Reaction #1001883

Reaction equation

phenylenediamine

3,3-diethoxyacrylic acid ethyl ester

→

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

Yield 56.5%

Solvents

acetic acid

—

xylenes

—

xylenes

Conditions

Workup

1. 1
   Temperaturewas cooled to room temperature
2. 2
   FiltrationThe resulting white precipitate was filtered
3. 3
   Washwas washed with ether (100 mL)
4. 4
   Otherwas dried under vacuum

Procedure

To a solution phenylenediamine (17.2 g, 159.2 mmol) and acetic acid (0.4 mL) in xylenes (225 mL) at 140° C. was added 3,3-diethoxyacrylic acid ethyl ester (30.0 g, 159.2 mmol) in xylenes (80 mL) dropwise over 50 minutes. The reaction was heated at 140° C. for 2 hours, was cooled to room temperature, and was stirred for 24 h. The resulting white precipitate was filtered, was washed with ether (100 mL), and was dried under vacuum to provide 18.37 g of 4-ethoxy-1,3-dihydro-benzo[b][1,4]diazepin-2-one as a white fluffy solid. MS 205 (M+1).

Source