the various groups represented by the symbols have the meaning defined below and these definitions are retained throughout this specification . the lower alkyl groups referred to througout this specification include straight or branched chain hydrocarbon groups containing 1 to 8 carbon atoms , preferably 1 to 4 carbons . examples of the type of groups contemplated are methyl , ethyl , propyl , isopropyl , butyl , t - butyl , etc . the lower alkoxy groups include such lower alkyl groups attached to an oxygen , e /. g ., methoxy , ethoxy , propoxy , etc . the phenyl - lower alkyl and diphenyl - lower alkyl groups include such lower alkyl groups attached to a phenyl , preferably benzyl , phenethyl , and diphenylmethyl . cycloalkyl refers to groups having 3 to 7 carbons in the ring , i . e . cyclopropyl , cyclobutyl , cyclopentyl , cyclohexyl , and cycloheptyl . the terms cycloalkenyl and cycloalkadienyl also represent rings having 3 to 7 carbons with one or two double bonds , i . e . cyclobutenyl , cyclopentenyl , cyclohexenyl , cyclopentadienyl , cyclohexadienyl , etc . the double bond or bonds may be located at various positions , i . e . 1 , 4 - cyclohexadienyl , etc . the substituted phenyl and substituted phenyl - lower alkyl groups include one to three ( preferably only one ) simple substituents selected from halogen ( preferably chlorine or bromine ), lower alkyl , lower alkoxy , and hydroxy , e . g . 2 -, 3 -, or 4 - chlorophenyl , 2 -, 3 -, or 4 - bromophenyl , 3 , 5 - dichlorophenyl , 2 - methylphenyl , 4 - ethoxyphenyl , 3 , 4 , 5 - trimethoxyphenyl , 2 -, 3 - or 4 - chlorobenzyl , 2 -, 3 -, or 4 - methylphenethyl , etc . the salt forming ions represented by r may be metal ions , e . g ., aluminum , alkali metal ions such as sodium or potassium , alkaline earth metal ions such as calcium or magnesium , or an amine salt ion , of which a number are known for this purpose , for example , phenyl - lower alkylamines such as dibenzylamine , n , n - dibenzylethylenediamine , lower alkylamines such as methylamine , triethylamine , and n - lower alkylpiperidines such as n - ethylpiperidine . the halogens are the four common halogens , of which chlorine and bromine are preferred . in the case of the trihaloethyl group represented by r , 2 , 2 , 2 - trichloroethyl is preferred . the heterocyclics represented by r 1 are thienyl , furyl , pyrryl , pyridyl , thiazolyl , isothiazolyl , oxazolyl , isoxazolyl , thiadiazolyl , and tetrazolyl . they are attached at any available carbon atom as for example 2 - or 3 - thienyl , 2 - or 3 - furyl , 2 - or 3 - pyrryl , 2 -, 3 - or 4 - pyridyl , 2 -, 4 - or 5 - thiazolyl , 3 -, 4 - or 5 - isothiazolyl , 2 -, 4 - or 5 - oxazolyl , 3 -, 4 - or 5 - isoxazolyl , 3 - or 5 -( 1 , 2 , 4 - thiadiazolyl ), etc . also included within the meaning of r 1 are such heterocyclics having a halogen ( preferably cl or br ) or a lower alkyl of 1 - 4 carbons ( preferably methyl or ethyl ) substituent , i . e . 5 -( 1 - methyltetrazolyl ), 2 -( 5 - chlorothienyl )- 2 -( 4 - chloropyrryl ), etc . the structural formula for the pyridazine refers to the 1 - oxide and to the 2 - oxide . the broken lines (. tbd .) between the cephalosporin nucleus and r 3 indicate that this substituent is in the α - configuration . r 1 is phenyl , benzyl , phenethyl , substituted phenyl , benzyl , or phenethyl , cycloalkyl , cycloalkenyl and cycloalkadienyl of 5 to 7 carbons , thienyl , furyl , pyrryl , or pyridyl . r 2 is hydrogen or lower alkyl of 1 to 4 carbons . r is hydrogen , lower alkyl of 1 to 4 carbons , benzyl , phenethyl , diphenylmethyl , trimethylsilyl , 2 , 2 , 2 - trichloroethyl , aluminum , alkaline earth metal , alkali metal , or ## str5 ## wherein r 6 is lower alkyl of 1 to 4 carbons , phenyl , benzyl or phenethyl . r 1 is phenyl , substituted phenyl , 1 , 4 - cyclohexadien - 1 - yl , 2 - thienyl , 3 - thienyl , or 3 - pyridyl . compounds of formula i are obtained by reacting an α - ureido compound of the formula ## str6 ## with a 3 - heterothio - 7 - amino substituted cephalosporin of the formula ## str7 ## wherein r is preferably diphenylmethyl or t - butyl or other ester protecting groups . this reaction is carried out by converting the α - ureido compound of formula ii to a mixed carbonic or other anhydride by treating a solution of the α - ureido compound in an organic solvent containing a tri ( lower alkyl ) amine with an anhydride forming agent , i . e . a lower alkyl chloroformate , an aryl chloroformate , or an acyl halide , at reduced temperatures of from about 0 ° c to about - 20 ° c . alternatively , the α - ureido compound of formula ii can be converted to an activated ester by reacting with a carboxyl group activating agent such as dicyclohexylcarbodiimide or bisimidazole carbonyl . in some cases the carboxyl group may be activated by conversion to an acid halide , e . g . the chloride , or to an azide . the methods of preparing the α - ureido compounds of formula ii are known to those skilled in the art and a number of such methods are discussed in u . s . pat . nos . 3 , 673 , 183 and 3 , 833 , 568 referred to above . the compounds of formula i can also be prepared by acylating the compound of formula iii with an acid chloride of formula ## str8 ## or an α -( substituted ) amino acid of the formula ## str9 ## wherein y is a protecting group such as ## str10 ## to yield after removal of the protecting group the intermediate of formula the intermediate of formula vi is converted to the final products of formula i by treatment with an isocyanate of the formula or when r 2 is hydrogen an alkali or alkaline earth cyanate such as potassium cyanate in solution at a ph of from about 7 to about 8 . the final products of formula i wherein r 3 and r are hydrogen can also be prepared by reacting the compound of formula ii with 7 - aca to yield the compound of formula viii ## str11 ## followed by treatment with the compound of the formula ## str12 ## or a salt thereof , preferably an alkali metal salt like the potassium or sodium salt . this reaction is effected by bringing together the reactants in an aqueous solvent , preferably at a slightly alkaline ph with heating and under an inert atmosphere like nitrogen . the starting material of formula ix is prepared as described in british pat . no . 1 , 363 , 333 . similarly , the final products of formula i can be prepared by reacting the compounds of formula iv or v with an ester of 7 - aca or 7α - methoxy - 7aca preferably in the presence of dicyclohexylcarbodiimide followed by treatment with an acid ( hx ), preferably trifluoroacetic acid in the presence of anisole , to yield the salt of formula ## str13 ## the salt of formula x is treated with the isocyanate of formula vii ( or the alkali or alkaline earth cyanate where r 2 is hydrogen ) followed by treatment with the compound of formula ix as described above to yield the final product of formula i . the compounds of formula i wherein r is lower alkyl , phenyl - lower alkyl , substituted phenyl - lower alkyl , diphenyl - lower alkyl , or the acyloxymethyl group ## str14 ## may be obtained by reacting the 3 - heterothio - 7 - amino substituted cephalosporin of formula iii or the 7 - aca or the 7α - methoxy - 7aca either before or after the acylation of the 7 - amino