Studies in the triazanaphthalene and triazaphenanthrene series.
2015-11-19T08:48:23Z (GMT) by
The original work described in this thesis consists of attempts to extend the Widman-Stoermer and Borsche cinnoline syntheses to the preparation of a number of derivatives of the hitherto unreported 1,2,5- and 1,2,7-triazanaphthalenes, (I) and (II), and 1,2,9- and 3,4, 8-triazaphehanthrenes, (III) and (IV). The application of the Widman-Stoermer reaction to the preparation of the 4-nethyltriazanaphthalenes (I) and (II; R1=R2=H; R1=R2=CH3; R1=CH3,R3=C6H5) met with only limited success, probably due to the inhibiting effect of heterocyclic nuclei on the reaction. However, a synthetic route to 4-methyl-l,2,7-triazanaphthalene was developed, and in this case the reactivity of the methyl group was established. Attempts were made to extend the Borsche reaction to the ring closure of diazotised 2-acetyl-3-aminopyridine, 4-acetyl-3-aminopyridine and 3-acetyl-2-amlnopyridine but in no case was a product resulting from cyclisation obtained. The preparation of the triazaphenanthrenes, (III) and (IV) was more successful. The 1,2,9-triazaphenanthrenes (III; R1=CH3,R2=H; R1=C6H5,R3=H; R1C6H5,R2=CH3) were all obtained. The beneficial effect of aryl nuclei on the reaction was illustrated by the excellent yield of the 4-phenyl compound. l-Methyl-3,4,8-triazaphenanthrene (IV) was also prepared in fair overall yield. A modified Borsche reaction in alkali gave 4-hydroxy- 3-methyl-10-phenyl-1,2,9-trisiazaphenanthrene (III; R1=OH, R2=CH3) in good yield. The 4-hydroxy compound was converted via the 4-chloro compound (III; R1=C1,R2=CH3) to the amino compound (III; R1=NH2,R2=CH3).