26638-97-1

Basic information

• Product Name: 3,4-dihydro-2H-pyran-2-one
• Synonyms: 2H-Pyran-2-one, 3,4-dihydro-; 3,4-Dihydro-2H-pyran-2-one
• CAS NO: 26638-97-1
• Molecular Formula: C₅H₆O₂
• Molecular Weight: 98.0999
• Mol File: 26638-97-1.mol
• Article Data: 6

Chemical Properties

• Boiling Point: 196.4°C at 760 mmHg
• Flash Point: 69.6°C
• Density: 1.123g/cm³
• Vapor Pressure: 0.398mmHg at 25°C
• Refractive Index: 1.47
• CAS DataBase Reference: 3,4-dihydro-2H-pyran-2-one(CAS DataBase Reference)
• NIST Chemistry Reference: 3,4-dihydro-2H-pyran-2-one(26638-97-1)
• EPA Substance Registry System: 3,4-dihydro-2H-pyran-2-one(26638-97-1)

Safety Data

• Hazardous Substances Data: 26638-97-1(Hazardous Substances Data)

Upstream product

• 6089-09-4 4-pentynoic acid 
• 10374-51-3 5-hydroxymethyl-4,5-dihydrofuranone 
• 930-30-3 cyclopent-2-enone 

Downstream Products

• 146098-87-5 5,6-dihydro-2-(4-methoxyphenyl)-2H-pyran 
• 74189-56-3 4-(tetrahydropyran-2-yloxy)benzaldehyde 
• 34716-73-9 3-(tetrahydro-2H-2-pyranyloxy)benzaldehyde 

Relevant articles and documents

Regioselective cyclization of alpha,omega-alkynoic acids catalysed by TpRu complexes: synthesis of endocyclic enol lactones [Tp = hydrotris(pyrazolyl)borate].

The sigma-enynyl complex [TpRu(C(Ph)=C(Ph)C identical to CPh)(P-MeiPr2)] efficiently catalyses the regioselective cyclization of alpha,omega-alkynoic acids to yield endocyclic enol lactones having ring size up to 12 atoms.

Catalytic application of a Ru-alkylidene in the nucleophilic addition of several carboxylic acids on terminal alkynes and the homo-coupling of 1-alkynes

Thermal treatment of Ru-alkylidene (4) bearing a triazol-5-ylidene (NHC) ligand (2) at 110 °C and addition of a terminal alkyne generates a ruthenium vinylidene. The thermolysed Ru-alkylidene catalyses the vinylation and dimerisation of 1-alkynes. The nucleophilic addition of acetic acid on terminal alkynes proceeds smoothly and regioselective towards the Markovnikov addition. The addition reaction can be tuned by changing the acidity of the carboxylic acid. At increasing acidity, higher conversion of the triple bond is obtained and the vinylation/dimerisation ratio increases. The direct coupling between two 1-alkynes shows a reactivity order, which decreases from 1-octyne>1,7-octadiyne>phenylacetylene>3,3 dimethyl-1-butyne. The regioselectivity is strongly dependent on the nature of the terminal alkyne.

Process for preparing unsaturated six-membered lactones

There are disclosed and claimed substituted cyclic lactones and process for preparation thereof. In particular, there are disclosed substituted cyclic lactones having alkyl substituents on the ring, especially such lactones having substituents on the ring of which two on the same carbon atom. Additionally, the invention herein disclosed and claimed relates to a process for the preparation of lactones by heating a six-membered hydroxy substituted lactone in the presence of a catalyst.