Methanol, 1,1-diethoxy-, 1-acetate → 8-[Ethoxymethylidene]-6H-[1,3]thiazolo[5,4-e]indol-7-one

Participants

Reaction Steps

To a 250-ml round bottom flask was added a stir bar, 6,8-dihydro-l-thia-3,6-diaza-as-indacen-7-one (Procedure B, 4.0 g, 0.021 mol), 40 mL of glacial acetic and diethoxymethyl acetate (17.0 g, 0.105 moles). The flask was fitted with a reflux condensor and charged with nitrogen. The reaction was heated to reflux for 8 hours. The flask was cooled, the stir bar was removed and the reaction was concentrated to a wet solid. The solid was triturated with a solution of ether and ethanol. The mixture was filtered, the solid was washed with an ethanol—ether solution, and the solid was dried under vacuum to yield 8-ethoxymethylene-6,8-dihydro- 1-thia-3,6-diaza-as-indacen-7-one: 1H NMR (DMSO-d6): δ10.5 (s, 1H), 9.1 (s, 1H), 7.8 (d, 1H), 7.7 (s, 1H), 7.0 (d, 1H) (q, 2H), 1.4 (t, 3H); APCI−MS m/z 245 (M−H)−.

Provenance & Evidence