Tetrahydrofuran → 2-Propenoic acid, 2-cyano-3-ethoxy-, ethyl ester
Reaction equation
F[C:2]1(F)[O:6][C:5]2[CH:7]=CC=CC=2[O:3]1.C([Li])CCC.C[N:18]([CH2:20][CH2:21]N(C)C)C.CCCCCC.[O:31]1[CH2:35]C[CH2:33][CH2:32]1>>[CH2:5]([O:6][C:2](=[O:3])[C:21](=[CH:35][O:31][CH2:32][CH3:33])[C:20]#[N:18])[CH3:7]Participants
Procedure
7.9 g (50 mmol) of 2,2-difluoro-1,3-benzodioxole are metallated according to Example 2 at -15° C. with 35 ml (55 mmol) of n-butyllithium (1.60M in hexane) and 6.5 g (55 mmol) of TMEDA is 60 ml of hexane. To the 2,2-difluoro-1,3-benzodioxol-4-yllithium which precipitates there is added at -20° C., over a period of 30 minutes, a solution of 9.3 g (55 mmol) of ethoxymethylenecyanoacetic acid ethyl ester in 30 ml of tetrahydrofuran, an orange-red turbid solution being formed during the reaction, which is exothermic. After stirring for 20 minutes at -15° C., the solution is hydrolysed with 50 ml of 2N hydrochloric acid. The aqueous phase is extracted twice with 80 ml of diethyl ether each time. The organic solutions are washed twice with 50 ml of water each time, dried over MgSO4 and concentrated to dryness by evaporation in a vaccum rotary evaporator. The residue is crystallised from ethanol/water 4:1, affording 10.1 g (72%) of colourless platelets of m.p. 87°-88° C.
Workup
- customTo the 2,2-difluoro-1,3-benzodioxol-4-yllithium which precipitates there
- additionis added at -20° C., over a period of 30 minutes
Sources & evidence
- ORD record
- ord-d0476fd8a77c4becb988b1adbcf3b338
- Source dataset
- uspto-grants-1994_01
- Patent number
- US05281718
Reaction notes
Loading…