Triethyl 1,1,2-ethanetricarboxylate

Triethyl 1,1,2-ethanetricarboxylate 4-Toluenesulfonic acid monohydrate Lithium aluminum hydride Sodium hydroxide... 

To a suspension of lithium aluminum hydride (2.87 g, 76 mmol) in tetrahydrofuran (125 ml), a solution of triethyl 1,1,2-ethanetricarboxylate (9.2 ml, 9.85 g, 40 mmol) in tetrahydrofuran (25 ml) was added dropwise with stirring over 2 hours. The inorganic salts were filtered off and washed with ethanol (100 ml). The filtrate and washings were combined and the solvent was evaporated under reduced pressure to afford a colourless oil (4.85 g). To a suspension of this oil in acetone (100 ml) 2,2-dimethoxypropane (25 ml) and p-toluenesulphonic acid monohydrate (2.3 g, 12 mmol) were added. The mixture was stirred for 1 hour. The resulting solution was neutralised with Amberlite IR 45 (methanol washed), filtered and the solvent evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, eluting with chloroform-methanol mixtures (40 1 and 25 1) to afford 5-(2-hydroxyethyl)-2,2-dimethyl-l,3-dioxan as a colourless liquid (3.01 g, 47%). 

Compounds 161 and 162 were found to be unstable in basic, protic media, presumably due to the presence of the acidic hydrogen atom of the malonic ester. As a result, their synthetic utility is somewhat limited. It was, however, found possible to alkylate 162 with ethyl bromoacetate in the presence of sodium hydride,125 to give triethyl 1 - (2,3,5-tri-O-benzoyl- /3-d-ribofuranosyl) -1,1,2-ethanetricarboxylate (166). This product was obtained in 20% yield by treatment of 81... 

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