substituent with one or two moles of a compound of the formula wherein halo is preferably chlorine or bromine in an inert solvent such as dimethylformamide , acetone , dioxane , benzene , or the like at about ambient temperature or below . similarly , the compounds of formula i wherein r is tri ( lower alkyl ) silyl are obtained by introducing such groups onto the 3 - heterothio cephalosporanic acid moiety either before or after the acylation reaction . the carboxylate salts of the compound of formula i are formed by reacting the carboxyl group of the cephalosporanic acid moiety , i . e . r is hydrogen , with any of the salt forming ions described above . it will be appreciated that the compounds of formula i are optically active due to the presence of an asymmetric carbon atom in the 7 - position side chain . by selection of the appropriate starting material it is possible to obtain the compounds of formula i as a mixture of optically active isomers or isolated as a single isomer . the various isomers as well as their mixtures are within the scope of this invention . where possible , it is generally preferred to obtain the d - isomer since that is the one which exhibits greater biological activity . illustrative process details are provided in the examples for the various reactions . the compounds of formula i have a broad spectrum of antibacterial activity against both gram positive and gram negative organisms such as staphylococus aureus , salmonella schottmuelleri , pseudomonas aeruginosa , proteus vulgaris , escherichia coli and streptococcus pyogenes . they may be used as antibacterial agents in a prophylactic manner , e . g ., in cleaning or as surface disinfecting compositions , or otherwise to combat infections due to organisms such as those named above , and in general may be utilized in a manner similar to cephalothin and other cephalosporins . for example , a compound of formula i or a physiologically acceptable salt thereof may be used in various animal species in an amount of about 1 to 100 mg ./ kg ., daily , orally or parenterally , in single or two to four divided doses to treat infections of bacterial origin , e . g ., 5 . 0 mg ./ kg . in mice . up to about 600 mg . of a compound of formula i or a physilogically accceptable salt thereof may be incorporated in an oral dosage form such as tablets , capsules or elixirs or in an injectable form in a sterile aqueous vehicle prepared according to conventional pharmaceutical practice . they may also be used in cleaning or disinfecting compositions , e . g ., for cleaning barns or dairy equipment , at a concentration of about 0 . 2 to 1 % by weight of such compounds admixed with , suspended or dissolved in conventional inert dry or aqueous carriers for application by washing or spraying . the following examples are illustrative of the invention . all temperatures are on the centigrade scale . 15 . 8 g . ( 0 . 1 mol .) of dl - 2 - thienylglycine are heated together with 8 . 2 g . ( 0 . 1 mol .) of potasssium cyanate in 100 ml . of water . after 30 minutes , the mixture is cooled and acidified with dilute hydrochloride acid . the precipitated product , d - β - ureido - 2 - thiopheneacetic acid , is filtered , washed with ice water and a small amount of ethanol . recrystallization from methanol yields 17 g . of white crystals , of dl - α - ureido - 2 - thiopheneacetic acid ; m . p . 183 °- 185 °. 9 . 2 g . ( 50 mmol .) of dl - α - ureido - 2 - thiopheneacetic acid from part ( a ) are dissolved in 40 ml . of absolute dimethylformamide . 10 . 3 g . ( 50 mmol .) of dicyclohexylcarbodiimide dissolved in 1 ml . of methylene chloride are added dropwise at 0 °. after stirring for 1 / 2 hour , a solution of 13 . 