(2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide

C107H157F2N13O31 — CID 161218252

About (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide

(2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide (PubChem CID 161218252) has the molecular formula C107H157F2N13O31 and a molecular weight of 2159.49 g/mol. Its IUPAC name is (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide.

Molecular Properties

• Compound Name: (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide
• PubChem CID: 161218252
• Molecular Formula: C107H157F2N13O31
• Molecular Weight: 2159.49 g/mol
• Exact Mass: 2158.11
• IUPAC Name: (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide
• SMILES: CCCC1O[C@@H]2C[C@H]3[C@@H]4C[C@H](F)C5=CC(=O)C=C[C@]5(C)[C@@]4(F)[C@@H](O)C[C@]3(C)[C@]2(C(=O)COc2ccc(NC(=O)[C@H](C)CC(=O)[C@@H](NC(=O)[C@@H](CCCCNC(=O)COC3CCCCCC4=C3NNN4[C@H]3O[C@H](CO)[C@@H](O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@H]4O)C(O)[C@H]3O)NC(=O)CCOCCOCCOCCOCCNC(=O)CCC(=O)N3Cc4ccccc4/C(NCCOCCOCCOCCNC)=C(/NN)c4ccccc43)C(C)C)cc2)O1
• InChI: InChI=1S/C107H157F2N13O31/c1-8-18-89-151-84-56-71-72-55-74(108)73-54-67(125)32-34-104(73,5)106(72,109)82(127)57-105(71,6)107(84,153-89)83(128)61-147-68-28-26-66(27-29-68)115-100(138)64(4)53-78(126)90(63(2)3)117-101(139)75(22-16-17-35-112-87(131)62-148-79-25-11-9-10-24-77-93(79)119-120-122(77)102-97(136)96(135)99(81(60-124)149-102)152-103-98(137)95(134)94(133)80(59-123)150-103)116-86(130)33-39-140-43-47-144-51-52-146-49-45-142-41-37-113-85(129)30-31-88(132)121-58-65-19-12-13-20-69(65)91(92(118-110)70-21-14-15-23-76(70)121)114-38-42-143-46-50-145-48-44-141-40-36-111-7/h12-15,19-21,23,26-29,32,34,54,63-64,71-72,74-75,79-82,84,89-90,94-99,102-103,111,114,118-120,123-124,127,133-137H,8-11,16-18,22,24-25,30-31,33,35-53,55-62,110H2,1-7H3,(H,112,131)(H,113,129)(H,115,138)(H,116,130)(H,117,139)/b92-91-/t64-,71+,72+,74+,75-,79?,80-,81-,82+,84-,89?,90+,94-,95+,96?,97-,98-,99-,102+,103-,104+,105+,106+,107-/m1/s1
• InChIKey: UXDWIGBBBYILNX-AMFZZXSZSA-N
• XLogP: 1.85
• TPSA: 597.49 Ų
• H-Bond Donors: 19
• H-Bond Acceptors: 38
• Rotatable Bonds: 60
• Heavy Atoms: 153
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	2159.49
LogP ≤ 5	1.85
H-Bond Donors ≤ 5	19
H-Bond Acceptors ≤ 10	38

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'Aliphatic_long_chain', 'substructure': 'N/A'}, {'alert_name': 'hydrazine', 'substructure': 'N/A'}, {'alert_name': 'Oxygen-nitrogen_single_bond', 'substructure': 'N/A'}, {'alert_name': 'stilbene', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide?

The IUPAC name of (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide (CID 161218252) is (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide.

What is the SMILES notation for (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide?

The canonical SMILES for (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide is CCCC1O[C@@H]2C[C@H]3[C@@H]4C[C@H](F)C5=CC(=O)C=C[C@]5(C)[C@@]4(F)[C@@H](O)C[C@]3(C)[C@]2(C(=O)COc2ccc(NC(=O)[C@H](C)CC(=O)[C@@H](NC(=O)[C@@H](CCCCNC(=O)COC3CCCCCC4=C3NNN4[C@H]3O[C@H](CO)[C@@H](O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@H]4O)C(O)[C@H]3O)NC(=O)CCOCCOCCOCCOCCNC(=O)CCC(=O)N3Cc4ccccc4/C(NCCOCCOCCOCCNC)=C(/NN)c4ccccc43)C(C)C)cc2)O1.

What is the InChIKey of (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide?

The InChIKey is UXDWIGBBBYILNX-AMFZZXSZSA-N. The full InChI is InChI=1S/C107H157F2N13O31/c1-8-18-89-151-84-56-71-72-55-74(108)73-54-67(125)32-34-104(73,5)106(72,109)82(127)57-105(71,6)107(84,153-89)83(128)61-147-68-28-26-66(27-29-68)115-100(138)64(4)53-78(126)90(63(2)3)117-101(139)75(22-16-17-35-112-87(131)62-148-79-25-11-9-10-24-77-93(79)119-120-122(77)102-97(136)96(135)99(81(60-124)149-102)152-103-98(137)95(134)94(133)80(59-123)150-103)116-86(130)33-39-140-43-47-144-51-52-146-49-45-142-41-37-113-85(129)30-31-88(132)121-58-65-19-12-13-20-69(65)91(92(118-110)70-21-14-15-23-76(70)121)114-38-42-143-46-50-145-48-44-141-40-36-111-7/h12-15,19-21,23,26-29,32,34,54,63-64,71-72,74-75,79-82,84,89-90,94-99,102-103,111,114,118-120,123-124,127,133-137H,8-11,16-18,22,24-25,30-31,33,35-53,55-62,110H2,1-7H3,(H,112,131)(H,113,129)(H,115,138)(H,116,130)(H,117,139)/b92-91-/t64-,71+,72+,74+,75-,79?,80-,81-,82+,84-,89?,90+,94-,95+,96?,97-,98-,99-,102+,103-,104+,105+,106+,107-/m1/s1.

What are the key properties of (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide?

(2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide has a molecular weight of 2159.49 g/mol, XLogP of 1.85, 60 rotatable bonds, 19 hydrogen bond donors, and 38 hydrogen bond acceptors.

Where does this data come from?

All data for (2R,5S)-N-[4-[2-[(1S,2S,4R,8S,9S,11S,12R,13S,19S)-12,19-difluoro-11-hydroxy-9,13-dimethyl-16-oxo-6-propyl-5,7-dioxapentacyclo[10.8.0.02,9.04,8.013,18]icosa-14,17-dien-8-yl]-2-oxoethoxy]phenyl]-5-[[(2R)-6-[[2-[[1-[(2S,3R,4R,5S,6R)-3,4-dihydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-2-yl]-2,3,4,5,6,7,8,9-octahydrocycloocta[d]triazol-4-yl]oxy]acetyl]amino]-2-[3-[2-[2-[2-[2-[[4-[(11Z)-12-hydrazinyl-11-[2-[2-[2-[2-(methylamino)ethoxy]ethoxy]ethoxy]ethylamino]-6H-benzo[c][1]benzazocin-5-yl]-4-oxobutanoyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]hexanoyl]amino]-2,6-dimethyl-4-oxoheptanamide is sourced from PubChem (CID 161218252), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).