1: N,N-Phthaloylglycine tert-butyl ester With hydrazine hydrate in ethanol Ring cleavage; 4 h; Heating; 2: benzenesulfonyl chloride With triethylamine in ethanol Substitution; 24 h; Further stages.;

in benzene

1.1: 81 percent / hexadecyltributylphosphonium bromide / toluene / 24 h / Heating 2.1: hydrazine monohydrate / ethanol / 4 h / Heating 2.2: 95 percent / Et3N / ethanol / 24 h View Scheme

trifluoroacetic acid 0.5 h;