Nitrogen → 4-Methyl-3-[3-(2,3,4-trihydroxy-phenyl)-acryloylamino]-benzoic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

(The following reaction is done in an anhydrous N2 atmosphere.) Dissolve anilide (53) (40 mg, 0.10 mmol) in anhydrous DCM (1.3 mL) at −78° C., add dropwise a 1M solution of BBr3 in DCM (830 μL, 0.83 mmol) and stir for additional 30 min at −78° C. After slowly warming up stir the reaction solution for additional 4 h at rt. Cool reaction mixture to 0° C., add dropwise water and DCM under vigorous stirring followed by MeOH to homogenize the mixture. Partition the hydrolized reaction mixture between water and EtOAc, extract the aqu. layer with EtOAc (3×), wash combined organic layer with brine and dry it with Na2SO4. Purify the crude product by preparative RP HPLC (gradient, water/CH3CN 95:5 to 5:95) to obtain 4-Methyl-3-[3-(2,3,4-trihydroxy-phenyl)-acryloylamino]-benzoic acid (54) (6.5 mg, 19%) as an yellowish solid and 4-Methyl-3-[3-(2,3,4-trihydroxy-phenyl)-acryloylamino]-benzoic acid methyl ester (55) (9 mg, 25%) as an yellowish solid. 1H NMR (400 MHz, CD3OD) (54): 2.40 (s, 3H); 6.43 (d, 1H, J=8.6 Hz); 6.90 (d, 1H, J=15.6 Hz); 6.97 (d, 1H, J=8.6 Hz); 7.40 (d, 1H, J=8.1 Hz); 7.83 (dd, 1H, J1=8.1 Hz, J2=1.5 Hz); 7.93 (d, 1H, J=15.6 Hz); 8.17 (br.s, 1H); (55): 2.40 (s, 3H); 3.93 (s, 3H); 6.43 (d, 1H, J=8.6 Hz); 6.90 (d, 1H, J=15.7 Hz); 6.97 (d, 1H, J=8.6 Hz); 7.40 (d, 1H, J=8.1 Hz); 7.82 (dd, 1H, J1=7.8 Hz, J2=1.7 Hz); 7.93 (d, 1H, J=15.9 Hz); 8.18 (br.s, 1H).

Herkunft & Nachweise