Propanedioic acid, monoethyl ester → 2-hydroxy-7,7-dimethyl-1H,4H,6H,7H,8H-[1,3]diazino[1,2-a]pyrimidin-4-one

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Reaction Conditions

Reaction Steps

1.4 g of sodium are added in a fractionated way to 15 mL of MeOH. After total dissolution, 2.7 g of 5,5-dimethyl-1,4,5,6-tetrahydropyrimidin-2-amine solubilized beforehand in 5 mL of MeOH, and then 16.5 mL of ethyl malonate are added. The mixture is heated to 100° C., after 4 h of heating, the medium is dry concentrated. The obtained oil is taken up in ether. The precipitate is filtered and then the residue is taken up in 7 mL of H2O and acidified with conc. HCl up to pH 3-4. The precipitate formed is filtered, washed with ether and dried in the oven in vacuo. 2 g (yield=72%) of 2-hydroxy-7,7-dimethyl-6,7,8,9-tetrahydro-4H-pyrimido[1,2-a]pyrimidin-4-one are obtained as a beige solid used as such.

Provenance & Evidence