N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack adducts with 1,3,5-triazine compounds as efficient catalysts for the transesterification of β-ketoesters

Abstract

N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack (VH) adducts with 1,3,5-triazine compunds such as trichloroisocyanuric acid (TCCA) and trichlorotriazine (TCTA) were prepared by replacing classical oxy chlorides POCl₃, and SOCl₂, which were explored as efficient catalysts for the transesterification of β-ketoesters. The prepared (TCCA/DMF) and (TCTA/DMF) adducts improved greenery of the classical Vilsmeier–Haack reagents (POCl₃/DMF), and (SOCl₂/DMF), and demonstrated their better efficient catalytic ativity. Reaction times were in the range: 3.5 to 6.5 hr (SOCl₂/DMF); 2.8–5.2 hr (POCl₃/DMF); 2.5–5.2 hr (TCCA/DMF) and 2.5–5.0 hr (TCTA/DMF) catalytic systems. Ultrasonically (US) assisted protocols with these reagents further reduced the reaction times (two to three times), while microwave assisted (MW) protocols with these reagents were much more effective. The reactions could be completed in only few seconds (less than a minute) in MWassisted protocols as compared to US assited reactions, followed by good product yields.

Graphical Abstract

Keywords:

• β-Ketoesters
• oxychloride/DMF adducts
• rate enhancements
• symmetric triazine/DMF adducts
• transesterification

Acknowledgments

We greatly acknowledge Head of the Chemistry Department, Osmania University Hyderabad for laboratory facilities and Professor P.K. Saiprakash (former Dean, Science Faculty, O.U.) for constant encouragement.

Disclosure statement

Authors declare that they do not have any conflict of interest.