Fluoromethyl ethers

The limitations of this reagent are several. It caimot be used to replace a single unactivated halogen atom with the exception of the chloromethyl ether (eq. 5) to form difluoromethyl fluoromethyl ether [461 -63-2]. It also caimot be used to replace a halogen attached to a carbon—carbon double bond. Fluorination of functional group compounds, eg, esters, sulfides, ketones, acids, and aldehydes, produces decomposition products caused by scission of the carbon chains. 

Both methyltriethylphosphonium fluoride and methyltributylphospho-nium fluoride have been prepared The latter generates benzyl fluoride from benzyl chloride in 80% yield and ethyl fluoroacetate from ethyl bromoacetate in 53% yield Methyltnbutylphosphonium fluoride converts 1-bromododecane to a 50 50 mixture of 1-fluorododecane and 1-dodecene Methyltnbutylphosphonium fluoride also quantitatively forms styrene from 1-bromo-1-phenylethane [26] Methyl-tnbutylphosphonium fluonde is the reagent of choice for the conversion of N,N dimethylchloroacetamide to its fluoride, but it is not able to convert chloro-acetonitnle to fluoroacetomtrile Methyltnbutylphosphonium fluoride changes chloromethyl octyl ether to the crude fluoromethyl ether in 66% yield The stereoselectivity of methyltnbutylphosphonium fluoride is illustrated by the reac tions of the 2-tert-butyl-3-chlorooxiranes [27] (Table 2)... 

Figure 7.1.11 The molecular structure of sevoflurane (ultane or 1,1,1,2,2,2-hexafluorethyl fluoromethyl ether).

Diethylene glycol monomethyl ether acetate Difluoromethyl fluoromethyl ether 162.21 -9 209.1 29.9 ... 

Fluoromethanol (4) and symmetrical bis(fluoromethyl) ethers (5) are obtained from paraformaldehyde in hydrogen fluoride.205,209 Dissociation of fluoromethanol creates the electrophilic species [HOCH2 + ]F, which then attacks the 7r-bond of an alkene (electrophilic addition).209... 

Fluoromethyl ethers may additionally be attacked by a further alkene molecule under the reaction conditions, which then inserts between the C-F bond of the fluoromethyl group. Thus, 1,1-dihaloethene and the hydrogen fluoride/formaldehyde reagent react to form the symmetrical ether 6. 

Dimethyl sulfoxide reacts exothermically with tungsten(VI) fluoride to give a viscous oil which could be a complex, and from which a low yield of bis(fluoromethyl) ether can be obtained 44 sulfur tctrafluoride gives the same product, but in good yield. Also like sulfur tetrafluoride, tungsten(VI) fluoride will cleave45 sulfites [(RO)2SO] into fluorosulfites (ROSOF) at 0 C. 

Hydrogen fluoride under vigorous conditions may be used in favourable circumstances, for example to make fluoromethyl ethers [44] (Figure 3.3a). 

At elevated reaction temperatures Le vis catalysts cause a certain amount of inter-molecular and intramolecular halogen migration. Not only hydrofluoric acid can be used as the fluoride source, but also other fluoroaliphatic compounds, for example fluoromethyl ethers [54] (Scheme 2.18). 

Approximately 3% of absorbed sevoflurane is biotransformed by hepatic CYP2E1, the predominant product being hexafluoroisopropanol metabolism of sevoflurane also produces inorganic fluoride. Interaction of sevoflurane with soda lime (CO absorbent) produces decomposition products, one of which, compound A (pentafluoroisopropenyl fluoromethyl ether), may have toxicity (see Side Effects Kidney, Liver, and Gastmintestinal Tract below). 

Controversy has surrounded the potential nephrotoxicity of compound A (pentafluoroisopropenyl fluoromethyl ether), a chemical produced by interaction of sevoflurane with the CO2 absorbent soda lime. Although biochemical evidence of transient renal injury has been reported, large clinical studies have shown no evidence of renal impairment following sevoflurane administration. 

The synthesis of novel corticoids possessing rings a and b in a 10(5 — 4t)abeo system has been described.In the simplest case, the corticoid (263) was used as starting material. The C-17-chain was converted into a bismethylenedioxy-group (BMD), after protection of the hydroxyl at C-11/3 as the fluoromethyl ether (264). Acid hydrolysis liberated the 11-alcohol (265). This with alkaline hydrogen... 

Exhibits low reactivity due to a greater degree of halogen substitution Synonyms Enflurane Efrane methylflur-ether 2-chloro-l,l,2-trifluoroethyl di-fluoromethyl ether 2-chloro-l-(difluoro-methoxy)-1,1,2-trifluoroethane... 

III-G-26. l,l,l,3,3,3-Hexafiuoro-2-(fluoromethoxy)propane [l,l,l,3,3,3-Hexafiuoro-2-propyl Fluoromethyl Ether,... 

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