ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
-butyrolactone: Mechanism of its formation and utilization in 2-methyl-1-tetralone synthesis
Vladislav Semak, Andrej Boháč, Marta Sališová, Gabriela Addová, and Peter Danko
Department of Organic Chemistry, Comenius University, Mlynská dolina, 842 15 Bratislava, Slovakia
Received: 21 July 2007 Revised: 15 October 2007 Accepted: 16 October 2007
Abstract: α-Methyl-γ-butyrolactone (III) has been prepared directly from γ-butyrolactone (I) in 89 % yield by selective monomethylation conditions: K2CO3/DMC/210°C/7 h. The reaction mechanism was elucidated and described. An intermediate and two byproducts: methyl tetrahydro-3-methyl-2-oxofuran-3-carboxylate
(II), 3-(methoxycarbonyl)propyl methyl carbonate (IV) and 3-(methoxycarbonyl)butyl methyl carbonate (V) were identified. The high temperature disproportionation of K2CO3 in the presence of dimethyl carbonate to MeOK was observed. The new selective synthesis of 2-methyl-1-tetralone (VI) from α-methyl-γ-butyrolactone (III) by Friedel-Crafts conditions was performed in 79 % yield.
Keywords: dihydro-3-methylfuran-2(3H)-one -
α-methyl-γ-butyrolactone - dimethyl carbonate - reaction mechanism - selective monomethylation - 2-methyl-1-tetralone -
Full paper is available at www.springerlink.com.
Chemical Papers 62 (3) 275–280 (2008)