10.1016/S0040-4039(00)84436-6
The research focused on the structure and synthesis of WF 3681, a novel aldose reductase inhibitor isolated from a Chaetomella species. The purpose of the study was to elucidate the structure of WF 3681 and confirm it through total synthesis. The researchers concluded that WF 3681, a fungal metabolite, possesses potent aldose reductase-inhibitory activity and has the chemical structure C13H1205. Key chemicals used in the synthesis process included (E)-5-phenyl-4-pentenol, benzyl bromide, MCPBA (m-chloroperoxybenzoic acid), methyl malonate, NaOH (sodium hydroxide), CH2O/Me2NH (formaldehyde/dimethylamine), Os04-NaI04 (osmium tetroxide-sodium periodate), Pd-black (palladium on carbon), EtOCOCl (ethyl chloroformate), Cr03 (chromium trioxide), and K2CO3 (potassium carbonate). The synthesis involved a series of reactions, including protection of hydroxy groups, oxidation, regiospecific opening of epoxide rings, alkaline hydrolysis, formation of Mannich bases, and oxidation to form the final product, which was confirmed to be identical to the natural product WF 3681.
10.1016/j.tetasy.2011.01.009
This research investigates the synthesis and catalytic properties of a series of (1S,1′S)-4,4′- biquinazoline-based primary amines derived from natural amino acids. The study aims to develop a protocol for the large-scale preparation of enantiomerically pure biquinazoline amines and explore their potential as organocatalysts in asymmetric transformations. The synthesis involves a six-step reaction sequence, including protection, condensation, chlorination, nickel(0)-mediated homocoupling, and deprotection. Key chemicals used in the synthesis include (S)-N-Boc-amino acids, 2-aminobenzamide, ethyl chloroformate, phosphoryl chloride, and nickel(0) generated from NiCl2. The synthesized amines were tested for their catalytic activity in the asymmetric ethylation of aryl aldehydes, yielding alcohols with (S)-configuration and enantiomeric excesses (ee) ranging from 2% to 95%. The study concludes that these novel amines can serve as effective catalysts for asymmetric transformations, with ligand 2c achieving the highest enantioselectivity (95% ee) under optimized conditions. Further investigation into the effects of these catalysts on enantioselective processes is ongoing.
10.1016/j.tetasy.2013.11.001
The study focuses on the total syntheses of both enantiomers of bacillamide C and neobacillamide A, natural products with bioactivity, and their optical activities. The researchers aimed to resolve the confusion regarding the absolute configurations of these metabolites, which have been derived from microorganisms growing in marine and terrestrial environments. They synthesized the compounds using a stereospecific route from D-(-)-alanine and compared the specific rotation of the synthesized compounds to those reported in literature. The results indicated that the absolute configurations previously proposed for bacillamide C and neobacillamide A should be revised to (S). This finding is significant for genomic studies of their biosynthesis and for the use of bacillamide C as a building block in bioactive cyclic peptides.
10.1016/j.tetlet.2009.03.006
The study presents the stereoselective total synthesis of synparvolide B and epi-synparvolide A, complex molecules containing an a,b-unsaturated d-lactone motif, which are of interest to medicinal chemists due to their presence in plants with potent biological activities. The synthesis was achieved through a convergent approach, with key steps including Noyori asymmetric Transfer Hydrogenation of ketone and Wadsworth–Emmons olefination reaction. Various chemicals were used in the process, such as L(+)-DET, cyclohexanone, pTSA, LiAlH4, TsCl, NaBH4, I2, TPP, imidazole, alkyne 13, n-BuLi, ethylchloroformate, N-methyl methoxy aminohydrochloride salt, and others, serving as starting materials, reagents, and catalysts in the multi-step synthesis process. These chemicals were essential for constructing the complex molecular structures of the target compounds, enabling their synthesis for further biological evaluation and potential therapeutic property identification.
10.1002/ejoc.201000569
The research focuses on the development and application of C3-symmetric proline-functionalized organocatalysts for enantioselective Michael addition reactions. The purpose of this study was to design catalysts with higher symmetry to reduce the number of reaction pathways and enhance selectivity in asymmetric synthesis. The researchers synthesized a series of C3-symmetric catalysts based on 1,3,5-triethylbenzene and evaluated their performance in the Michael addition of carbonyl compounds to β-nitrostyrenes. The catalysts were synthesized from Boc-protected L-proline and various substituted amines, and the key chemicals used in the process included ethyl chloroformate, trifluoroacetic acid (TFA), and borane-tetrahydrofuran complex (BH3·SMe2). The study concluded that the C3-symmetric catalyst 4, which allowed for conformational flexibility, was highly effective for the Michael addition reactions, leading to products with high diastereo- and enantioselectivities. This work demonstrates the potential of C3-symmetric catalysts in organocatalysis and their ability to control molecular order in enantioselective reactions.
10.1039/c39860001524
The research details a novel method for oxygen-to-carbon ester migration in the benzofuranone ring system, catalyzed by 4-(N,N-dimethylamino)pyridine (DMAP). The purpose of this study was to address the challenge in synthetic chemistry of regioselective carbon acylation of enolates, particularly those that are highly delocalized, as the kinetically-formed oxygen-acylated products usually predominate. The researchers reported a method that quantitatively rearranges the initially-formed enol carbonate to its carbon-acylated isomer, using DMAP as a catalyst. The benzofuranones, which have a wide spectrum of pharmacological activity, were the focus of this study due to their importance in the synthesis of potential anti-neoplastic agents. Key chemicals used in the process included sodium hydride in dimethylformamide (DMF) for deprotonating 3-phenyl-2(3H)-benzofuranone, ethyl chloroformate for the formation of enol carbonate, and DMAP for catalyzing the rearrangement to the C-acylated ester. The study concluded that DMAP could effectively catalyze the carbon acylation, leading to the desired C-acylated ester, and that this reaction was general for several alkyl chloroformates.
10.1002/hlca.19500330323
This study focuses on the synthesis and analysis of various derivatives of p-aminosalicylic acid. The key chemicals involved include 2-nitro-p-toluidine, ethyl chloroformate, and sodium methoxide, which are used to produce 2-nitro-4-methoxytoluidine (I). This compound is then oxidized with potassium permanganate to give 2-nitro-4-carboxyaminobenzoic acid (II). Other derivatives synthesized include p-nitro-o-acetylsalicylic acid (III), ethyl p-acetylamidosalicylate (IV), and ethyl p-N-nicotinamidosalicylate (V), each of which is generated through specific reactions involving acetic anhydride, acetyl chloride, nicotinic chloride, and other reagents. The study also discusses esters of methionine and other specific amino acids, which react with crystalline chymotrypsin to form peptides, highlighting potential relevance to biological peptide synthesis. The study details the synthetic procedures and properties of the resulting compounds, and provides yields and melting points for each derivative, demonstrating chemical transformations and their analytical significance.