1: 2-hydroxybenzoic acid methyl ester With di-isopropyl azodicarboxylate; triphenylphosphine in tetrahydrofuran T=20°C; 1 h; 2: N-(2-hydroxyethyl)-pyrrolidine in tetrahydrofuran T=20°C; 1.5 h;

1: 2-hydroxybenzoic acid methyl ester With bis(1-methylethyl) ester diazenedicarboxylic acid; triphenylphosphine in tetrahydrofuran T=20°C; 1 h; 2: N-(2-hydroxyethyl)-pyrrolidine T=20°C; 1.5 h;