Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

A practical and high-yielding Schmidt reaction for the synthesis of fused tetrazoles from bile acid precursors was developed. Mild reaction conditions using TMSN3 instead of hydrazoic acid as an azide source produced good yields of the desired tetrazoles. These conditions could be applied to other steroidal precursors. Additionally, an improved methodology for the synthesis of different ketone and enone precursors from cholic acid, deoxycholic acid, and chenodeoxycholic acid was established. Newly obtained tetrazole derivatives were characterized by NMR and X-ray diffraction spectroscopy. In a number of cases, preliminary antiproliferative tests of new compounds showed strong and selective activity towards certain tumor cell lines.

Green Chemistry Approaches To The Synthesis Of Flavonoids

: In nature, flavonoids constitute a relatively diverse family of aromatic molecules such as flavones, flavonols, flavanones, isoflavone, chalcones, and their derivatives. Natural and synthetic flavonoids have reported diverse biological activity including antimycobacterial, antimicrobial, antiproliferative, antiarrhythmic, antiviral, antihypertensive, antioxidant, and anti-inflammatory. Flavonoids have garnered much attention as potential targets for nutraceuticals and pharmaceuticals. The recent development of ‘‘Green Chemistry’’ has enabled us to manipulate biosynthetic pathways to generate a library of synthetic flavonoids and to diminish the hazards for human health and environmental pollution from conventional methods. This paper presents an exhaustive review of the green synthesis of flavonoids. Green chemistry is the need of the day; hence chalcones can be synthesized in an eco-friendly manner without using solvents. The chalcone synthesis involves the solvent-free solid-state trituration between acetophenone derivatives and substituted benzaldehydes in the presence of NaOH/KOH as a base (Claisen-Schmidt reaction). Using these chalcone derivatives, synthesis of flavonoids can be done. In the pharmaceutical arena, economical bulk production of different types of flavonoids has been successfully established by green chemistry techniques.

(E)-5-Benzyl-7-(3,4-dimethoxybenzylidene)-3-(3,4-dimethoxyphenyl)-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3c] Pyridine

A new pyrazolo-pyridine analogue (title compound) was synthesized in two steps. The first stage was synthesis of monoketone curcumin analogue through Claisen–Schmidt reaction. The second stage was synthesis of the title compound through intermolecular cyclization under reflux condition. The structure of the title compound has been confirmed by spectroscopic analysis including UV, FT-IR, HRMS, 1D NMR (1H-NMR, 13C-NMR, 1D-TOCSY), and 2D NMR (COSY, HSQC, HMBC). Based on the DPPH assay, the compound has moderate antioxidant activity, with an IC50 value of 194.06 ± 7.88 µg/mL (0.337 mM).

Sulfonium Ion-Promoted Traceless Schmidt Reaction of Alkyl Azides

Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction showcased ring-opening, -expansion, and one-pot further conversion of the substrates as well as the application with C-H azidation.

Sulfonium Ion-Promoted Traceless Schmidt Reaction of Alkyl Azides

Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction showcased ring-opening, -expansion, and one-pot further conversion of the substrates as well as the application with C-H azidation.

Sulfonium Ion-Promoted Traceless Schmidt Reaction of Alkyl Azides

Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction showcased ring-opening, -expansion, and one-pot further conversion of the substrates as well as the application with C-H azidation.