ChemicalBook CAS DataBase List 2-METHYL-1-BUTEN-3-YNE

2-METHYL-1-BUTEN-3-YNE synthesis

10synthesis methods

Product Name:2-METHYL-1-BUTEN-3-YNE
CAS Number:78-80-8
Molecular formula:C5H6
Molecular Weight:66.1

335-03-5 Synthesis

Cyclopropane, 1,1-difluoro-2,2-dimethyl-

335-03-5
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814-78-8
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$15.00/1g

338-68-1 Synthesis

338-68-1
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78-80-8
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$45.32/5 G

Yield:338-68-1 33% ，78-80-8 10% ，814-78-8 7%

Reaction Conditions:

with aluminum oxide at 200; for 0.75 h;Inert atmosphere;Gas phase;Flow reactor;Pyrolysis;

Steps:

General procedure: Pyrolysis of gem-difluorocyclopropanes 1a-d in reactor B (in the presence of Al₂O₃). A quartz flow-tube reactor containing Al₂O₃ (10 g) was heated over 1 h at 450-550 °C in the flow of N₂(300 mL min^-1) for the activation (removal of water) of Al₂O₃, then the reactor was cooled in the flow of N₂ to 185 °C.Then, cis-3,3-difluoro-1,2-dimethylcyclopropane (1a) (3.00 g, 28.30 mmol) was passed at a constant rate through the reactor at 185 °C in the flow of N₂ (70 mL min^-1) over 45 min, using a syringe. The pyrolysis products coming out of the reactor were collected in a trap cooled with a mixture of CO₂-propan-2-ol. The pyrolysate (1.97 g) was sequentially washed with 10% aqueous Na₂CO₃ and water, dried with Na₂SO₄, and distilled to obtain a mixture of the products (1.68 g, b.p. 45- 52 °C) containing according to the ¹H and ¹⁹F NMR spectra (calculated using fluorobenzene as an internal standard) the starting cyclopropane 1a (0.27 mmol), (Z)-3-fluoropenta-1,3-diene (Z2a) (15.62 mmol), (E)-3-fluoropenta-1,3-diene (E2a) (1.95 mmol), and pent-1-en-3-yne 3a (1.53 mmol). The yields (in the mixture) were 55% (Z-2a), 8% (E-2a), 5% (3a).