Yield: 93%

Reaction Conditions:

with ammonium hydroxide in water at 110; for 16 h;sealed tube;

Steps:

54.1
Example 54; Step 1; A suspension of 1 (3 g, 11.64 mmol) in 25% aq. NH₄OH (15 mL) in sealed tube was heated at 110° C. for 16 h. After completion of reaction (reaction progress was monitored by TLC), the reaction mixture was partitioned between ethyl acetate-water (3×50 mL). The combined extracts were washed with saturated brine, dried and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel eluted with 15% ethyl acetate-hexane to afford 2 as a yellow solid (2.1 g, 93%). MS m/z (ES): 189 (M+H)⁺.

References:

de Vicente Fidalgo, Javier;Hermann, Johannes Cornelius;Lemoine, Remy;Li, Hongju;Lovey, Allen John;Sjogren, Eric Brian;Soth, Michael US2011/59118, 2011, A1 Location in patent:Page/Page column 81-82