3,4-Dichloro-5-(6-chloro-9-(4-fluorobenzyl)-9H-purin-8-yl)isothiazole,a novel purine derivative,was synthesized by the cyclization of pyrimidine amine.Its structure was characterized by 1H NMR,13C NMR,19F NMR,H RMS and single-crystal X-ray diffraction.This compound 3 is crystallized from a mixed solvent of dichloromethane and n-hexane (1∶2,v/v) for structural identification as monoclinic crystal system,space group P21/n with a =11.66250(10),b =8.21300(10),c =17.77920(10) (A),V=1676.34(3) (A)3,Z =4,Dc =1.643 g/cm3,F(000) =832.0 and μ =6.301 mm-1.22315 reflections were measured (8.43≤2θ≤ 158.10°),of which 3532 were unique (Rint =0.0311) and used in all calculations.The final R =0.0334 (Ⅰ > 2σ(Ⅰ)) and wR =0.0842 (reflections).The title compound showed over 50% of growth inhibition against Botrytis cinereal,Cercospora arachidicola,Gibberella zeae,Rhizoctonia solani and Sclerotinia sclerotiorum at 50 mg/L,and its EC50 value against R.solani was 60.44 μmol/L,which was active at the same level as that of positive control diflumetorim with its EC50 value of 60.29 μmol/L and less active than YZK-C22 with its EC50 value of 12.32 μmol/L,respectively.Our studies discovered that the combination of bioactive substructures of isothiazole with purine could be an effective way to novel fungicide development.