3-propanediamines 2a-h with aldehydes. Reactions with formaldehyde proceeded in hydroalcoholic solution, while condensation with aromatic aldehydes required in general the use of activated molecular sieves. 1H NMR spectra of compounds la-1 were analyzed and the results correlated with their conforma-tional features. Derivatives devoid of a 2-substituent la-g show fast ring reversal and N-inversion. The presence
一系列Ñ -arylhexahydropyrimidines LA-1通过的缩合合成ñ -芳基- ñ “ -烷基(或芳基)-
1,3-丙二胺2A-H与醛。与
甲醛的反应在
水醇溶液中进行,而与芳族醛的缩合通常需要使用活化的
分子筛。分析了化合物1A-1的1 H NMR光谱,并将结果与其构型特征相关联。不含2个取代基la-g的衍
生物显示快速环逆转和N-反转。2-芳基的存在将环反转平衡移向其中2-芳基取代基是赤道的构象。根据偶联常数和
化学位移值对这些化合物中的轴向和赤道氢进行了不同的分配。在化合物1k中,光谱数据表明N-甲基的轴向取向。在相应的NOESY谱图中证实了这些发现。