Succinic acid monoethyl ester chloride (3) was prepared by alcoholysis , acetylation reaction from succinic anhydride.The important intermediate, (5-amino-[1,3,4] thiadiazol-2-yl)-propionic acid ethyl ester , was synthesized by cyclization of 3 with thiosemicarbazide catalyzed by methane sulfo-nic acid.The structure was confirmed by 1 H NMR, IR and MS.The reaction conditions for cyclizating reaction was investigated by the orthogonal design .The results showed that the optimal reaction condi-tions were as followed:3 132 mmol, n(thiosemicarbazide) ∶n(3) ∶n(methane sulfonic acid)=1∶3∶3, reaction at 110 ℃for 3 h, the total yield was 51.3%.

The present study compared the chemical and physical deactivation methods of urease anti-nutrition factors in soybean meal by orthogonal experimental design.The results showed that the optimized conditions were deactivated soybean meal with 0.03 mol·L-1 Na2SO3 for 60 min at 75℃ for chemical deactivation method;treated at 230 W for 90 s with the soybean particle size of 60 mesh sieve for microwave deactivation method;adding 20 mL H2O reacted 30 min with the soybean particle size of 60 mesh sieve for physical ultrasonic method.The urease activities were lower than 0.3 U after these three deactivated processes and accorded with the standard of high quality feeds.