Organocatalytic Functionalization of Carboxylic Acids: Isothiourea-Catalyzed Asymmetric Intra- and Intermolecular Michael Addition−Lactonizations
摘要:
Tetramisole promotes the catalytic asymmetric intramolecular Michael addition-lactonization of a variety of enone acids, giving carbo- and heterocyclic products with high diastereo- and enantiocontrol (up to 99:1 dr, up to 99% ee) that are readily derivatized to afford functionalized indene and dihydrobenzofuran carboxylates. Chiral isothioureas also promote the catalytic asymmetric intermolecular Michael addition-lactonization of arylacetic acids and alpha-keto-beta,gamma,-unsaturated esters, giving anti-dihydropyranones with high diastereo- and enantiocontrol (up to 98:2 dr, up to 99% ee).
Facile synthesis of substituted diaryl sulfones <i>via</i> a [3 + 3] benzannulation strategy
作者:Xiang-zheng Tang、Lang Tong、Hua-ju Liang、Jie Liang、Yong Zou、Xue-jing Zhang、Ming Yan、Albert S. C. Chan
DOI:10.1039/c8ob00662h
日期:——
base-mediated [3 + 3] benzannulation strategy for the conversion of 1,3-bis(sulfonyl)propenes and β,γ-unsaturated α-ketoesters to diaryl sulfones has been developed. This method provides facile, metal-free and efficient access to highly substituted diaryl sulfones in good to excellent yields. In addition, the sulfonyl group could be easily removed or converted to other functional groups via an organostannane
Synthesis of Chiral Bispirotetrahydrofuran Oxindoles by Cooperative Bimetallic-Catalyzed Asymmetric Cascade Reaction
作者:Meng-Meng Liu、Xiao-Chao Yang、Yuan-Zhao Hua、Jun-Biao Chang、Min-Can Wang
DOI:10.1021/acs.orglett.9b00386
日期:2019.4.5
Under mild conditions, a broad range of bispirotetrahydrofuran oxindoles have been synthesized with excellent stereoselectivities through the cascadeMichael/hemiketalization/Friedel–Crafts reaction of β,γ-unsaturated α-ketoamide and 2-hydroxy-1-indanone. The reaction can be performed on a gram scale with low catalyst loading (2 mol %) without impacting its efficiency.
Diaryl Dihydropyrazole-3-carboxamides with Significant In Vivo Antiobesity Activity Related to CB1 Receptor Antagonism: Synthesis, Biological Evaluation, and Molecular Modeling in the Homology Model
作者:Brijesh Kumar Srivastava,*、Amit Joharapurkar、Saurin Raval、Jayendra Z. Patel、Rina Soni、Preeti Raval、Archana Gite、Amitgiri Goswami、Nisha Sadhwani、Neha Gandhi、Harilal Patel、Bhupendra Mishra、Manish Solanki、Bipin Pandey、Mukul R. Jain、Pankaj R. Patel
DOI:10.1021/jm061490u
日期:2007.11.1
A number of analogues of diaryl dihydropyrazole-3-carboxamides have been synthesized. Their activities were evaluated for appetite suppression and body weight reduction in animal models. Depending on the chemical modification of the selected dihydropyrazole scaffold, the lead compounds-the bisulfate salt,of (+/-)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-1H-pyrazole-3-carboxylic acid morpholin-4-ylamide 26 and the bisulfate salt of (-)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-1H-pyrazole3-carboxylic acid morpholin-4-ylamide 30-showed significant body weight reduction in vivo, which is attributed to their CB1 antagonistic activity and exhibited a favorable pharmacokinetic profile. The molecular modeling studies also showed interactions of two isomers of (+/-)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)4,5-dihydro- 1H-pyrazole-3-carboxylic acid morpholin-4-ylamide 9 with CB I receptor in the homology model similar to those of N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxarnide (rimonabant) 1 and 4S-(-)-3-(4-chlorophenyl)-N-methyl-N'-[(4-chlorophenyl)-sulfonyl]-4-pheny1-4,5-dihydro-1H-pyrazole-1-carboxamidine (SLV-319) 2.
Interaction of Hydroxylamine with Esters of 2-Oxobutenoic Acids. Synthesis of 1-Hydroxy-3-hydroximino-2-pyrrolidinones