8种新型7胺-基取代的1,4二-氢-3H-2,3苯-并噁嗪-3甲-酸乙酯衍生物的合成

1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯经过硝化、还原和重氮化溴代得到了7溴--1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯(C)。以Pd(OAc)2/R(+)B INAP(2,2′-二苯膦-1,1′-联萘)为催化体系,C与苯胺、N-甲基苯胺、对氟苯胺、对乙氧基苯胺、环己胺、吗啡、四氢吡咯及六氢吡啶等8种有机胺类化合物(Am ine1~8),在氮气保护下,以碳酸铯为碱于干燥的甲苯中100℃反应16~24 h,生成了相应的8种新的7胺-基取代的1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯类化合物(D1~8),反应收率分别为83%、85%、71%、90%、72%、63%、75%和83%。通过1HNMR、质谱和元素分析对这些化合物的结构进行了表征。

Synthesis of Eight New Ethyl 7-Amino-substituted 1,4-Dihydro-3H-2,3-benzoxazines-3-carboxylate

Ethyl 7-bromo-1,4-dihydro-3H-2,3-benzoxazines-3-carboxylate(C) was obtained from ethyl 1,4-dihydro-3H-2,3-benzoxazines-3-carboxylate by nitration at the 7-position,reduction of the nitro group to amino group,diazotation and replacement by bromine atom.Using Cs_2CO_3 and Pd(OAc)_2 /R(+)BINAP as the catalytic system under N_2 protection at 100 ℃,C coupled with aniline,N-methylaniline,4-fluroaniline,4-ethoxyaniline,cyclohexylamine,morpholine,pyrrolidine and piperidine separately for 16～24 h in anhydrous toluene,giving the corresponding eight ethyl 7-amino-substituted 1,4-dihydro-3H-2,3-benzoxazines-3-carboxylate(D1～8) in the yields of 83%,85%,71%,90%,72%,63%,75% and 83%,respectively.Structures of D 1～8 were determined by ~1HNMR,MS and elementary analysis.