Phenanthridines, amino-, reactions

Phenanthridine is known to undergo direct amination readily with hydride extrusion (the Chichibabin reaction) and further examples have been reported.22 More interesting is the preparation of 6-aminophenanthridine in high yield by the action of the sodium salt of N,N-dimethylhydrazine on phenanthridine in benzene. The adduct (224) (R = Me) loses dimethylamine on heating leaving the sodium salt of the 6-amino compound (225).318... 

Pictet-Hubert reaction. Phenanthridine cychzation by dehydrative ring closure of acyl-o-amino-biphenyls on heating with zinc chloride at 250-300C or with phosphorus oxychloride in boiling nitrobenzene. 

The reaction between o-bromoaniline and 2-formylbenzeneboronic acid by the coupling procedure provides a new method for the preparation of phenanthridine. Applied to 2-amino-3-bromopyridines aza analogs are formed, as exemplified by the benzo[c][l,8]naphthyridine (232). Isomeric o-formylthiopheneboronic acids yield the corresponding thienylpyridines,... 

Perhaps the most efficient method for the preparation of the Af-amino-azonium salts is that using MSH.23 This rather new procedure has been shown to have many advantages over the other known methods (i) the procedure is very simple, (if) the reaction conditions are extremely mild, (iff) the scope is wide (i.e., it appears to parallel closely that of iV-oxidation by peracids24), and (iv) the yields are generally high. Recent applications of MSH (after 1976 for earlier applications, see Ref. 23) include pyridines,25-28 quinolines,29-31 naphthyridines,32 fused pyridines,32 phenanthridines,33,34... 

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