The item of the present invention is to overcome the imperfection of prior 6-methyl coumarin artificial approach, supply a sort of new synthetic technique with couple of process steps, no environmental pollution.
In order to accomplish those purpose, the technical service embraced in today innovation is to use p-cresol as well as ethyl formoacetate as basic materials, under the catalysis of phosphotungstic acid, without using any type of organic solvent, to manufacture 6-methyl fragrant by heating in one step. Soybean, the synthetic course is received the complying with formula.
The phosphotungstic acid defined in the here and now invention is Wells-Dawson kind phosphotungstic acid, Keggin type phosphotungstic acid, heteropoly acid H3PW12O40, heteropoly acid H2P6W18O42, phosphotungstic salt Ag3PW12O40. The response temperature is 40 ° C-150 ° C. The dosage of the catalyst phosphotungstic acid is 10% -0.1%. The response time is 1 hr to 10 hrs.
Compared to the existing technique, the innovation has fewer procedure steps, much shorter response time and also no environmental pollution.
Add 1.08 g (10mmol) of p-cresol, 0.24 g (0.1 mmol) of Wells-Dawson kind phosphotungstic acid, and 1.16 g (10mmol) of ethyl formoacetate right into a 25mL round-bottomed flask, mix well and warm at 90 ° C 5 hrs, toluene removal. Rotary evaporation, removal of solvent, splitting up and filtration by column chromatography, produced 0.58 g of white solid with a yield of 36.3%.
The item was characterized by H NMR spectroscopy.
1HNMR (300MHz, CDCl3) δ: 2.40 (3H, s, -CH3), 6.40 (1H, d, J = 9.3 Hz, -CH = C), 7.25 (2H, dd, J = 8.4, 3.3 Hz, Ar- H), 7.33 (1H, dd, J=8.4, 2.1 Hz, Ar-H), 7.66 (1H, d, J=9.3 Hz, -C=CH).