Author: tianli

Yu, Fei; Dickson, Jalen L.; Loka, Ravi S.; Xu, Hengfu; Schaugaard, Richard N.; Schlegel, H. Bernhard; Luo, Long; Nguyen, Hien M. published the artcile< Diastereoselective sp3 C-O Bond Formation via Visible Light-Induced, Copper-Catalyzed Cross-Couplings of Glycosyl Bromides with Aliphatic Alcohols>, Application of C12H20O6, the main research area is LED copper catalyzed diastereoselective coupling bromoglycoside aliphatic alc; C(sp3)–O bond; copper catalysis; cross-coupling; stereoselective; visible light.

Copper-catalyzed cross-coupling reactions have become one of the most powerful methods for generating carbon-heteroatom bonds, an important framework of many organic mols. However, copper-catalyzed C(sp3)-O cross-coupling of alkyl halides with alkyl alcs. remains elusive because of the sluggish nature of oxidative addition to copper. To address this challenge, we have developed a catalytic copper system, which overcomes the copper oxidative addition barrier with the aid of visible light and effectively facilitates the cross-couplings of glycosyl bromides with aliphatic alcs. to afford C(sp3)-O bonds with high levels of diastereoselectivity. Importantly, this catalytic system leads to a mild and efficient method for stereoselective construction of α-1,2-cis glycosides, which are of paramount importance, but challenging. In general, stereochem. outcomes in α-1,2-cis glycosidic C-O bond-forming processes are unpredictable and dependent on the steric and electronic nature of protecting groups bound to carbohydrate coupling partners. Currently, the most reliable approaches rely on the use of a chiral auxiliary or hydrogen-bond directing group at the C2- and C4-position of carbohydrate electrophiles to control α-1,2-cis selectivity. In our approach, earth-abundant copper not only acts as a photocatalyst and a bond-forming catalyst, but also enforces the stereocontrolled formation of anomeric C-O bonds. This cross-coupling protocol enables highly diastereoselective access to a wide variety of α-1,2-cis-glycosides and biol. relevant α-glycan oligosaccharides. Our work provides a foundation for developing new methods for the stereoselective construction of natural and unnatural anomeric carbon(sp3)-heteroatom bonds.

ACS Catalysis published new progress about Alcohols Role: RCT (Reactant), RACT (Reactant or Reagent) (glycoside). 4064-06-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C12H20O6, Application of C12H20O6.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Lee, Jeong Hwan; Hong, Suk Bong published the artcile< Dehydration of 1,3-butanediol to butadiene over medium-pore zeolites: Another example of reaction intermediate shape selectivity>, Electric Literature of 627-27-0, the main research area is butanediol butadiene dehydration pore zeolite intermediate shape selectivity.

Here we compare the catalytic properties of the proton form of 11 medium-pore zeolites, with different framework topologies and/or compositions for the dehydration of biomass-derived 1,3-butanediol at 300°C under excess water conditions (H2O/1,3-butanediol = 45). It was found that high-silica H-ferrierite (Si/Al = 130) with intersecting 10- and 8-ring channels exhibits the highest butadiene yield, together with the best durability, among the zeolites tested. Due to its highly inactive nature, however, 3-buten-1-ol, one of the butenol reaction intermediates in 1,3-butanediol dehydration, also remained a major byproduct. IR spectroscopy with adsorbed 3-buten-1-ol shows that intramolecularly hydrogen-bonded 3-buten-1-ol exists predominantly in H-ZSM-5 with two intersecting 10-ring channels, while the one with no intramol. hydrogen bonding is another species found not only in H-ferrierite but also in the one-dimensional 10-ring zeolite H-ZSM-22. By combining both exptl. and theor. results, we conclude that 1,3-butanediol dehydration over medium-pore zeolites may constitute another example of reaction intermediate shape selectivity.

Applied Catalysis, B: Environmental published new progress about Acidity. 627-27-0 belongs to class alcohols-buliding-blocks, and the molecular formula is C4H8O, Electric Literature of 627-27-0.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Rodriguez, Andrea C.; Sad, Maria E.; Cruchade, Hugo; Pinard, Ludovic; Padro, Cristina L. published the artcile< Study of catalyst deactivation during 1,3-butanediol dehydration to produce butadiene>, Electric Literature of 627-27-0, the main research area is tungstophosphoric acid supported catalyst deactivation butanediol dehydration butadiene.

