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Activated Alumina Balls under Neat Conditions: A Green Catalyst for the Synthesis of Spiro‐Heterocyclic Scaffolds by Ring‐Opening versus Annulation of the Isatin Moiety
Author(s) -
Mondal Animesh,
Banerjee Biplab,
Bhaumik Asim,
Mukhopadhyay Chhanda
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500885
Subject(s) - regioselectivity , catalysis , moiety , yield (engineering) , isatin , annulation , chemistry , ring (chemistry) , chemical engineering , organic chemistry , combinatorial chemistry , materials science , composite material , engineering
We report a green, efficient and straightforward approach for the regioselective synthesis of new spiro‐heterocyclic scaffolds using environmentally benevolent activated alumina balls (3–5 mm diameter) as a catalyst under neat reaction conditions. The methodology is advantageous because of its short reaction time, moderate to excellent yields, easy work‐up, practical simplicity and high regioselectivity without any troublesome/hazardous disposal of the catalyst or toxic byproducts. The pore size of the catalyst plays a key role in the formation of the spiro derivatives. Specifically, we observed that the reaction yield was hardly affected by the surface area or pore volume, but surprisingly, the yield correlated directly with the pore size of the catalyst.