TetraEthyl orthocarbonate

Tetraethyl orthocarbonate (ethyl orthocarbonate, tetraethoxy ethane) [78-09-1] M... 

Condensation of prednisone, 40 with tetraethyl orthocarbonate leads to the cyelie ortho-carbonate 41 liydrolysis proceeds by protonation on the most accessible ether oxygen (that on carbon 21) to give the 17 mixed carbonate ester 42. Acylation with propionyl chloride proceeds on the remaining hydroxyl group to afford prednicarbate (43) [10],... 

Guanidinium salt 139 was synthesized from the reaction of dry cyclen 1 hydrochloride with tetraethyl orthocarbonate (EtOH, reflux, 19 h, 96%) and transformed into various cyclen derivatives (Scheme 20) <1998ACS1247>. 

Correct Dimethyl ether Diethyl sulfate Diphenyl ether Dimethyl oxalate Diethyl malonate Dibcnzoyl peroxide Triethyl orthoformatc Tetraethyl orthocarbonate... 

Tetradecanal-14-ol, 252 Tetraethylammonium acetate, 277 Tetraethylammonium bromide, 140 Tetraethyl dimethylaminomethylene-diphosphonate, 277—278 Tetraethyl orthocarbonate, 285 A8-Tetrahydrocannabinol, 307 A9-Tetrahydrocannabinol, 307 1,2,3,4-Tetrahydrocarbazole, 231... 

Preparation. The reagent is prepared by the reaction of chloropicrin (irritant and lachrymator) with sodium methoxide.1 Compare the preparation of tetraethyl orthocarbonate.2... 

An important practical method920 is the treatment of the carbonyl compound with an orthoformic ester or some other orthoester (tetramethyl or tetraethyl orthocarbonate) in the presence of a small amount of mineral acid ... 

In an extension of these reactions, 4-amino-2-methyl-l,2,3-triazole-5-aldehyde was refluxed with tetraethyl orthocarbonate. The isolated intermediate (86), stirred with cold ethanolic ammonia, provided 2-ethoxy-8-methyl-8-azapurine in good yield.87 This reaction seems to be unique for producing a 2-alkoxy-substituted pyrimidine ring. 

A recent patent for candesartan cilexetil describes the formation of the benzimidazole at a relatively late stage of the synthesis by cyclization of the highly functionalized diaminobenzene core under modified Phillips conditions with tetraethyl orthocarbonate at 90 Alternative syntheses of candesartan cilexetil use similar condensation conditions on variously elaborated benzimidazole precursors. ... 

A mixture of p-toluenesulfonamide and tetraethyl orthocarbonate heated with stirring whereupon alcohol distils at 120-160° during 2 hrs. (after which a 67% yield of the intermediate diethyl N-(p-toluenesulfonyl)imidocarbonate can be isolated), the temp, allowed to reach finally 200-205° ->> ethyl ethyl-(p-toluene-sulfonyl) carbamate. Y 92%. R. F. Meyer, J. Org. Ghem. 28, 2902 (1963). 

Ethylenepyridinium salts. Orthoesters, such as tetraethyl orthocarbonate, triethyl orthoformate, and also acetals, in carboxylic acid anhydrides can replace... 

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