# Alpha-Lactose monohydrate

CAS: 64044-51-5
PubChem CID: 104938
InChIKey: WSVLPVUVIUVCRA-KPKNDVKVSA-N
Wikidata: Q27277391
Molecular formula: C₁₂H₂₄O₁₂
Molar mass: 360.31 g/mol
IUPAC: (2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-[(2R,3S,4R,5R,6S)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxyoxane-3,4,5-triol;hydrate
SMILES: C([C@@H]1[C@@H]([C@@H]([C@H]([C@@H](O1)O[C@@H]2[C@H](O[C@@H]([C@@H]([C@H]2O)O)O)CO)O)O)O)O.O
InChI: InChI=1S/C12H22O11.H2O/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17;/h3-20H,1-2H2;1H2/t3-,4-,5+,6+,7-,8-,9-,10-,11+,12+;/m1./s1
PSA: 191 A^2
Hydrogen bond donors: 9
Hydrogen bond acceptors: 12
Rotatable bonds: 4
Heavy atoms: 24
3D structure: 48 atoms, 48 bonds

## About the compound

Alpha-Lactose monohydrate is a chemical compound registered under CAS number 64044-51-5. Molecular formula: C₁₂H₂₄O₁₂. Molar mass: 360.31 g/mol. The full systematic IUPAC name is: (2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-[(2R,3S,4R,5R,6S)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxyoxane-3,4,5-triol;hydrate. The molecule contains 48 atoms connected by 48 chemical bonds. 
Chemical data comes from the PubChem (NIH), ChEMBL (EBI) and NIST WebBook databases. GHS statement translations comply with the CLP Regulation (EC 1272/2008). Interactive 3D model and 2D skeleton available at: https://molgod.org/molecule/64044-51-5/


## Synonyms

  - 5989-81-1
  - alpha-Lactose monohydrate
  - alpha-D-Glucopyranose, 4-O-beta-D-galactopyranosyl-, monohydrate
  - RefChem:1076517
  - DTXCID90820517
  - 611-913-4
  - Lactose monohydrate
  - alpha-D-Lactose monohydrate
  - D-Lactose monohydrate
  - 64044-51-5
  - Respitose
  - alpha-lactose hydrate

## Data sources

  - PubChem CID 104938: https://pubchem.ncbi.nlm.nih.gov/compound/104938
  - Wikidata: https://www.wikidata.org/wiki/Q27277391
  - NIST WebBook: https://webbook.nist.gov/cgi/cbook.cgi?ID=64044-51-5
  - ChEMBL: https://www.ebi.ac.uk/chembl/g/#search_results/all/query=64044-51-5

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Last updated: 2026-10-17
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