Sodium Bicarbonate → (6R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl]amino]-8-oxo-3-[(E)-prop-1-enyl]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Participants

Reaction Steps

To a stirred solution of 7-amino-3-trans-propenyl derivatives XIII (E, R3 =R4a =H) (720 mg, 3 m moles) and sodium bicarbonate (504 mg, 6 m moles) in 50% DMF (60 ml) was added 1-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetoxy]benzotriazole (954 mg, 3 m moles) and the mixture was stirred for 30 min. An additional amount of the active ester (1.81 g, 6 m moles) was added in four portions at 30-min intervals. The mixture was stirred for additional 2 hr at room temperature and passed through a column packed with the packing of prepPAK-C18 cartridge (300 ml, Waters). The column was washed with water and then eluted successively with 10% methanol and 20% methanol. Fractions of 20% methanol eluate showing a peak at retention time 5.57 min by HPLC* were collected and evaporated to dryness. The residue was dissolved in methanol and filtered. The filtrate was concentrated to 5 ml and the residue was triturated with a mixture of ether-isopropyl ether to give 805 mg (63%) of the title compound, melting at 180° C. (grad. dec.), 80% pure by HPLC*.

Provenance & Evidence