6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide

C136H112N42O19 — CID 158768456

About 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide

6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide (PubChem CID 158768456) has the molecular formula C136H112N42O19 and a molecular weight of 2638.67 g/mol. Its IUPAC name is 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide.

Molecular Properties

• Compound Name: 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide
• PubChem CID: 158768456
• Molecular Formula: C136H112N42O19
• Molecular Weight: 2638.67 g/mol
• Exact Mass: 2636.91
• IUPAC Name: 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide
• SMILES: C=CC(=O)N1CC(c2nc(C#N)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C#N)c3c(=O)n(-c4cc(O)cc5ccccc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)cnc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4cc(O)cc5ccccc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4cc(O)cc5ccccc45)cnc3n2)C1
• InChI: InChI=1S/C24H20N6O4.C24H18N6O3.C23H18N6O4.C22H20N8O3.C22H18N8O2.C21H18N8O3/c1-3-18(32)29-10-14(11-29)22-27-20(21(25)33)19-23(28-22)26-12(2)30(24(19)34)17-9-15(31)8-13-6-4-5-7-16(13)17;1-3-20(32)29-11-15(12-29)22-27-18(10-25)21-23(28-22)26-13(2)30(24(21)33)19-9-16(31)8-14-6-4-5-7-17(14)19;1-2-17(31)28-9-13(10-28)21-26-19(20(24)32)18-22(27-21)25-11-29(23(18)33)16-8-14(30)7-12-5-3-4-6-15(12)16;1-4-15(31)29-8-12(9-29)20-26-17(19(23)32)16-21(27-20)25-11(3)30(22(16)33)18-10(2)5-6-14-13(18)7-24-28-14;1-4-17(31)29-9-13(10-29)20-26-16(7-23)18-21(27-20)25-12(3)30(22(18)32)19-11(2)5-6-15-14(19)8-24-28-15;1-3-14(30)28-7-11(8-28)19-25-16(18(22)31)15-20(26-19)23-9-29(21(15)32)17-10(2)4-5-13-12(17)6-24-27-13/h3-9,14,31H,1,10-11H2,2H3,(H2,25,33);3-9,15,31H,1,11-12H2,2H3;2-8,11,13,30H,1,9-10H2,(H2,24,32);4-7,12H,1,8-9H2,2-3H3,(H2,23,32)(H,24,28);4-6,8,13H,1,9-10H2,2-3H3,(H,24,28);3-6,9,11H,1,7-8H2,2H3,(H2,22,31)(H,24,27)
• InChIKey: IPODTQGYBIXLQX-UHFFFAOYSA-N
• XLogP: 8.23
• TPSA: 852.55 Ų
• H-Bond Donors: 10
• H-Bond Acceptors: 48
• Rotatable Bonds: 22
• Heavy Atoms: 197
• Complexity: —

Lipinski Rule of Five

4 violations

Rule	Value
MW ≤ 500	2638.67
LogP ≤ 5	8.23
H-Bond Donors ≤ 5	10
H-Bond Acceptors ≤ 10	48

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'Michael_acceptor_1', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide?

The IUPAC name of 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide (CID 158768456) is 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide.

What is the SMILES notation for 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide?

The canonical SMILES for 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide is C=CC(=O)N1CC(c2nc(C#N)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C#N)c3c(=O)n(-c4cc(O)cc5ccccc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4c(C)ccc5[nH]ncc45)cnc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4cc(O)cc5ccccc45)c(C)nc3n2)C1.C=CC(=O)N1CC(c2nc(C(N)=O)c3c(=O)n(-c4cc(O)cc5ccccc45)cnc3n2)C1.

What is the InChIKey of 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide?

The InChIKey is IPODTQGYBIXLQX-UHFFFAOYSA-N. The full InChI is InChI=1S/C24H20N6O4.C24H18N6O3.C23H18N6O4.C22H20N8O3.C22H18N8O2.C21H18N8O3/c1-3-18(32)29-10-14(11-29)22-27-20(21(25)33)19-23(28-22)26-12(2)30(24(19)34)17-9-15(31)8-13-6-4-5-7-16(13)17;1-3-20(32)29-11-15(12-29)22-27-18(10-25)21-23(28-22)26-13(2)30(24(21)33)19-9-16(31)8-14-6-4-5-7-17(14)19;1-2-17(31)28-9-13(10-28)21-26-19(20(24)32)18-22(27-21)25-11-29(23(18)33)16-8-14(30)7-12-5-3-4-6-15(12)16;1-4-15(31)29-8-12(9-29)20-26-17(19(23)32)16-21(27-20)25-11(3)30(22(16)33)18-10(2)5-6-14-13(18)7-24-28-14;1-4-17(31)29-9-13(10-29)20-26-16(7-23)18-21(27-20)25-12(3)30(22(18)32)19-11(2)5-6-15-14(19)8-24-28-15;1-3-14(30)28-7-11(8-28)19-25-16(18(22)31)15-20(26-19)23-9-29(21(15)32)17-10(2)4-5-13-12(17)6-24-27-13/h3-9,14,31H,1,10-11H2,2H3,(H2,25,33);3-9,15,31H,1,11-12H2,2H3;2-8,11,13,30H,1,9-10H2,(H2,24,32);4-7,12H,1,8-9H2,2-3H3,(H2,23,32)(H,24,28);4-6,8,13H,1,9-10H2,2-3H3,(H,24,28);3-6,9,11H,1,7-8H2,2H3,(H2,22,31)(H,24,27).

What are the key properties of 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide?

6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide has a molecular weight of 2638.67 g/mol, XLogP of 8.23, 22 rotatable bonds, 10 hydrogen bond donors, and 48 hydrogen bond acceptors.

Where does this data come from?

All data for 6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;6-(3-hydroxynaphthalen-1-yl)-7-methyl-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(3-hydroxynaphthalen-1-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carbonitrile;7-methyl-6-(5-methyl-1H-indazol-4-yl)-5-oxo-2-(1-prop-2-enoylazetidin-3-yl)pyrimido[4,5-d]pyrimidine-4-carboxamide is sourced from PubChem (CID 158768456), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).