3-[[(2R)-4-carboxy-1-oxobutan-2-yl]amino]oxy-3-[(4-methoxyphenyl)methoxycarbonyl]-5-methylhexanoic acid;(4R)-4-[[4-[[2-[[(2R)-4-carboxy-1-oxobutan-2-yl]amino]oxy-4-[(4-methoxyphenyl)methoxy]-4-oxo-2-propan-2-ylbutanoyl]oxymethyl]phenoxy]amino]-5-oxopentanoic acid;(4R)-4-[[4-[[2-hydroxy-2-[2-[(4-methoxyphenyl)methoxy]-2-oxoethyl]-3-methylpentanoyl]oxymethyl]phenoxy]amino]-5-oxopentanoic acid;(4R)-4-[[4-[[2-hydroxy-2-[2-[(4-methoxyphenyl)methoxy]-2-oxoethyl]-4-methylpentanoyl]oxymethyl]phenoxy]amino]-5-oxopentanoic acid;1-O-[(4-methoxyphenyl)methyl] 4-O-methyl 2-hydroxy-2-propan-2-ylbutanedioate