Month: December 2022

Mahl, Magnus published the artcileMultilayer stacks of polycyclic aromatic hydrocarbons, Safety of Coronene, the publication is Nature Chemistry (2022), 14(4), 457-462, database is CAplus and MEDLINE.

Polycyclic aromatic hydrocarbons (PAHs) show promise for applications in functional devices such as organic photovoltaics and field-effect transistors, but, although nanometer-sized PAHs-often referred to as nanographenes-have been well investigated as single-layer mols., their multilayer counterparts remain rather unexplored. Here we show the assembly of a C₆₄ nanographene derivative (comprising a planar core decorated with four meta-terphenyl-imide moieties at its periphery) into multilayer stacks with smaller PAHs ranging from naphthalene to ovalene and hexabenzocoronene. The functionalized C₆₄ nanographene serves as a ditopic host that can accommodate a smaller PAH on either side of its planar core, in cavities delimited by its bulky imide substituents. Bilayers and trilayers (i.e., complexes with 1:1 and 1:2 host:guest ratios, resp.) were observed in solution, and dimers of these complexes as well as multilayer compounds were isolated in the solid state. Quantum-chem. calculations indicate that dispersion forces are the main stabilizing factor for these complexes.

Nature Chemistry published new progress about 191-07-1. 191-07-1 belongs to catalysis-chemistry, auxiliary class Electronic Materials, name is Coronene, and the molecular formula is C24H12, Safety of Coronene.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Sieburth, Scott McN. published the artcileSilanediols: a new class of potent protease inhibitors, Synthetic Route of 312-40-3, the publication is Angewandte Chemie, International Edition (1998), 37(6), 812-814, database is CAplus and MEDLINE.

The preparation and ACE inhibitor activity of the silanediol-based dipeptide analogs PhC(O)NHCHⁱBuSi(OH)₂CH₂CHRC(O)R¹ (R¹ = (S)-2-carboxy-1-pyrrolidinyl; R = H, Me) are reported.

Angewandte Chemie, International Edition published new progress about 312-40-3. 312-40-3 belongs to catalysis-chemistry, auxiliary class Organic Silicones, name is Difluorodiphenylsilane, and the molecular formula is C11H21BF4N2O2, Synthetic Route of 312-40-3.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Mutahi, Mwangi Wa published the artcileSilicon-Based Metalloprotease Inhibitors: Synthesis and Evaluation of Silanol and Silanediol Peptide Analogues as Inhibitors of Angiotensin-Converting Enzyme, Recommanded Product: Difluorodiphenylsilane, the publication is Journal of the American Chemical Society (2002), 124(25), 7363-7375, database is CAplus and MEDLINE.

Silanols are best known as unstable precursors of siloxane (silicone) polymers, substances generally considered stable and inert, but have the potential to mimic a hydrated carbonyl and inhibit protease enzymes. While previous testing of simple silanediol and silanetriol compounds as inhibitors of hydrolase enzymes found them ineffective, this study reports the synthesis of peptidomimetics containing a central methylsilanol, -Si(Me)(OH)-, or silanediol, -Si(OH)₂-, group and their assessment as effective transition state analog inhibitors of metalloprotease angiotensin-converting enzyme (ACE). Central to the synthesis strategy, phenylsilanes were employed as acid-hydrolyzable precursors of the silanol group. The N-benzoyl Leu-[SiMeOH]-Gly benzyl amides, PhCONHCH(iso-Bu)Si(Me)(OH)CH₂CH₂CONHBn, proved to be stable and readily characterized. In contrast, the Leu-[Si(OH)₂]-Gly, PhCONHCH(iso-Bu)Si(OH)₂CH₂CH₂CONHBn, structure was difficult to characterize, possibly because of self-association Capping the silanediol with chlorotrimethylsilane gave a well-defined trisiloxane, demonstrating that the silanediol was monomeric. The Leu-[Si]-Gly structures were converted to Leu-[Si]-Ala analogs by enolate alkylation. Coupling of the silanol precursors with L-proline tert-Bu ester, followed by treatment with TFA, gave N-benzoyl Leu-[Si]-Gly-Pro I (R = H; R¹ = Me, OH) and N-benzoyl Leu-[Si]-Ala-Pro I (R = Me; R¹ = Me, OH) tripeptide analogs. Silanediol peptides I (R = H, Me; R¹ = OH) inhibited ACE with IC₅₀ values ¡Ü 14 nM. Methylsilanol peptides I (R = H, Me; R¹ = Me), in contrast, were poor inhibitors, with IC₅₀ values > 3000 nM. These data, including comparisons with inhibition data from peptide carbon analogs II and III, are consistent with binding of the silanediols by chelation of the ACE active site zinc, whereas the methylsilanols ligate poorly.

