Exact Mass: 561.2951044
Exact Mass Matches: 561.2951044
Found 74 metabolites which its exact mass value is equals to given mass value 561.2951044,
within given mass tolerance error 4.0E-5 dalton. Try search metabolite list with more accurate mass tolerance error
8.0E-6 dalton.
Ergocornine
N-[2-hydroxy-5,8-dioxo-4,7-bis(propan-2-yl)-3-oxa-6,9-diazatricyclo[7.3.0.0²,⁶]dodecan-4-yl]-6-methyl-6,11-diazatetracyclo[7.6.1.0²,⁷.0¹²,¹⁶]hexadeca-1(16),2,9,12,14-pentaene-4-carboxamide
8-Epimer-Beta-Ergoptine|8-Epimer-betabeta-Ergoptine|Beta-Ergoptine|betabeta-Ergoptine
8-Epimer-Beta-Ergoptine|8-Epimer-betabeta-Ergoptine|Beta-Ergoptine|betabeta-Ergoptine
(32S,6S)-6-benzyl-31-[N-(N-methyl-L-alanyl)-L-valyl]-(32rH,33tH)-2-oxa-5,8-diaza-1(1,4)-benzena-3(3,2)-pyrrolidina-cyclodecaphan-9c-ene-4,7-dione|Mauritin-F|Mauritine F|mauritine-F
(32S,6S)-6-benzyl-31-[N-(N-methyl-L-alanyl)-L-valyl]-(32rH,33tH)-2-oxa-5,8-diaza-1(1,4)-benzena-3(3,2)-pyrrolidina-cyclodecaphan-9c-ene-4,7-dione|Mauritin-F|Mauritine F|mauritine-F
Ergocornine
Ergocorninine
Ergotaman bearing a hydroxy group at the 12 position, isopropyl groups at the 2 and 5alpha positions, and oxo groups at positions 3, 6, and 18. It is a natural ergot alkaloid. CONFIDENCE Reference Standard (Level 1) relative retention time with respect to 9-anthracene Carboxylic Acid is 1.024 relative retention time with respect to 9-anthracene Carboxylic Acid is 1.021 relative retention time with respect to 9-anthracene Carboxylic Acid is 1.019 relative retention time with respect to 9-anthracene Carboxylic Acid is 1.017
Phe Ile Pro Trp
(2S)-2-{[(2S)-1-[(2S,3S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanoic acid
Phe Ile Trp Pro
(2S)-1-[(2S)-2-[(2S,3S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-methylpentanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carboxylic acid
Phe Leu Pro Trp
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-4-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanoic acid
Phe Leu Trp Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-4-methylpentanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carboxylic acid
Phe Pro Ile Trp
(2S)-2-[(2S,3S)-2-{[(2S)-1-[(2S)-2-amino-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-methylpentanamido]-3-(1H-indol-3-yl)propanoic acid
Phe Pro Leu Trp
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-4-methylpentanamido]-3-(1H-indol-3-yl)propanoic acid
Phe Pro Trp Ile
(2S,3S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanamido]-3-methylpentanoic acid
Phe Pro Trp Leu
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanamido]-4-methylpentanoic acid
Phe Trp Ile Pro
(2S)-1-[(2S,3S)-2-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-(1H-indol-3-yl)propanamido]-3-methylpentanoyl]pyrrolidine-2-carboxylic acid
Phe Trp Leu Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-(1H-indol-3-yl)propanamido]-4-methylpentanoyl]pyrrolidine-2-carboxylic acid
Phe Trp Pro Ile
(2S,3S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-methylpentanoic acid
Phe Trp Pro Leu
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-4-methylpentanoic acid
Ile Phe Pro Trp
(2S)-2-{[(2S)-1-[(2S)-2-[(2S,3S)-2-amino-3-methylpentanamido]-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanoic acid
Ile Phe Trp Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S,3S)-2-amino-3-methylpentanamido]-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carboxylic acid
Ile Pro Phe Trp
(2S)-2-[(2S)-2-{[(2S)-1-[(2S,3S)-2-amino-3-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoic acid
Ile Pro Trp Phe
(2S)-2-[(2S)-2-{[(2S)-1-[(2S,3S)-2-amino-3-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoic acid
Ile Trp Phe Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S,3S)-2-amino-3-methylpentanamido]-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoyl]pyrrolidine-2-carboxylic acid
Ile Trp Pro Phe
(2S)-2-{[(2S)-1-[(2S)-2-[(2S,3S)-2-amino-3-methylpentanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanoic acid
Leu Phe Pro Trp
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-4-methylpentanamido]-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanoic acid
Leu Phe Trp Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-4-methylpentanamido]-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carboxylic acid
Leu Pro Phe Trp
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-4-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanamido]-3-(1H-indol-3-yl)propanoic acid
Leu Pro Trp Phe
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-4-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoic acid
Leu Trp Phe Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-4-methylpentanamido]-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoyl]pyrrolidine-2-carboxylic acid
Leu Trp Pro Phe
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-4-methylpentanamido]-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanoic acid
Pro Phe Ile Trp
(2S)-3-(1H-indol-3-yl)-2-[(2S,3S)-3-methyl-2-[(2S)-3-phenyl-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]pentanamido]propanoic acid
Pro Phe Leu Trp
(2S)-3-(1H-indol-3-yl)-2-[(2S)-4-methyl-2-[(2S)-3-phenyl-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]pentanamido]propanoic acid
