A Base-Catalyzed, Domino Aldol/hetero-Diels–Alder Synthesis of Tricyclic Pyrano[3,4-c]chromenes in Glycerol

Abstract

The domino aldol/hetero-Diels-Alder synthesis of some new tricyclic pyrano[3,4-c]chromene derivatives has been achieved successfully after assembling a variety of acyclic or cyclic monoketones with prenyl ether-tethered aldehydes in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene in glycerol at 120 °C. The hitherto unreported stereochemical outcome of this synthetic sequence was studied and established on the basis of single-crystal X-ray diffraction data and 2D NMR NOESY spectroscopy along with the isolation and characterization of the intermediate Aldol condensation product.

Engineering a Cu‐MOF Nano‐Catalyst by using Post‐Synthetic Modification for the Preparation of 5‐Substituted 1H‐Tetrazoles

“…FT‐IR, 1 H and 13 C NMR spectroscopies and melting points were used to confirm the structure of the products. The results were also compared with the corresponding reported spectral data …”

“…The results were also compared with the corresponding reported spectral data. [40,43,60,[65][66][67][68][69][70][71][72][73][74] A plausible mechanism for the synthesis of tetrazole derivatives catalyzed by the nano-scale Cu-MOF is suggested in Scheme 3. Cu-MOF as Lewis acid plays a role in increasing the electrophilic character of the nitrile Compounds via coordination to nitrogen atoms (Step 1).…”

Domino Transformations of Ene/Yne Tethered Salicylaldehyde Derivatives: Pluripotent Platforms for the Construction of High sp3 Content and Privileged Architectures

“…This cascade proceeded through a rare domino Aldol/hetero‐Diels–Alder (DAHDA) reaction of prenyl ether tethered aldehydes ( 33 ) with acyclic or cyclic monoketones ( 150 ). In this protocol, glycerol was employed as an efficient and recyclable medium for the reaction, demonstrating its reusability for at least three runs, in the same synthetic sequence without losing its activity (Scheme ) …”

“…In this protocol, glycerolw as employed as an efficient and recyclable mediumf or the reaction, demonstrating its reusability for at least three runs, in the same synthetics equence without losing its activity (Scheme36). [62] Bakthadoss and co-workers constructed tetra/pentacyclic hybrid pyrazole, pyrimidine, and coumarin annulated coumarinopyran frameworks (155-158). This stereoselective reaction proceeded through ad omino Knoevenagel/hetero Diels-Alder reactionb yu sing as olid-state meltr eaction (SSMR) procedure (Scheme 37).…”

Synthesis, spectroscopic and computational characterization of the tautomerism of pyrazoline derivatives from chalcones

“…The interest in obtaining chalcones and their pyrazolines analogues has grown in the past ten years because of numerous pharmacological properties have been discovered, namely: antimicrobial [1][2][3][4][5][6], anti-tubercular [1,7,8], anticancer [8,9], anti-inflammatory [8] and antioxidant [5] activities. The wide range of pharmacological activities of these compounds shows the importance of this family of heterocyclic compounds in the area of medicinal chemistry.…”