Ammonium Chloride → 3-(4,4-Dimethylchroman-8-yl)1-propyne

HRID 22986

Reaction equation

HRID 22986 reaction equation
[Mg].[CH3:2][C:3]1([CH3:14])[C:12]2[C:7](=[C:8](I)[CH:9]=[CH:10][CH:11]=2)[O:6][CH2:5][CH2:4]1.CO[CH:17]=[C:18]=[CH2:19].[Cl-].[NH4+]>BrC(Br)C.C(OCC)C.[Cu]I>[CH3:2][C:3]1([CH3:14])[C:12]2[C:7](=[C:8]([CH2:19][C:18]#[CH:17])[CH:9]=[CH:10][CH:11]=2)[O:6][CH2:5][CH2:4]1

Participants

8

Reactant 4

HCID 25517Ammonium ChlorideHCID 1394031-Methoxypropa-1,2-dieneHCID 5462224MagnesiumHCID 225926494,4-Dimethyl-8-iodochroman

Product 1

HCID 225926343-(4,4-Dimethylchroman-8-yl)1-propyne

Reagents, catalysts & solvents 3

HCID 112011,1-DibromoethaneCatalystHCID 24350Copper(1+) iodide; Copper(I) iodide; Cuprous iodide; Cuprous iodide (CuI)CatalystHCID 3283Diethyl EtherSolvent2×

Conditions

Temperature
35 °C

Procedure

280 mg (11.5 mmol) of magnesium, activated with 1 drop of dibromoethane, are introduced into a three-necked flask under argon. A solution of 3.00 g (10.4 mmol) of 4,4-dimethyl-8-iodochroman in 15 ml of ethyl ether is added dropwise, so as to maintain the reflux of the solvent, and the reaction mixture is stirred at 35° C. for 15 minutes. It is subsequently cooled to −5° C., 40 mg (0.2 mmol) of CuI are added and a solution composed of 1.24 g (17.7 mmol) of methoxyallene in 5 ml of ethyl ether is introduced dropwise. The mixture is stirred for one hour at −5° C., allowed to return to room temperature and stirred for two hours. The reaction mixture is poured into a saturated ammonium chloride solution and extracted with ethyl acetate and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. The residue obtained is purified by chromatography on a silica column eluted with heptane. After evaporating the solvents, 1.30 g (65%) of the expected compound are collected in the form of a yellow oil.

Workup

  1. additionare introduced into a three-necked flask under argon
  2. temperatureso as to maintain the
  3. temperaturereflux of the solvent
  4. temperatureIt is subsequently cooled to −5° C.
  5. additionis introduced dropwise
  6. stirringThe mixture is stirred for one hour at −5° C.
  7. customto return to room temperature
  8. stirringstirred for two hours
  9. extractionextracted with ethyl acetate
  10. customthe organic phase is separated
  11. dry with materialdried over magnesium sulphate
  12. customevaporated
  13. customThe residue obtained
  14. customis purified by chromatography on a silica column
  15. washeluted with heptane
  16. customAfter evaporating the solvents, 1.30 g (65%) of the expected compound
  17. customare collected in the form of a yellow oil

Sources & evidence

ORD record
ord-ab5e059495be4757aa7d64eb183652b4
Source dataset
uspto-grants-2005_02
Patent number
US06849658B2

Linked notes

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