Hexamethylenetetramine → 2-Naphthalenecarboxaldehyde, 5,6,7,8-tetrahydro-1-methoxy-3,5,5,8,8-pentamethyl-

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Reaction Steps

1-Methoxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene (50 g, 0.2155 mol) was added to a stirred mixture of hexamethylenetetramine (31.4 g, 0.224 mol) and trifluoroacetic acid (250 mL) at 35°-40° C., under a nitrogen atmosphere. The stirred reaction mixture was heated to 85°-90° C. and maintained at this temperature for 1.5 h. Trifluoroacetic acid was removed by distillation and the residue was poured onto an ice-water mixture (800 mL). The mixture was then stirred for 0.5 h, neutralized with a 10% sodium carbonate solution and the product extracted with benzene (2×150 mL). The combined extracts were washed with brine (50 mL) and dried (Na2SO4). The solvent was then removed by distillation and the residue crystallized from hexane to provide 1-methoxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene-2-carboxaldehyde (14 g), mp 78° C., GLC purity 100%, exhibiting the expected spectral data.

Provenance & Evidence