Reaction #1829

Reaction equation

1-tetralone oxime

methanesulfonic acid

phosphorus pentoxide

sodium hydroxide

methanesulfonic acid

→

product

Yield 95.0%

2,3,4,5-Tetrahydro-1H-1-benzazepin-2-one

Yield 95.0%

Solvents

Conditions

Workup

1. 1
   Temperaturea temperature probe, nitrogen inlet and reflux condenser
2. 2
   Washto wash all the phosphorus pentoxide into the vessel
3. 3
   Temperaturethen cooled to 50° C.
4. 4
   TemperatureThe mixture was heated at 63° C. for 10 minutes
5. 5
   Temperaturethen slowly heated to 80° C.
6. 6
   Temperatureto maintain the temperature below 28° C
7. 7
   FiltrationThe mixture was filtered
8. 8
   Washto rinse the vessel
9. 9
   WashThe wet cake (pink) was washed with 8 L of water
10. 10
    Othersuction dried for 45 minutes
11. 11
    Otherdried under vacuum at 40° C. for 2 days

Procedure

To 10 L of methanesulfonic acid in a 22 L 3-neck flask equipped with an overhead stirrer, a temperature probe, nitrogen inlet and reflux condenser was added 2.6 Kg (18.61 mol) of phosphorus pentoxide. An additional 1.6 L of methanesulfonic acid was used to wash all the phosphorus pentoxide into the vessel. The mixture was heated at 90° C. for 2.5 hours then cooled to 50° C. using an ice bath and treated with 2.00 Kg (12.41 mol) of 1-tetralone oxime in several portions over 15 minutes. The mixture was heated at 63° C. for 10 minutes then slowly heated to 80° C. and kept at 80° C. for 3 hours, The reaction mixture was pumped into 70 L of ice then treated slowly with 11.25 L of 50% aqueous sodium hydroxide over 90 minutes at such a rate so as to maintain the temperature below 28° C. The mixture was filtered and 4 L of the filtrate was used to rinse the vessel. The wet cake (pink) was washed with 8 L of water then suction dried for 45 minutes then transferred to two trays and dried under vacuum at 40° C. for 2 days to give 1.9 Kg (11.79 mol, 95%) of product. 1H NMR (250 MHz,CDCl3): 2.24 (m,2H), 2.38 (t,6 Hz,2H), 2.82 (t,6 Hz,2H), 7.03 (d,8 Hz,1H), 7.13 (m,1H), 7.24 (m,2H), 8.63 (br s,1H).

Source