Abstract: A synthesis method for selamectin was developed, where doramectin is oxidized by manganese dioxide, oximated and de-sugared in one-step by an aqueous solution of hydroxylamine hydrochloride, and then selectively reduced in the presence of Wilkinson's catalyst and hydrogen to obtain selamectin. Doramectin is oxidized to a carbonyl group firstly, so that the generation of impurities during the subsequent reaction is reduced; t-butyl alcohol with a larger steric hindrance is used as a solvent, so that transesterification impurities are avoided; the hydrogenation is implemented in the final step, and the crude product is recrystallized before the hydrogenation reaction, so that the cost is greatly reduced. The method of the present application with an overall yield of 57%. The purity of product was 97.11%. All impurities meet the requirements of Pharmacopoeia. The present application is a simpler, more economical and more efficient synthesis method, and is suitable for industrial production.

Abstract: A preparation method of 1-(4-aminophenyl)cyclopentanecarbonitrile includes the following steps: step 1: in the presence of Li2CuCl4, adding a nitrochlorobenzene-zinc reagent dropwise to a 1-chlorocyclopentanecarbonitrile solution to prepare a compound 1-(4-nitrophenyl)cyclopentanecarbonitrile; and step 2: subjecting the compound 1-(4-nitrophenyl)cyclopentanecarbonitrile obtained in step 1 to a nitroreduction reaction under the action of a catalyst to prepare the compound 1-(4-aminophenyl)cyclopentanecarbonitrile. The preparation method involves cheap and easily-available raw materials, mild reaction conditions, and convenient operations, leads to high yield, and is environmentally-friendly and suitable for industrial large-scale production.

Abstract: A preparation method of 1-(4-aminophenyl)cyclopentanecarbonitrile includes the following steps: step 1: in the presence of Li2CuCl4, adding a nitrochlorobenzene-zinc reagent dropwise to a 1-chlorocyclopentanecarbonitrile solution to prepare a compound 1-(4-nitrophenyl)cyclopentanecarbonitrile; and step 2: subjecting the compound 1-(4-nitrophenyl)cyclopentanecarbonitrile obtained in step 1 to a nitroreduction reaction under the action of a catalyst to prepare the compound 1-(4-aminophenyl)cyclopentanecarbonitrile. The preparation method involves cheap and easily-available raw materials, mild reaction conditions, and convenient operations, leads to high yield, and is environmentally-friendly and suitable for industrial large-scale production.

Abstract: A process and a device for recycling waste acid produced in the process of producing Zoalene. The process comprises steps: heating, depressurizing and distilling the waste acid recycled after nitration reaction; collecting acid liquid A and distilled water A; mixing the acid liquid A with new concentrated sulfuric acid in proportion, and putting the mixture to a new Zoalene nitration reaction process; and putting the distilled water A into a diluting pot for diluting the liquid produced in the nitration reaction. The waste acid produced in the process of producing Zoalene is recycled and not directly discharged; water resources are recycled, waste of the water resources is reduced, and discharge of waste water produced in the process of producing Zoalene is greatly reduced, so that not only production cost is saved, but also environment pressure is reduced.

Abstract: A process and a device for recycling waste acid produced in the process of producing Zoalene. The process comprises steps: heating, depressurizing and distilling the waste acid recycled after nitration reaction; collecting acid liquid A and distilled water A; mixing the acid liquid A with new concentrated sulfuric acid in proportion, and putting the mixture to a new Zoalene nitration reaction process; and putting the distilled water A into a diluting pot for diluting the liquid produced in the nitration reaction. The waste acid produced in the process of producing Zoalene is recycled and not directly discharged; water resources are recycled, waste of the water resources is reduced, and discharge of waste water produced in the process of producing Zoalene is greatly reduced, so that not only production cost is saved, but also environment pressure is reduced.