Alkylation Studies with Isopropylidene Malonate under PTC and Dibenzo-(18)-Crown-6

✍ Scribed by A. R. Kore; R. B. Mane; M. M. Salunkhe

• Publisher: Wiley (John Wiley & Sons)
• Year: 2010
• Weight: 185 KB
• Volume: 104
• Category: Article
• ISSN: 0037-9646
• DOI: 10.1002/bscb.19951041104

✦ Synopsis

lsopropylidene malonate (2,2-dimethyl-4,6-dioxo-l,3-dioxane, Meldrum's acid) has a high acidity (pK1 = 4.97), a rigid cyclic structure and can undergo easy hydrolysis. It has become an attractive reagent in or anic synthesis.' For example, it can readily undergo Knoevena el conden~ation?'~ Michael addition,"' and acylationei'reactions. However, few reports on its alkylation are On alkylation of isopropylidene malonate under (20% aqueous sodium hydroxide (TEBA) the ring underwent cleavage and the main product was a,a-dimethylmalonic acid methyl ester. This problem was solved by the use of solid potassium carbonate in place of 20% aqueous sodium hydroxide to avoid hydrolysis and let the reaction undergo under solid-liquid phase-transfer conditions. l4 However, these require reflux conditions and prolonged reaction times (4 to 8 h.). Our results on the use of combination of a phase-transfer catalyst and crown ether" promoted us to investigate the bis alkylation studies with isopropylidene malonate.