Serinolic Amino‐s‐triazines: Iterative Synthesis of N‐Substituted Amino‐1,3‐dioxane Derivatives from l‐(p‐Nitrophenyl)serinols and Rotational Stereochemistry Phenomena

Abstract

We report the first iterative and chemioselective approach towards the synthesis of highly elaborated N-substituted 2,4,6-triamino-s-triazines (melamines) and precursors, by amination of cyanuric chloride with anancomeric and enantiomerically pure primary and tertiary amino-1,3-dioxanes. The starting nucleophiles were prepared by direct diastereospecific and diastereoselective acetalization of N-substituted (1S,2S)-2-amino-1-(p-nitrophenyl)propane-1,3-diols

Singlet oxygen stimulus for switchable functional organic cages

“…Although single crystals suitable for crystallographic analysis could not be obtained, the structures and composition of 1a and 2a were confirmed by mass spectrometry and VT-NMR studies. At 20 °C, the NMR signals of 1a and 2a are complicated by significant signal broadening attributed to the presence of rotamers originating from the restricted rotation around the C(s-triazine)– N -(2,4,6-amino substituents) bonds 20 and to the different polyether conformers.…”

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

“…As in the case of other amino- s -triazines [ 30 – 33 36 , 45 – 46 ], for G-0 dendrons 2a and 3 , a topologically idealised model predicted a three terms ( syn–syn anti–syn anti–anti ) rotational equilibrium about the C( s -triazine)–N(exocyclic) ( Fig. 2 ) partial double bonds, at room temperature.…”

“…A well-documented restricted rotation effect that causes diastereomerism is thus induced [ 43 – 45 ]. In the case of some dendritic melamines, this intrinsic feature can promote specific spatial arrangements at room temperature in solution, for example, asymmetric vs propeller ( C 3 -symmetric) [ 30 , 36 , 45 – 46 ], “dendritic choreography” [ 47 ], “open-gates closed-gates” frontier rotamerism [ 31 ] and “in out” axial chirality [ 33 ].…”

“…At room temperature, dendrimers 5 , 7a , 8 and 9 displayed unique signals for the topologically equivalent 1 H and 13 C nuclei of the m- trivalent core and their adjacent angular connections, i.e., consistent with a propeller as local dominant arrangement ( Fig. 1 ) [ 45 – 46 ]. Except for G-2 dendrimer 5 , upon heating to 90 °C, all compounds became single mediated structures, in states with rapid and free rotation about all the C( s -triazine)–N(exocyclic) bonds.…”