Synthesis And Fungicidal Activity Of 1-(arylaminoethyl)-3,1-benzoxazines And Benzoxazinodiazepines

Pesticides play very important role in agricultural production and national economic life.The development of efficient,low toxicity,low residue and friendly environment green pesticides has become the focus of today's pesticide researches.3,1-Benzoxazine compounds have received increasing atention in the field of drugs and pesticides researches because of their important biological activity.So,in this paper we designed and synthesized novel 1-(arylaminoethyl)-2-aryl-3,1-benzoxazines and 9-aryl-3,1-benzoxazinodiazepines,and preliminary studied their fungicidal activity.The structures of the synthesized compounds were characterized by 1H NMR,13 C NMR and IR.The crystal structures of some3,1-benzoxazinodiazepines were also determined.(1)2-Bromoacetamides VIII-1? VIII-16 were prepared in 80.9%~98.7% yields using bromoacetyl bromide and aromatic amines or benzylamines as raw materials in the presence of triethylamine.The reaction yield of the N atom directly connected with a benzyl group is higher than those of the N atom connected with an aryl group.(2)A series of N-substituted arylacetamides VI-1? VI-16 were synthesized in a yield of57.5%~82.8% by reactions of 2-bromoacetamides with 2-aminobenzyl alcohol.The reaction yield of the N atom directly connected with an aryl group is higher than those of the N atom attached to a benzyl group.The reaction conditions were: V(DMF):V(THF)=1: 2 as solvent,potassium carbonate as base,n(VIII): n(2-aminobenzyl alcohol): n(K2CO3)=1.0:1.2:1.4,reaction time 12 h,temperature 65?.(3)A series of 2-(arylaminoethylamino)benzyl alcohols V-1?V-16 was synthesized in62.9%~ 95.3% yields by the reduction of N-substituted arylacetamide compounds VI with LiAlH4.The yield of the N atom directly attached to an aryl group is higher than that of the N atom attached to a benzyl group.(4)A series of 1-(arylaminoethyl)-2-aryl-3,1-benzoxazines I-1~ I-27 was synthesized in47.3%~91.5% yields by reactions of compound 2-(arylaminoethylamino)benzyl alcohols V and nitrobenzaldehydes with high chemoselectivity.No imidazoline compounds were produced.The optimum conditions were: the ratio of V to nitrobenzaldehyde 1:1.4,La(CF3SO3)3(10% mol)as catalyst,CHCl3 and cyclohexane(V:V= 1:4)as solvent,65°C,5 h.The reaction yield is related to the position of the nitro group on the phenyl group at the2-position of the benzoxazine ring abidying the order of para> meta > ortho.(5)1-(Arylaminoethyl)-3,1-benzoxazines II were synthesized in 30.6%~55.3% yields by reactions of 2-(arylaminoethylamino)benzyl alcohols V with paraformaldehyde.The reactionconditions were: the molar ratio of V to paraformaldehyde 1:1:4,65°C,5 h,La(CF3SO3)3(10% mol)as catalyst,CHCl3 and cyclohexane(V:V=1:4)as solvent.(6)9-Arylamino-3,1-benzoxazinodazepiazepines III-1~III-14 were synthesized in33.1%~56.3% yields by reactions of 2-(arylaminoethylamino)benzyl alcohols V with paraformaldehyde.The reaction conditions were as follows: the molar ratio of V to paraformaldehyde was 1: 3,La(CF3SO3)3(10% mol)as catalyst,CHCl3 and cyclohexane(V:V=1:4)as solvent.(7)The fungicidal activities of the synthetic compounds were evaluated.The results showed that the inhibition rate of compound II-4 against Magnaporthe grisea was 83.2% at the concentration of 50 ?g/mL,and 76.7% activity against the Botrytis cinerea.The inhibition rate of compound III-14 against Pellicularia sasakii was 80.5%.The inhibition rate of compound I-7 against Botrytis cinerea was 76.7%,and 71.9% for compound I-4.The inhibition activity of compound III-3 against Sclerotinia sclerotiorum was 78.8%,73.4%activity against Pellicularia sasakii,and 66.3% against Magnaporthe grisea.These results indicated that compound III-3 showed broad activity.In general,the fungicidal activity of the2-unsubstituted 3,1-benzoxazine compounds is greater than those of the3,1-benzoxazinodiazepines,greater than those of the 2-aryl-3,1-benzoxazines.