Acetic Acid → (2,2-Dimethyl-5-oxo-[1,3]dioxolan-4-ylidene)-acetic acid

The crude (Z)-2,2-dimethyl-5-(tert-butyldimethylsilyloxycarbonylmethylene)-1,3-dioxolan-4-one (72.4 mmol) in tetrahydrofuran (50 ml) was treated at 22° C. with acetic acid (13 ml, 0.227 mmol) followed by 73 ml (73.0 mmol) of a 1M solution of tetrabutylammonium fluoride in tetrahydrofuran. After 1 h at 22° C., the reaction mixture was diluted with ethyl acetate (500 ml), washed with water, brine and dried (anhydrous magnesium sulfate). Evaporation of the solvent under reduced pressure and trituration of the residual solid with toluene (50 ml) gave 7.70 g (62% yield for 3 steps) of the title Z-isomer as a white crystalline solid. Concentration of the mother liquors yielded another 0.2 g of a 75:25 mixture of Z and E isomers. Z-Isomer; 1H NMR (400 MHz, CDCl3) δ: 1.78 (s, 3), 5.89 (s, 1). E-Isomer: 1H NMR (400 MHz, CDCl3) δ: 1.80 (s, 3), 6.03 (s, 1).

1. washwashed with water, brine
2. dry with materialdried (anhydrous magnesium sulfate)
3. customEvaporation of the solvent under reduced pressure and trituration of the residual solid with toluene (50 ml)
4. customgave 7.70 g (62% yield for 3 steps) of the title Z-isomer as a white crystalline solid
5. customConcentration of the mother liquors yielded
6. additionanother 0.2 g of a 75:25 mixture of Z and E isomers

ORDレコード

ord-4a02acb295164b139664d66e794b12be

出典データセット

uspto-grants-2004_08

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US06777440B2