NOVELTY - Gliclazide is prepared by reacting N-acetyl-1,2-cyclopentanedicarboximide, tetrahydrofuran, and copper oxide-zinc oxide catalyst to obtain 6H-cyclopenta(c)pyrrole-2-amine crude product (I); adding bis(trichloromethyl) carbonate and methylbenzene, cooling in ice-brine bath, dropwise adding mixed solution of (I) and methylbenzene, and reacting to obtain 8H-cyclopenta(c)pyrrole-2-isocyanate crude product (II); and adding p-methylbenzenesulfonamide, potassium carbonate and acetone, heating to backflow state, and dropwise adding mixture of (II) and acetone and reacting to obtain gliclazide.    USE - Method of preparing gliclazide (claimed).    ADVANTAGE - The method utilizes raw material having rich resource, involves mild reaction condition and simple and green production process, and has reduced production cost. The 6H-cyclopenta(c)pyrrole-2-amine crude product can be directly used for the next reaction without needing a further purification. The 8H-cyclopenta(c)pyrrole-2-isocyanate crude product can be easily decomposed and be used for the next reaction without performing purification.    DETAILED DESCRIPTION - Preparation of gliclazide comprises:    (A) preparing 6H-cyclopenta(c)pyrrole-2-amine by adding (pts.wt.) N-acetyl-1,2-cyclopentanedicarboximide (1), tetrahydrofuran (8-12), and copper oxide-zinc oxide catalyst (0.1) to a high pressure reactor with stirring and heating devices, after stirring uniformly, displacing the system air by hydrogen, and pressing by hydrogen, stirring to react for 4-10 hours at 5-15 MPa and at 200-250 degrees C, after finishing reaction, cooling to room temperature, filtering to remove the catalyst, distilling the filtrate to remove the tetrahydrofuran solvent, adding 10% sodium hydroxide aqueous solution (10) and dichloromethane (15) to the remainder removal of the solvent, stirring for 10 minutes, separating liquid, drying the organic phase by anhydrous sodium sulfate, after filtering to remove the drying agent, and distilling to remove the solvent to obtain yellow oily substance which is 6H-cyclopenta(c)pyrrole-2-amine crude product;    (B) preparing 8H-cyclopenta(c)pyrrole-2-isocyanate by adding (pts.wt.) bis(trichloromethyl) carbonate (0.82-0.95) and methylbenzene (5-8) to a reactor, after stirring uniformly, cooling in ice-brine bath so that the temperature of the mixture is 0-10 degrees C, and then dropwise adding mixed solution of 6H-cyclopenta(c)pyrrole-2-amine crude product (1) and methylbenzene (2-3) at controlled temperature of not greater than 20 degrees C, after finishing dropwise adding, removing the ice-brine bath, gradually heating to 110 degrees C for 2 hours, keeping temperature while stirring to react for 4-6 hours, after finishing the reaction, and distilling to remove solvent to obtain brown oily substance which is 8H-cyclopenta(c)pyrrole-2-isocyanate crude product; and    (C) preparing gliclazide by adding (pts.wt.) p-methylbenzenesulfonamide (1.18-1.24), potassium carbonate (0.95-1.01) and acetone (10-15) to a reactor, after stirring uniformly, heating to backflow state, and dropwise adding mixture of 8H-cyclopenta(c)pyrrole-2-isocyanate crude product (1) and acetone (3-5) at such temperature, after finishing dropwise adding, continuously stirring to react for 3-6 hours in the backflow state, after finishing the reaction, distilling to remove large parts of acetone solvent, pouring the residual to 5% sodium hydroxide aqueous solution, regulating pH value to 12, precipitating the white solid, after filtering, collecting and drying to obtain refined gliclazide after performing recrystallization with ethyl acetate.