5-Oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-[[[(difluoromethyl)thio]acetyl]amino]-3-[[(4,5-dihydro-1,4-dimethyl-5-ox o-1H-1,2,4-triazol-3-yl)thio]methyl]-7-methoxy-8-oxo-, cis-