2-propan-2-yl-4,7-dihydro-1,3-dioxepine

Conditions: temp:180.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 12.6 g (60 millimoles) of 2-benzyl-4-methyl-5-ethoxy-oxazole and 42.6 g (300 millimoles) of 2-isopropyl-4,7-dihydro-1,3-dioxepine is heated for 5 hours at 180° C. On cooling the mixture in an ice bath, 4.2 g of 3-isopropyl-6-benzyl-8-methyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridin-9-ol crystallize out. A further 2.0 are obtained by evaporating the mother liquor, partitioning the residue between methylene chloride and dilute sodium hydroxide solution and neutralizing the alkaline phase. Recrystallization from ethyl acetate gives a pure product, of melting point 193°-194° C. On cooling the mixture in an ice bath 4.2 g of 3-isopropyl-6-benzyl-8-methyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridin-9-ol crystallize out A further 2.0 are obtained by evaporating the mother liquor partitioning the residue between methylene chloride and dilute sodium hydroxide solution Recrystallization from ethyl acetate gives a pure product