[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH2:9][CH2:10][CH2:11][C:12](=O)[CH2:13][CH2:14][C:15]2([CH3:22])[C:19](=[O:20])[CH2:18][CH2:17][C:16]2=O)[CH:6]=[CH:7][CH:8]=1.O>C1C=CC=CC=1>[CH3:22][C@:15]12[CH2:14][CH2:13][C:12]3[C:6]4[CH:7]=[CH:8][C:3]([O:2][CH3:1])=[CH:4][C:5]=4[CH2:9][CH2:10][C:11]=3[C:16]1=[CH:17][CH2:18][C:19]2=[O:20]To 2-(6-m-methoxyphenyl-3-oxohexyl)-2-methylcyclopentane-1,3-dione (3 g) in benzene (100 cc) add polyphosphoric acid (from orthophosphoric acid, 15 g. and phosphorus pentoxide, 6 g.) and heat the mixture at 90° for 4 minutes under such reduced pressure as the need to control frothing will allow. Cool, add water, and extract the mixture with ether and ethyl acetate; isolate the product from the resulting solution to obtain the colorless crystalline 13β-methyl-3-methoxygona-1,3,5(10),8,14-pentaen-17-one (2 g), b.p. 115°-116°; ultraviolet absorption peak at 313 mμ (ε35,100).
Wird geladen…