1 3 diphenylurea

Methyl N-phenyl carbamate (CAS: 2603-10-3) was purchased from TCI chemicals. Phenyl isocyanate (≥98%), aniline (≥99%), 1,3-Diphenylurea (98%), 1-(2-Pyridyl) piperazine (≥99%), Dimethyl sulfoxide (anhydrous ≥ 99.9%) and diphenyl ether (≥99%) were purchased from Sigma-Aldrich.
Acetonitrile (HPLC grade), water (HPLC grade), ammonium acetate (≥98%), and formic acid (For LC-MS 98–100%) were all purchased from Sigma-Aldrich for use in analytical equipment (LC).
Catalysts include montmorillonite K10 (H₂Al₂(SiO₃)₄−nH₂O, surface area 220–270 m²/g), zinc oxide (nanopowder, ≤100 nm, 10–25 m²/g), and aluminium oxide (50–300 mesh, acid, 155 m²/g) purchased from Sigma-Aldrich and Bismuth(III) oxide (nanopowder 99.9%, 3.8–5.5 m²/g) was purchased from Fischer scientific. The catalysts were stored in an oven (110 °C) prior to experiments.

Aniline (≥99%), 1,2-dichlorobenzene (99%), dimethyl sulfoxide (>99%), 1,3-diphenyl urea (98%), diphenyl ether (99%), $\gamma$ -valerolactone (98%), phenyl isocyanate (>98%), and 1-(2-pyridyl)piperazine (>99%) were purchased from Sigma-Aldrich. For the analytical equipment, acetonitrile (HPLC grade), ammonium acetate (>98%), formic acid (for LC-MS 98–100%), and water (HPLC grade) were purchased from Sigma-Aldrich.