Ammonium Chloride → cis-4b,5,9b,10-Tetrahydro-4b,6,7,9,9b-pentamethyl-8-methoxyindeno[1,2-b]indole

HRID 439869Notes

Reaction equation

[CH3:1][C:2]1[C:10]2[N:9]=[C:8]3[C:11]4[C:16]([CH2:17][C:7]3([CH3:18])[C:6]=2[C:5]([CH3:19])=[C:4]([O:20][CH3:21])[C:3]=1[CH3:22])=[CH:15][CH:14]=[CH:13][CH:12]=4.[CH3:23][Li].[NH4+].[Cl-]>C1COCC1.CCOCC>[CH3:23][C@@:8]12[C:11]3[C:16](=[CH:15][CH:14]=[CH:13][CH:12]=3)[CH2:17][C@:7]1([CH3:18])[C:6]1[C:5]([CH3:19])=[C:4]([O:20][CH3:21])[C:3]([CH3:22])=[C:2]([CH3:1])[C:10]=1[NH:9]2

Participants

Conditions

Temperature: -78 °C

Procedure

To a cold (-80° C.) solution of 1.1 g (0.0038 mol) of 9b,10-dihydro-6,7,9,9b-tetramethyl-8-methoxyindeno[1,2-b]indole in 20 ml of dry THF was added 4 ml of 1.6M methyl lithium in ether under argon. The mixture was stirred at -78° C. for 1 hour and then at -20° C. for 1 hour. After attaining 0° C. aqueous NH4Cl and ether was added. The phases were separated, and the organic phase was washed once with water, dried (MgSO4) and evaporated. The resulting crude product was purified by chromatography on silica using ethyl acetate/isooctane (2/10) as eluant. This gave 0.3 g (25%) of the expected product. 1H NMR (CDCl3): 1.41 (3H,s), 1.43 (3H,s), 1.96 (3H,s), 2.07 (3H,s), 2.35 (3H,s), 3.0 (1H,d), 3.55 (3H,s), 3.65 (1H,d), 7.1 (3H,m), 7.25 (1H,m).

Workup

waitat -20° C. for 1 hour
customAfter attaining 0° C.
additionwas added
customThe phases were separated
washthe organic phase was washed once with water
dry with materialdried (MgSO4)
customevaporated
customThe resulting crude product was purified by chromatography on silica

Sources & evidence

ORD record: ord-b21f90eb529046a490fea73bfa45df42
Source dataset: uspto-grants-1996_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05516788

Reaction notes

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