Reaction #987306

Reaction equation

1,2-diamino-4,5-difluorobenzene

3,3-diethoxyacrylic acid ethyl ester

→

4-ethoxy-7,8-difluoro-1,3-dihydro-benzo[b][1,4]diazepin-2-one

Yield 80.7%

Solvents

acetic acid

—

xylenes

—

xylenes

Conditions

Workup

1. 1
   Temperaturewas cooled to room temperature
2. 2
   Concentrationwas concentrated
3. 3
   OtherThe residue was triturated in hexanes

Procedure

To a solution of 1,2-diamino-4,5-difluorobenzene (4.0 g, 27.75 mmol) in xylenes (50 mL) at 140° C. was added acetic acid (200 μL) followed by a solution of 3,3-diethoxyacrylic acid ethyl ester (5.22 g, 27.75 mmol) in xylenes (25 mL) over 1 hour. The reaction was heated at 140° C. for 2 hours, was cooled to room temperature, and was concentrated. The residue was triturated in hexanes to provide 5.38 g of 4-ethoxy-7,8-difluoro-1,3-dihydro-benzo[b][1,4]diazepin-2-one. 1H NMR (CDCl3) δ 7.05 (q, 1H), 6.87 (q, 1H), 4.29 (q, 2H), 3.18 (s, 2H), 1.35 (t, 3H).

Source