Reacción #345200

Ecuación de reacción

methanol

boron tribromide

9-methoxy-phenanthrenone

→

1,2,3,4,7,8-Hexahydro-9-hydroxy-5(6H)-phenanthrenone

Disolventes

methylene chloride

methylene chloride

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.WAITat +20° C. for 3 h
2. 2
   Temperaturacooled again to -78° C.
3. 3
   Otroto come to 20° C.
4. 4
   Otrois evaporated
5. 5
   OtroThe residue is partitioned between 200 ml of CH2Cl2 and 200 ml of 1N NaOH solution
6. 6
   Otrothe NaOH phase is separated
7. 7
   FiltraciónThe precipitate is filtered off
8. 8
   Otrodried in a high vacuum

Procedimiento

47.4 g (0.22 mol) of the 9-methoxy-phenanthrenone from Example 3 are dissolved in 605 ml of absolute methylene chloride and 440 ml of a 1 molar solution of boron tribromide in methylene chloride are added dropwise at -78° C. The mixture is stirred at -78° C. for 0.5 h, then at +20° C. for 3 h, cooled again to -78° C. and 620 ml of methanol is slowly added. The mixture is allowed to come to 20° C. and is evaporated. The residue is partitioned between 200 ml of CH2Cl2 and 200 ml of 1N NaOH solution, and the NaOH phase is separated and acidified to pH 1 using concentrated HCl solution with ice cooling. The precipitate is filtered off and dried in a high vacuum.

Fuente