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Record Information
StatusDetected and Quantified
Creation Date2007-04-12 18:42:28 UTC
Update Date2020-10-09 21:04:11 UTC
Secondary Accession Numbers
  • HMDB0062767
  • HMDB05960
  • HMDB62767
Metabolite Identification
Common NameD-Pipecolic acid
DescriptionD-Pipecolic acid is a normal human metabolite found in human biofluids. Normal adults excrete pipecolic acid primarily as the D-enantiomer even though it is present in the blood stream mainly as the L-enantiomer. It is believed that D-pipecolic acid originates from the metabolism of intestinal bacteria and from dietary sources. High levels of D-pipecolic acid are not found in plasma, but they are increased in urine of patients with chronic liver disease (PMID: 6501504 , 6490790 , 11719476 , 8398594 ).
(R)-Pipecolic acidChEBI
(R)-Piperidine-2-carboxylic acidChEBI
(+)-Pipecolic acidHMDB
(+)-Pipecolinic acidHMDB
(2R)-2-Piperidinecarboxylic acidHMDB
(2R)-Piperidine-2-carboxylic acidHMDB
(R)-()-2-Piperidinecarboxylic acidHMDB
(R)-(+)-Pipecolic acidHMDB
(R)-2-Piperidinecarboxylic acidHMDB
(R)-Pipecolinic acidHMDB
D-(+)- Pipecolic acidHMDB
D-(+)-Pipecolic acidHMDB
D-Pipecolinic acidHMDB
D-Piperidine-2-carboxylic acidHMDB
Chemical FormulaC6H11NO2
Average Molecular Weight129.157
Monoisotopic Molecular Weight129.078978601
IUPAC Name(2R)-piperidine-2-carboxylic acid
Traditional Name(+)-pipecolic acid
CAS Registry Number1723-00-8
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as d-alpha-amino acids. These are alpha amino acids which have the D-configuration of the alpha-carbon atom.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassCarboxylic acids and derivatives
Sub ClassAmino acids, peptides, and analogues
Direct ParentD-alpha-amino acids
Alternative Parents
  • D-alpha-amino acid
  • Piperidinecarboxylic acid
  • Piperidine
  • Amino acid
  • Carboxylic acid
  • Secondary aliphatic amine
  • Monocarboxylic acid or derivatives
  • Secondary amine
  • Organoheterocyclic compound
  • Azacycle
  • Organic oxygen compound
  • Organic nitrogen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Amine
  • Carbonyl group
  • Organopnictogen compound
  • Hydrocarbon derivative
  • Organic oxide
  • Aliphatic heteromonocyclic compound
Molecular FrameworkAliphatic heteromonocyclic compounds
External Descriptors
Physiological effect

Health effect:


Biological location:


Physical Properties
Experimental Properties
Melting Point266 - 268 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility158 g/LALOGPS
pKa (Strongest Acidic)2.06ChemAxon
pKa (Strongest Basic)10.39ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area49.33 ŲChemAxon
Rotatable Bond Count1ChemAxon
Refractivity32.67 m³·mol⁻¹ChemAxon
Polarizability13.47 ųChemAxon
Number of Rings1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-001i-9100000000-335cf7f41fca5cbc84cfSpectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-001i-9100000000-4611bf819d3b9d4fd062Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-001i-3900000000-bf71d20a7c8e71d335e5Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-001i-9400000000-fa70645b026293d659deSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-053u-9000000000-f849cc3c4b11bc7d4de7Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-004i-2900000000-bf800b5cd197887a11d5Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-003r-7900000000-8a0e9f51df4006740863Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-001i-9000000000-effc196b5c15971f985aSpectrum
Biological Properties
Cellular LocationsNot Available
Biospecimen Locations
  • Blood
Tissue LocationsNot Available
Normal Concentrations
BloodDetected and Quantified0.11 +/- 0.10 uMAdult (>18 years old)BothNormal details
Abnormal Concentrations
BloodDetected and Quantified0.16 +/- 0.14 uMAdult (>18 years old)BothUremia details
BloodDetected and Quantified1.58 +/- 0.50 uMAdult (>18 years old)Both
Hepatic Encephalopathy
Associated Disorders and Diseases
Disease References
  1. Fujita T, Amuro Y, Hada T, Higashino K: Plasma levels of pipecolic acid, both L- and D-enantiomers, in patients with chronic liver diseases, especially hepatic encephalopathy. Clin Chim Acta. 1999 Sep;287(1-2):99-109. [PubMed:10509899 ]
Hepatic encephalopathy
  1. Fujita T, Amuro Y, Hada T, Higashino K: Plasma levels of pipecolic acid, both L- and D-enantiomers, in patients with chronic liver diseases, especially hepatic encephalopathy. Clin Chim Acta. 1999 Sep;287(1-2):99-109. [PubMed:10509899 ]
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FooDB IDFDB023791
KNApSAcK IDNot Available
Chemspider ID643442
KEGG Compound IDNot Available
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkPipecolic acid
METLIN IDNot Available
PubChem Compound736316
PDB IDNot Available
ChEBI ID41582
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB IDMDB00000476
Synthesis ReferenceFadel, Antoine; Lahrache, Nabil. An efficient synthesis of enantiomerically pure (R)-pipecolic acid, (S)-proline, and their N-alkylated derivatives. Journal of Organic Chemistry (2007), 72(5), 1780-1784.
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Lam S, Azumaya H, Karmen A: High-performance liquid chromatography of amino acids in urine and cerebrospinal fluid. J Chromatogr. 1984 Oct 19;302:21-9. [PubMed:6501504 ]
  2. Lam S: Stereoselective analysis of D and L dansyl amino acids as the mixed chelate copper(II) complexes by HPLC. J Chromatogr Sci. 1984 Sep;22(9):416-23. [PubMed:6490790 ]
  3. Rashed MS, Al-Ahaidib LY, Aboul-Enein HY, Al-Amoudi M, Jacob M: Determination of L-pipecolic acid in plasma using chiral liquid chromatography-electrospray tandem mass spectrometry. Clin Chem. 2001 Dec;47(12):2124-30. [PubMed:11719476 ]
  4. Armstrong DW, Gasper M, Lee SH, Zukowski J, Ercal N: D-amino acid levels in human physiological fluids. Chirality. 1993;5(5):375-8. [PubMed:8398594 ]