查看更多>>摘要：Treatment of a variety of 2(3)- mono-substituted anilines with benzyltrimethylammonium dichloroiodate (1.2 equiv) and ammonium thiocyanate (1.2 equiv) in DMSO:H2O (9:1) at 70 degrees C gave the corresponding 4-thiocyanato-2(3)-substituted anilines in excellent isolated yields (60-99%; ave. yield for all anilines = 90%). The reaction worked well for substrates with 2-halo, 2-alkoxy, 2-aryloxy, 2-alkyl, 2-dialkylamino, 2-N-sulfonylamino, 2-alkyn-1-yl, 2-cyano, 2-acyl, 2-sulfonyl, and 2-heteroaryl substitution. 3-Substituted, 3,5- or 2,6-disubstituted anilines and substituted phenols were also well tolerated. 4-Substituted anilines gave the corresponding 2-aminobenzothiazole products, whereas 4-, 5-, 6-, or 7-substituted indoles were not reactive. Regioselective thiocyanation of 2-quinoline, 3-amino1-methylpyrazole, 2-amino-4-phenylthiazole, and 2-phenylimidazo[1,2-a] pyridine was achieved in 93-99% yield, thus demonstrating the broad-substrate scope for this thiocyanation reaction. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Cynotofuranoside A-C (1-3), three previously undescribed C21-steroidal furanosides were isolated from the acid hydrolysate of Cynanchum otophyllum roots. Their structures were elucidated by extensive spectroscopic analysis including UV, IR, 1D and 2D NMR and HR-ESI-MS. Compounds 1-3 represented the first examples of 2,6-dideoxy-aldohexose in the form of furan ring attaching to 3b-OH of natural occurring C21-steroidal aglycones. The cytotoxicity of these compounds against human cancer MCF-7, HCT-116, HeLa, and HepG2 cells were evaluated. Compounds 1 and 3 showed moderate cytotoxic activities against HepG2 cancer cells with IC50 values of 43.15 and 34.36 mu M, respectively. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：An effective base-catalyzed Knoevenagel, Michael and intramolecular/Paal-Knorr cyclization strategy for the construction of heterocyclic [4.3.3] tetrahydro epoxyetheno benzo-furan propellanes (TEBFs) from cyclic alpha-diketones and alpha cyanoketones is reported through single-step reaction. The reaction proceeds under mild reaction conditions and shows excellent chemo and distereoselectivity in the absence of any external transition metal and ligands. The one-pot two-component procedure also shows the merits of straightforward reaction conditions, simple operation, using available feedstock, wide substrate scope, and high atom and step economy. This reaction provides facile access to highly substituted fused tetrahydro furo-furan propellanes, which can be used in the field of chemical and pharmaceutical research. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A cobalt-catalyzed decarboxylative oxyalkylation of styrenes with alpha-cyanoacid has been established, leading to a variety of gamma-ketonitriles in moderate yields. alpha-Cyanoacid was applied as the nitrile sources. This methodology was distinguished by operational simplicity, easily available starting materials and good functionality tolerance. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A three-component reaction for the preparation of 2-amino-2-butene-1,4-diones has been established. The reaction proceeds without requirement of any catalyst or additive, affording the corresponding products in good to excellent yields. In addition, a plausible reaction pathway was proposed, which was supported by control experiments.(c) 2022 Elsevier Ltd. All rights reserved.
Massing, Justin O.Almounajed, LeilaMinder, Kyle A.Lange, Joseph D....
4页
查看更多>>摘要：Herein we report two separate F-19 magnetic resonance (MR) probes responsive towards formaldehyde. Both agents were synthesized in a single step via aminoallylation of either 4-fluorobenzaldehyde (1FA) or 4-(trifluoromethyl)benzaldehyde (3FA) with ammonia and allylboronic acid pinacol ester. Condensation of the resulting homoallylic amines 1FA and 3FA with formaldehyde, followed by a 2-aza-Cope rearrangement and subsequent hydrolysis affords 4-fluorobenzaldehyde and 4-(trifluoromethyl)benzaldehyde, respectively. In the case of 1FA, this transformation is evidenced by a concomitant downfield shift in the F-19 MR signal from -115 ppm to -103 ppm. Further, this transformation is selective towards formaldehyde over other reactive carbonyl species. While 3FA exhibits similar selectivity towards formaldehyde, this more sensitive probe is limited by the small chemical shift difference (0.7 ppm) following its activation. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A transition metal free mechanically induced C(sp(2))-H arylation of quinoxalin(on)es is described. In this study, diaryliodonium salts generate aryl radical by planetary ball milling, with the assist of piezoelectric material BaTiO3. A broad range of functional groups are tolerated to give products in moderate to good yields via radical mechanism. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：We have previously demonstrated that 5-bromo-2-chloro-4-fluoro-3-iodopyridine (6) can serve as a versatile intermediate to penta-substituted pyridines. This work describes regioselective SNAr reactions of 6 and its 3-substituted analogs with a variety of nucleophiles to deliver highly functionalized pyridines as valuable building blocks in medicinal chemistry and drug design. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Herein an efficient and simple protocol was developed for the synthesis of pyrazoles and phthalazin-1 (2H)-ones from a common precursor hydrazines catalyzed by nickel chloride. The reactions proceeded in water at room temperature. The advantages of the protocol are that both the medicinally important scaffolds could be synthesized with low-cost catalyst, green solvent, relatively lower reaction time and superior yield of the product making the protocol synthetically very useful. Electronically diversed pyrazoles and phthalazinones could be achieved in good to excellent yields in relatively shorter reaction time. CO 2022 Elsevier Ltd. All rights reserved.
Mojtahedi, Mohammad M.Darvishi, KianaAbaee, M. SaeedHalvagar, Mohammad R....
4页
查看更多>>摘要：A new series of dihydropyrano-dioxine products were synthesized via one-pot combination of 2,2dimethyl-1,3-dioxan-5-one with aromatic aldehydes and malononitrile. The first step occurs rapidly in an aqueous alcoholic medium at reflux, followed by nucleophilic addition of malononitrile to the olefinic site of the intermediate and iodine induced oxidation to the final products, which directly precipitate in the vessel, avoiding time consuming and expensive chromatographic separations. The structure of the products was elucidated based on their NMR data and verified by X-ray crystallography. In the case of a-substituted derivatives, rotational barrier caused by the bulk of the ortho substituent led to the formation of atropisomeric products. To study this aspect, molecular geometry of 4 g was optimized by ChemDraw professional 20 and then MM2 calculation was performed. (c) 2022 Elsevier Ltd. All rights reserved.
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