3,4-Dihydro-2H-pyran

• Catalog No.: L02731
• CAS Number: 110-87-2
• M. F.: C5H8O
• M. W.: 84.11642
• Purity: 99%

SYNONYMS

• Title: 3,4-二氢-2H-吡喃
• IUPAC name: 3,4-dihydro-2H-pyran
• IUPAC Traditional name: dihydropyran
• Synonyms: 2,3-Dihydropyran

DATABASE IDS

• Beilstein Number: 103493
• MDL Number: MFCD00006558
• EC Number: 203-810-4
• CAS Number: 110-87-2

PROPERTIES

• Purity: 99%
• Boiling Point: 85-86°C
• Density: 0.926
• Flash Point: -15°C(5°F)
• Melting Point: -70°C
• Refractive Index: 1.4420
• GHS Hazard statements: H225-H315-H319-H335
• European Hazard Symbols: Irritant (Xi)
• European Hazard Symbols: Flammable (F)
• GHS Precautionary statements: P210-P261-P280G-P305+P351+P338-P403+P233
• Risk Statements: 11-36/37/38
• Safety Statements: 7/9-16-23-26-37
• TSCA Listed: 是
• Hazard Class: 3
• UN Number: UN2376
• Packing Group: II

REFERENCES

• Protects OH groups as their tetrahydropyranyl, (THP) ethers, stable to bases, Grignard or organolithium reagents, metal hydrides, etc., but readily removed by mild acid. Introduction (acetal formation) generally employs an acid catalyst, often p-TsOH. For example of protection, reaction with Grignard, and deprotection, see: Org. Synth. Coll., 7, 334 (1990). For alternative catalysts for THP ether formations, see: Pyridinium p-toluenesulfonate, A15708, Triphenylphosphine hydrobromide, L14290, Boron trifluoride diethyl etherate, A15275, Amberlyst? 15, 89079, Montmorillonite K10, L15160, Acetonyltriphenylphosphonium bromide, B22434, Indium(III) trifluoromethanesulfonate, 40131. Sulfuric acid/silica gel: Synth. Commun., 22, 159 (1992), allows the catalyst to be removed by simple filtration. POCl₃, described for the protection of diethyl hydroxymethylphosphonate, permits use in the Horner-Wadsworth-Emmons reaction: Org. Synth. Coll., 7, 160 (1990). See also Iodotrimethylsilane, A12902, providing non-acidic conditions; cf also Tetrahydropyran, A13392. For selective monotetrahydropyranylation of symmetrical diols, catalyzed by acidic ion-exchange resin, Dowex? 50WX2 50-100 (H), L13943, see: J. Org. Chem., 63, 8183 (1998).
• For selective deprotection of THP ethers under non-acidic conditions with LiCl in wet DMSO, see: J. Org. Chem., 61, 6038 (1996).
• The lithio-derivative, formed with tert-BuLi, reacts with, e.g. alkyl iodides or carbonyl compounds: Tetrahedron Lett., 4187 (1977).
• Acetals and ortho esters, in the presence of Lewis acid catalysts, add readily to the vinyl ether system: Chem. Lett., 1101 (1988).