Asmarines are marine alkaloids, with a unique tetrahydro [1, 4] diazepino-[1, 2, 3-g, h] purine (THDAP) structure and interesting biological properties. Three synthetic approaches were employed for the preparation of the THDAP system. Several N-9, of the purine, protecting groups were investigated. 15N-Chemical shifts measured from 15NH HMBC experiments for several compounds, that demonstrate the influence of various structural features on the ...