Journal of the American Chemical Society published new progress about 312-40-3. 312-40-3 belongs to catalysis-chemistry, auxiliary class Organic Silicones, name is Difluorodiphenylsilane, and the molecular formula is C12H10F2Si, Recommanded Product: Difluorodiphenylsilane.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Takahashi, Hitoe published the artcileSelenoureas and thioureas are effective superoxide radical scavengers in vitro, Product Details of C3H8N2S, the publication is Life Sciences (2005), 76(19), 2185-2192, database is CAplus and MEDLINE.

The authors investigated scavenging of superoxide radicals by selenoureas and thioureas using a highly sensitive and quant. chemiluminescence method. At 330 nM, five selenoureas and five thioureas scavenged fractions of superoxide radicals (O^–₂) ranging from 8.4% to 87.6%. Among five N,N-unsubstituted selenoureas and N,N-unsubstituted thioureas, 1-selenocarbamoylpiperidine and 1-thiocarbamoylpyrrolidine were the most effective scavengers. The study showed that selenoureas could be used as new superoxide anion-scavenging substances.

Life Sciences published new progress about 6972-05-0. 6972-05-0 belongs to catalysis-chemistry, auxiliary class Thiourea,Amine,Aliphatic hydrocarbon chain,Amide, name is 1,1-Dimethylthiourea, and the molecular formula is C8H6ClF3, Product Details of C3H8N2S.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Ishihara, Kazuaki published the artcileEnantio- and Site-Selective ¦Á-Fluorination of N-Acyl 3,5-Dimethylpyrazoles Catalyzed by Chiral ¦Ð-Cu^II Complexes, Formula: C8H7NO4, the publication is Angewandte Chemie, International Edition (2020), 59(40), 17641-17647, database is CAplus and MEDLINE.

Catalytic enantioselective ¦Á-fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active ¦Á-fluorinated carbonyl compounds Nevertheless, ¦Á-fluorination of ¦Á-nonbranched carboxylic acid derivatives is still a big challenge because of relatively high pK_a values of their ¦Á-hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3-(2-naphthyl)-L-alanine-derived amides are highly effective catalysts for the enantio- and site-selective ¦Á-fluorination of N-(¦Á-arylacetyl) and N-(¦Á-alkylacetyl) 3,5-dimethylpyrazoles [e.g., I ¡ú II (99%, 91% ee)]. The substrate scope of the transformation is very broad (25 examples including a quaternary ¦Á-fluorinated ¦Á-amino acid derivative). ¦Á. ¦Á-Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcs. with almost no epimerization in high yield.

Angewandte Chemie, International Edition published new progress about 104-03-0. 104-03-0 belongs to catalysis-chemistry, auxiliary class Nitro Compound,Carboxylic acid,Benzene, name is 4-Nitrophenylacetic acid, and the molecular formula is C8H7NO4, Formula: C8H7NO4.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Toyota, Masahiro published the artcileAn expeditious and efficient formal synthesis of (¡À)-aphidicolin, Application In Synthesis of 4141-48-4, the publication is Tetrahedron Letters (1994), 35(35), 6495-8, database is CAplus.

An expeditious and efficient formal total synthesis of antiviral and antitumor tetracyclic diterpene aphidicolin has been developed. An intramol. Heck reaction and an intramol. Diels-Alder reaction were utilized as key steps in the sequence.

Tetrahedron Letters published new progress about 4141-48-4. 4141-48-4 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Allyldiphenylphosphine oxide, and the molecular formula is C9H8BNO2, Application In Synthesis of 4141-48-4.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Toyota, Masahiro published the artcileEnantioselective total synthetic route to (+)-aphidicolin, Application In Synthesis of 4141-48-4, the publication is Tetrahedron Letters (1995), 36(30), 5379-82, database is CAplus.

Enantioselective total synthetic route to (+)-aphidicolin has been described. Cycloisomerization reaction of I to give II and intramol. Diels-Alder reaction of III to give IV were employed for the key steps of the sequence.

