Isoquinoline, 1 -amino-4-nitro-, reaction with

Reactions of 6-chloro-8-nitro-3,4-dihydro-2//-pyrimido[2,l-a]isoquinolin (153) with cyclic amines at 90°C yielded the 6-amino derivatives (154) (67IJC403). Reactions at higher temperature gave 6-hydroxy derivative 155. 

A solution of N-(2-aminobenzyl)-l-phenyl-2-methylaminoethanol-l was prepared by the reaction of a-bromo-acetophenone and (2-nitrobenzyl)methylamine, followed by hydrogenation of the nitro group by means of nickel on diatomaceous earth at room temperature and reduction of the CO group by means of sodium borohydride. The intermediate thus produced was dissolved in 100 ml of methylene chloride and introduced dropwise into 125 ml of sulfuric acid at 10° to 15°C. After a short standing, the reaction mixture was poured onto ice and rendered alkaline by means of a sodium hydroxide solution. By extraction with ether, there was obtained l,2,3,4-tetrahydro-2-methyl-4-phenyl-8-amino-isoquinoline. The base is reacted with maleic acid to give the maleate melting point of the maleate 199° to 201°C (from ethanol). 

The nitro-enamine (304), formed in the one-pot condensation of 2-amino-pyridine with triethyl orthoformate and ethyl nitroacetate, cyclizes in poly-pnosphoric acid to the 4//-pyrido[l,2-a]pyrimidinone (305 R = N02, R = H) 256 bicyclic system is also obtainable by the action of trichloroacetic anhydride in boiling toluene on 2-benzylideneaminopyridine, as illustrated in Scheme 71, Analogous reactions also occur with 2-arylideneamino-quinolines and -isoquinolines. 

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