Nitrophenyl-group-containing Heterocycles. Part I. Synthesis, Characterization, Anticancer Activity and Antioxidant Properties of Some New 5,6,7,8-tetrahydro-isoquinolines Bearing 3(4)-nitrophenyl Group

Regioselective cyclocondensation of 2,4-diacetyl-5-hydroxy-5-methyl-3-(3-nitrophenyl/4-nitrophenyl)cyclohexanones 1a,b with cyanothioacetamide afforded the corresponiing 7-acetyl-4-cyano-1,6-dimethyl-6-hydroxy-8-(3-nitrophenyl/4-nitrophenyl)-5,6,7,8-tetrahydro-soquinoline-3(2H)-thiones 2a,b in 93-96% yield. Reaction of compounds 2a,b with some ethyl iodide, 2-chloroacetamide (4a) or its N-aryl derivatives 4b-e by refluxing in ethanol, in the presence of slightly excess molar amounts of sodium acetate trihydrate, for one hour gave 3-ethylthio-5,6,7,8-tetrahydro-isoquinoline 3 and (5,6,7,8-tetrahydroisoquinolin-3-ylthio)acetamides 5a-i, respectively. On heating compounds 5b-d,f,g in ethanol containing a catalytic amount of sodium carbonate, they converted into their isomeric 1-amino- 6,7,8,9-tetrahydrothieno[2,3-c]isoquinoline-2-carboxamides 6b-d,f,g. Structural formulae of all synthesized compounds were characterized on the basis of their elemental analyses and spectroscopic data. Also, the biological evaluation of the synthesized isoquinolines as anticancer and antioxidant agents have been carried out and the obtained results are reported herein.