Abstract
A simple and more convenient method has been developed for regioselective α-bromination of various aralkyl ketones with N-bromosuccinimide (NBS) in the presence of Montmorillonite K-10 catalyst in methanol at 60–65 °C. The present procedure offers advantages of short reaction time, simple workup, good yields of products and reusability of the catalyst for four times without loss of activity.
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GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
We are thankful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India, for financial support for this work under a major research project (No. 01 (2391)/10/EMR-II).
Notes
a Reaction conditions: Acetophenone (10 mmol), NBS [10 (+2) mmol: portionwise addition], 10% Montmorillonite K-10, and methanol (20 ml).
b Scheme 2.
a Reaction conditions: Acetophenone (10 mmol), NBS (11 (+2) mmol: portionwise addition), 10% Montmorillonite K-10, methanol (20 ml), and temperature 30–35 °C.
b Isolated yield.
c Isolated yields were shown in parentheses, when the reactions were carried out under reflux temperature.
a Reaction conditions: Acetophenone (10 mmol), NBS [10 (+2) mmol: portionwise addition], 10% Montmorillonite K-10, and methanol (20 ml).
b Isolated yield.
a Reaction conditions: Acetophenone (10 mmol), NBS [10 (+2) mmol)], 10% Montmorillonite K-10, and methanol (20 ml) at 65 °C.
b Isolated yield.
a Reaction conditions: Substrate (10 mmol), NBS 10 (+2) mmol added in either one or six portions, 10% Montmorillonite K-10 catalyst, methanol (20 ml), and temperature 60–65 °C.