Refernces
10.1002/anie.201007772
The research primarily investigates atropisomerism in the vasopressin receptor ligands, known as "vaptans," focusing on the active conformation recognized by the receptor. The study examines the scaffold region of N-benzoyl-1,5-benzodiazepines (1–4), which are ligands for the vasopressin receptor, and explores the impact of axial chirality on their biological activity. Experiments involved the synthesis of these ligands with various substituents at the ortho position to freeze the conformation and facilitate the separation of isomers. Benzoyl chloride and p-(2-methylbenzamido)benzoyl chloride were used for N-benzoylation to synthesize the N-benzoyl derivatives of 1,5-benzodiazepin-2-ones (1–3) and the reduced-type 1,5-benzodiazepine (4). The researchers used 1H NMR spectroscopy to analyze the conformations and determine the presence of axial chirality, and X-ray crystallography to confirm the absolute stereochemistry of the separated enantiomers. They also evaluated the in vitro affinities of the compounds at the human vasopressin V1a and V2 receptors to understand the role of stereochemistry in receptor binding. The results indicated that the receptor recognizes and binds to the cis,aS form of the ligands, highlighting the importance of considering axial chirality in drug design and development.
10.1002/chem.201201032
The research focuses on the development of a new class of chiral supramolecular ligands, named BenzaPhos, for use in asymmetric hydrogenation reactions. The purpose of this study was to create highly efficient ligands that are straightforward to prepare and possess a modular structure, which can be easily varied to optimize catalytic performance. The BenzaPhos ligands were designed for use in rhodium-catalyzed asymmetric hydrogenation, a key process in the synthesis of enantiopure compounds, particularly important in the pharmaceutical industry. The research concluded that these ligands, derived from (S)-BINOL and featuring a benzamide group, indeed showed outstanding levels of activity and enantioselectivity, especially in the hydrogenation of challenging olefins like enamide S4 and b-dehydroamino ester S5, achieving enantiomeric excess (ee) values greater than 99%. Control experiments and computational studies suggested that the ligand's amide group plays a crucial role in substrate orientation through hydrogen bonding, which significantly contributes to the improved catalytic properties. The chemicals used in the process include a variety of aminoalcohols, benzoyl chlorides, (S)-BINOL-PCl, and rhodium complex [Rh(cod)2BF4], among others, to synthesize and test the BenzaPhos ligands.
10.1007/BF00506592
The research investigates the reactions of 1-methylene-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives with acyl chlorides to synthesize 2-oxopyrimido[4,3-a]isoquinoline derivatives and 2-iminopyrimido[4,3-a]isoquinoline hydrochlorides. The study explores the properties and transformations of 1-cyanomethylene and 1-carbamidomethylene-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines, using reactions with benzoyl chloride, acetyl chloride, and dimethylformamide acetal to form various compounds. The key chemicals used include benzoyl chloride, acetyl chloride, dimethylformamide acetal, and phosphorus oxychloride. The research concludes that the synthesized compounds are strong bases, with ionization constants indicating significant energy gain during salt formation. The study also establishes a linear relationship between the pKa values of the synthesized compounds and the Hammett constants of their substituents, suggesting coplanarity between the benzene ring and the C=N bond in these compounds.
10.1002/ejoc.200701140
The study presents the first synthesis and characterization of open-chain cyclopropylpolyketides through a combination of experimental and computational methods. Researchers synthesized cyclopropylpolyketides by a sequence of chain elongation via acylation and subsequent cyclopropanation. Key chemicals involved include 1(cyclopropyl)butane-1,3-dione and benzoylacetone, which were used as starting materials for cyclopropanation with 1,2-dibromoethane to form cyclopropanes 2a and 2b. These cyclopropanes were then reacted with cyclopropanecarboxylic chloride and benzoyl chloride to produce compounds 3a–c, which were further cyclopropanated to yield the desired cyclopropyltriketides 4a–c. The structure of 4c was confirmed by X-ray crystal structure analysis. Additionally, dimethyl cyclopropane-1,1-dicarboxylate (5) was reacted with 1-cyclopropylethan-1-one to form 7, which was transformed into triketide 8. The study also involved density functional theory computations to analyze the structural and energetic properties of the cyclopropylpolyketides, providing insights into their conformations and stabilities.
10.1002/anie.201303039
The study focuses on the discovery and characterization of a novel polyoxygenated ether lipid called mycalol (1), which exhibits promising cytotoxic properties against human anaplastic thyroid carcinoma (ATC) cells. ATC is an aggressive form of thyroid cancer with limited treatment options. Mycalol was identified through a screening method involving FRO cells, which are ATC-derived cells with high levels of HMGA1, and FRO-asHMGA1 cells, which are genetically modified to block HMGA1 synthesis. The chemical served as a potential candidate for novel compounds against tumors that are otherwise resistant to cytotoxic agents. The study used various chemicals for extraction, fractionation, and analysis, including chloroform, methanol, and a modified Kupchan method for extraction, as well as silica gel radial chromatography and reverse-phase HPLC for purification. Additionally, deuterated acetone and dimethoxypropane were used to synthesize triacetonide derivatives for NMR analysis, and pivaloyl chloride and benzoyl chloride were used for selective derivatization to determine the stereochemistry of mycalol. The purpose of these chemicals was to isolate, purify, and structurally characterize mycalol, as well as to assess its cytotoxic activity against different cell lines, particularly those derived from ATC.
