Facile Assembling of Novel 2,3,6,7,9-pentaazabicyclo- [3.3.1]nona-3,7-diene Derivatives under Microwave and Ultrasound Platforms

Abstract

Reactions of a series of 3-oxo-2-arylhydrazonopropanal derivatives with two molar ratio of ammonium acetate afforded a library of tetrasubstituted 2,3,6,7,9-pentaazabicyclo[3.3.1]nona- 3,7-diene derivatives in good to excellent isolated yields. The reaction was activated with triethylamine catalyst under three different heating modes: thermal, ultrasonic and microwave irradiating conditions in ethanol solvent. The structures of the isolated products were fully characterized by spectral and analytical data as well as X-ray single crystal of selected examples.

Microwave-assisted chemoselective synthesis and photophysical properties of 2-arylazo-biphenyl-4-carboxamides from hydrazonals

“…[56][57][58] The straightforward amidation of carboxylic acids was successfully modied by microwave activation. [59][60][61][62][63][64][65] Therefore, in continuation of our research interest in microwave-assisted organic synthesis, [66][67][68][69][70][71][72][73][74][75][76][77] herein we re-investigated our previous work on a supplemental reaction of 3-oxo-2-arylhydrazonopropanals 1 with acetoacetanilide 2, 68 by optimization of reaction conditions (components' molar ratios, solvents, bases and activation modes) towards chemoselective construction of the 2-(arylazo)-5-hydroxy-N-phenyl-[1,1 ′ -biphenyl]-4-carboxamide derivatives 3 instead of the cinnoline derivatives 4 (Scheme 1) and the photophysical properties of the obtained biphenyl-4-carboxamides were evaluated. The structures of the new products were characterized by IR, 1 H-and 13 C-NMR, MS and HRMS spectral data as well as Xray single crystallography of selected examples.…”

Ultrasound irradiation in heterocycle synthesis: An overview

“…The double Mannich reaction of 3‐oxo‐2‐arylhydrazonopropanal derivative and ammonium acetate for the synthesis of 2,3,6,7,9‐pentaazabicyclo[3.3.1]nonane derivative was discussed by Al‐Matar et al [49] The reaction proceeded via the optimized condition of 15 mol% Et 3 N as catalyst under ultrasound irradiation for 60 min. Afforded the expected product in 82% yield (Scheme 31).…”

Synthesis of a fused N-bridged [3.3.1]nonadiquinoline multicyclic skeleton via a metal-free formal [4 + 2] cycloaddition/Mannich/dearomatization domino reaction

“…Alkaloid skeletons have become hot synthetic targets in modern organic synthesis. 1 Azabicyclo[3.3.1]nonanes are one of the most important classes of polycyclic alkaloids 2 that are ubiquitous in complex bioactive natural products 3 and pharmaceuticals, such as ajmaline, 4 granisetron, 5 and sarpagine, 6 used as an antiarrhythmic agent, to prevent nausea and vomiting, and as an anti-inflammatory agent, respectively (Fig. 1).…”