Tetrahedron Letters published new progress about 4141-48-4. 4141-48-4 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Allyldiphenylphosphine oxide, and the molecular formula is C4H12ClNO, Application In Synthesis of 4141-48-4.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Toyota, Masahiro published the artcileSynthesis of a cancer growth-inhibiting diterpene – stereoselective formal synthesis of (+)-aphidicolin, Product Details of C15H15OP, the publication is Tetrahedron (1996), 52(31), 10347-10362, database is CAplus.

Stereoselective formal synthesis of the diterpene tetraol (+)-aphidicolin is described, employing as key steps the cycloisomerization of the enyne I to provide the bicyclo[3.2.1]octane derivative II and the intramol. Diels-Alder reaction of the triene III to form the aphidicolane-type ring system. This route is, in principal, highly stereocontrolled and extremely efficient.

Tetrahedron published new progress about 4141-48-4. 4141-48-4 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Allyldiphenylphosphine oxide, and the molecular formula is C9H12BNO4, Product Details of C15H15OP.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Nishimura, Takahiro published the artcilePalladium-Catalyzed Transformation of Cyclobutanone O-Benzoyloximes to Nitriles via C-C Bond Cleavage, Computed Properties of 4141-48-4, the publication is Journal of Organic Chemistry (2004), 69(16), 5342-5347, database is CAplus and MEDLINE.

Pd-catalyzed transformation of cyclobutanone O-benzoyloximes to a variety of nitriles is described. The reaction may proceed via two important steps, i.e., (i) oxidative addition of the N-O bond of oximes to Pd(0) to give a cyclobutylideneaminopalladium(II) species and (ii) ¦Â-C elimination of this species to afford a reactive alkylpalladium species. The kind of products is very dependent on the nature of substituents on the cyclobutane ring. The direction of the C-C bond cleavage is controlled by the kind of ligand employed. For example, (Z)-2-Allyl-3,3-dibenzylcyclobutanone O-benzoyloxime gave 19/81 and 78/22 2,2-Dibenzyl-4-methylenecyclopentanecarbonitrile and (E)-3,3-Dibenzylhepta-4,6-dienenitrile when two different chiral ligands were used. The sequential reaction composed of the C-C bond cleavage and the subsequent intra- and intermol. C-C bond formations via the corresponding alkylpalladium species is also demonstrated. For example, an oxime having an alkynyl moiety at a suitable position reacts with a variety of alkenes to afford nitriles bearing dienylcyclopentane moiety in moderate to good yields. For example, 50 % [3-[(E,E)-4-(diphenylphosphinyl)-1-phenylbut-2-enylidene]-1-methylcyclopentyl]acetonitrile (characterized by x-ray crystallog.) was obtained from 3-methyl-3-(4-phenylbut-3-ynyl)cyclobutanone O-benzoyloxime and Ph₂P(O)CH₂CH:CH2 in DMF in the presence of K₂CO₃, Pd(dba)₂ and (R)-BINAP.

Journal of Organic Chemistry published new progress about 4141-48-4. 4141-48-4 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Allyldiphenylphosphine oxide, and the molecular formula is C15H15OP, Computed Properties of 4141-48-4.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Yamamoto, Yukio published the artcilePulse radiolysis study of salt effects on reactions of aromatic radical cations with chloride: rate constants in the absence and presence of quaternary ammonium salts, Safety of N-hexadecyltrimethylammoniumhexafluorophosphate, the publication is Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases (1987), 83(6), 1795-804, database is CAplus.

The effect of quaternary ammonium salts on the decays of the radical cations of biphenyl, trans-stilbene, anthracene, and pyrene generated by pulse radiolysis in chlorohydrocarbons has been investigated. The decays, which are due to the neutralization reactions with Cl^–, are retarded by the addition of salts containing nonnucleophilic PF₆^–, BF₄^–, and ClO₄^–; the radical cations are rapidly quenched by salts containing I^– and BPh₄^–. The retarding effect of the salts is attributed to the formation of ion pairs between the reacting ions and the counter-ions from the salts. The rate constants for the neutralization reactions in 1,2-dichloroethane have been determined for the free-ion and ion-paired states; the latter state is attained by the addition of Bu₄NPF₆.

Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases published new progress about 101079-29-2. 101079-29-2 belongs to catalysis-chemistry, auxiliary class Surfactants, name is N-hexadecyltrimethylammoniumhexafluorophosphate, and the molecular formula is C17H20ClN3, Safety of N-hexadecyltrimethylammoniumhexafluorophosphate.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia