Synthesis of 3,3-dialkyl-1-(2-furyl)-3,4-dihydro-isoquinolines and their reaction with maleic anhydride
摘要:
The cyclocondensation of dialkylbenzylcarbinols with 2-cyanofuran in the presence of H2SO4 gave 3,3-dialkyl-1-(2-furyl)-3,4-dihydroisoquinolines. Analogously, naphthalene derivatives form 4-(2-furyl)benzo[f]isoquinolines. The Diels-Alder reaction of 2,2-dimethyl-4-(2-furyl)-1,2-dihydrobenzo[f]iso-quinoline with maleic anhydride proceeds at N(1) and C(4) of the isoquinoline system to give exo-19,19-dimethyl-1-(2-furyl)-15-oxa-18-azapentacyclo[10.5.2.0(2,11).O-4,O-9.O-13,O-17]nonadeca-2,4,6,8,10-pentaene-14,16-dione. The structure of this dione product was proven by X-ray structural analysis.