10.1016/S0040-4020(01)96078-8
The research focuses on the enantioselective syntheses of D- and L-ribo- and arabino-C,S-phytosphingosines, which are biologically important compounds found in plant sphingolipids and human brain and kidney lipids. The purpose of the study was to develop practical syntheses of these homochiral compounds from (R)-2,3-O-isopropylidene glyceraldehyde, utilizing key steps such as (Z)-selective olefination, selective monobenzoylation, Mitsunobu-type introduction of nitrogen, and osmylation. The conclusions drawn from the research indicate that the method is efficient, using inexpensive reagents and simple conditions suitable for gram-scale synthesis, and it also allows for the preparation of N- and O-protected derivatives, which could be useful for incorporating these compounds into biologically active ceramide and cerebroside structures. Chemicals used in the process include (R)-2,3-O-isopropylidene glyceraldehyde, phosphorane, benzoyl chloride, triphenylphosphine, diethyl azodicarboxylate, phthalimide, N-methyl-morpholine-N-oxide, osmium tetroxide, and various other reagents for protection and deprotection steps, as well as for chromatographic separation and analysis.
10.1016/S0960-894X(97)00278-3
The research focuses on the synthesis of novel non-nucleosidic phosphoramidites and controlled pore glass (CPG) supports, which are based on a cyclohexyl-4-amino-1,1-dimethanol backbone. The purpose of this study was to develop a series of reagents that could be used to label oligonucleotides with biotin and fluorescein at various positions, including the 5'-, 3'-, and internal sites. The researchers aimed to improve the efficiency of synthesis and mimic the stereochemical properties of the natural polynucleotide backbone, while also keeping the reporter groups away from the oligonucleotide chain to enhance hybridization efficiency. The key chemicals used in the process included 3-cyclohexene-1,1-dimethanol, benzoyl chloride, sodium borohydride, BF3-Et2O, hydroxylamine-O-sulfonic acid, biotin-N-hydroxysuccinimide ester (biotin-NHSu), fluorescein-NHSu, and various other reagents for the protection, deprotection, and coupling steps. The conclusions of the research were that these novel biotin, fluorescein, and amino labeled phosphoramidites and CPG supports could be used advantageously for the introduction of multiple reporter groups onto oligonucleotides in a cost-effective and efficient manner, retaining the natural 3-carbon atom internucleotide phosphate distance in DNA/RNA, which does not affect the hybridization and annealing properties of the duplex.
10.1021/jo00137a015
The research discusses the stereoselectivity in the epoxide hydrolase-catalyzed hydrolysis of stereoisomeric 3-tert-butyl-1,2-epoxycyclohexanes, aiming to provide further evidence for the topology of the enzyme active site. The study investigates the enzymatic hydrolysis of cis- and trans-3-tert-butyl-1,2-epoxycyclohexanes, revealing that the reaction is enantiospecific and regiospecific, with only one enantiomer being practically attacked and the nucleophilic attack occurring exclusively at C(1). The results support the hypothesis of a large hydrophobic pocket in the enzyme's active site that accommodates bulky substituents, influencing the enzyme's selectivity. Key chemicals used in the process include the epoxides 1 and 3, their hydrolysis products 2 and 4, and various derivatives such as benzoyl chloride, Jones reagent, and chiral shift reagents for the determination of enantiomeric excesses and absolute configurations. The study concludes that the enzymatic hydrolysis is consistent with a general-base mechanism rather than a general-acid mechanism, emphasizing the role of general-base catalysis in the nucleophilic attack by water at an oxirane carbon.
10.1016/j.tet.2004.09.049
This research investigates the use of aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the Friedel-Crafts acylation of aromatic compounds under solvent-free conditions. The purpose is to develop an efficient and environmentally friendly method for synthesizing aromatic ketones, which are important in the manufacture of fine chemicals and pharmaceuticals. The study finds that AlPW12O40 is a stable, easily available, and cost-effective catalyst that works well with various acylating agents such as carboxylic acids, acetic anhydride, and benzoyl chloride. The reactions proceed under mild conditions and yield the desired products in good to excellent yields.
10.1021/jo01353a009
The study explores the synthesis of various substituted naphthyridines and biphenyls through different chemical reactions. Key chemicals involved include N-(3-amino-4-picolylidene)-p-toluidine, which serves as a precursor for multiple reactions to produce compounds like 1,7-naphthyridine-2-aldoxime, 2,9-diaza-6,8-dihydro-7,7-dimethyl-5-oxoanthracene, and 7,9-diazabenz[f]indane. These compounds are formed by reacting the precursor with different reagents such as isonitrosoacetone, dimethyldihydroresorcinol, and cyclopentanone under specific conditions like heating and refluxing. The products are characterized by their melting points, yields, and elemental analysis. In another part of the study, the reaction of various p-aroylpropionic acids with benzoyl chloride is investigated, yielding substituted phthalides in the biphenyl series. The study also delves into the infrared and ultraviolet spectral analysis of these products to understand their structural properties.
10.1002/anie.201604921
The study presents a novel method for transforming alcohols into chlorides, amines, and ethers using formamides as Lewis base catalysts. The key chemicals involved are formamides, which act as catalysts, and benzoyl chloride (BzCl), which serves as the sole reagent for the transformation. The method is highly efficient, with excellent functional group tolerance, scalability, and a favorable waste balance (E-factor down to 2). The process proceeds through iminium-activated alcohol intermediates and can be performed under solvent-free conditions. Enantioenriched alcohols (99% ee) are converted with high stereoselectivity into the corresponding chlorides. The study also demonstrates a one-pot procedure where the initially formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles, highlighting the method's versatility and potential for synthesizing bioactive compounds.
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