1073426-06-8

175281-76-2

General procedure for the synthesis of 4-[4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy]butanoic acid from ethyl 4-[4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy]butanoate: ethyl 4-[4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy]butanoate (8.53 g) was dissolved in a mixture of trifluoroacetic acid (10 mL) and water ( 100 mL) in a mixed solvent, heated to 80 °C and maintained for 18 hours. The progress of the reaction was monitored by 1H NMR and the conversion was found to be incomplete. Subsequently, additional trifluoroacetic acid (5 mL) was added and the reaction was continued for 24 hours. Upon completion of the reaction, the mixture was cooled to room temperature and a solid precipitate was precipitated, which was collected by filtration. Finally, the resulting solid was freeze-dried to afford the target product 4-[4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy]butanoic acid (8.53 g, 86% yield) as a yellow powder.1H NMR (δ, ppm, acetone-d6): 1.53 (d, CHCH3), 2.12 (p, ArOCH2CH2CH2), 2.55 (t , ArOCH2CH2CH2), 4.03 (s, ArOCH3), 4.16 (m, ArOCH2), 5.47 (q, CHCH3), 7.47 (d, neighboring aromatic H of ArOCH2), 7.59 (s, neighboring aromatic H of ArOCH3).