Catalyst deactivation and mechanism of coke formation during the gas phase dehydration of 1,3-butanediol were studied on solid acids of different nature: Al2O3, SiO2/Al2O3, HZSM5 and tungstophosphoric acid (TPA) supported on SiO2. All the catalysts deactivated on stream with a significant coke content ranged between 9% and 14% C. Fresh and spent catalysts as well as carbonaceous deposits were thoroughly characterized using different techniques such as N2 physisorption, FTIR spectroscopy, FTIR of adsorbed pyridine, DSC-TGA, GC-MS and MALDI-TOF MS (matrix-assisted laser desorption/ionization time of flight mass spectrometry). The IR spectra of spent and washed (after direct extraction with CH2Cl2) samples and the superficial soluble coke characterized by MALDI-TOF MS showed the different nature of coke formed in each catalyst with carbonaceous products of higher mol. weights on HZSM5 and TPA/SiO2 than on Al2O3 and SiO2/Al2O3. After catalyst dissolution using hydrofluoric acid and extraction with CH2Cl2 both total soluble and insoluble coke were analyzed. Insoluble coke was only detected on TPA/SiO2 and it was attributed to the strength of its Bronsted acid sites. GC-MS chromatograms of total soluble coke showed the presence of aromatic and polyromantic species, that were very alkylated in the case of HZSM5. Particularly, the well differentiated nature of coke on HZSM5 including alkylnaftalenes and alkylantracenes suggested the coke formation by a shape selectivity mechanism.

Microporous and Mesoporous Materials published new progress about Acidity. 627-27-0 belongs to class alcohols-buliding-blocks, and the molecular formula is C4H8O, Electric Literature of 627-27-0.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Singer, M. V.; Schmausser, H.; Schoenfeld, G. published the artcile< Efficacy and tolerability of olsalazine (dipentum) in the treatment of patients with ulcerative colitis-results of a field study>, Formula: C14H8N2Na2O6, the main research area is Dipentum ulcerative colitis.

Background/Aims: In the treatment of ulcerative colitis, 5-aminosalicylic acid is the standard therapy for both acute exacerbations of the disease and the maintenance of remission. Clin. studies have shown that olsalazine (Dipentum) – a prodrug converted to two mols. of 5-ASA by colonic bacteria – induces and maintains remission. This study aimed to investigate the efficacy and tolerability of olsalazine in patients with ulcerative colitis who were being treated in daily practice by private physicians specializing in gastroenterol. Methodol.: A total of 260 patients with ulcerative colitis (aged 17-77 years, 116 men) were studied. The doses of olsalazine and the clin. data (including acute disease symptoms and the occurrence of adverse events) were recorded over a 6-mo period. Results: Twenty per cent of patients had pancolitis, 48% had left-sided disease and 32% had proctitis or proctosigmoiditis. At study entry, 86% of patients had active disease; the percentages of these patients in remission after 6 wk and 6 mo were 42% and 91%, resp. Patients with active disease received a mean dose of olsalazine – 2324mg per day initially and 1325mg per day at 6 mo. The corresponding figures for patients in remission at study entry were 1386mg and 1162mg per day, resp. Seventy-three per cent of patients took olsalazine with food, as recommended. The overall rate of adverse events was low; no serious adverse events occurred. Conclusions: Olsalazine therapy resulted in a rapid regression in the acute symptoms of ulcerative colitis. Olsalazine was also effective in maintaining remission. The drug was well tolerated.

Hepato-Gastroenterology published new progress about Gastrointestinal agents. 6054-98-4 belongs to class alcohols-buliding-blocks, and the molecular formula is C14H8N2Na2O6, Formula: C14H8N2Na2O6.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Buhaibeh, Ruqaya; Filippov, Oleg A.; Bruneau-Voisine, Antoine; Willot, Jeremy; Duhayon, Carine; Valyaev, Dmitry A.; Lugan, Noel; Canac, Yves; Sortais, Jean-Baptiste published the artcile< Phosphine-NHC Manganese Hydrogenation Catalyst Exhibiting a Non-Classical Metal-Ligand Cooperative H2 Activation Mode>, Application In Synthesis of 403-41-8, the main research area is manganese NHC phosphine complex hydrogenation catalyst cooperative hydrogen activation; DFT calculations; N-heterocyclic carbenes; manganese; metal-ligand cooperation; phosphonium ylides.