5 g . ( 50 mmol .) of 7 - aminocephalosporanic acid and 10 g . ( 100 mmol .) of triethylamine is added . this mixture is stirred for 24 hours at 5 °. after filtering , the filtrate is concentrated under vacuum , the oily residue is taken up in water , filtered and after treating with activated carbon at 5 ° it is layered over with ethyl acetate and acidifid with 2n hydrochloric acid . the ethyl acetate solution is washed with water , dried and concentrated . 8 . 1 g . of a viscid residue are obtained . the product , 3 -[( acetyloxy ) methyl ]- 7β -[[[( aminocarbonyl )- amino ]( dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo -[ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , is recrystallized twice from isopropanol ; yield 2 . 1 g . the intermediate of part ( b ) can also be obtained by the following synthesis : 3 . 8 g . ( 25 mmol .) of dl - 2 - thienylglycine and 2 g . ( 50 mmol .) of magnesium oxide in 50 ml . of water / dioxane ( 1 : 1 ) are stirred for 1 hour at room temperature . 4 . 25 g . ( 28 mmol .) of t - butyloxycarbonylazide dissolved in 15 ml . of dioxane are added dropwise and the reaction mixture is stirred for 24 hours at 50 ° after filtering , the filtrate is concentrated under vacuum , the oily residue is treated with ethyl acetate and then taken up with water . this is then acidified with citric acid while cooling with ice and the aqueous acid solution is extracted with ethyl acetate . the solvent is drawn off from the ethyl acetate solution to obtain 4 g . of white product , dl -[[[( 1 , 1 - dimethylethoxy ) carbonyl ] amino ] thien - 2 - yl ] acetic acid ; m . p . 70 °- 72 °. 5 . 4 g . ( 20 mmol .) of dl -[[[( 1 , 1 - dimethylethoxy ) carbonyl ]- amino ] thien - 2 - yl ] acetic acid from part ( c ) are dissolved in 50 ml . of tetrahydrofuran and 4 . 05 g . ( 20 mmol .) of dicyclohexylcarbodiimide are added at 0 °. after stirring for 30 minutes , 8 . 8 g . ( 20 mmol .) of 7 - aminocephalosporanic acid , diphenylmethyl ester are added dropwise . after 24 hours , the precipitated dicyclohexylurea is filtered off . after drawing off the solvent and recrystallizing the beige residue from methylene chloride / potassium ether 10 . 5 g . of the product , 3 -[( acetyloxy )- methyl - 7β -[[[[( 1 , 1 - dimethylethoxy ) carbonyl ] amino ] dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , diphenylmethyl ester , are obtained as a light beige powder ; m . p . 78 ° ( dec .). 5 g . of 3 -[ ( acetyloxy ) methyl ]- 7β -[[[[( 1 , 1 - dimethyl - ethoxy ) carbonyl ] amino ]( dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ]- oct - 2 - ene - 2 - carboxylic acid , diphenylmethyl ester from part ( d ) are stirred for 15 minutes in a mixture of 20 ml . of trifluoroacetic acid and 3 ml . of anisole at 5 °. after evaporating the trifluoroacetic acid under vacuum and washing the residue with ether , 2 . 3 g . of 3 -[( acetyloxy )- methyl ]- 7β -[[( 2 - amino - dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , trifluoroacetic acid salt are obtained . this product is dissolved in water and the solution is adjusted to ph 8 with sodium hydroxide . it is then quickly heated to 80 ° and 0 . 4 g . of potassium cyanate dissolved in 2 ml . of water are added . after stirring for 1 minute , the reaction mixture is quickly cooled , layered over with ethyl acetate and acidified to ph 3 . 