(4-Nitrophenyl) 1,3-thiazol-5-ylmethyl carbonate is used as an intermediate of ritonavir. Ritonavir is an effective oral inhibitor of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) aspartate protease. Blocking the enzyme can promote the production of polyproteins required for morphologically mature HIV particles, so that HIV particles remain immature, thus slowing down the spread of HIV in cells, In order to prevent a new round of infection and delay the development of the disease.