Formaldehyde → 5,6,7,8-Tetrahydroisoquinoline 2-oxide

Participants

Reaction Conditions

Reaction Steps

5,6,7,8-Tetrahydroisoquinoline (13.3 g, 100 mmole) is dissolved in 35 ml glacial acetic acid in a 200 ml one neck round bottom flask. The solution is warmed to 95-100° C. and is treated dropwise with 30% hydrogen peroxide (28 ml). The reaction is stirred at 95-100° C. for 6h, is treated portionwise with paraformaldehyde until negative to starch iodide paper, and the volatiles are removed in vacuo. The residue is azeotroped with 2×100 ml toluene and the crude material is chromatographed over 500 g silica gel (230-400 mesh), eluting with 4 l 6% methanol/dichloromethane followed by 1 l 10% methanol/dichloromethane while collecting 50 ml fractions. Fractions 39-82 are combined and concentrated to afford 12.8 g (86%) of 5,6,7,8-tetrahydroisoquinoline-N-oxide.

Provenance & Evidence