Two new steroidal alkaloids, paxillarines A (1) and B (2), were isolated from Pachysandra axillaris. Their structures were determined by means of spectrometric methods as 3α-N-methylbenzoylamino-4β-acetoxy-16β-hydroxy-20α-dimethylamino-5α-pregnane and 3α-N-methylbenzoylamino-4β-acetoxy-12β-hydroxy-20α-dimethyl-amino-5α-pregnane, respectively. Some of the expected characteristic 1H-NMR signals were not observed due to hindered rotation when the spectra were measured on a 400 MHz spectrometer, although all of the signals appeared clearly on a 90 MHz machine. The conformation of the ring A moiety of these alkaloids is discussed.
从厚叶草中分离出两种新的甾体
生物碱,即paxillarines A(1)和B(2)。通过光谱测定法确定其结构分别为3α-N-甲基苯甲酰
氨基-4β-乙酰氧基-16β-羟基-20α-二甲基
氨基-5α-孕烷和3α-N-甲基苯甲酰
氨基-4β-乙酰氧基-12β-羟基-20α-二甲基
氨基-5α-孕烷。在400
MHz的频谱仪上测量时,由于旋转受阻,一些预期的特征1H-NMR信号没有观察到,尽管所有信号在90
MHz的仪器上清晰可见。本文讨论了这些
生物碱的A环部分的构象。