Reaction #51617

Reaction equation

HCl

cyclohexanone

borane

NaOH

pyridine

3-amino-6,7-dimethoxy-quinoline hydrochloride

NaOMe

→

light-yellow solid

Yield 57.0%

3-Aminocyclohexyl-6,7-dimethoxy-quinoline

Yield 57.0%

Solvents

MeOH

Conditions

Workup

1. 1
   workup.STIRRINGThe mixture is stirred for 4.5 h
2. 2
   workup.STIRRINGThe reaction mixture is stirred 45 min.
3. 3
   OtherThe mix is partitioned between EtOAC and H2O
4. 4
   Washthe aqueous layer is washed with EtOAc (2×)
5. 5
   WashThe combined organic layers are washed with brine, (1×),
6. 6
   Dryingdried (MgSO4)
7. 7
   Otherchromatographed (50% EtOAc/hexanes)
8. 8
   Otherrecrystallized from EtOAc/hexanes

Procedure

To a MeOH (3 mL) solution of 4 Å powdered molecular sieves (0.11 g) under argon is added 3-amino-6,7-dimethoxy-quinoline hydrochloride (0.17 g, 0.68 mmol) and NaOMe (0.039 g, 0.71 mmol). The reaction mixture is stirred at room temperature for 30 min., and cyclohexanone (0.074 mL, 0.71 mmol), then pyridine.borane (0.072 mL, 0.071 mmol) are added portionwise. The mixture is stirred for 4.5 h, then 5N HCl (1.4 mL, 6.8 mmol) is added portionwise. The reaction mixture is stirred 45 min., then made strongly basic with 5N NaOH. The mix is partitioned between EtOAC and H2O, and the aqueous layer is washed with EtOAc (2×). The combined organic layers are washed with brine, (1×), dried (MgSO4), chromatographed (50% EtOAc/hexanes), and recrystallized from EtOAc/hexanes to obtain 0.112 g light-yellow solid in 57% yield (m.p. 164-165). Anal. calcd for C17H22N2O2: C, 71.30; H, 7.74; N, 9.78. Found: C, 71.45; H, 7.49; N, 9.80.

Source