Syntheses and transformations of azeto[2,1-a]- and -[2,1-b]isoquinolines and azeto[1 ',2 ': 1,2]pyrido[3,4-b]indoles

The syntheses, transformations and some of the biological features of azeto [2,1-a]- and -[2,1-b]isoquinolines and azeto[1',2':1,2]pyrido[3,4-b]indoles are reviewed. Both angularly and linearly fused azetidine derivatives of i soquinolines are known. As concerns the related pyridoindoles, only the ang ularly fused azeto[1',2':1,2]pyrido[3,4-b]indoles have been prepared and in vestigated. The most interesting and characteristic transformations of azet oisoquinolines and azeto[1',2':1,2]pyrido[3,4-b]indoles are the ring enlarg ement reactions; these result, for example, in eight-membered ring derivati ves which were difficult to synthesize by earlier methods. Such derivatives are versatile intermediates for the synthesis of biologically important co mpounds. Some of the azetoisoquinolin-2-ones synthesized and tested to date display weak antibiotic activity. Several other azetoisoquinolines exhibit a wide range of pharmacological activities.