5 with 2n hydrochloric acid . this is extracted with 5 × 100 ml . of ethyl acetate . the combined ethyl acetate extracts are dried , concentrated to about 1 / 3 the volume , treated with activated carbon and the product , 3 -[( acetyloxy ) methyl ] - 7β -[[[( aminocarbonyl )- amino ]( dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo -[ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , is precipitated with petroleum ether . the product is crystallized from isopropanol as light being crystals ; m . p . 145 ° ( dec .). the 3 -[( acetyloxy ) methyl ] - 7β -[[[( aminocarbonyl ) amino ]-( dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ]- oct - 2 - ene - 2 - carboxylic acid from part ( b ) or ( e ) is dissolved in a mixture of acetone / water ( 1 : 1 ) with the aid of 5n sodium hydroxide . 1 - oxopyridazine - 3 - thiol , sodium salt is added under nitrogen and the solution is heated for several hours at 60 °. the solution is diluted with 150 ml . of water and acidified to ph 5 with 2n hydrochloric acid while cooling . a precipitate forms which is filtered under suction to yield 7β -[[[( aminocarbonyl ) amino ]( dl - 2 - thienyl ) acetyl ] amino ]- 3 -[[( 1 - oxopyridazin - 3 - yl ) thio ] methyl ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . an equimolar solution of the final product from example 1 and potassium bicarbonate is freeze - dried to yield the titled compound as a powder . 3 - thienylbromide is treated with butyl lithium and chloral to obtain 3 -[( 1 - hydroxy - 2 - trichloro ) ethyl ] thiophene which is then treated with sodium methoxide to obtain α - methoxy - 3 - thienylacetic acid [ gronowitz et al ., ark . chemi ., 17 , 561 ( 1961 )]. 150 ml . of 30 % hydrogen bromide in acetic acid is added to a solution of 16 g . ( 100 mmol .) of ( α - methoxy - 3 - thienyl ) acetic acid in 50 ml . of glacial acetic acid . the mixture is left to stand at room temperature for 24 hours and then poured into ice water . the solution is extracted three times with 60 ml . of ether . the ether phase is washed with water , dried over magnesium sulfate and evaporated . the residue , 18 g . of crude dl - α - bromo - 3 - thiopheneacetic acid are recrystallized from cyclohexane ; yield 14 g . ; m . p . 80 °- 82 °. 4 g . ( 62 mmol .) of sodium azide and 3 . 5 g . ( 33 mmol .) of sodium carbonate are added to a solution of 12 g . ( 54 mmol .) of dl - α - bromo - 3 - thiopheneacetic acid in 75 ml . of acetone ( 96 %). the mixture is stirred at room temperature for 12 hours in darkness and after this time the solvent is evaporated and the residue is dissolved in 75 ml . of water . 50 ml . of ether is added , the water phase is acidified with 2n sulfuric acid and extracted quickly twice more with 50 ml . of ether . after washing with water and drying over sodium sulfate , the combined ether phases are evaporated . crystallization of the residue from cyclohexane yields 7 . 4 g . of white crystalline dl - α - azido - 3 - thiopheneacetic acid ; m . p . 58 °- 59 °. 0 . 3 g . of palladium / barium sulfate catalyst are added to a solution of 6 g . of dl - β - azido - 3 - thiopheneacetic acid in 40 ml . of ethanol and 40 ml . of 0 . 5n hydrochloric acid . hydrogenation takes place at about 60 psig . after 2 hours . after filtration , the volume is concentrated to about 30 ml . when the ph is brought to 6 . 5 with ammonia , the amino acid separates as a white powder . after washing with ethanol / water and drying , 3 . 5 g . of the product , dl - α - amino - 3 - thiopheneacetic acid , are obtained ; m . p . 283 °- 285 °. 1 . 9 g . ( 12 . 5 mmol .) of dl - α - amino - 3 - thiopheneacetic acid and 1 g . of magnesium oxide are stirred in 25 ml . of water and 25 ml . of dioxane . after stirring for 1 hour , 3 . 0 g . ( 15 mmol .) of [( p - methoxybenzyl ) oxy ] carbonylazide are added . stirring is continued for 24 hours . the mixture is filtered and extracted with 2 ml . of ether . 