Method for preparing acetylenic ketone through oxidizing propargyl alcohol

[0017] Example 1. Investigation of reaction conditions

[0018] First, we used 1,3-diphenyl-2-propyn-1-ol to produce 1,3-diphenyl-2-yn-1-acetone as a model reaction to investigate the reaction conditions.

[0019] The results are shown in Table 1.

[0020] Table 1 Investigation of reaction conditions

[0021]

[0022]

[0023] Note: The reaction temperature is 25°C, the substrate is 1,3-diphenyl-2-propyn-1-ol, and the organic solvent is methylene chloride (30ml). The product is 1,3-diphenyl-2-yne-1-propanone, a pale yellow solid, 1 H NMR(300MHz, CDCl 3 )δ7.56-7.43(m,5H),7.72-7.62(m,3H),8.26-8.22(m,2H), 13 CNMR(100.6MHz, CDCl 3 )δ86.8, 93.0, 119.9, 128.5, 128.6, 129.4, 130.7, 132.9, 134.0, 136.7, 177.8. IR(KBr,cm -1 ): 3063, 2955, 2921, 2851,2198 (C≡C), 1727 (C=O).

[0024] Table 1 shows that DDQ, nitric acid, and oxygen play a vital role in the progress of the oxidation reaction and are indispensable. The oxygen pressure is high, the reaction is fast, and the result is good. This may be because the oxygen pressure is high, and the solubility of oxygen in the liquid is large, which is beneficial to the reaction. The oxygen pressure is low. Better reaction results can be obtained by prolonging the reaction time. The oxygen pressure is determined to be 0.2~0.5MPa.

[0025] Example 2. The influence of different solvents on the reaction

[0026] Table 2 The influence of solvent on the reaction

[0027]

[0028] Note: The reaction conditions are 0.1mol 1,3-diphenyl-2-propyn-1-ol oxidation, 0.01mol DDQ, 0.04mol 98% nitric acid, 0.3Mpa O 2 , 25℃, 15h.

[0029] It can be seen from Table 2 that when dichloromethane, dichloroethane, chloroform and ethyl acetate are used as solvents, the yield of the product 1,3-diphenyl-2-yne-1-acetone is higher, which is environmentally friendly and convenient. The treatment considers dichloromethane and ethyl acetate as preferred solvents.

[0030] Example 3. Oxidation of 1-phenyl-2-propyn-1-ol

[0031]

[0032] Add 13.2g (100mmol) 1-phenyl-2-propyn-1-ol and 2.72g (9.8mmol) DDQ to 30mL of dichloromethane solvent, cool with an ice water bath, and slowly add 1.15g ( 18mmol) nitric acid, inject 0.2MPa oxygen, react at 25°C for 18h, slowly release the pressure, add NaOH aqueous solution to neutralize, extract with dichloromethane, wash with water, dry, and evaporate the solvent. The obtained mixture was separated by column to obtain 9.8 g (yield: 75%) of 1-phenyl-2-propyn-1-one. Yellow solid, melting point 42.5-43.5℃; 1 H NMR(300MHz, CDCl 3 )δ3.45(s,1H), 7.49(t,J=7.4Hz,2H), 7.63(t,J=7.4Hz,1H), 8.16(d,J=7.4Hz,2H). 13 C NMR(100.6MHz, CDCl 3 )δ 80.2, 80.7, 128.7, 129.6, 134.5, 136.1, 177.3. IR(KBr,cm -1 ): 3311(-C≡H), 3045, 2109(C≡C), 1666(C=O).