Tin (IV) Chloride-promoted Synthesis of 4-Aminopyridines and 4-Aminoquinolines

A Novel and Facile synthesis of Pyrazolo [3,4-b]Pyridines

Pyrazolo[3,4- b]pyridines have been obtained by the condensation of 5-amino-4-cyanopyrazole, readily available by the reaction of dithioacetals with substituted hydrazines, with β-ketoesters or β-diketone in the presence of tin(IV) chloride at reflux temperature in dry toluene.

Superacidic Cyclization of Activated Anthranilonitriles into 2-Unsubstituted-4-aminoquinolines

4-Aminoquinolines were prepared in a three-step synthesis starting from substituted anthranilonitriles. The condensation on 1,1,1-trichloro-4-ethoxybut-3-enone proceeded efficiently either neat or in refluxing EtOH. Cyclization in superacidic trifluoromethanesulfonic acid provided unstable intermediate, which upon treatment with NaOEt in ethanol, afforded the expected esters. Theoretical investigations pointed out a monoprotonated nitrilium as the reactive species during the cyclization process.

Environmentally benign synthesis of 4-aminoquinoline-2-ones using recyclable choline hydroxide

Biocompatible and recyclable choline hydroxide for rapid synthesis of 4-aminoquinoline-2-ones.

Synthesis and structure elucidation of five new pyrimido[5,4-c]quinoline-4(3H)-one derivatives using 1D and 2D NMR spectroscopy

Five new 2-(amino/aroxy)-5-methylpyrimido[5,4-c]quinolin-4(3H)-one derivatives have been designed and synthesized via an aza-Wittig reaction, and the structure elucidation was accomplished using extensive 1D ((1)H, (13)C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC experiments).

Highly Regioselective Friedländer Reaction

[reaction: see text]. A highly regioselective Friedländer reaction is described. By introduction of a phosphonate group at one of the alpha-carbons of a ketone, regioselectivity can be perfectly controlled.