Search results for "X ray data"
showing 2 items of 2 documents
Spiroterpenoids from Hypericum reflexum
1993
Abstract Two new spiroterpenoids, hyperireflexolide A and B, were isolated from Hypericum reflexum . Their structures and stereochemistry were established by spectroscopic methods, including 13 C NMR, DEPT and HMQC, and X-ray data.
New Synthesis oftrans-Disubstituted Cyclam Macrocycles – Elucidation of the Disubstitution Mechanism on the Basis of X-ray Data and Molecular Modeling
1998
A new way to synthesize trans-disubstituted cyclam tetraazamacrocycles 1 is reported. The synthesis proceeds in three steps via the tricyclic 1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane system 2, which can be selectively dialkylated and hydrolyzed under basic conditions to give the final product 1. An understanding of the reactivity, based on the X-ray experimental electrostatic potential and molecular modeling of the 1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane macrotricycle, has permitted the elucidation of a new reaction pathway leading to the trans-disubstituted cyclam.