HCID 21311858, compound → HCID 21311879, compound

Participants

Reaction Steps

A solution of 0.051 g of 1-formyl-2-(2-acetyloxy-2-propyl-mercapto)-3-(N-phenyloxyacetyl-amino)-azetidin-4-one in 3 ml of anydrous benzene is treated with 0.13 g of tristriphenyl-phosphine-rhodium chloride and boiled for 3 hours under reflux. The initially red solution turns brown, with a small quantity of a precipitate forming. After cooling, the precipitate is filtered off and the filtrate is evaporated under reduced pressure. The residue is chromatographed on 5 g of acid-washed silica gel, with fractions of 5 ml each being collected. The elution is carried out with 10 ml of benzene, 30 ml of a 9:1-, 25 ml of a 4:1- and 10 ml of a 1:1-mixture of benzene and ethyl acetate and then with 25 ml of ethyl acetate. Fractions 2-6 yield a rhodium complex having a strong CO-absorption at 5.18μ in the infra-red absorption spectrum. A small quantity of 1-formyl-2-isopropenylmercapto-3-(N-phenyloxyacetyl-amino)-azetidin-4-one can be isolated from fractions 10- 12, while fractions 15- 17 yield the 2-isopropenylmercapto-3-(N-phenyloxyacetyl-amino)-azetidin-4-one of the formula ##STR23## in an amorphous form. The product is obtained in crystalline form when the solution of the eluate is filtered through 0.5 g of acid-washed silica gel and the product is eluted with a 1:1-mixture of benzene and ethyl acetate, m.p. 156°-158°; [α]D20 = -70° ± 2° (c = 0.665 in chloroform); infra-red absorption spectrum (in methylene chloride): characteristic bands at 3.07μ, 5.65μ, 5.96μ, 6.29μ, 6.59μ, 6.74μ, 8.19μ, 9.25μ and 9.92μ.

Provenance & Evidence