50 ml . of ethyl acetate and 20 g . of dowex 50 ( h + form ) are added to the filtrate and the mixture is stirred well for two hours . the ethyl acetate phase is separated , washed with 50 ml . of water , dried over sodium sulfate and evaporated . the oily residue crystallizes after the addition of pentane to yield 3 . 4 g . of white crystalline dl - α -[[[( 4 - methoxyphenyl ) methoxy ] carbonyl ] amino ]- 3 - thiopheneacetic acid ; m . p . 118 ° ( dec .). 5 g . of the product from part ( d ), 1 . 5 g . of triethylamine and 1 . 8 g . of chloroformic acid ethyl ester in 50 ml . of tetrahydrofuran are converted to the mixed anhydride . the mixed anhydride is reacted with a solution of 4 g . of 7 - aminocephalosporanic acid and 2 . 5 g . of triethylamine in methylene chloride for 12 hours . the solvent is then removed from the solution and the partially solid residue is dissolved with water and a small amount of sodium carbonate and extracted with 50 ml . of ethyl acetate . the aqueous phase is cooled , acidified to ph 2 . 5 with 2n hydrochloric acid and extracted with ethyl acetate . the organic phase is treated with activated carbon and concentrated to obtain 3 . 7 g . of light beige product , 3 -[( acetyloxy ) methyl ]- 7β -[[[[[( 4 - methoxyphenyl ) methoxy ] carbonyl ]- amino ]( dl - 3 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 , 0 ] oct - 2 - ene - 2 - carboxylic acid ; m . p . 113 ° ( dec . ), which is recrystallized from methylene chloride / petroleum ether . the product from part ( e ) is stirred with 15 ml . of trifluoroacetic acid and then reacted with potassium cyanate as described in example 1 ( e ) to yield the titled compound . the 3 -[( acetyloxy ) methyl ]- 7β -[[[( aminocarbonyl ) amino ]-( dl - 3 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid from part ( f ) is treated with 1 - oxopyridazine - 3 - thiol according to the procedure of example 1 ( f ) to yield the titled compound . 15 . 7 g . of d -( 2 - thienyl ) glycine ( m . p . 218 °- 219 °, produced from the racemate with d - camphor - 10 - sulfonic acid ) and 8 g . of magnesium oxide are suspended in 200 ml . of water . to this suspension is added a solution of 22 . 8 g . of ( p - methoxyphenyl ) methoxycarbonylazide in 200 ml . of dioxane and this mixture is stirred for 3 days at room temperature . the mixture is filtered , the filtrate is extracted once with ether , the aqueous phase is layered over with ethyl acetate , cooled to about 10 ° and acidified to ph 2 with dilute hydrochloric acid . the aqueous phase is once more extracted with ethyl acetate , the combined extracts are washed once with water , dried with magnesum sulfate and concentrated . the residue crystallizes upon trituration with petroluem ether . the crude product d - α -[[[( 4 - methoxyphenyl ) methoxy ] carbonyl ] amino ]- 2 - thiopheneacetic acid , is recrystallizeed from ethyl acetate / petroleum ether , yield 25 . 2 g ., m . p . 65 °- 67 °. 3 . 2 g . ( 0 . 01 mol .) of the product from part ( a ) is brought into solution in 40 ml . of methylene chloride with 1 . 1 ml . of n - methylmorpholine . the solution is cooled to - 15 °, 1 . 39 ml . of isobutylchloroformate are added , and the mixture is stirred for 10 minutes . to this is added a solution of 4 . 7 g . ( 0 . 01 mol .) of 7β - amino - 7α - methoxy cephalosporanic acid diphenylmethyl ester and 3 . 1 ml . of triethylamine in 40 ml . of methylene chloride . the mixture is stirred for 1 hour at - 5 ° and 1 hour at 5 °. this mixture is then evaporated to dryness in a rotary evaporator and the solid residue is triturated with ether and filtered under suction to yield the titled compound . 