Reaction #2186205

Reaction equation

piperidine

4-[(2-Fluoro-ethyl)-methyl-amino]-2-hydroxy-benzaldehyde

benzothiazol-2-yl-acetic acid methyl ester

→

desired product

Yield 48.0%

3-Benzothiazol-2-yl-7-[(2-fluoro-ethyl)-methyl-amino]-chromen-2-one

Yield 48.0%

Solvents

benzene

acetonitrile

Conditions

Workup

1. 1
   Temperatureheated
2. 2
   Temperatureto reflux for 45 minutes
3. 3
   Extractionthe crude product is extracted with AcOEt/isopropanol 9:1 and saline
4. 4
   Dryingdried over sodium sulfate
5. 5
   Otherevaporated
6. 6
   workup.DISSOLUTIONThe crude product is dissolved in 20 mL methanol
7. 7
   Concentrationslowly concentrated down to 10 mL at 50° C
8. 8
   FiltrationThe orange crystals are filtered
9. 9
   Otherdried under high vacuum

Procedure

130 mg (ca. 0.65 mmol) crude 4-[(2-Fluoro-ethyl)-methyl-amino]-2-hydroxy-benzaldehyde and 202 mg (1.5 eq.) benzothiazol-2-yl-acetic acid methyl ester are dissolved in 3 mL acetonitrile and 6 mL benzene, treated with 0.14 mL (2 eq.) piperidine and heated to reflux for 45 minutes. After cooling to room temperature, the crude product is extracted with AcOEt/isopropanol 9:1 and saline, dried over sodium sulfate and evaporated. The crude product is dissolved in 20 mL methanol, and slowly concentrated down to 10 mL at 50° C. The orange crystals are filtered and dried under high vacuum to yield 110 mg (48%) desired product.

Source