4-Nitrobenzaldehyde → 5-Acetyl-5-methyl-2-(4-nitrophenyl)-1,3-dioxane

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Reaction Steps

3,3-bis(Hydroxymethyl)-2-butanone (39.7 parts) and 4-nitrobenzaldehyde (30.2 parts) are combined in toluene (300 parts) containing p-toluenesulfonic acid, (p-TSA), (1.0 part) and the mixture held under reflux until a theoretical amount of water is removed by a Dean-Stark moisture trap. The solution is concentrated in vacuo and the residue washed once with dilute sodium bicarbonate solution. The product is recrystallized from ethyl acetate-heptane mixed solvent to give colorless needles, m.p. 101-102.5° C. Proton NMR and combustion analysis are consistent with those values predicted for the desired product. Combustion Analysis for C13H15NO5 --Calculated: C, 58.9%; H, 5.7%; N, 5.3%. Found: C, 59.0%; H, 5.8%; N, 5.4%.

Provenance & Evidence