反应详情

To a suspension of the title B compound in Example 9, 2-(2,4-dimethoxy-benzyl)-1,1-dioxo-1,2,5-thiadiazolidin-3-one (13.87 g, 48.4 mmol) and 4-bromomethylbenzoic acid (10.42 g, 48.4 mmol) in CH2Cl2 (150 mL) is added DBU (14.5 mL, 96.9 mmol) at once and the mixture is stirred at RT overnight. The reaction mixture is washed two times with 1N aqueous HCl, one time with brine, then dried over anhydrous MgSO4 and concentrated to a small volume to crystallize the product. The solid is collected by filtration, washed with ethyl ether and dried under high vacuum to afford 4-[5-(2,4-dimethoxy-benzyl)-1,1,4-trioxo-1,2,5-thiadiazolidin-2-ylmethyl]-benzoic acid: mp=175-177° C.; [M−1]−=419.

1. washThe reaction mixture is washed two times with 1N aqueous HCl, one time with brine
2. dry with materialdried over anhydrous MgSO4
3. concentrationconcentrated to a small volume
4. customto crystallize the product
5. filtrationThe solid is collected by filtration
6. washwashed with ethyl ether
7. customdried under high vacuum