Imino-aldol type condensations

Certain chemical reactions are common to the formation of many types of alkaloids (Geissman and Crout, 1969). Among these are decarboxylation, Schiff-base formation, Mannich-base condensation, and imino-aldol-type condensations. 

Pteridine, 4-imino-1 -methyl-1,4-dihydro-basicity, 3, 270 Pteridine, 7-methoxy-synthesis, 3, 297 Pteridine, 2-methyl- H NMR, 3, 285 reactions, 3, 288 structure, 3, 266 Pteridine, 4-methyl-Gabriel s synthesis, 3, 309 H NMR, 3, 285 reactions, 3, 288 structure, 3, 266 Pteridine, 6-methyl-bromination, 3, 301 structure, 3, 266 synthesis, 3, 312 Pteridine, 7-methyl-aldol-type condensation, 3, 302 bromination, 3, 301 H NMR, 3, 285 structure, 3, 266 synthesis, 3, 312 Pteridine, 2-methylamino-solubility, 3, 271 Pteridine, 2-methyl-3,4-dihydro-striicture, 3, 279 Pteridine, 6-methyl-3,4-dihydro-structure, 3, 279... 

Equilibria between hexa- and pentacoordinated sUicon complexes have been examined carefully by Kost et al. Exemplaiily the following works might be cited here Neutral hexacoordinated siUcon complexes derived from hydrazide chelating ligands with imino-donor groups form pentacoordinated Si complexes in the course of ionic dissociation reactions. Such complexes were shown to undergo facile intramolecular aldol-type condensation [176]. In a related system... 

Aldol and aldol-like condensations between compounds containing imino groups also occur frequently. This enamine variation of the aldol-type reaction may be illustrated by the formation of tetrahydroanabasine, as in Fig. 27.2c. 

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