Syntheses of condensed pyrimidines as organic catalysts and the biomimetic redox catalyzed by them

1)在寻找一种高效的自循环氧化催化剂的过程中，人们发现吡啶并二嘧啶衍生物，一种新型的NAD模型，在中性条件下用于醇的氧化。本研究选择了新型黄素模型化合物嘧啶并蝶啶衍生物作为催化剂进行自循环氧化反应。实际上，嘧啶并吡啶类化合物不仅可以在中性条件下氧化多种醇类化合物，还可以在120 ℃下氧化胺类化合物10-25 h，生成相应的羰基化合物和亚胺类化合物，其催化转化率非常高（约20 -180）。然而，这些NADH模型只能还原羰基化合物，这些羰基化合物因缺电子或金属离子的存在而高度活化。1978年，Yoneda等报道了在强质子源如盐酸或三氟乙酸存在下，用1，5-二氢-5-脱氮黄素以化学计量产率将失活的简单羰基底物还原为相应醇的第一个实例.我们现在研究了在循环系统中由5-脱氮黄素和甲酸产生的1，5-二氢-5-脱氮黄素将羰基化合物自动循环还原为醇。特别地，使用3，7-二甲基-10-对甲苯基-5-脱氮黄素在120 ℃下还原50小时，直到苯甲醛底物耗尽，得到100%产率的苄醇。基于催化剂的产率为3129%，这意味着催化剂的31次循环。Morcover是一种有效的自动循环体系，可用于3，7-二甲基-10-对甲苯基-5-脱氮黄素在甲酸中催化α，β-不饱和羰基化合物的1，4-还原反应。

1) During the search for an efficient autorecycling oxidation catalyst, pyridodipyrimidine derivatives, new type NAD models, have been found to work under neutral conditions in oxidation of alcohols. This time, pyrimidopteridine derivatives as the catalysts, new type flavin models, were selected in the autorcycling oxidation. Actually, the pyrimidopteridines oxidized not only a variety of alcohols but also amines under neutral conditions at 120ﾟC for 10-25 hours to yield the corresponding carbonyl compounds and imines, catalytically with a markedly high turnover number (ca.20-180 turnover number).2) The biomimetic reduction of carbonyl compounds by NADH models such as N-alkylnicotinamides or Hantzsch esters has been extensively studied. However, these NADH models can reduce only carbonyl compounds which are highly activated by the presence of electron-deficient or by the presence of metal ions. In 1978, Yoneda et al.were reported first example of the reduction of inactivated simple carbonyl substrates to the corresponding alcohols by 1,5-dihydro-5-deazaflavin in the presence of strong proton sources such as hydrochloric acid or trifluoroacetic acid in stoichiometric yields. We studied now the autorecycling reduction of carbonyl compounds to alcohols by 1,5-dihydro-5-deazaflavins which are produced by 5-deazaflavin and formic acid in a circulatory system. In particular, the reduction using 3,7-dimethyl-10-p-tolyl-5-deazaflavin at 120ﾟC for 50 hours proceeded until the benzaldehyde substrate was exhausted to give 100% yield of benzyl alcohol. The yield based on the catalyst was 3129%, which means 31 recyclings of the catalyst. Morcover, a useful autorecycling system for the specific 1,4-reduction of alpha, beta-unsaturated carbonyl compounds to the corresponding saturated carbonyl compounds catalyzed by the 3,7-dimethyl-10-p-tolyl-5-deazaflavin in formic acid was studied.