Multicomponent Reactions (MCRs) Leading to Silaheterocycles via Dianion Cyclization

Abstract

Nucleophilic asymmetrical Schiff base that incorporating aromatic rings to induce rigidity to the system was prepared by the condensation of o-hydroxyacetophenone and salicylaldehyde hydrazone in a 1:1 molar ratio. A useful sequence of reactions for the synthesis of a variety of previously unknown silaheterocycles is described. The reaction of salicylidene o-hydroxyacetophenone with sodium hydride in dioxane produces a 1,10-remote dianion. The cyclization of this dianion with diorganodichlorosilanes affords dibenzodioxadiazasilaundecines in good yields. The products were characterized by satisfactory elemental analyses and spectral (IR, ¹ H, ¹³ C, ²⁹ SiNMR, andmass) studies.

Keywords:

• dianion
• dibenzodioxadiazasilaundecines
• diorganodichlorosilanes
• electrophilic cyclizations
• o-hydroxyacetophenone
• salicylaldehyde hydrazone

Acknowledgments

The authors are grateful for financial support of this work from the Council of Scientific and Industrial Research (CSIR), New Delhi, India.