(6R,7R)-3-(Chloromethyl)-8-oxo-7-[[2-(2-thienyl)acetyl]amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic Acid (4-Methoxyphenyl)methyl Ester

(6R,?7R)?-3-?(Chloromethyl)?-?8-?oxo-?7-?[[2-?(2-?thienyl)?acetyl]?amino]?-5-?thia-?1-?azabicyclo[4.2.0]?oct-?2-?ene-?2-?carboxylic Acid (4-?Methoxyphenyl)?methyl Ester is an intermediate in synthesizing Nitrocefin (N493815), a chromogenic β-lactamase substrate that undergoes colour change from yellow to red as the amide bond in the β-Lactam ring is hydrolyzed by β-lactamase. Nitrocefin undergoes colour changes induced by lactamases produced by Gram-positive and Gram-negative bacteria. Several studies have utilized the colour changing properties of Nitrocefin for the detection of β-lactamase activity from bacterial cell extracts by isoelectric focusing and spectroscopy. Nitrocefin has also been used in studies involving β-lactamase resistant antibiotics.