Organocatalytic approach toward the green one-pot synthesis of novel benzo[<Emphasis Type="Italic">f</Emphasis>]chromenes and 12<Emphasis Type="Italic">H</Emphasis>-benzo[5,6]chromeno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridines

An efficient tandem reaction approach is described to prepare novel benzo[f]chromenes from 2,3-dihydroxynaphthalene, malononitrile and aldehydes using 10 mol% guanidine hydrochloride as the catalyst under solvent-free conditions. The method was also extended to the preparation of novel 12H-benzo[5,6]chromeno[2,3-b]pyridines from 2-aminoprop-1-ene-1,1,3-tricarbonitrile instead of malononitrile under the same reaction conditions. The described one-pot three-component reaction is characterized by short reaction times, high-product yield, mild reaction conditions, simple workup procedure, and simple purification.     

Synthesis of benzo[<Emphasis Type="Italic">f</Emphasis>]quinoline derivatives by condensation of <Emphasis Type="Italic">N</Emphasis>-arylmethylene-2-naphthylamines with acetylcyclohexane and 1-acetylcyclohexene

N-Arylmethylene-2-naphthylamines react with acetylcyclohexane and 1-acetylcyclohexene under mild conditions to afford 2-aryl-2-(2-naphthylamino)ethyl cyclohexyl and 1-cyclohexenyl ketones, respectively. Under more severe conditions (110°C), the reaction is accompanied by cyclization with formation of 3-aryl-1-cyclohexyl(or 1-cyclohexenyl)benzo[f]quinolines. Proper choice of the amount of catalyst, temperature, and reaction time allows isolation of intermediate 3-aryl-1-cyclohexyl(or 1-cyclohexenyl)-3,4-dihydrobenzo[f]quinolines.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1878–1883.Original Russian Text Copyright © 2004 by Grachek.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and structures of benzo[<Emphasis Type="Italic">cd</Emphasis>]furo[2,3-<Emphasis Type="Italic">f</Emphasis>]indol-4(5<Emphasis Type="Italic">H</Emphasis>)-one derivatives

A procedure was developed for the synthesis of derivatives of the new heterocyclic system, benzo[cd]furo[2,3-f]indole, based on the cyclodehydration of 6-acylmethyloxy-1-alkyl-benzo[cd]indol-2(1H)-ones. Either 7- or 8-aryl derivatives of benzo[cd]furo[2,3-f]indol-4(5H)-ones can be prepared depending on the reaction conditions. The molecular and crystal structures of 7- and 8-phenylbenzo[cd]furo[2,3-f]indol-4(5H)-ones were established by X-ray diffraction.     

Synthesis of 1,3-diazapyrenes from benzo[<Emphasis Type="Italic">f</Emphasis>]quinazolines

Methods have been developed for the synthesis of 1,3-diazapyrenes based on the reactions of 1-methylbenzo[f]quinazolines with DMF dimethyl acetal or with 1,3,5-triazine in PPA. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 2, pp. 260–262, February, 2009.