Pro Phe Trp Ile
(2S,3S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-3-phenyl-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]propanamido]-3-methylpentanoic acid
Pro Phe Trp Leu
(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-3-phenyl-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]propanamido]-4-methylpentanoic acid
Pro Ile Phe Trp
(2S)-3-(1H-indol-3-yl)-2-[(2S)-2-[(2S,3S)-3-methyl-2-[(2S)-pyrrolidin-2-ylformamido]pentanamido]-3-phenylpropanamido]propanoic acid
Pro Ile Trp Phe
(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S,3S)-3-methyl-2-[(2S)-pyrrolidin-2-ylformamido]pentanamido]propanamido]-3-phenylpropanoic acid
Pro Leu Phe Trp
(2S)-3-(1H-indol-3-yl)-2-[(2S)-2-[(2S)-4-methyl-2-[(2S)-pyrrolidin-2-ylformamido]pentanamido]-3-phenylpropanamido]propanoic acid
Pro Leu Trp Phe
(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-4-methyl-2-[(2S)-pyrrolidin-2-ylformamido]pentanamido]propanamido]-3-phenylpropanoic acid
Pro Trp Phe Ile
(2S,3S)-2-[(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]-3-phenylpropanamido]-3-methylpentanoic acid
Pro Trp Phe Leu
(2S)-2-[(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]-3-phenylpropanamido]-4-methylpentanoic acid
Pro Trp Ile Phe
(2S)-2-[(2S,3S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]-3-methylpentanamido]-3-phenylpropanoic acid
Pro Trp Leu Phe
(2S)-2-[(2S)-2-[(2S)-3-(1H-indol-3-yl)-2-[(2S)-pyrrolidin-2-ylformamido]propanamido]-4-methylpentanamido]-3-phenylpropanoic acid
Trp Phe Ile Pro
(2S)-1-[(2S,3S)-2-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-phenylpropanamido]-3-methylpentanoyl]pyrrolidine-2-carboxylic acid
Trp Phe Leu Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-phenylpropanamido]-4-methylpentanoyl]pyrrolidine-2-carboxylic acid
Trp Phe Pro Ile
(2S,3S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-3-methylpentanoic acid
Trp Phe Pro Leu
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-phenylpropanoyl]pyrrolidin-2-yl]formamido}-4-methylpentanoic acid
Trp Ile Phe Pro
(2S)-1-[(2S)-2-[(2S,3S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-methylpentanamido]-3-phenylpropanoyl]pyrrolidine-2-carboxylic acid
Trp Ile Pro Phe
(2S)-2-{[(2S)-1-[(2S,3S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-3-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanoic acid
Trp Leu Phe Pro
(2S)-1-[(2S)-2-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-4-methylpentanamido]-3-phenylpropanoyl]pyrrolidine-2-carboxylic acid
Trp Leu Pro Phe
(2S)-2-{[(2S)-1-[(2S)-2-[(2S)-2-amino-3-(1H-indol-3-yl)propanamido]-4-methylpentanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanoic acid
Trp Pro Phe Ile
(2S,3S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanamido]-3-methylpentanoic acid
Trp Pro Phe Leu
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-phenylpropanamido]-4-methylpentanoic acid
Trp Pro Ile Phe
(2S)-2-[(2S,3S)-2-{[(2S)-1-[(2S)-2-amino-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-3-methylpentanamido]-3-phenylpropanoic acid
Trp Pro Leu Phe
(2S)-2-[(2S)-2-{[(2S)-1-[(2S)-2-amino-3-(1H-indol-3-yl)propanoyl]pyrrolidin-2-yl]formamido}-4-methylpentanamido]-3-phenylpropanoic acid
(8alpha)-12-hydroxy-2,5alpha-diisopropylergotaman-3,6,18-trione
(8alpha)-12-hydroxy-2,5alpha-diisopropylergotaman-3,6,18-trione
1-[[(2S,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2S,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2R,3R)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3R)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3R)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2S,3R)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2R,3R)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2S,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2S,3S)-5-[(2S)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2R,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2R,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2S,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2S,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-10-[[(1-naphthalenylamino)-oxomethyl]amino]-6-oxo-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-propan-2-ylurea
1-[[(2R,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
1-[[(2R,3S)-5-[(2R)-1-hydroxypropan-2-yl]-3-methyl-6-oxo-8-[[oxo-(propan-2-ylamino)methyl]amino]-3,4-dihydro-2H-1,5-benzoxazocin-2-yl]methyl]-1-methyl-3-(1-naphthalenyl)urea
(6aS,9S)-N-[(1S,2S,4R,7S)-2-hydroxy-5,8-dioxo-4,7-di(propan-2-yl)-3-oxa-6,9-diazatricyclo[7.3.0.02,6]dodecan-4-yl]-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
(6aS,9S)-N-[(1S,2S,4R,7S)-2-hydroxy-5,8-dioxo-4,7-di(propan-2-yl)-3-oxa-6,9-diazatricyclo[7.3.0.02,6]dodecan-4-yl]-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
(4s,7r)-n-[(1s,2s,4r,7s)-2-hydroxy-4,7-diisopropyl-5,8-dioxo-3-oxa-6,9-diazatricyclo[7.3.0.0²,⁶]dodecan-4-yl]-6-methyl-6,11-diazatetracyclo[7.6.1.0²,⁷.0¹²,¹⁶]hexadeca-1(16),2,9,12,14-pentaene-4-carboximidic acid
(4s,7r)-n-[(1s,2s,4r,7s)-2-hydroxy-4,7-diisopropyl-5,8-dioxo-3-oxa-6,9-diazatricyclo[7.3.0.0²,⁶]dodecan-4-yl]-6-methyl-6,11-diazatetracyclo[7.6.1.0²,⁷.0¹²,¹⁶]hexadeca-1(16),2,9,12,14-pentaene-4-carboximidic acid