Synthesis 2004(12): 1959-1962  
DOI: 10.1055/s-2004-829171
PAPER
© Georg Thieme Verlag Stuttgart · New York

Improved Method for the Synthesis of 2-Methyl-2-Aryloxypropanoic Acid Derivatives

Roman D. Davis, Russ N. Fitzgerald*, Jiasheng Guo
GlaxoSmithKline, Chemical Development-Synthetic Chemistry, 5 Moore Drive, Research Triangle Park, NC 27709, USA
Fax: +1(919)3158735; e-Mail: russ.n.fitzgerald@gsk.com;
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Publication History

Received 11 March 2004
Publication Date:
27 July 2004 (online)

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Abstract

An improved method for the formation of 2-methyl-2-aryloxypropanoic acid derivatives, an important class of compounds for the potential treatment of type II diabetes, is reported. This method offers several advantages over the existing chemistry for this transformation.

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The alkylation of one of our compounds using conditions reported by Bargellini was monitored by reaction calorimetry with a Metler Toledo RC1 unit. The total heat generated during the addition (1 h addition time) of the 1,1,1-trichloro-2-methyl-2-propanol was measured at 2180 kJ/kg. The average heat output rate for the duration of the addition was measured at 550 W/kg. Based on the reaction calorimetry, an adiabatic temperature rise of 58 °C was calculated.

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We thank Prof. Barry Trost, Stanford University, for first suggesting this reagent to us.

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The alkylation of the compound noted in ref. [6] with 2-bromo-2-methylpropanoic acid was monitored by reaction calorimetry with a Metler Toledo RC1 unit. The total heat generated during the addition (1 h addition time) of the 2-bromo-2-methylpropanoic acid was measured at 669 kJ/kg. The average heat output rate for the duration of the addition was measured at 141 W/kg. Based on the reaction calorimetry, an adiabatic temperature rise of 35 °C was calculated.

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Aldrich Chemical Co. 2002-2003.