2-Dimethylaminopyridine → N-(2-amino-5-iodobenzoyl)-beta-alanine benzyl ester

Participants

Reaction Steps

a magnetically stirred solution of 5 grams of 5-iodoisatoic anhydride (0.0173 mol), 5.85 grams of β-alanine benzyl ester tosylate (0.0173 mol), 35 mL pyridine, and 0.5 of dimethylaminopyridine (0.0041 mol) was heated to 80° C. for 2 hrs. The reaction mixture was allowed to cool to room temperature and concentrated in vacuo. The resulting residue was dissolved in 100 mL ethyl acetate and washed 2×50 mL of 10% cupric sulfate, 1×50 mL sat. sodium bicarbonate, 1×50 mL brine, dried over sodium sulfate, filtered and concentrated in vacuo. The product was further purified by column chromatography, using silica gel, eluting with a 1:1 mixture of ethyl acetate and hexane (TLC, SiO2, 1:1 EtOAc/hexane, Rf =0.65, υν positive) to yield 1.85 grams (25%) of N-(2-amino-5-iodobenzoyl)-β-alanine benzyl ester. 1H NMR (CDCl3, δTMS) 7.54 (1H, d, 4JHH =2 Hz, Ar--H, o-CON), 7.42 (1H, dd, 3JHH =9 Hz, 4JHH =2 Hz, Ar--H p-CON), 7.38-7.32 (5H, s, ArH Ph), 6.65 (1H, bt, 3JHH =6 Hz, CONH), 6.46 (1H, d, 3JHH =9 Hz, Ar--H m-CON), 5.16 (2H, s, OCH2), 3.68 (2H, q, 3JHH 6 Hz, NCH2), 2.69 (2H, t, 3JHH =6 Hz, CH2CO2). 13C NMR (CDCl3, δTMS) 172.4, 167.8, 148.6, 140.6, 135.6, 135.5, 128.7, 128.4, 128.3, 119.3, 118.1, 76.3, 66.7, 35.2, 34.0.

Provenance & Evidence