110-87-2

Basic information

• Product Name: Dihydropyran
• Synonyms: 3,4-Dihydro-2H-pyran,99%;2,3-Dihydro-2H-pyran;2,3-Dihydropyran, DHP;3,4-Dihydro-2H-pyran ,98%;3,4-Dihydro-2H-pyran (DHP);3,4-Dihydro-2H-pyran, 99% 100GR;3,4-Dihydro-2H-pyran, 99% 500GR;Dihydropyran,3,4-Dihydro-2H-pyran
• CAS NO: 110-87-2
• Molecular Formula: C₅H₈O
• Molecular Weight: 84.12
• EINECS: 203-810-4
• Product Categories: Protection and Derivatization;Halogenated Heterocycles ,Isoquinolines ,Quinolines ,Quinazolines ,Quinaldines;Oxygen cyclic compounds;Protection & Derivatization Reagents (for Synthesis);Synthetic Organic Chemistry;Others;Protecting and Derivatizing Reagents
• Mol File: 110-87-2.mol

Chemical Properties

• Melting Point: −70 °C(lit.)
• Boiling Point: 86 °C(lit.)
• Flash Point: 4 °F
• Appearance: Clear colorless to yellow/Liquid
• Density: 0.922 g/mL at 25 °C(lit.)
• Vapor Density: 2.9 (vs air)
• Vapor Pressure: 74.4mmHg at 25°C
• Refractive Index: n20/D 1.440(lit.)
• Storage Temp.: Flammables area
• Solubility: 7.7g/l
• Explosive Limit: 1.1-13.8%(V)
• Water Solubility: 20 g/L (20 ºC)
• Stability: Volatile
• BRN: 103493
• CAS DataBase Reference: Dihydropyran(CAS DataBase Reference)
• NIST Chemistry Reference: Dihydropyran(110-87-2)
• EPA Substance Registry System: Dihydropyran(110-87-2)

Safety Data

• Hazard Codes: F,Xi
• Statements: 11-36/37/38-36/38-19
• Safety Statements: 16-26-36-37/39-33-7/9
• RIDADR: UN 2376 3/PG 2
• WGK Germany: 3
• RTECS: UP7700000
• TSCA: Yes
• HazardClass: 3
• PackingGroup: II
• Hazardous Substances Data: 110-87-2(Hazardous Substances Data)

Usage

Uses

Used in Organic Synthesis:
3,4-Dihydro-2H-pyran is used as a hydroxyl-protecting reagent in organic synthesis. It serves to protect various reactive functional groups during chemical reactions, ensuring the desired product formation without unwanted side reactions.
Used in Polymer Industries:
In the polymer industry, 3,4-Dihydro-2H-pyran is involved in polymerization reactions, either alone or with unsaturated compounds. Its presence contributes to the development of polymers with specific properties and applications.
Used in the Preparation of Bicyclic Compounds:
3,4-Dihydro-2H-pyran is also employed in the synthesis of epoxide-fused bicyclic compounds, halo compounds, and allenic alcohols. These compounds find applications in various fields, including pharmaceuticals, materials science, and chemical research.
Overall, 3,4-Dihydro-2H-pyran is a versatile compound with a wide range of applications in different industries, primarily due to its ability to protect reactive functional groups and act as an intermediate in synthetic chemistry.

Flammability and Explosibility

Flammable

Safety Profile

A flammable and very dangerous fire hazard when exposed to heat or flame; can react vigorously with oxidzing materials. Keep away from heat and open flame. To fight fire, use alcohol foam, CO2, or dry chemical. When heated to decomposition it emits acrid smoke and irritating

Purification Methods

Partially dry dihydropyran with Na2CO3, then fractionally distil it. The fraction b 84-85o is refluxed with Na until hydrogen no longer evolves when fresh Na is added. It is then dried, and distilled again through a 60 x 1.2cm column packed with glass rings [Brandon et al. J Am Chem Soc 72 2120 1950, UV: Elington et al. J Chem Soc 2873 1952, NMR: Bushweller & O'Neil Tetrahedron Lett 4713 1969]. It has been characterised as the 3,5-dinitrobenzoyloxy-tetrahydrofuran derivative, m 103o which forms pale yellow crystals from dihydropyran/Et2O [Woods & Kramer J Am Chem Soc 69 2246 1947]. [Beilstein 17/1 V 181.]

InChI:InChI=1/C5H8O/c1-2-4-6-5-3-1/h2,4H,1,3,5H2

Upstream product

• 6581-54-0 3-chlorotetrahydropyran 
• 97-99-4 Tetrahydrofurfuryl alcohol 
• 6581-60-8 3-chloro-2-ethoxy-tetrahydro-pyran 
• 2622-51-7 pentyl-tetrahydropyran-2-yl-amine 
• 6581-58-4 2-butoxy-3-chloro-tetrahydro-pyran 
• 6581-61-9 2-methoxy-3-chlorotetrahydropyran 
• 3422-09-1 2,3-Dihydrooxepin 
• 72081-15-3 6-lithio-3,4-dihydro-2H-pyran 
• 625-23-0 2-methylhexan-2-ol 
• 94800-75-6 2-(2,4,6-Trimethyl-phenoxy)-tetrahydro-pyran 
• 74-85-1 ethene 
• 107-02-8 acrolein 
• 109-92-2 ethyl vinyl ether 
• 6559-34-8 6-methoxy-3,6-dihydro-2H-pyran 

Downstream Products

• 21890-96-0 7-(tetrahydro-2H-pyran-2-yloxy)hept-3-yn-1-ol 
• 710-14-5 tetrahydrofurfuryl tetrahydropyranyl ether 
• 72229-08-4 ethyl 2-oxabicyclo<4.1.0>heptane-7-carboxylate 
• 6581-64-2 2-propoxy-tetrahydro-pyran 
• 98198-84-6 3,4-dihydro-2H-pyran-5-carbonyl chloride 
• 56660-59-4 2,3-dibromotetrahydropyran 
• 26274-19-1 5-bromo-3,4-dihydro-2H-pyran 
• 98949-99-6 N-(3-bromo-tetrahydro-pyran-2-yl)-succinimide 
• 39150-42-0 3-Brom-2-aethoxytetrahydropyran 
• 30778-86-0 1-methoxy-3-tetrahydropyran-2-yloxybenzene 
• 100118-15-8 (+/-)-trans-2-Benzoyloxy-tetrahydro-pyran-3-ol 
• 111841-07-7 2-hydroxy-4-(tetrahydropyran-2-yloxy)acetophenone 
• 1206-23-1 1-tetrahydropyran-2-yloxy-cyclohexanecarbonitrile 
• 36603-49-3 4-(tetrahydropyran-2'-yloxy)-1-bromobenzene 

Related news

Control of reactivity of novolac resins: the use of 3,4-Dihydro-2H-pyran (cas 110-87-2) as a labile protecting group08/26/2019

The control of the reactivity of novolac resins towards common crosslinkers through the use of 3,4-dihydro-2H-pyran as a protecting group is reported. This thermally labile protecting group is shown to be effective for the control of the cure of the novolac resin system through the use of models...detailed

3,4-Dihydro-2H-pyran (cas 110-87-2) promoted aerobic oxidative aromatization of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines08/25/2019

An unprecedented facile oxidation of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines (DHPs) to the corresponding pyrazoles and pyridines was observed, mediated by 3,4-dihydro-2H-pyran in air. The reaction showed excellent reactivity, functional group tolerance, and high yield ...detailed

Relevant articles and documents

Manganese-Catalyzed Desaturation of N-Acyl Amines and Ethers

Enamines and enol ethers are versatile synthons for chemical synthesis. While several methods have been developed to access such molecules, prefunctionalized starting materials are usually required, and direct desaturation methods remain rare. Herein, we report direct desaturation reactions of N-protected cyclic amines and cyclic ethers using a mild I(III) oxidant, PhI(OAc)2, and an electron-deficient manganese pentafluorophenylporphyrin catalyst, Mn(TPFPP)Cl. This system displays high efficiency for α,β-desaturation of various cyclic amines and ethers. Mechanistic probes suggest that the desaturation reaction occurs via an initial α-C-H hydroxylation pathway, which serves to protect the product from overoxidation.

Regioselective Ni(II)-assisted alkylation of 2-methoxy-5,6- dihydro-2H-pyran: A new route to 2-n.alkyl-5,6-dihydro-2H-pyrans

In the presence of a catalytic amount of NidppeCl2, 2-methoxy- 5,6-dihydro-2H-pyran reacts with primary Grignard reagents to give the corresponding 2-n.alkyl-5,6-dihydro-2H-pyrans in satisfactory yields.

Combined experimental and theoretical studies of the elimination kinetic of 2-methoxytetrahydropyran in the gas phase

The products formed in 2-methoxytetrahydropyran elimination reaction in the gas phase are 3, 4-dihydro-2H-pyran and methanol. The kinetic study was carried out in a static system, with the vessels deactivated with allyl bromide, and the presence of the free radical suppressor toluene. Temperature and pressure ranges were 400-450 °C and 25-83 Torr, respectively. The process is homogeneous, unimolecular, and follows a first-order rate law. The observed rate coefficient is represented by the following equation: log k (s-1) = (13.95 ± 0.15) - (223.1 ± 2.1) (kJ mol-1) (2.303RT)-1. The reactant exists mainly in two low energy chair-like conformations, with the 2-methoxy group in axial or equatorial position. However, the transition state (TS) for the elimination of the two conformers is the same. Theoretical calculations of this reaction were carried for two possible mechanisms from these conformations by using DFT functionals B3LYP, MPW1PW91, and PBE with the basis set 6-31G(d,p) and 6-31G++(d,p). The calculation results demonstrate that 2-methoxytetrahydropyran exists mainly in two conformations, with the 2-methoy group in axial or equatorial position, that are thermal in equilibrium. The average thermodynamic and kinetic parameters, taking into account the populations of the conformers in the equilibrium, are in good agreement with experimental values at B3LYP/6-31++(d,p) level of theory. Copyright

Stable vapor-phase conversion of tetrahydrofurfuryl alcohol into 3,4-2H-dihydropyran

Vapor-phase synthesis of 3,4-2H-dihydropyran (DHP) from tetrahydrofurfuryl alcohol (THFA) was investigated over acidic catalysts modified with transition metals. Catalytic activity of alumina was seriously deactivated in the reaction of THFA in nitrogen at 300 °C although the initial activity was high. Tetragonal ZrO2 showed the catalytic activity to produce DHP at 350 °C. Alumina modified with Cu exhibits stable catalytic activity with high selectivity to DHP under hydrogen flow conditions, and the optimum activity was obtained at CuO contents of 5-10 wt.%: the selectivity to DHP was as high as 85%. Prior to the reaction, CuO was reduced to metallic Cu, which probably works as a product remover together with hydrogen to prevent coke formation. The reaction pathway from THFA to DHP was discussed: it is speculated that THFA is initially rearranged into 2-hydroxytetrahydropyran, which rapidly dehydrated to DHP.

Effect of pretreatment conditions on acidity and dehydration activity of CeO2-MeOx catalysts

A series of MeOx-modified CeO2 (CeO2-MnOx, CeO2-ZnO, CeO2-MgO, CeO2-CaO, and CeO2-Na2O) catalysts were prepared by the impregnation of CeO2 with corresponding metal nitrates. Acidity and oxidation state of cerium were investigated on both oxidized and reduced catalysts by employing Fourier Transform Infrared spectroscopy (FTIR) on adsorbed pyridine and in situ H2-Temperature Programmed Reduction/X-ray Absorption Spectroscopy (H2-TPR/XAS) techniques, respectively. Metal oxide addition tended to alter both type and number of acid sites on ceria. EXAFS data showed a significant difference in NCe-O between unmodified and CeO2-MeOx, suggesting that added MeOx interferes with vacancy formation on ceria during reduction. In comparison with air-pretreated samples, H2-pretreated ones under similar conversion of 1,5 pentanediol exhibited a higher selectivity towards linear alcohols. Alcohol conversion found to correlate with total acidity (i.e., Br?nsted and Lewis). CeO2 benefited from the addition of alkali (Na) or alkaline earth metals (Mg, Ca) by producing unsaturated alcohols.

Production of 1,5-pentanediol via upgrading of tetrahydrofurfuryl alcohol

A method of making 1,5-pentanediol from tetrahydrofurfural alcohol. The method includes the steps of dehydrating tetrahydrofurfural alcohol (THFA) to dihydropyran (DHP); hydrating at least a portion of the DHP to 2-hydroxy-tetrahydropyran (2-HY-THP) in the presence of a solid acid catalyst; and hydrogenating at least a portion of the 2-HY-THP to 1,5-pentanediol. The method can be conducted entirely in the absence of noble metal catalysts.

The kinetics and mechanism of the homogeneous, unimolecular gas-phase elimination of 2-(4-substituted-phenoxy)tetrahydro-2H-pyranes

The gas-phase elimination kinetics of tetrahydropyranyl phenoxy ethers: 2-phenoxytetrahydro-2H-pyran, 2-(4-methoxyphenoxy)tetrahydro-2H-pyran, and 2-(4-tert-butylphenoxy)tetrahydro-2H-pyran were determined in a static system, with the vessels deactivated with allyl bromide, and in the presence of the free radical inhibitor toluene. The working temperature and pressure were 330 to 390°C and 25 to 89?Torr, respectively. The reactions yielded DHP and the corresponding 4-substituted phenol. The eliminations are homogeneous, unimolecular, and satisfy a first-order rate law. The Arrhenius equations for decompositions were found as follows: 2-phenoxytetrahydro-2H-pyran log k1 (s?1)?=?(14.18?±?0.21)???(211.6?±?0.4)?kJ?mol?1 (2.303 RT)?1 2-(4-methoxyphenoxy)tetrahydro-2H-pyran log k1 (s?1)?=?(14.11?±?0.18)???(203.6?±?0.3)?kJ?mol?1 (2.303 RT)?1 2-(4-tert-butylphenoxy)tetrahydro-2H-pyran log k1 (s?1)?=?(14.08?±?0.08)???(205.9?±?1.0)?kJ?mol?1 (2.303 RT)?1. The analysis of kinetic and thermodynamic parameters for thermal elimination of 2-(4-substituted-phenoxy)tetrahydro-2H-pyranes suggests that the reaction proceeds via 4-member cyclic transition state. The results obtained confirm a slight increase of rate constant with increasing electron donating ability groups in the phenoxy ring. The pyran hydrogen abstraction by the oxygen of the phenoxy group appears to be the determinant factor in the reaction rate.

PRODUCTION OF 1,5-PENTANEDIOL VIA UPGRADING OF TETRAHYDROFUFURYL ALCOHOL

A method of making 1,5-pentanediol from tetrahydrofurfural alcohol. The method includes the steps of dehydrating tetrahydrofurfural alcohol (THFA) to dihydropyran (DHP); hydrating at least a portion of the DHP to 2-hydroxy-tetrahydropyran (2-HY-THP) in the absence of homogeneous acid; and hydrogenating at least a portion of the 2-HY-THP to 1,5-pentanediol. The method can be conducted entirely in the absence of noble metal catalysts.

PRODUCTION METHOD OF 3,4-DIHYDRO-2H-PYRAN

PROBLEM TO BE SOLVED: To provide a method of producing 3,4-dihydro-2H-pyran at a high raw material conversion rate and with excellent selection rate, while maintaining high catalyst activity, in production of 3,4-dihydro-2H-pyran from a raw material tetrahydrofurfuryl alcohol due to a gas phase reaction that uses a solid catalyst. SOLUTION: A production method of 3,4-dihydro-2H-pyran for obtaining 3,4-dihydro-2H-pyran by making a tetrahydrofurfuryl alcohol gas contact with a catalyst under presence of hydrogen gas is a method of producing 3,4-dihydro-2H-pyran in which the catalyst is a catalyst in which ruthenium is supported by a metal oxide. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT

Comparison of “on water” and solventless procedures in the rhodium-catalyzed hydroformylation of diolefins, alkynes, and unsaturated alcohols

Catalytic systems containing Rh(acac)(CO)2 or Rh/PAA (PAA?=?polyacrylic acid) and hydrophobic phosphine (PPh3) were used in the hydroformylation of diolefins, alkynes, and unsaturated alcohols under solventless and “on water” conditions. The total yield of dialdehydes obtained from 1,5-hexadiene and 1,7-octadiene reached 99%, and regioselectivity towards linear dialdehydes was higher in the “on water” system. The tandem hydroformylation-hydrogenation of phenylacetylene led to the formation of saturated aldehydes (3-phenylpropanal and 2-phenylpropanal) at 98% conversion with a good regioselectivity towards the linear aldehyde in the “on water” reaction. In contrast, solventless conditions appeared better in the hydroformylation of 1-propen-3-ol. 4-Hydroxybutanal, formed in this reaction with an excellent selectivity, was next transformed to tetrahydrofuran-2-ol via a ring-closure process. Cyclic products were also obtained in hydroformylation of 1-buten-3-ol. In reaction of undec-1-ol and 2-allylphenol linear aldehydes were formed with the yield 69–87%. The hydroformylation of 3-buten-1-ol performed under “on water” conditions showed very good regioselectivity towards a linear aldehyde, 5-hydroxypentanal. Further cyclization of the aldehyde to tetrahydropyran-2-ol was observed.