Enaminones as Building Blocks in Heterocyclic Synthesis: New Syntheses of Nicotinic Acid and Thienopyridine Derivatives.

New and Facile Synthesis of Substituted Pyrrole, Pyridine, Pyrazolo[4,3-b] Pyridine, Pyrano[3,2-c] Quinoline, Napthopyran, Naphthodipyran and Coumarin Derivatives

“…The later aromatized through elimination of hydrogen cyanide or ethyl formate and water. Similar sequence for the formation of similar systems has been reported before [3,7] ). Structure 20 was also supported through the formation from reaction of 4-hydroxy-1-methylquinolin-2(1H)one (18) with arylidenes 1g, h utilizing the same reaction conditions.…”

“…Amomg these derivatives are biologically interesting antimicrobials [1,2], antimalarials [3], as pharmaceuticals [4], antitumor activity [5], as nonpeptide human deficiency virus (HIV) protease inhibitors [6] and antischistosomal agents [7]. Some years ago, our main interest was focused on a program aimed at developing of new synthetic approaches to Polyfunctionally substituted heterocycles [8,9] utilizing simple, inexpensive and readily available starting materials.…”

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

“…Enaminones has been recently extensively utilized as precursors for the synthesis of heteroaromatics [5][6][7][8]. We report herein on the synthesis of iminoarylhydrazonopropanone, azolopyrimidine and 3-oxaloalkanonitrile derivatives of potential interest as pharmaceuticals and photochromic dyes [9][10][11][12][13], starting from enaminones. It has been reported that methylalkyl ketones and methylaryl ketones condense readily with dimethylformamide dimethylacetal (DMFDMA) to yield enaminones, whose chemistry has recently attracted considerable interest [5,6,[12][13][14][15][16][17][18][19][20].…”

Synthesis of 6,7-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by Azomethine Imine-Alkyne Cycloadditions Using Immobilized Cu(II)-Catalysts

“…Active methylene compounds 1a – g , 3-aminopropyl silica gel ( 3 ) (for preparative chromatography, 40–63 µm, 0.9 mmol/g amino groups, pore size ~9 nm), 4-aminobenzoic acid ( 12 ), Cu(OAc) 2 ·H 2 O, N,N -dimethylformamide dimethylacetal (DMFDMA, for synthesis, ≥96%), tert -butoxy-bis(dimethylamino)methane (TBDMAM, technical grade), and 1,1′-carbonyldiimidazole (CDI) are commercially available (Sigma-Aldrich). Enaminones 2a [ 72 ], 2b [ 73 ], 2c [ 74 ], 2d [ 75 ], 2e [ 76 ], 2f [ 77 ], and 2g [ 78 ], bis-enaminones 9a , 9b [ 70 ], and 9c [ 71 ], and azomethine imines 6a , f [ 79 ], 6b , e [ 80 ], 6c [ 81 ], and 6d [ 82 ] were prepared following the literature procedures.…”