tetrahydroquinazoline-6-carboxaldehyde (26) by reductive amination with the appropriate amine. Compound 26 was obtained via a Diels-Alder reaction of 2-(trimethylsiloxy)-1, 3- butadiene with acrolein to afford cyclohexanone-4-carboxaldehyde dimethyl acetal (23) after deprotection of the silyloxy group and protection of the aldehyde in a single step. Cyclocondensation of 23 with dicyandiamide followed by protection of the 2, 4-diamino ...
