Reaction #1552067

Reaction equation

n-BuLi

H2SO4

Cyclohexanone

2-bromo-N-methyl-N-phenylaniline

→

desired compound

Yield 30.0%

10-methyl-10H-spiro[acridine-9,1′-cyclohexane]

Yield 30.0%

Solvents

THF

Conditions

Workup

1. 1
   Temperatureto warm to room temperature
2. 2
   workup.STIRRINGstirred overnight under argon
3. 3
   OtherAfter quenching with saturated ammonium chloride
4. 4
   Extractionthe reaction was extracted with Et2O
5. 5
   Washwashed with brine and water
6. 6
   Dryingdried over anhydrous MgSO4
7. 7
   Otherthe solvent evaporated under reduced pressure
8. 8
   OtherTo the neat residue thus obtained
9. 9
   workup.STIRRINGthe mixture stirred at room temperature for 1 h under argon
10. 10
    ExtractionAfter dilution with 30 mL DI H2O, the reaction was extracted with Et2O (5×50 mL)
11. 11
    Washwashed with brine and water
12. 12
    Dryingdried over anhydrous MgSO4
13. 13
    Otherthe solvent was evaporated under reduced pressure
14. 14
    OtherThe residue was purified by flash column chromatography

Procedure

A flame-dried two-necked flask was charged with 2-bromo-N-methyl-N-phenylaniline (1.0 g, 3.8 mmol) and 100 mL dry THF under argon and cooled to −78° C. in a dry ice-acetone bath. 2.6 mL of a 1.6 M solution of n-BuLi in hexanes (4.16 mmol) was added dropwise over 5 minutes and the reaction stirred at −78° C. under argon for 1 h. Cyclohexanone (0.43 mL, 0.412 g, 4.2 mmol) was added in one portion to the reaction mixture at −78° C., the reaction allowed to warm to room temperature and stirred overnight under argon. After quenching with saturated ammonium chloride, the reaction was extracted with Et2O, the organic layers combined, washed with brine and water and dried over anhydrous MgSO4 and the solvent evaporated under reduced pressure. To the neat residue thus obtained was added 2 mL of concentrated H2SO4 under argon and the mixture stirred at room temperature for 1 h under argon. After dilution with 30 mL DI H2O, the reaction was extracted with Et2O (5×50 mL), the organic layers were combined, washed with brine and water and dried over anhydrous MgSO4, and the solvent was evaporated under reduced pressure. The residue was purified by flash column chromatography using hexanes as the eluent to yield 0.3 g (30%) of the desired compound as a clear oil. 1H NMR (400 MHz, CHCl3) δ 1.53 (m, 4H), 2.10 (m, 4H), 3.12 (s, 3H), 5.65 (m, 1H), 6.66 (m, 3H), 7.18 (m, 6H). 13C NMR (100 MHz, CHCl3) δ 22.0, 23.0, 25.6, 28.2, 39.2, 113.7, 116.9, 125.6, 126.3, 127.7, 128.2, 128.5, 130.3, 137.9, 142.8, 145.6, 149.0. HRMS (ESI) calc for C19H21N [M+H]+ 264.1747, found 264.1758. IR (KBr plate) 693 (m), 747(m), 1069 (s), 1155 (m), 1263 (m), 1345 (m), 1499 (s), 1602(s), 2853 (m), 2921 (s) cm−1.

Source