Deprotonation of the MnI NHC-phosphine complex fac-[MnBr(CO)3(κ2P,C-Ph2PCH2NHC)] (2, II) under a H2 atmosphere readily gives the hydride fac-[MnH(CO)3(κ2P,C-Ph2PCH2NHC)] (3, III) via the intermediacy of the highly reactive 18-e NHC-phosphinomethanide complex fac-[Mn(CO)3(κ3P,C,C-Ph2PCHNHC)] (6a, VI). DFT calculations revealed that the preferred reaction mechanism involves the unsaturated 16-e mangana-substituted phosphonium ylide complex fac-[Mn(CO)3(κ2P,C-Ph2P=CHNHC)] (6 b) as key intermediate able to activate H2 via a non-classical mode of metal-ligand cooperation implying a formal λ5-P-λ3-P phosphorus valence change. Complex 2 is shown to be one of the most efficient pre-catalysts for ketone hydrogenation in the MnI series reported to date (TON up to 6200).

Angewandte Chemie, International Edition published new progress about Carbene complexes, N-heterocyclic, transition metal complexes Role: CAT (Catalyst Use), PEP (Physical, Engineering or Chemical Process), PRP (Properties), SPN (Synthetic Preparation), USES (Uses), PROC (Process), PREP (Preparation). 403-41-8 belongs to class alcohols-buliding-blocks, and the molecular formula is C8H9FO, Application In Synthesis of 403-41-8.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Zhang, Yudi; Wang, Zi; Kouznetsova, Tatiana B.; Sha, Ye; Xu, Enhua; Shannahan, Logan; Fermen-Coker, Muge; Lin, Yangju; Tang, Chuanbing; Craig, Stephen L. published the artcile< Distal conformational locks on ferrocene mechanophores guide reaction pathways for increased mechanochemical reactivity>, Related Products of 627-27-0, the main research area is distal conformational lock ferrocene mechanophore guide reaction mechanochem reactivity.

Mechanophores can be used to produce strain-dependent covalent chem. responses in polymeric materials, including stress strengthening, stress sensing and network remodelling. In general, it is desirable for mechanophores to be inert in the absence of force but highly reactive under applied tension. Metallocenes possess potentially useful combinations of force-free stability and force-coupled reactivity, but the mechanistic basis of this reactivity remains largely unexplored. Here, we have used single-mol. force spectroscopy to show that the mech. reactivities of a series of ferrocenophanes are not correlated with ring strain in the reactants, but with the extent of rotational alignment of their two cyclopentadienyl ligands. Distal attachments can be used to restrict the mechanism of ferrocene dissociation to proceed through ligand ‘peeling’, as opposed to the more conventional ‘shearing’ mechanism of the parent ferrocene, leading the dissociation rate constant to increase by several orders of magnitude at forces of ∼1 nN. It also leads to improved macroscopic, multi-responsive behavior, including mechanochromism and force-induced crosslinking in ferrocenophane-containing polymers.

Nature Chemistry published new progress about Activation entropy. 627-27-0 belongs to class alcohols-buliding-blocks, and the molecular formula is C4H8O, Related Products of 627-27-0.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Zhou, Siai; Zhong, Xuemei; Guo, Aoxin; Xiao, Qian; Ao, Jiaming; Zhu, Wanmeng; Cai, Hui; Ishiwata, Akihiro; Ito, Yukishige; Liu, Xue-Wei; Ding, Feiqing published the artcile< ZnI2-Directed Stereocontrolled α-Glucosylation>, Category: alcohols-buliding-blocks, the main research area is glycoside preparation disaccharide oligosaccharide stereoselective glycosylation serine; transition state Gibbs free energy electron density stereoselective glycosylation.

Here we report a glucosylation strategy mediated by ZnI2, a cheap and mild Lewis acid, for the highly stereoselective construction of 1,2-cis-O-glycosidic linkages using easily accessible and common 4,6-O-tethered glucosyl donors. The versatility and effectiveness of the α-glucosylation strategy were demonstrated successfully with various acceptors, including complex alcs. This approach demonstrates the feasibility of the modular synthesis of various α-glucans with both linear and branched backbone structures.

