About tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate
tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate (PubChem CID 158454784) has the molecular formula C274H367F6N29O80
and a molecular weight of 5461.06 g/mol. Its IUPAC name is tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate.
Frequently Asked Questions
What is the IUPAC name of tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate?
The IUPAC name of tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate (CID 158454784) is tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate.
What is the SMILES notation for tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate?
The canonical SMILES for tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate is C#CCOCC(COCC#C)(COCC#C)CC(=O)CCOCCOCCOCCOCCOCCOCCCC(=O)CC[C@H](C(=O)OCC1c2ccccc2-c2ccccc21)C(=O)OC(C)(C)C.C#CCOCC(COCC#C)(COCC#C)CC(=O)CCOCCOCCOCCOCCOCCOCCCC(=O)CC[C@H](N)C(=O)OC(C)(C)C.C#CCOCC(COCC#C)(COCC#C)CC(=O)CCOCCOCCOCCOCCOCCOCCCC(=O)CC[C@H](NC(=O)c1ccc(N(Cc2cnc3nc(N)[nH]c(=O)c3n2)C(=O)C(F)(F)F)cc1)C(=O)OC(C)(C)C.C#CCOCC(COCC#C)(COCC#C)CC(=O)CCOCCOCCOCCOCCOCCOCCCC(=O)CC[C@H](NC(=O)c1ccc(NCc2cnc3nc(N)[nH]c(=O)c3n2)cc1)C(=O)OC(C)(C)C.C#CCOCC(COCC#C)(COCC#C)CC(=O)CCOCCOCCOCCOCCOCCOCCCC(=O)CC[C@H](NC(=O)c1ccc(NCc2cnc3nc(N)[nH]c(=O)c3n2)cc1)C(=O)OC(C)(C)C.Nc1nc2ncc(CN(C(=O)C(F)(F)F)c3ccc(C(=O)ON4C(=O)CCC4=O)cc3)nc2c(=O)[nH]1.
What is the InChIKey of tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate?
The InChIKey is HEKZJPLSVRATMA-JMWMUQNOSA-N. The full InChI is InChI=1S/C55H72F3N7O16.C54H72O15.2C53H73N7O15.C39H63NO13.C20H14F3N7O6/c1-7-19-78-37-54(38-79-20-8-2,39-80-21-9-3)34-44(67)18-23-73-25-27-75-29-31-77-33-32-76-30-28-74-26-24-72-22-10-11-43(66)16-17-45(50(70)81-53(4,5)6)62-48(68)40-12-14-42(15-13-40)65(51(71)55(56,57)58)36-41-35-60-47-46(61-41)49(69)64-52(59)63-47;1-7-23-65-40-54(41-66-24-8-2,42-67-25-9-3)38-44(56)22-27-60-29-31-62-33-35-64-37-36-63-34-32-61-30-28-59-26-14-15-43(55)20-21-49(52(58)69-53(4,5)6)51(57)68-39-50-47-18-12-10-16-45(47)46-17-11-13-19-48(46)50;2*1-7-19-72-37-53(38-73-20-8-2,39-74-21-9-3)34-44(62)18-23-67-25-27-69-29-31-71-33-32-70-30-28-68-26-24-66-22-10-11-43(61)16-17-45(50(65)75-52(4,5)6)58-48(63)40-12-14-41(15-13-40)55-35-42-36-56-47-46(57-42)49(64)60-51(54)59-47;1-7-15-50-31-39(32-51-16-8-2,33-52-17-9-3)30-35(42)14-19-45-21-23-47-25-27-49-29-28-48-26-24-46-22-20-44-18-10-11-34(41)12-13-36(40)37(43)53-38(4,5)6;21-20(22,23)18(35)29(8-10-7-25-15-14(26-10)16(33)28-19(24)27-15)11-3-1-9(2-4-11)17(34)36-30-12(31)5-6-13(30)32/h1-3,12-15,35,45H,10-11,16-34,36-39H2,4-6H3,(H,62,68)(H3,59,60,63,64,69);1-3,10-13,16-19,49-50H,14-15,20-42H2,4-6H3;2*1-3,12-15,36,45,55H,10-11,16-35,37-39H2,4-6H3,(H,58,63)(H3,54,56,59,60,64);1-3,36H,10-33,40H2,4-6H3;1-4,7H,5-6,8H2,(H3,24,25,27,28,33)/t45-;49-;2*45-;36-;/m01000./s1.
What are the key properties of tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate?
tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate has a molecular weight of 5461.06 g/mol, XLogP of 17.66, 208 rotatable bonds, 14 hydrogen bond donors, and 99 hydrogen bond acceptors.
Where does this data come from?
All data for tert-butyl (2S)-2-amino-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;bis(tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methylamino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate);tert-butyl (2S)-2-[[4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoyl]amino]-5-oxo-8-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]octanoate;3-O-tert-butyl 1-O-(9H-fluoren-9-ylmethyl) (2R)-2-[3-oxo-6-[2-[2-[2-[2-[2-[3-oxo-6-prop-2-ynoxy-5,5-bis(prop-2-ynoxymethyl)hexoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]hexyl]propanedioate;(2,5-dioxopyrrolidin-1-yl) 4-[(2-amino-4-oxo-3H-pteridin-6-yl)methyl-(2,2,2-trifluoroacetyl)amino]benzoate is sourced from PubChem (CID 158454784), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).