4-((4-((((Methylamino)oxacetyl)amino)sulfonyl)phenyl)amino)-4-oxobutanoic acid methyl ester 85877-87-8 BUTANOIC ACID, 4-((4-((((METHYLAMINO)OXACETYL)AMINO)SULFONYL)PHENYL)AMINO)-4-OXO Butanoic acid, 4-((4-((((methylamino)oxacetyl)amino)sulfonyl)phenyl)amino)-4-oxo-, methyl ester