Ammonium Chloride → alpha-Ethynyl-4,4-dimethylchroman-8-methanol

HRID 1699423Notes

Reaction equation

HRID 1699423 reaction equation
C[Si]([C:5]#[CH:6])(C)C.C([Li])CCC.[CH3:12][C:13]1([CH3:25])[C:22]2[C:17](=[C:18]([CH:23]=[O:24])[CH:19]=[CH:20][CH:21]=2)[O:16][CH2:15][CH2:14]1.[Cl-].[NH4+]>C1COCC1>[C:5]([CH:23]([C:18]1[CH:19]=[CH:20][CH:21]=[C:22]2[C:17]=1[O:16][CH2:15][CH2:14][C:13]2([CH3:25])[CH3:12])[OH:24])#[CH:6]

Participants

6

Reactant 4

HCID 25517Ammonium ChlorideHCID 66111TrimethylsilylacetyleneHCID 225926624,4-Dimethylchroman-8-carbaldehydeHCID 178418339Butyllithium

Product 1

HCID 22592658alpha-Ethynyl-4,4-dimethylchroman-8-methanolYield 132.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

7.6 ml (54.0 mmol) of trimethylsilylacetylene and 50 ml of THF are introduced into a three-necked flask. A solution of 22 ml (54.0 mmol) of n-butyllithium (2.5M in hexane) is added dropwise at −78° C. under a stream of nitrogen and the mixture is allowed to return to room temperature. The reaction mixture is introduced dropwise into a cold (−78° C.) solution composed of 9.30 g (49.0 mmol) of 4,4-dimethylchroman-8-carbaldehyde and of 50 ml of THF. The reaction mixture is allowed to return to room temperature, poured onto an aqueous ammonium chloride solution and extracted with ethyl ether and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. 14.00 g (100%) of the expected compound are obtained in the form of a yellow oil. 3.00 g (10.0 mmol) of this oil are mixed with 50 ml of THF, and 11.5 ml (12.6 mmol) of a tetrabutylammonium fluoride solution (1.1M in THF) are added dropwise. The reaction mixture is stirred at room temperature for one hour, is poured into water and extracted with ethyl ether and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. 2.30 g (100%) of the expected compound are collected in the form of a colourless oil.

Workup

  1. customto return to room temperature
  2. additionThe reaction mixture is introduced dropwise into a cold (−78° C.) solution
  3. customto return to room temperature
  4. extractionextracted with ethyl ether
  5. customthe organic phase is separated
  6. dry with materialdried over magnesium sulphate
  7. customevaporated

Sources & evidence

ORD record
ord-9f1f067102b240a9920e8400fa868076
Source dataset
uspto-grants-2002_02
Patent number
US06346546B1

Reaction notes

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