Triethylamine → 3-oxo-1-cyclohexen-1-yl 2,3-dihydrospiro[4H-1-benzothiopyran-4,2'-[1,3]dioxolane]-6-carboxylate 1,1-dioxide

Participants

Reaction Conditions

Reaction Steps

2.0 g (7.0 mmol) of the title compound of Step E, 1.2 mL (0.014 mol) of oxalyl chloride (purchase from Janssen), and 2 drops of N,N-dimethylformamide were added to 50 mL of methylene chloride. The mixture was refluxed under nitrogen for 2 h, and was then evaporated to dryness. 50 mL of methylene chloride was added to the residue and the resulting mixture was evaporated to dryness. Another 50 mL of methylene chloride was added to the residue, and the solution was cooled to about 0° C. 0.86 g (7.7 mmol) of 1,3-cyclohexanedione (purchased from Aldrich Chemical Company) was added followed by 2.7 mL (0.0196 mol) of triethylamine, and the mixture was stirred overnight while warming to room temperature. The mixture was evaporated to dryness, the residue was stirred in 100 mL of water and filtered. The crude product was washed with hexane to yield 2.19 g of the title compound of Step F as a solid melting at 185-186° C. 1H NMR (CDCl3): δ2.2 (m,2H), 2.5 (t,2H), 2.7 (t,4H), 3.7 (m,2H), 4.2 (m,2H), 4.3 (m,2H), 6.0 (s,1H), 8.0-8.25 (3H).

Provenance & Evidence