查看更多>>摘要：An efficient copper-catalyzed decarboxylative cross coupling reaction of coumarin 3-carboxylic acid with 4-thiazolidinones has been developed. The described strategy operated smoothly via subsequent decarboxylation and radical addition in the presence of copper catalyst and oxidant. Various coumarinyl-4-thiazolidinone derivatives were obtained easily in moderate to good yield by employing this strategy. Substrate scope and optimization have been carried out appropriately. Optimization was carried out through various copper catalyst, oxidants, and additives. (C) 2021 Published by Elsevier Ltd.
查看更多>>摘要：In humans, oxidative metabolites 2-4 of (S)-4-fluoro-5-(2-methyl-1,4-diazepan-1-ylsulfonyl)-isoquinoline hydrochloride dihydrate (K-115, 1), a novel Rho-kinase inhibitor, are mainly formed by aldehyde oxidase and CYP3A4 / 3A5 in human liver S9 and hepatocytes. We synthesized the proposed compounds 2-4 and determined the metabolite structure by LC-MS/MS analysis. Metabolites 2-4 were synthesized by rearrangement of isoquinoline N-oxide and/or by using (S)-5-keto-2-methyl-1,4-diazepane moiety as a key structure, which in turn was prepared from (R)-3-amino-2-propanol and 3-amino-propionic acid through a Mitsunobu intramolecular cyclization reaction. (C) 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：We developed a facile one-pot synthesis of 2-oxazolines from carboxylic acid and 2-chloroethyl isocyanate, involving amide bond formation and a following intramolecular cyclization using 4-dimethylaminopyridine as the catalyst. A large variety of functional groups are well tolerated by the mild reaction conditions to afford diverse 2-oxazolines in good to excellent yields. This reaction will keep the chirality of the isocyanate at position 1, the R-2 substituted carbon. Microwave-assisted synthesis can further enhance the reaction yield and reduce the reaction time to <5 min. This method facilities the synthesis of 2-oxazolines for diverse applications, such as 2-oxazoline derived polymers and materials. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Two monomer compounds of CDTOH, 6(A)-deoxy-6(A)-(4-(2-hydroxyethyl)-1H-1,2,3-triazol-1-yl)-per-O-methylated beta-cyclodextrin 4 and 6(A)-deoxy-6(A)-(4-(2-hydroxyethyl)-1H-1,2,3-triazol-1-yl) beta-cyclodextrin 7, have been synthesized via click chemistry. The structures were confirmed by H-1 NMR, C-13 NMR and ESI-HRMS. In comparison to the 1H NMR spectra of compound 4 and intermediate 6, two sets of peaks in the high field of 7 are somewhat unusual. The X-ray single-crystal analysis of 7 showed the existence of an intramolecular hydrogen bond between the CH2OH donor of glucose B and the terminal hydroxy acceptor of the side chain, leading to the 4-(2-hydroxyethyl)-1H-1,2,3-triazole group protruding outside the cavity and embedding in the hydrophobic cavity of the adjacent molecule (interinclusion) to form an interlocked helical columnar superstructure. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：The carbon-fluorine (C-F) bond is one of the strongest bonds in organic chemistry and generally inert toward nucleophilic substitution reactions. To overcome the relative inertness of the C-F bond, this work focused on the ability of simple lithium salts (Lewis acid) to activate alkyl fluorides (Lewis base) leading to F/I exchange in high yields and selectivity for displacement of fluoride versus chloride and bromide. The exchange of fluorine for iodine was effective on both activated and neutral alkyl fluorides leading to yields as high as 99%. Published by Elsevier Ltd.
查看更多>>摘要：Two different strategies have been considered to achieve the total synthesis of metacridamides A and B. The first approach based on Horner-Wittig olefination reaction was unsuccessful. The second approach, involving desymmetrization, a highly diastereoselective aldolization, Wittig olefination, amide formation and finally tethering formation, furnished an advanced intermediate 39 with all stereocenters present in metacridamides A and B. (C) 2022 Published by Elsevier Ltd.
Matsushima, YoshitakaIshii, KoheiHuffaker, AlisaSchmelz, Eric A....
3页
查看更多>>摘要：The first concise method for the synthesis of zealexin B1, a maize sesquiterpenoid phytoalexin, was developed via Suzuki-Miyaura coupling. The coupling components were prepared as their corresponding triflates or boronates, starting from the corresponding commercially available ketone and a known ketoester; the latter is a Diels-Alder product. The reaction was also performed by interchanging the boronate and triflate coupling partners, and the yields were significantly different for the two combinations. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：We firstly describe a catalyst-free direct ring-opening of cyclic aldimines with abundant aliphatic primary amines to construct o-hydroxy schiff bases under mild reaction conditions. The corresponding products were generated in good to excellent yields (80-99%). In addition, a gram-scale reaction and further application of the reaction strategy were performed. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A facile and efficient synthesis of C1-aminosugar derivatives under catalyst-free conditions is described here. In particular, readily available benzoyl glycosyl bromides react smoothly to give a broad scope of C1-aminosugar derivatives in good yields. The present method proves to be efficient and facile in terms of short reaction time, high yield and the broad substrate scope. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Benzyl alkynes are important organic building blocks in organic synthesis. We report herein a B(C6F5)(3)-catalyzed site-selective 1,2-reduction of readily available alkynones to access benzyl alkyne derivatives. Under the developed conditions, an array of alkynone substrates are transformed into the corresponding benzyl alkyne products in good to excellent yields. This transformation displays many advantages including transition metal-free, mild reaction conditions, low catalyst loading (5 mol%), high yield (up to 99%), broad substrate scope and functional group tolerance. Moreover, the method's utility is demonstrated by the diverse transformation of the benzyl alkyne products into other useful chemical compounds in only one-step operation. This protocol offers an expedient way to the synthesis of benzyl alkynes. (C) 2022 Elsevier Ltd. All rights reserved.
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