Aniline → N-(2-Methylbut-3-yn-2-yl)aniline

HRID 1604819Notes

Reaction equation

HRID 1604819 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(O[C:12]([CH3:16])([CH3:15])[C:13]#[CH:14])(=O)C.CCN(CC)CC>C1COCC1.Cl[Cu]>[CH3:15][C:12]([NH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1)([CH3:16])[C:13]#[CH:14]

Participants

6

Reactant 3

HCID 6115AnilineHCID 8471TriethylamineHCID 741441,1-Dimethylprop-2-ynyl acetate

Product 1

HCID 345768N-(2-Methylbut-3-yn-2-yl)anilineYield 67%

Reagents, catalysts & solvents 2

HCID 62652Cuprous chlorideCatalystHCID 8028TetrahydrofuranSolvent

Procedure

A solution of aniline (19 mL, 0.20 mol), 3-acetoxy-3-methyl-1-butyne (26 g. 0.20 mol), CuCl (1.0 g, 10 mmol) and Et3N (28 mL, 0.20 mol) in THF (120 mL) was heated at reflux for 5 h and was filtered through a pad of Celite™. Removal of solvent and chromatography of the crude mixture (silica gel, EtOAc/hexane, 3/7) afforded 21 g (67%) of 3-methyl-3-phenylamino-1-butyne. Treatment of the aminobutyne with CuCl (0.70 mg, 7.0 mmol) in THF (200 mL) at 70° C. for 16 h followed by chromatography (silica gel, EtOAc/hexane, 3/7) afforded 13 g (60%) of 1,2-dihydro-2,2-dimethylquinoline (structure 75A of Scheme LII, where R1 =H, R2-3 =methyl). Treatment of the quinoline with di-tert-butyl dicarbonate (22 g, 0.10 mol) and DMAP (12 g, 0.10 mol) in THF (100 mL) for 16 h followed by chromatography (silica gel, EtOAc/hexane, 2/8) afforded 15 g (71%) of 1-tert-butoxycarbonyl-1,2-dihydro-2,2-dimethylquinoline. 1-tert-Butoxycarbonyl-1,2-dihydro-2,2-dimethylquinoline (3.0 g, 11 mmol) in THF (30 mL) was treated with 1.0M BH3 -THF in THF (29 mL, 29 mmol) at rt for 3 h and was quenched with 3M KOH (20 mL). To the above solution 30% H2O2 (5 mL) was added and the mixture was stirred for 60 min, then 5mL of water was introduced. The mixture was extracted, washed with brine and concentrated. Chromatography of the crude mixture on a silica gel column using a 10-30% mixture of EtOAc/Hexane as eluents afforded a 2:1 mixture of two isomers (0.87 g, 3.1 mmol), which was oxidized with PCC (2.5 g, 11 mmol) in 60 mL of methylene chloride at rt for 60 min. Removal of solvent and chromatography of the black oil on a silica gel column using a 20% mixture of EtOAc and hexane as solvent afforded 0.58 g (68%) of 1-tert-butoxycarbonyl-1,2,3,4-tetrahydro-2,2-dimethyl-4-quinolinone as a white solid. Data for 1-tert-butoxycarbonyl-1,2,3,4-tetrahydro-2,2-dimethyl-4-quinolinone: 1H NMR (400 MHz, CDCl3) 7.93 (d, J=7.8, 1H), 7.42 (t, J=7.8, 1H), 7.31 (d, J=7.8, 1H), 7.02 (t, J=7.8, 1H), 2.73 (s, 2H), 1.56 (s, 9H), 1.49 (s, 6H).

Workup

  1. temperatureat reflux for 5 h
  2. filtrationwas filtered through a pad of Celite™
  3. customRemoval of solvent and chromatography of the crude mixture (silica gel, EtOAc/hexane, 3/7)

Sources & evidence

ORD record
ord-1b0dacdf110549429a12936eaab5ecde
Source dataset
uspto-grants-1999_11
Patent number
US05994544

Reaction notes

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