About [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane
[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane (PubChem CID 159121989) has the molecular formula C152H212Cl4N16O36
and a molecular weight of 2981.26 g/mol. Its IUPAC name is [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane.
Frequently Asked Questions
What is the IUPAC name of [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane?
The IUPAC name of [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane (CID 159121989) is [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane.
What is the SMILES notation for [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane?
The canonical SMILES for [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane is C.CNCCC(=O)N(C)[C@@H](C)C(=O)O[C@H]1CC(=O)N(C)c2cc(cc(C)c2Cl)C/C(C)=C/C=C/[C@@H](OC)[C@@]2(O)C[C@H](OC(=O)N2)[C@@H](C)[C@@H]2O[C@@]12C.CNCCCC(=O)N(C)[C@@H](C)C(=O)O[C@H]1CC(=O)N(C)c2cc(cc(C)c2Cl)C/C(C)=C/C=C/[C@@H](OC)[C@@]2(O)C[C@H](OC(=O)N2)[C@@H](C)[C@@H]2O[C@@]12C.CO[C@@H]1/C=C/C=C(\C)Cc2cc(C)c(Cl)c(c2)N(C)C(=O)C[C@H](OC(=O)[C@H](C)N(C)C(=O)CCCN)[C@]2(C)O[C@H]2[C@H](C)[C@@H]2C[C@@]1(O)NC(=O)O2.CO[C@@H]1/C=C/C=C(\C)Cc2cc(C)c(Cl)c(c2)N(C)C(=O)C[C@H](OC(=O)[C@H](C)N(C)C(=O)c2ccc3c(c2)CCNC3)[C@]2(C)O[C@H]2[C@H](C)[C@@H]2C[C@@]1(O)NC(=O)O2.
What is the InChIKey of [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane?
The InChIKey is KFURDDLWTHICLH-LMDZQYQPSA-N. The full InChI is InChI=1S/C42H53ClN4O9.C37H53ClN4O9.2C36H51ClN4O9.CH4/c1-23-10-9-11-33(53-8)42(52)21-32(54-40(51)45-42)25(3)37-41(5,56-37)34(20-35(48)47(7)31-18-27(16-23)17-24(2)36(31)43)55-39(50)26(4)46(6)38(49)29-12-13-30-22-44-15-14-28(30)19-29;1-21-12-10-13-28(48-9)37(47)20-27(49-35(46)40-37)23(3)33-36(5,51-33)29(50-34(45)24(4)41(7)30(43)14-11-15-39-6)19-31(44)42(8)26-18-25(16-21)17-22(2)32(26)38;1-20-11-10-12-27(47-9)36(46)19-26(48-34(45)39-36)22(3)32-35(5,50-32)28(49-33(44)23(4)40(7)29(42)13-14-38-6)18-30(43)41(8)25-17-24(15-20)16-21(2)31(25)37;1-20-11-9-12-27(47-8)36(46)19-26(48-34(45)39-36)22(3)32-35(5,50-32)28(49-33(44)23(4)40(6)29(42)13-10-14-38)18-30(43)41(7)25-17-24(15-20)16-21(2)31(25)37;/h9-13,17-19,25-26,32-34,37,44,52H,14-16,20-22H2,1-8H3,(H,45,51);10,12-13,17-18,23-24,27-29,33,39,47H,11,14-16,19-20H2,1-9H3,(H,40,46);10-12,16-17,22-23,26-28,32,38,46H,13-15,18-19H2,1-9H3,(H,39,45);9,11-12,16-17,22-23,26-28,32,46H,10,13-15,18-19,38H2,1-8H3,(H,39,45);1H4/b11-9+,23-10+;13-10+,21-12+;12-10+,20-11+;12-9+,20-11+;/t25-,26+,32+,33-,34+,37+,41+,42+;23-,24+,27+,28-,29+,33+,36+,37+;2*22-,23+,26+,27-,28+,32+,35+,36+;/m1111./s1.
What are the key properties of [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane?
[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane has a molecular weight of 2981.26 g/mol, XLogP of 16.20, 27 rotatable bonds, 12 hydrogen bond donors, and 40 hydrogen bond acceptors.
Where does this data come from?
All data for [(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[4-aminobutanoyl(methyl)amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[4-(methylamino)butanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl-[3-(methylamino)propanoyl]amino]propanoate;[(1S,2R,3S,5S,6S,16E,18E,20R,21S)-11-chloro-21-hydroxy-20-methoxy-2,5,9,12,16-pentamethyl-8,23-dioxo-4,24-dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosa-10,12,14(26),16,18-pentaen-6-yl] (2S)-2-[methyl(1,2,3,4-tetrahydroisoquinoline-6-carbonyl)amino]propanoate;methane is sourced from PubChem (CID 159121989), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).