2 . 0 g . of the product from part ( b ) are added at - 5 ° to a mixture of 10 ml . of trifluoroacetic acid and 4 ml . of anisole . the mixture is stirred for 15 minutes and is then concentrated in a rotary evaporator . the residue is treated with ether and filtered under suction . the crude 3 -[( acetyloxy ) methyl ]- 7β -[[( 2 - amino - d - 2 - thienyl ) acetyl ] amino ]- 7 . alpha .- methoxy - 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , trifluoroacetic acid salt is dissolved in 50 ml . of water and 20 ml . of a solution of the acetate form of the ion exchange resin amberlite la 1 in isobutylmethylketone are added . the mixture is stirred for 2 hours at room temperature . the layers are separated , the aqueous phase is washed several times with ether and freeze - dried to yield 3 -[( acetyloxy ) methyl ]- 7β -[[( α - amino - d - 2 - thienyl ) acetyl ] amino ]- 7α - methoxy - 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . a mixture of 1 g . of the product from part ( c ) and 0 . 194 g . of potassium cyanate in 7 . 5 ml . of water are quickly heated in a preheated bath at 80 °. the mixture is then immediately cooled to room temperature and permitted to stand overnight . the reaction mixture is concentrated to about 4 ml . and the ph is adjusted to 1 . 5 with 2n hydrochloric acid . the precipitate is filtered under suction to obtain 3 -[( acetyloxy ) methyl ]- 7β -[[[( aminocarbonyl ) amino ] ( d - 2 - thienyl ) acetyl ] amino ]- 7α - methoxy - 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . 0 . 01 moles of the product from part ( d ) and 0 . 011 moles of 1 - oxopyridazine - 3 - thiol are heated in an aqueous acetone solution according to the procedure of example 1 ( f ) to yield 7β -[[[( aminocarbonyl ) amino ] ( d - 2 - thienyl ) acetyl ] amino ]- 7α - methoxy - 3 -[[[( 1 - oxopyridazin - 3 - yl ) thio ] methyl ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . following the procedure of example 1 but substituting for the 1 - oxopyridazine - 3 - thiol one of the following : following the procedure of example 4 but substituting for the 1 - oxopyridazine - 3 - thiol the pyridazines of examples 5 - 11 one obtains the following compounds : following the procedure of either example 1 or 4 but employing the α - amino acid shown in col . i one obtains the compound shown in col . ii ( procedure of example 1 ) or col . iii ( procedure of example 4 ). ______________________________________col . i ## str15 ## col . ii ## str16 ## col . iii ## str17 ## ex . r . sub . 1______________________________________19 h20 ch . sub . 321 c . sub . 2 h . sub . 522 t - c . sub . 4 h . sub . 923 n - c . sub . 5 h . sub . 1124 ## str18 ## 25 ## str19 ## 26 ## str20 ## 27 ## str21 ## 28 ## str22 ## 29 ## str23 ## 30 ## str24 ## 31 ## str25 ## 32 ## str26 ## 33 ## str27 ## 34 ## str28 ## 35 ## str29 ## 36 ## str30 ## 37 ## str31 ## 38 ## str32 ## 39 ## str33 ## 40 ## str34 ## 41 ## str35 ## 42 ## str36 ## 43 ## str37 ## 44 ## str38 ## 45 ## str39 ## 46 ## str40 ## 47 ## str41 ## 48 ## str42 ## 49 ## str43 ## 50 ## str44 ## 51 ## str45 ## 52 ## str46 ## 53 ## str47 ## 54 ## str48 ## 55 ## str49 ## 56 ## str50 ## 57 ## str51 ## 58 ## str52 ## 59 ## str53 ## 60 ## str54 ## 61 ## str55 ## 62 ## str56 ## 63 ## str57 ## 64 ## str58 ## 65 ## str59 ## 66 ## str60 ## 67 ## str61 ## 68 ## str62 ## 69 ## str63 ## 70 ## str64 ## 71 ## str65 ## 72 ## str66 ## ______________________________________ 1 . 5 g . of 3 -[( acetyloxy ) methyl ]- 7β -[[( 2 - amino - dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , trifluoroacetic acid salt from example 1 ( e ) and 1 . 