Methyl 2-(3-((benzylamino)methyl)-6-nitro-2,3-dihydrobenzo[b][1,4]dioxin-5-yl)acetate → 2-((Benzylamino)methyl)-2,3-dihydro-7H-[1,4]dioxino[2,3-e]indol-8(9H)-one

Participants

Reaction Conditions

Reaction Steps

The methyl ester from Example 5 (43 mg) was dissolved in 1:1 ethyl acetate/ethanol (10 mL) and filtered through a syringe filter to remove insoluble material. Platinum oxide (35 weight percent) was added and the mixture placed under 50 psi of hydrogen gas on a Parr shaker overnight. TLC analysis with 95:5 CH2Cl2/MeOH showed consumption of starting material with a more polar product having been formed. The mixture was filtered through a 0.5 μm syringe filter, washing with 1:1 EtOAc/EtOH, and the filtrate concentrated under reduced pressure to a pale red-brown glass. The crude material was redissolved in ethanol (20 mL) and 20 μL of concentrated HCl were added. The solution was warmed to 70° C. and allowed to stir overnight. TLC of the reaction mixture (96:4 CH2Cl2/MeOH) showed the formation of a new product with no remaining starting material. The reaction mixture was cooled to ambient temperature and concentrated under reduced pressure to a light orange film. This was chromatographed over silica gel eluting with 96:4 CH2Cl2/MeOH. The title product was isolated in 22% yield.

Provenance & Evidence