3-(Chloromethyl)pyridine hydrochloride → 6-ethyl-4-(3-pyridylmethyl)-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione-1-oxide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

0.48 g (60 mmol) of lithium hydride is added in portions to a solution of 5.0 g (25 mmol) of 6-ethyl-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione-1-oxide in 250 ml of DMF. The mixture is heated at 60° C. for 15 minutes, then 4.9 g (30 mmol) of 3-picolyl chloride hydrochloride are added and the mixture is heated at 80° C. for 3 hours. It is then largely concentrated, the residue is taken up with ethyl acetate and the mixture is extracted with 10% strength hydrochloric acid. The aqueous extract is neutralised and extracted with ethyl acetate. Relatively readily volatile impurities are removed by distillation in vacuo at 100° C./0.5 mm Hg and the residue is chromatographed. 1.4 g (20%) of 6-ethyl-4-(3-pyridylmethyl)-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione-1-oxide are obtained as a highly viscous oil.

Herkunft & Nachweise