crosslinked nature of the former. The experimental process involved the reaction of 2,2-Dimethylpropane-1,3-diyl bis(2-methylacrylate)(cas: 1985-51-9).Product Details of 1985-51-9

The Article related to water sorption methacrylate monomer polymer, Physical Properties of Synthetic High Polymers: Physical Properties Of Polymers and other aspects.Product Details of 1985-51-9

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics