反应详情

To a cooled (0° C.) solution of the sulfide obtained in step B (3.59 g) in chloroform (30 c.c.) was added m-chloroperoxybenzoic acid (1.87 g) and the suspension was stirred for 1 hr. It was than warmed up to R.T. and Ca(OH)2 (1.11 g) was added and stirred for 45 min. Insolubles were filtered off and trifluoroacetic anhydride (10 g) was added to the filtrate and the mixture heated to reflux for 1 hr. Volatiles were removed in vacuo to yield a residue to which was added a solution of MeOH (50 c.c.) and triethylamine (50 c.c.); the mixture was then concentrated in vacuo to dryness and this process was repeated 3 times. The residue was finally taken up in ethyl acetate (100 c.c.) and washed with 1N HCl (3×25 c.c.), brine, dried and evaporated to dryness to yield the title compound as an oil which was used immediately in the following step.

1. stirringstirred for 45 min
2. filtrationInsolubles were filtered off
3. additiontrifluoroacetic anhydride (10 g) was added to the filtrate
4. temperaturethe mixture heated
5. temperatureto reflux for 1 hr
6. customVolatiles were removed in vacuo
7. customto yield a residue to which
8. concentrationthe mixture was then concentrated in vacuo to dryness
9. washwashed with 1N HCl (3×25 c.c.), brine
10. customdried
11. customevaporated to dryness