Organic Letters published new progress about Disaccharides Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 4064-06-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C12H20O6, Category: alcohols-buliding-blocks.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Kinsinger, Thorsten; Kazmaier, Uli published the artcile< Application of Vinyl Nucleophiles in Matteson Homologations>, Synthetic Route of 76-84-6, the main research area is allyl boronic ester preparation enantioselective; alkyl boronic ester vinyl nucleophile Grignard reagent Matteson homologation.

The Matteson homologation with vinyl nucleophiles was found to be a versatile tool for the synthesis of highly substituted and functionalized allyl boronic esters I (R = phenylethyl, Me, butan-2-yl, etc.), II (R1 = H, Me; R2 = H, Me; R3 = H, Me), III and IV (R4 = Me, Et, n-Pr; R5 = H, Me). High yields and stereoselectivities are obtained with sterically demanding alkyl boronic esters and/or Grignard reagents. With the application of such vinyl Matteson homologations, the polyketide fragment of lagunamide B is synthesized.

Organic Letters published new progress about Boronic acids, esters Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 76-84-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C19H16O, Synthetic Route of 76-84-6.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Kishore, Jugal; Thiyagarajan, Subramanian; Gunanathan, Chidambaram published the artcile< Ruthenium(II)-catalyzed direct synthesis of ketazines using secondary alcohols>, Recommanded Product: 1-(4-Fluorophenyl)ethyl Alcohol, the main research area is ketazine preparation diastereoselective; secondary alc hydrazine hydrate oxygen hydrogen bond activation; ruthenium pincer complex catalyst.

Direct one-pot synthesis of ketazines (E,E)-R1R2C:NN:CR1R2 (R1 = Me, Et, Pr, etc.; R2 = C6H5, 4-MeC6H4, 2-MeOC6H4, etc.) from secondary alcs. R1R2CH(OH) and hydrazine hydrate catalyzed by a ruthenium pincer complex is reported, which proceeds through O-H bond activation of secondary alcs. via amine-amide metal-ligand cooperation in the catalyst. Remarkably, liberated mol. hydrogen and water are the only byproducts.

Chemical Communications (Cambridge, United Kingdom) published new progress about Azines Role: SPN (Synthetic Preparation), PREP (Preparation) (ketazines). 403-41-8 belongs to class alcohols-buliding-blocks, and the molecular formula is C8H9FO, Recommanded Product: 1-(4-Fluorophenyl)ethyl Alcohol.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts

Schaugaard, Richard N.; Nguyen, Hien M.; Schlegel, H. Bernhard published the artcile< Alkyl Radical-Free Cu(I) Photo-catalytic Cross-Coupling: A Theoretical Study of Anomerically Specific Photo-catalyzed Glycosylation of Pyranosyl Bromide>, Recommanded Product: ((3aR,5R,5aS,8aS,8bR)-2,2,7,7-Tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methanol, the main research area is reductive elimination transition state free energy cyclic voltammetry glycosylation; thermodn solvation chromophore copper iodide xantphos DTMP phenanthroline catalyst; photochem catalyzed glycosylation pyranosyl bromide cross coupling disaccharide preparation.

Previously, we reported a visible light-activated Cu(I) photocatalyst capable of facilitating C-O bond formation of glycosyl bromides and aliphatic alcs. with a high degree of diastereoselectivity. This catalyst functions equally well in the presence of radical traps, suggesting an entirely inner sphere mechanism atypical for heteroleptic Cu photocatalysis. Further, exptl. estimates put the chromophore reducing power at -1.30 V vs Ag/AgCl. This is much more pos. than the ~-2.0 V vs Ag/AgCl onset observed for irreversible reduction of glycosyl bromides in our experiments Theor. investigations were undertaken to explain the function of the catalyst. Outer sphere electron transfer from a chromophore to substrate was discounted based on thermodn. and electron transfer barriers determined by Marcus theory and non-equilibrium solvation calculations Addition of a nucleophilic alc. and oxidation of the Cu(II) species to Cu(III) result in rapid reductive elimination forming products and resetting the catalytic cycle.

Inorganic Chemistry published new progress about Catalysis. 4064-06-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C12H20O6, Recommanded Product: ((3aR,5R,5aS,8aS,8bR)-2,2,7,7-Tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methanol.

Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts