Tetrahydrofuran Oxolane

The simple hexaalkylditins, RsSnSnRs, do not disproportionate on heating, but, in oxolane (tetrahydrofuran) or acetonitrile in the presence of a base such as a Grignard reagent, or in the more strongly basic solvent hexamethylphosphoric triamide (HMPT), disproportionation readily occurs at room temperature, and, in HMPT, addition occurs to such alkynes as phenylacetylene and diphenylbutadiyne. The disproportionation is considered to proceed by nucleophilic attack upon tin (259, 260), e.g.,... 

The oxolane (tetrahydrofuran) ring system can be incorporated into polymers either by polymerization of the suitably substituted heterocycle itself or by addition polymerization of a dihydrofuran derivative. A prime example of the former case is found in the utilization, as a component of adhesives and coatings for example, of the acrylate (38) and methacrylate (39) esters of tetrahydrofurfuryl alcohol. Although the bulk of the investigations concerning these monomers is recorded in the patent literature, a detailed study of the polymerization behavior of ester (39) has appeared (74MI11101) that indicates it is a fairly typical methacrylate monomer. 

The lesser known four-membered cyclic ether, oxacyclobutane (oxe-tane), (CH2)30, also is cleaved readily, but less so than oxacyclopropane. Oxacyclopentane (oxolane, tetrahydrofuran) is a relatively unreactive water-miscible compound with desirable properties as an organic solvent. It often is used in place of diethyl ether in Grignard reactions and reductions with lithium aluminum hydride. 

Monosaccharides occur as substances with a free carbonyl group (acyclic compounds) and as cyclic hemiacetals, also called lac-tols. Trioses are exclusively acyclic substances, tetroses and higher monosaccharides exist predominantly in five- and six-membered and, exceptionally, also in seven-membered cyclic structures. They can therefore be regarded as substances derived from oxolane (tetrahydrofuran), oxane (tetrahydropyran) or oxepane, and are thus actually heterocyclic compounds. Acyclic forms, which exist in constitutional equilibrium with cyclic forms, occur in zigzag conformers, as well as alditols (see Section 4.3.1.1.1). 

In each case the ring is numbered starting at the oxygen The lUPAC rules also permit oxirane (without substituents) to be called ethylene oxide Tetrahydrofuran and tetrahy dropyran are acceptable synonyms for oxolane and oxane respectively... 

Oxitol, see 2-Ethoxyethanol Oxitol acetate, see 2-Ethoxyethyl acetate 2-Oxobornane, see Camphor Oxocyclohexane, see Cyclohexanone Oxolane, see Tetrahydrofuran Oxomethane, see Formaldehyde Oxybenzene, see Phenol 1,1 Oxybisbenzene, see Phenyl ether l,l -Oxybis(2-chloroethane), see Bis(2-chloroethyl) ether Oxybis(chloromethane), see s/m-Dichloromethyl ether 2,2 -Oxybis(l-chloropropane), see Bis(2-chloroisopropyl) ether... 

Cyclic ethers can be named simply as oxacycloalkanes, such as oxacyclopropane, oxacyclo-butane, oxacyclopentane, and oxacyclohexane, where the prefix oxa indicates the replacement of CH2 by O in corresponding cycloalkanes. Most cyclic ethers, however, are known by other names. The 3-, 4-, 5-, and 6-membered rings are oxirane, oxetane, oxolane, and oxane, respectively, or ethylene oxide (or epoxide), trimethylene oxide, tetrahydrofuran, and tetrahydropyran. 

Using this terminology, furan becomes oxole and tetrahydrofuran is named oxolane pyridine is azine and piperidine is azinane. As with trivial names, the potential difficulty over partly reduced heterocycles is resolved... 

Solvents that meet all or most of the criteria are propylene carbonate, dimethyl sulfoxide, 4-butyrolactone, acetonitrile, sulfur dioxide, thionyl chloride, and phosphorus oxychloride. Certain other solvents, with fairly low s values, such as tetrahydrofuran, dimethoxyethane, and 1,3-oxolane are used in conjunction with a high s solvent, in order to reduce the viscosity without impairing excessively the other desirable properties of the co-solvent. All these solvents are on the List, with properties shown in the tables mentioned. Commercial implementation of such batteries has been highly successful, with energy densities of primary dischargeable batteries of 0.3 W h g 1 or 0.5 W h cm 3 and a self discharge rate of < 2% per year of the open-circuit battery being achieved. 

F. Smith, Advan. Carbohydrate Chem. 2, 79-106 (1946). Tetrahydrofuran (oxolane), polymerization ... 

Furan, tetrahydro-, tetrahydrofuran, oxolane, 1,4-epoxybutane, butylene oxide 1109-99-9)... 

Oxirane, 620. See also Ethylene oxide Oxolane, 620. See also Tetrahydrofuran Oxoniumions, 134, 135-136, 226... 

---