A method of processing a hydrocarbon feed to remove undesired organosulfur compounds comprising: a. subjecting the hydrocarbon feed to a hydrodesulfurizing process carried out in mild hydrotreating conditions to produce a hydrotreated effluent, said mild conditions consisting in a hydrogen partial pressure of less than 55 bars, an operating temperature of 300 to 400 °C, a hydrogen feed rate of from 100 liters of hydrogen to 1000 liters of hydrogen per liter of oil, a reaction pressure of 20 to 100 bars, and a feed rate of 0.5 hr -1 to 10 hr -1; b. flashing the hydrotreated effluent at a temperature cut point between 320 °C and 360 °C, preferably about 340 °C, to provide a low boiling temperature fraction that contains a reduced level of organosulfur compounds and a high boiling temperature fraction having refractory organosulfur compounds; c. separating the high and low boiling temperature fractions; d. contacting the high boiling temperature fraction in a gas phase catalytic oxidation reaction zone with a gaseous oxidizing agent and an oxidizing catalyst having a formula Cu x Zn 1-x Al 2 O 4 wherein x ranges from 0.1 to 0.6 to convert refractory organosulfur compounds including dibenzothiophenes, alkyl derivatives of dibenzothiophenes and long-chain alkylated derivatives of benzothiophene having a boiling point in the range of the high boiling temperature fraction, to SO x by breaking the C-S bonds, wherein the operating conditions for said gas phase catalytic oxidation reaction zone comprise a weight hourly space velocity in the range of from 1 h -1 to 20 h -1, a gas hourly space in the range of from 1000 h -1 to 20,000 h -1, an operating pressure in the range of from 1 bar to 30 bar, and an operating temperature in the range of from 200 °C to 600 °C, wherein said oxidizing catalyst comprises from 30 wt% to 45 wt% CuO, from 12 wt% to less than 20 wt% ZnO, and from 20 wt% to 40 wt% Al 2 O 3, an X-ray amorphous oxide phase, and highly dispersed crystalline ZnO and CuO, and e. separating the SO x from products of (d). a. subjecting the hydrocarbon feed to a hydrodesulfurizing process carried out in mild hydrotreating conditions to produce a hydrotreated effluent, said mild conditions consisting in a hydrogen partial pressure of less than 55 bars, an operating temperature of 300 to 400 °C, a hydrogen feed rate of from 100 liters of hydrogen to 1000 liters of hydrogen per liter of oil, a reaction pressure of 20 to 100 bars, and a feed rate of 0.5 hr -1 to 10 hr -1; b. flashing the hydrotreated effluent at a temperature cut point between 320 °C and 360 °C, preferably about 340 °C, to provide a low boiling temperature fraction that contains a reduced level of organosulfur compounds and a high boiling temperature fraction having refractory organosulfur compounds; c. separating the high and low boiling temperature fractions; d. contacting the high boiling temperature fraction in a gas phase catalytic oxidation reaction zone with a gaseous oxidizing agent and an oxidizing catalyst having a formula Cu x Zn 1-x Al 2 O 4 wherein x ranges from 0.1 to 0.6 to convert refractory organosulfur compounds including dibenzothiophenes, alkyl derivatives of dibenzothiophenes and long-chain alkylated derivatives of benzothiophene having a boiling point in the range of the high boiling temperature fraction, to SO x by breaking the C-S bonds, wherein the operating conditions for said gas phase catalytic oxidation reaction zone comprise a weight hourly space velocity in the range of from 1 h -1 to 20 h -1, a gas hourly space in the range of from 1000 h -1 to 20,000 h -1, an operating pressure in the range of from 1 bar to 30 bar, and an operating temperature in the range of from 200 °C to 600 °C, wherein said oxidizing catalyst comprises from 30 wt% to 45 wt% CuO, from 12 wt% to less than 20 wt% ZnO, and from 20 wt% to 40 wt% Al 2 O 3, an X-ray amorphous oxide phase, and highly dispersed crystalline ZnO and CuO, and e. separating the SO x from products of (d).