p-Toluenesulfonic acid → 2-Bromomethyl-1,4-dioxa-7-azaspiro[4.4]nonane benzyl carbamate

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Reaction Conditions

Reaction Steps

A 1.00 g (4.56 mmol) sample of 3-pyrrolidinone benzyl carbamate, from Step 2 Example 1, was dissolved in 20 mL of toluene with 1.00 g (11.4 mmol) of 3-bromo-1,2-propanediol and 0.043 g (0.23 mmol) of p-toluenesulfonic acid and heated at 110° C. for 24 hours. The reaction solution was poured into 20% sodium bicarbonate solution and the mixture extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate and the solvent removed under vacuum to afford 1.22 g of the title compound as a dark liquid: MS M/Z 356 (M). NMR: d 2.06 (m, 2H), 3.32 (m, 1H), 3.44 (m, 2H), 3.55 (m, 3H), 3.91 (m, 1H), 4.11 (m, 1H), 4.37 (m, 1H), 5.13 (s, 2H), 7.35 (m, 5H).

Provenance & Evidence