Hydrochloric Acid → 2-Methylphenylacetylene

HRID 556334Notes

Reaction equation

HRID 556334 reaction equation
[OH-].[K+].C[Si](C)(C)[C:5]#[C:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[CH3:13].C(OCC)(=O)C.Cl>CO.CCCCCC>[C:6]([C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[CH3:13])#[CH:5]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 8857Ethyl AcetateHCID 14797Potassium HydroxideHCID 44632812-[(Trimethylsilyl)ethynyl]toluene

Product 1

HCID 1365982-MethylphenylacetyleneYield 73.4%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8058HexaneSolvent

Conditions

Temperature
0 °C

Procedure

Potassium hydroxide (10 g, 1.8 mol) added in 4 portions to a stirred solution of trimethyl-(2-methylphenyl)ethynylsilane (114.0 g, 0.61 mol) in methanol (400 ml) at 0° C. The mixture was stirred at 0° C. until the reaction was complete (by tlc 1:1 ethyl acetate:hexane). The mixture was neutralised by the addition of 10% hydrochloric acid and the product was extracted into dichloromethane (2×150 ml). The combined extracts were dried (MgSO4) and evaporated in vacuo. The residual oil was purified by short path distillation (Kugelrohr) to give 1-ethynyl-2-methylbenzene (52.03 g) as a clear oil. B.pt. 45° C./12 mBar. 250 MHz 1H-NMR (CDCl3) δ (ppm): 2.35 (s, 3H) (ArCH3), 3.2 (s, 1H)(CH), 7.0-7.2 (m, 3H) (3×ArH), 7.4 (m, 1H) (ArH); GC purity 98%, GC retention time 7.94 min.

Workup

  1. extractionthe product was extracted into dichloromethane (2×150 ml)
  2. dry with materialThe combined extracts were dried (MgSO4)
  3. customevaporated in vacuo
  4. distillationThe residual oil was purified by short path distillation (Kugelrohr)

Sources & evidence

ORD record
ord-10272a69aaa0423a94a2fd557ef2e908
Source dataset
uspto-grants-2011_11
Patent number
US08058283B2

Reaction notes

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