(6R,7aS)-6-hydroxy-2-methyl-hexahydro-1H-pyrrolo[1,2-c]imidazolidin-3-one

(6R,7aS)-6-hydroxy-hexahydropyrrolo[1,2-c][1,3]oxazol-3-one

(6R,7R)-3-methyl-8-oxo-7-(2-phenylacetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-3-[(acetyloxy)methyl]-7-(3-bromo-4-methylbenzamido)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-3-[(acetyloxy)methyl]-7-(4-cyanobenzamido)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-3-[(acetyloxy)methyl]-8-oxo-7-[2-(thiophen-2-yl)acetamido]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-3-[(carbamoyloxy)methyl]-7-[(2Z)-2-(furan-2-yl)-2-(methoxyimino)acetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-3-(hydroxymethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-amino-3-(hydroxymethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-amino-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-amino-3-{[(1-methyl-1H-1,2,3,4-tetrazol-5-yl)sulfanyl]methyl}-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-[(2R)-2-amino-2-(4-hydroxyphenyl)acetamido]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-[(2R)-2-amino-2-(cyclohexa-1,4-dien-1-yl)acetamido]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-[(2R)-2-[(4-ethyl-2,3-dioxopiperazine-1-carbonyl)amino]-2-(4-hydroxyphenyl)acetamido]-3-{[(1-methyl-1H-1,2,3,4-tetrazol-5-yl)sulfanyl]methyl}-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-(methoxyimino)acetamido]-3-{[(1-methyl-1H-1,2,3,4-tetrazol-5-yl)sulfanyl]methyl}-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,7R)-7-[(5R)-5-amino-5-carboxypentanamido]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(6R,8S)-6,8-dimethyl-7-oxa-2-azaspiro[3.5]nonane hydrochloride

(6R,8S)-6,8-dimethyl-7-oxaspiro[3.5]nonan-2-one

(6S)-1,2,5-triazaspiro[2.4]hept-1-ene-6-carboxylic acid hydrochloride

(6S)-1,4-oxazepan-6-ol

(6S)-1H,4H,5H,6H,7H-imidazo[4,5-c]pyridine-6-carboxylic acid

(6S)-2,2,6-trimethylmorpholine hydrochloride

(6S)-2,8,11-triazatricyclo[8.4.0.0,2,6]tetradeca-1(14),10,12-triene

(6S)-2,8,14-triazatricyclo[8.4.0.0,2,6]tetradeca-1(14),10,12-triene

(6S)-2,8-diazatricyclo[8.4.0.0,2,6]tetradeca-1(14),10,12-triene

(6S)-2-bromo-4,5,6,7-tetrahydro-1,3-benzothiazol-6-amine dihydrobromide

(6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-2-en-1-one

(6S)-4,5,6,7-tetrahydro-1,3-benzothiazol-6-amine dihydrochloride

(6S)-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine

(6S)-4-oxaspiro[2.4]heptan-6-ol

(6S)-4-oxo-1H,4H,5H,6H,7H-pyrazolo[4,3-c]pyridine-6-carboxylic acid

(6S)-4H,5H,6H,7H-thieno[3,2-c]pyridine-6-carboxylic acid hydrochloride

(6S)-5-azaspiro[2.4]heptane-6-carboxylic acid hydrochloride

(6S)-5-methyl-5-azaspiro[2.4]heptane-6-carboxylic acid hydrochloride

(6S)-5-[(tert-butoxy)carbonyl]-1,2,5-triazaspiro[2.4]hept-1-ene-6-carboxylic acid

(6S)-5-[(tert-butoxy)carbonyl]-5-azaspiro[2.4]heptane-6-carboxylic acid

(6S)-5-{[(9H-fluoren-9-yl)methoxy]carbonyl}-5-azaspiro[2.4]heptane-6-carboxylic acid

(6S)-6-(difluoromethyl)piperidin-2-one

(6S)-6-(hydroxymethyl)morpholin-3-one

(6S)-6-(hydroxymethyl)piperazin-2-one

(6S)-6-(hydroxymethyl)piperazin-2-one hydrochloride

(6S)-6-(methoxymethyl)-2,2-dimethylmorpholine

(6S)-6-ethyloxane-2,4-dione

(6S)-6-ethynyl-5-azaspiro[2.4]heptane hydrochloride