Scheme 1.

Synthesis of 4-(4-(hydroxymethyl)-2-methoxy-5-nitrophenoxy)butanoic acid and 4-(4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy)butanoic acid.

Synthesis of 4-(4-(hydroxymethyl)-2-methoxy-5-nitrophenoxy)butanoic acid and 4-(4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy)butanoic acid.