4-Aminopyrimidine-5-carboxaldehyde

Several routes to benzo[h]quinolines utilise other heterocyclic systems as the precursor. The fused pyrimidopyridine (66), obtained from 4-aminopyrimidine-5-carboxaldehyde and 1-tetralone, is readily l drolysed to 2-aminohenzo[h]quinoline-3-carboxaldehyde (67) (T. 

Some diazinodiazincs undergo a spontaneous addition of water or protic solvents,2,115-13covalent hydration.149 As could be shown by 2H NMR studies, hydrated monocations are formed under acidic conditions, followed by hydrolytic ring opening to furnish 4-aminopyrimidine-5-carboxaldehydes l.115... 

Aminopyrimidine-5-carboxaldehyde 284 with aromatic ketomethy-lenes provides 7- and 6,7-disubstituted pyrido[2,3-d]pyrimidines 285. Facile ring opening of the pyrimidine moiety of this heterocyclic system gives substituted 2-aminonicotinaldehydes 286 (Scheme 62) (75J(3C1438). 

In the another attempt, 1,8-naphthyridines 377 were prepared via 4-aminopyrimidine-5-carboxaldehyde (Figure 17) and used as receptors in complexation studies with several guanidinium and ammonium guests, including derivatives of the amino acids arginine and lysine (02JA14092). 

Aminopyrimidine-5-carboxaldehyde 421 (67CB3664) and 1,3-cyclo-hexanedione react in a 1 2 molar ratio to form 422 in quantitative yield. 

Thummel et al. have used 4-aminopyrimidine-5-carboxaldehyde 421 as a useful synthon for the stereochemically controlled introduction of the polycondensed 1,8-naphthyridines 440 (88JA7894) (Scheme 95) (86IC1675). 

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