Figure 13.
(1) Typical alkaloid–alkaloid synthons observed in the crystal structures of alkaloid–carboxylic acid complexes. (2) The most frequently observed alkaloid–acid heterosynthons observed in alkaloid–acid systems. (3) The two most common types of carboxylic acid dimers in crystal structures.71 The number of structures found in the CSD base with a given synthon is given in blue (Search conditions: 3D coordinates determined, structure with R ≤ 0.1, no errors, only organic structures. An additional condition for carboxylic acid synthons was “normalize terminal H positions”).