01 ml . of triethylamine are dissolved at 0 °- 5 ° in 20 ml . of anhydrous methylene chloride . to the clear solution is added 2 . 49 g . of a 10 % solution of methylisocyanate in methylene chloride . this mixture is stirred for 2 hours at 0 °- 5 ° and then concentrated . the residue is taken up in a little water , shaken with ether , filtered and acidified with 2n hydrochloric acid to yield 3 -[( acetyloxy ) methyl ]- 7β -[[[( methylaminocarbonyl )- amino ] ( dl - 2 - thienyl ) acetyl ] amino ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . 0 . 01 mol . of the product from part ( a ) and 0 . 011 mol . of 1 - oxopyridazine - 3 - thiol are reacted according to the procedure of example 1 ( f ) to yield 7β -[[[( methylaminocarbonyl ) amino ]( dl - 2 - thienyl ) acetyl ] amino ]- 3 -[[[( 1 - oxopyridazine - 3 - yl ) thio ] methyl ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . following the procedure of example 73 but substituting for the methylisocyanate one of the following : similarly , by employing the methylisocyanate from example 73 or the alkylisocyanates of examples 74 - 80 in the procedure of examples 3 , 5 to 11 , and 19 to 72 , other compounds within the scope of this invention are obtained . 1 . 5 g . of 3 -[( acetyloxy ) methyl ]- 7β -[[( 2 - amino - d - 2 - thienyl ) acetyl ] amino ]- 7 . alpha .- methoxy - 8 - oxo - 5 - thia - 1 - azabicyclo -[ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid , trifluoroacetic acid salt from example 4 ( c ) and 1 . 01 ml . of triethylamine are dissolved at 0 °- 5 ° in 20 ml . of anhydrous methylene chloride . to the clear solution is added 2 . 49 g . of a 10 % solution of methylisocyanate in methylene chloride . this mixture is stirred for 2 hours at 0 °- 5 ° and then concentrated . the residue is taken up in a little water , shaken with ether , filtered and acidified with 2n hydrochloric acid to yield 3 -[( acetyloxy )- methyl ]- 7β -[ [[( methylaminocarbonyl ) amino ] ( d - 2 - thienyl ) acetyl ]- amino ]- 7α - methoxy - 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . 0 . 01 mol . of the product from part ( a ) and 0 . 011 mol . of 1 - oxopyradazine - 3 - thiol are reacted according to the procedure of example 1 ( f ) to yield 7β -[[[( methylaminocarbonyl )- amino ]( d - 2 - thienyl ) acetyl ] amino ]- 7α - methoxy - 3 -[[( 1 - oxopyradazin - 3 - yl ) thio ] methyl ]- 8 - oxo - 5 - thia - 1 - azabicyclo [ 4 . 2 . 0 ] oct - 2 - ene - 2 - carboxylic acid . following the procedure of examples 81 but substituting for the methylisocyanate one of the following : similarly , by employing the methylisocyanate from example 81 or the alkylisocyanates of examples 82 - 88 in the procedure of examples 12 to 18 other compounds within the scope of this invention are obtained . following the procedure of example 1 but employing the appropriate ester of 7 - aminocephalosporanic acid or by reacting the final product of example 1 , esters and salts of the following formula are obtained ______________________________________ ## str67 ## ex . r______________________________________89 ch . sub . 390 t - c . sub . 4 h . sub . 991 ## str68 ## 92 ## str69 ## 93 ## str70 ## 94 si ( ch . sub . 3 ). sub . 395 ch . sub . 2ccl . sub . 396 ## str71 ## 97 ## str72 ## 98 ## str73 ## 99 ## str74 ## 100 ## str75 ## 101 ca / 2102 mg / 2103 na104 al / 3105 [ ch . sub . 3 nh . sub . 3 ]. sup .⊕ 106 [( c . sub . 6 h . sub . 5 ch . sub . 2 ). sub . 2 nh . sub . 2 ]. sup .⊕ ______________________________________ similarly , the compounds of examples 3 - 88 can also be obtained in the various ester and salt forms shown in examples 89 - 106 .