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Preparation and Properties of, Isoquinoline, , Isoquinoline, , * Isoquinoline consists of a benzene ring, , fused to the B- and Y-positions of a pyridine, ring. S, * Occurs in coal-tar and bone oil, * Isoquinoline is also found as part of the Zz N, , total structure of a number of alkaloids e.g.,, papaverine and morphine., , * Isoquinoline is one of the very few, heterocyclic compounds in which, numbering of the ring atoms does, , 5 4, not start on the hetero atom. 6 Ca 3, 7 ZN,, , 8 1, , Preparation Methods, , (1) From Cinnamaldehyde: This involves condensation of cinnamaldehyde, with hydroxylamine to form the corresponding oxime. The oxime is then, heated with phosphorus pentoxide to yield Isoquinoline. It is believed, that the oxime first undergoes rearrangement which is then followed by, ring closure., , , , CINNAMAL DEH YDE HYDROXYL ~ CINNAMAL DOXIME SH, AMINE, , (UNSTABLE ), 208, — °, H20 .