Formamide → HCID 70926266, compound

Participants

Reaction Conditions

Reaction Steps

1,1,2,3,3-Pentamethyl-2,3,6,7-tetrahydro-1H-indene-4,5-dione is first prepared with 1,1,2,3,3-pentamethyl-1,2,3,5,6,7-hexahydro-inden-4-one (Cashmeran®) (commercially available at IFF) via oxidation with (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) (prepared as described by Barton in Tetrahedron Letters, 1984, 25(6), pages: 603-606). A 100 mL reaction flask is charged with 1,1,2,3,3-pentamethyl-2,3,6,7-tetrahydro-1H-indene-4,5-dione (10 g, 0.04 mol) and formamide (NH2CHO) (50 mL). The reaction mixture is heated to 200° C. and stirred for 24 hours. The crude mass is diluted with toluene (50 mL) and then washed once with aqueous sodium carbonate (10%, 100 mL) followed by twice with brine (30 mL). Toluene is recovered by roto-evaporation. The crude product is further purified with liquid chromatography (Biotage® system) and then crystallized. Product of a mixture of 6,6,7,8,8-pentamethyl-5,6,7,8-tetrahydro-4H-1-oxa-3-aza-as-indacene and 6,6,7,8,8-pentamethyl-5,6,7,8-tetrahydro-4H-indeno[4,5-d]oxazole (˜10 g) is obtained.

Provenance & Evidence