Reaction #1960507

Reaction equation

7-ethoxy-1,2-difluoro-3-[1-(4-propylcyclohexyl)prop-2-ynyloxy]naphthalene

→

8-ethoxy-5,6-difluoro-3-(4-propylcyclohexyl)-3H-benzo[f]chromene

Solvents

N,N-diethylaniline

MTBE

Conditions

Workup

1. 1
   Washwashed a number of times with hydrochloric acid
2. 2
   OtherThe organic phase is dried
3. 3
   Otherevaporated to dryness
4. 4
   OtherThe residue is purified by column chromatography (SiO2, n-heptane:MTBE=4:1)
5. 5
   OtherThe further purification
6. 6
   Otheris carried out by recrystallisation from n-heptane

Procedure

7.75 g (about 18.6 mmol) of 7-ethoxy-1,2-difluoro-3-[1-(4-propylcyclohexyl)prop-2-ynyloxy]naphthalene are heated at 205° C. for 4.5 h in 80 ml of N,N-diethylaniline. The batch is diluted with MTBE and washed a number of times with hydrochloric acid. The organic phase is dried using sodium sulfate and evaporated to dryness. The residue is purified by column chromatography (SiO2, n-heptane:MTBE=4:1). The further purification is carried out by recrystallisation from n-heptane, giving 8-ethoxy-5,6-difluoro-3-(4-propylcyclohexyl)-3H-benzo[f]chromene as a yellow solid.

Source