Synthesis of 3-Alkylbenzoxazolones from N-Alkyl-N-arylhydroxylamines by Contiguous O-Trichloroacetylation, Trichloroacetoxy ortho-Shift, and Cyclization Sequence
摘要:
Benzoxazolone pharmacophore is present in clinical pharmaceuticals, drug candidates, and many compounds having a wide spectrum of biological activities. The methods available for the synthesis of benzoxazolones have limited diversity due to problems in accessibility and air-sensitivity of diversely substituted o-aminophenols from which they are generally prepared by cyclocarbonylation with phosgene or its equivalents. The present paper describes a mild method for the synthesis of 3-alkylbenzoxazolones from easily accessible and air-stable nitroarenes. Nitroarenes were converted to N-alkyl-N-arylhydroxylamines in two steps involving partial reduction to arylhydroxylamines followed by selective N-alkylation. Treatment of N-alkyl-N-arylhydroxylamines with trichloroacetyl chloride and triethylamine afforded 3-alkylbenzoxazolones generally in good yields through an uninterrupted three-step sequence involving O-trichloroacetylation, N -> C-ortho trichloroacetoxy shift, and cyclization in a single pot at ambient temperatures. The present method is mild, wide in scope, economical, and regioselective. Many sensitive groups like alkyl and aryl esters, amide, cyano, and the carbon-carbon double bond survive the reaction.
Diethylenetriamine is effective for the direct cleavage of unactivated carbamates and ureas without additional reagents and catalysts. Various carbamates and ureas were cleaved to afford products in good yield, and the reactions were not affected by air or moisture. Unique chemoselective cleavage of carbamate and urea in the presence of amides was also achieved.
Synthesis and Anticonvulsant Activity of 2(3<i>H</i>)-Benzoxazolone and 2(3<i>H</i>)-Benzothiazolone Derivatives
作者:Huseyin Ucar、Kim Van derpoorten、Silvia Cacciaguerra、Santi Spampinato、James P. Stables、Paul Depovere、Majed Isa、Bernard Masereel、Jacques Delarge、Jacques H. Poupaert
DOI:10.1021/jm970682+
日期:1998.3.1
relationship between the 2(3H)-benzoxazolone and 2(3H)-benzothiazolonederivatives' structures and anticonvulsant activity. Several of these compounds showed significant anticonvulsant activity. Compounds 43 and 45 were the most active of the series against MES-induced seizures with ED50 values of 8.7 and 7.6 mg/kg, respectively. Compound 45 displayed good protection against MES-induced seizures and low toxicity
Enantioselective Total Synthesis of Quadrigemine C and Psycholeine
作者:Alec D. Lebsack、J. T. Link、Larry E. Overman、Brian A. Stearns
DOI:10.1021/ja0267425
日期:2002.8.1
The first total syntheses of higher-order members of the polypyrrolidinoindoline alkaloid family are reported. The synthesis of quadrigemine C (1) and psycholeine (3) begins with synthetic meso-chimonanthine (4), which is synthesized from commercially available oxindole and isatin in 13 steps and 35% overall yield. Double Stille cross coupling of diiodide 7, available in three steps from 4, with vinylstannane
Compounds of Formula (I′), and the use of the compounds of Formula (I′) as inhibitors of macrophage migration inhibitory factor (MIF). The use of compounds of Formula (I′) or pharmaceutical compositions thereof and method of using them, for treating disorders, diseases or conditions related to MIF.
Catalytic Asymmetric Synthesis of Quaternary Carbons Bearing Two Aryl Substituents. Enantioselective Synthesis of 3-Alkyl-3-Aryl Oxindoles by Catalytic Asymmetric Intramolecular Heck Reactions
作者:Amy B. Dounay、Keiko Hatanaka、Jeremy J. Kodanko、Martin Oestreich、Larry E. Overman、Lance A. Pfeifer、Matthew M. Weiss
DOI:10.1021/ja034525d
日期:2003.5.1
A practical sequence involving three consecutive palladium(0)-catalyzedreactions has been developed for synthesizing 3-alkyl-3-aryloxindoles in high enantiopurity. The Heck cyclization precursors 10 and 11a-k are generated in one step by chemoselective Stille cross-coupling of 2'-triflato-(Z)-2-stannyl-2-butenanilide 9 with aryl or heteroaryl iodides. The pivotal catalytic asymmetric Heck cyclization