Fused pyridine derivativesFused pyridine derivatives R 0450 A Facile Synthesis of 4-Aryl-1H-pyrazolo[3,4-b]quinolines -[based on thermal or microwave-induced three-component coupling of aromatic amines, dihydropyrazoles and aromatic aldehydes]. -(CHACZATRIAN, K.; CHACZATRIAN, G.; DANEL, A.; TOMASIK*, P.; Pol.

No abstract

New Pyrazoloquinolin€ s and their application in or8anic light-emitting diodes with po1y(N-vinylcarbazole) matńx sumnaty Tlrele \'olo śynrhcsizcd sn ncw Pylab]ogulnolilrc deńvaiivs (PAQ) dosdib '!ith a lońula (l), i]r which the neanings of & subsituent oc/,rrr, .crrr,-H, .ocHr,-cl. The n dhraĆfur'ed. among othcE, o| ih" b""i".f,H NMR"p-h ńd "l.*.t^l analyss .cs!]b' Mirhlr6 of ihesc PAQ d€ rivativ* $'jth poly(N vińylc'rbizol.) vcrc iPplicd jn ihe otgłli.li8hr emitrińs djodcs (LED)' sPecE ofab. sorption' Photolunimsem. {FL) and c|.dlo|uńlnesen..(EL) of LEDS PI?. parcd were Pte*trhd' Il ]i3s beń fould that the lyPe of Ę subshtueni n]n! cn.ś PL łnd ELqMntum yields Ke]' {ords: pyn2ljloguinolnr. dcrivłlivc' PoIy(N vinylcalbazo]e), otg.nn ts! "r, Td.J..Pho,oL,r cithcr eI.dro|-donilin3 or elechon-łc.cPlin3 side groups. Thc cl.ctoopti.al propcrtics oI PAQ .hiomo phoros rvsc icsbd in the brcDds wiih poly-N vinykar bazol.olVK) matii This nrbix k tłnspal.nr rh. Eoodfilmfomijr! ahility rnd hi8h lhsmal śability good holcs .oMuctor but on ih. Óthlr band its own bIU.

Aromatic aldehydes have been reported to react with 5-anilinopyrazoles in the presence of ZnCl 2 to give the corresponding benzylidenopyrazoles. In this paper evidence is given that the corresponding products are, in fact, 1H-pyrazolo [3,4-b]quinolines. This observation opens a novel route to these compounds. They show a blue emission in the solid state and, therefore, they are useful blue luminophores for electroluminescent devices. The synthetic procedure reported in the literature was significantly modified and improved by application of microwave heating. In our modified synthesis the reaction time was reduced from the usual 5 to 8 h to 5 to 7 min and the reaction products were formed without contamination.

In the reaction of anilines with 4-(benzylidene)-1,3-disubstituted pyrazol-5-ones, 1H-pyrazolo [3,4-b]quinolines were formed instead of anticipated 5-phenylimino derivatives. The same compounds were also available from the reaction of pyrazolin-5-ones with Schiff bases. In spite of moderate yields both methods present a facile route to 4-aryl-1H-pyrazolo [3,4-b]quinolines. These methods have advantages over the Friedländer cyclization commonly utilized for preparation of 4-aryl-1H-pyrazolo [3,4-b]quinolines. Thus, preparation of 2-aminobenzophenones, reagents indispensable in Friedlaender synthesis, can be avoided.