Structural basis of solid solution formation during chiral resolution

Crucial factors influencing racemic resolution of N-(4-nitrobenzoyl)-dl-serine by brucine

“…Orange crystals of brucinium N-(4-nitrobenzoyl)-D-serinate 3.25 hydrate (7) and brucinium N-(4-nitrobenzoyl)-L-serinate tetrahydrate (9) were grown from ethanol (10 mL) solutions containing an equimolar amount of brucine (0.254 mmol, 0.100 g) and suitable N-(4-nitrobenzoyl)-D-or N-(4-nitrobenzoyl)-L-serine (0.254 mmol, 0.064 g). As a result of a first re-crystallization of (7) and (9), colorless crystals of brucinium N-(4-nitrobenzoyl)-D-serinate 4.5 hydrate (8) and brucinium N-(4-nitrobenzoyl)-L-serinate 3.5 hydrate (10) were grown, respectively. As a result of a further re-crystallization of the brucinium salt of N-(4-nitrobenzoyl)-L-serine, the next two new crystalline products were obtained, yellow (11) and orange (12) polymorphic crystals of brucinium N-(4-nitrobenzoyl)-L-serinate ethanol solvate.…”

“…Structural data obtained by the systematic study of diastereomeric salt formations are useful for the rationalization of optical resolution and help in the experimental design of the most important parameters. [3][4][5][6][7][8][9] To the best of our knowledge, no structure of solid solution of brucinium diastereomeric salt is known. The structure of solid solution of diastereomeric salts can provide very valuable information about the process of racemic resolution and molecular recognition, especially if the structure of solid solution can be compared with structures of suitable diastereomeric salts.…”

An aza-cyclophane stacked in racemic columnar assemblies: whole-molecule disorder in a two-dimensional solid solution

“…Solid solutions are rare (Huang et al, 2006), but it has been suggested that chiral molecules with a pseudo-element of symmetry are more likely to crystallize as solid solutions (Chion et al, 1978). Similarly, pseudosymmetric diastereomers or enantiomers that are similar in shape to a sufficient extent are more likely to crystallize as solid solutions (Barabas et al, 2000). Strictly speaking, however, crystalline (2) does not belong to any of these three classes.…”

When in the presence of the strong hydrogen bonds, the weak hydrogen bonds gain an importance

“…[2][3][4] Structural data obtained by the systematic study of diastereomeric salt formations are useful for the rationalization of optical resolution and help in the experimental design of the most important parameters. [5][6][7][8][9][10][11] Specific self-assemblies of resolving agent can be a key in chiral discrimination. 12 Gould and Walkinshaw directed attention to the tendency for conserving a packing arrangement of brucine monolayers consisting of corrugated sheets capable of great versatility in forming complexes with wider variety of compounds.…”