Synthesis of substituted dihydrobenzo[f]pyrimido[4,5-b]-quinolines as tetracyclic 5-deaza nonclassical folates

Cyclocondensation of 2,4,6-triaminopyrimidine ( 10 ) with chlorovinyl aldehyde 7 afforded the linear regioisomer 9,1 1-diamino-5,6-dihydrobenzof]pyrimido4,5-c]quinoline ( 1 ) while the cyclocondensation of 2,6-diamino-4-hydroxypyrimidine ( 11 ) or 6-amino-2,4-dihydroxypyrimidine ( 12 ) with chlorovinyl aldehyde 7 was regiospecific affording the linear regioisomers 9-amino-11-oxo-5,6-dihydrobenzof]pyrimido4,5-c]quinoline ( 2 ) and 9,11-dioxo-5,6-dihydrobenzof]pyrimido4,5-c]quinoline ( 3 ) respectively. The linear structures of these compounds were established by ¹H nmr and ¹³C nmr spectral data.