A Triple Cascade Sequence as a Strategy for the Construction of the Erythrinane Skeleton
摘要:
alpha-Thiocarbocations generated from Pummerer reactions of several o-imido sulfoxides were intercepted by adjacent carbonyl groups to produce alpha-amido-substituted isobenzofurans as transient intermediates. When an olefinic tether was present, intramolecular Diels-Alder cycloaddition occurred followed by a ring-opening-elimination sequence that produced an N-acyliminium ion. Deprotonation of the iminium ion led to oxindole derivatives in good yields, When the iminium ion contained both a Mocking substituent, such as a carbomethoxy group, as a ell as an activated aromatic pi-tether, the N-acyliminium ion intermediate underwent stereoselective spirocyclization to afford cis-3,4-benzoerythrinane or homoerythrinane derivatives in good yield. The overall triple cascade sequence represents an efficient one-pot approach toward the erythrina skeleton in which the spirocyclic ABC skeleton is assembled in a single operation. The scope and limitations of the triple cascade were explored by varying both the olefinic and nucleophilic tethers. The required sulfoxide precursors for these Pummerer-induced transformations were easily synthesized starting from 2-[(ethylthio)methyl]benzoic acid. The tandem Pummerer/Diels-Alder/N-acyliminium ion cyclization was used for the synthesis of indoloisoquinoline 38. Since compound 38 was converted to 47 which, in turn, was transformed into erysotramidine (2), its preparation represents an extraordinarily facile, formal synthesis of this member of the Erythrina alkaloid family.
Generation and Subsequent Cycloaddition Chemistry of α-Amino Isobenzofurans Formed by Cationic Cyclization
作者:C. Oliver Kappe、John E. Cochran、Albert Padwa
DOI:10.1016/0040-4039(95)02013-f
日期:1995.12
The α-thiocarbocation generated from the Pummerer reaction of an o-amido substituted sulfoxide is intercepted by the adjacent carbonyl group to produce an α-amino isobenzofuran as a transientintermediate which undergoes a subsequent Diels-Alder cycloaddition with added dienophiles.
Studies Dealing with the Cycloaddition/Ring Opening/Elimination Sequence of 2-Amino-Substituted Isobenzofurans
作者:Albert Padwa、C. Oliver Kappe、John E. Cochran、James P. Snyder
DOI:10.1021/jo962358c
日期:1997.5.1
Pummerer reaction of an o-amido-substituted sulfoxide is intercepted by the adjacent amido carbonyl group to produce a 2-amino-substituted isobenzofuran as a transient intermediate. In the presence of an electron-deficient dienophile, the reactiveisobenzofuran undergoes a Diels-Alder cycloaddition followed by ring opening to furnish a vinylogous C-acyliminium ion that readily aromatizes. The one-pot
申请人:Sanford Burnham Prebys Medical Discovery Institute
公开号:US10626096B2
公开(公告)日:2020-04-21
The present invention relates to a novel azole derivative as an apelin receptor agonist and a method for treating cardiovascular disease, diabetic disease, renal disease, hypertension, and arteriosclerosis, etc., using the same. The present invention provides a compound represented by formula (I) or a pharmacologically acceptable salt thereof wherein X1 represents —NH═ or —CH═, X2 represents —CH═ or —N═, R1 and R2 each represent a C1 to C6 alkoxy group or the like, R3 represents a heteroaryl group (the heteroaryl group is optionally substituted by a methyl group or the like) or the like, and R4 represents a C1 to C6 alkylthio group or a C2 to C6 alkenyl group (the C1 to C6 alkylthio group and the C2 to C6 alkenyl group are each optionally substituted by one carboxy group or the like) or the like.
The stereoselective formation of anomerically pure 1-O-acyl derivatives of protected carbohydrates is achieved by reaction of the alpha-glycosyl halogenoses with cesium caboxylates.
Hard acid and soft nucleophile systems. 5. Ring-opening reaction of lactones to .omega.-alkylthio- or .omega.-arylthio carboxylic acids with aluminum halide and thiol