but-2-ynoic acid

• ChemBase ID: 140671
• Molecular Formular: C4H4O2
• Molecular Mass: 84.07336
• Monoisotopic Mass: 84.02112937
• SMILES: CC#CC(=O)O
• Canonical SMILES: CC#CC(=O)O
• InChI: InChI=1S/C4H4O2/c1-2-3-4(5)6/h1H3,(H,5,6)
• InChIKey: LUEHNHVFDCZTGL-UHFFFAOYSA-N

NAMES AND DATABASE IDS

Names

• IUPAC name: but-2-ynoic acid
• IUPAC Traditional name: 2-butynoic acid
• Synonyms: Tetrolic acid; 2-Butynoic acid; 丁炔酸; 2-丁炔酸

Database IDs

• CAS Number: 590-93-2
• EC Number: 209-695-7
• MDL Number: MFCD00004363
• Beilstein Number: 1740205
• PubChem SID: 162234912; 24858137
• PubChem CID: 68535

CALCULATED PROPERTIES

• Acid pKa: 2.4431221
• H Acceptors: 2
• H Donor: 1
• LogD (pH = 5.5): -1.9127828
• LogD (pH = 7.4): -2.4951365
• Log P: 1.0183998
• Molar Refractivity: 21.2848 cm^3
• Polarizability: 7.5779 Å^3
• Polar Surface Area: 37.3 Å^2
• Rotatable Bonds: 1
• Lipinski's Rule of Five: true

PROPERTIES

Physical Property

• Melting Point: 75-79°C; 78-80 °C(lit.)
• Boiling Point: 200-203°C
• Density: 0.964

Safety Information

• European Hazard Symbols: Corrosive (C)
• UN Number: 3261; UN3261
• German water hazard class: 3
• Hazard Class: 8
• Packing Group: 2; II
• Risk Statements: 34
• Safety Statements: 26-27-36/37/39-45; 26-36/37/39-45
• TSCA Listed: 是
• GHS Pictograms: GHS05
• GHS Signal Word: Danger
• GHS Hazard statements: H314; H314-H318
• GHS Precautionary statements: P280-P305 + P351 + P338-P310; P280-P305+P351+P338-P308+P313
• Personal Protective Equipment: Eyeshields, Faceshields, full-face particle respirator type N100 (US), Gloves, respirator cartridge type N100 (US), type P1 (EN143) respirator filter, type P3 (EN 143) respirator cartridges
• RID/ADR: UN 3261 8/PG 2

Product Information

• Purity: 98%
• Linear Formula: CH3C≡CCO2H

DETAILS

Sigma Aldrich - 303666

Packaging
1, 5 g in glass bottle
Application
Synthon employed in a variety of reactions, including cycloacylation of phenols to flavones and chromones,1 and cyclization to γ-butyrolactones.2

REFERENCES

• For Diels-Alder reactions with dienes, see: Chem. Ber., 114, 1793 (1981); Liebigs Ann. Chem., 1089 (1981).
• The dilithio derivative can be alkylated at the 4-position. The resulting Li salts can, if required, be converted directly to their TMS or methyl esters by reaction with TMS chloride or MeI: Tetrahedron Lett., 83 (1979).