Derivatives of aminoquinones with N-protected amino acids

The synthesis of derivatives of aminoquinones with N-protected amino acids is reported here. 2-Amino-1,4-benzoquinone and 2-amino-1,4-naphthoquinone, prepared by the azide method in yields of 60 and 95% respectively, were coupled with N-Boc-protected amino acids including glycine, serine, proline and tyrosine, to give the correspondening derivatives. N, N'-Diisopropylcarbodiimide/1-hydroxybenzotriazole or N, N'-dicyclohexylcarbodiimide/HOBt used as coupling reagents provided the expected products in satisfactory yields and purities as supported by TLC, HPLC and spectral analysis.