Methylidynetrisphosphonates: Promising C1 building block for the design of phosphate mimetics

Methylidynetrisphosphonates are representatives of geminal polyphosphonates bearing three phosphonate (PO3H2) groups at the bridged carbon atom. Like well-known methylenebisphosphonates (BPs), they are characterized by a P–C–P backbone structure and are chemically stable mimetics of the endogenous metabolites, i.e., inorganic pyrophosphates (PPi). Because of its analogy to PPi and an ability to chelate metal ions, the 1,1,1-trisphosphonate structure is of great potential as a C1 building block for the design of phosphate mimetics. The purpose of this review is to present a concise summary of the state of the art in trisphosphonate chemistry with particular emphasis on the synthesis, structure, reactions, and potential medicinal applications of these compounds

Deracemization of amino acids by partial sublimation and via homochiral self-organization.

International audienceDeracemization of a 50/50 mixture of enantiomers of aliphatic amino acids (Ala, Leu, Pro, Val) can be achieved by a simple sublimation of a pre-solubilized solid mixture of the racemates with a huge amount of a less-volatile optically active amino acid (Asn, Asp, Glu, Ser, Thr). The choice of chirality correlates with the handedness of the enantiopure amino acids--Asn, Asp, Glu, Ser, and Thr. The deracemization, enantioenrichment and enantiodepletion observed in these experiments clearly demonstrate the preferential homochiral interactions and a tendency of natural amino acids to homochiral self-organization. These data may contribute toward an ultimate understanding of the pathways by which prebiological homochirality might have emerged

High temperature sublimation of α-amino acids: a realistic prebiotic process leading to large enantiomeric excess.

International audienceThe reiterative high temperature co-sublimation of an enantiopure or an enantioenriched α-amino acid mixed with racemic α-amino acids leads to deracemization of the latter. A synergistic effect is observed for complex mixtures, and the sense of the handedness is, for all compounds, identical to that of the enantioenriched starting material

Attrition-induced spontaneous chiral amplification of the γ polymorphic modification of glycine

International audienceGlycine is the simplest achiral amino acid that undergoesspontaneous mirror symmetry breaking when it crystallizes in itschiral γ-polymorphic modification. As a result of Ostwaldripening, its racemic mixture stochastically becomes opticallyactive. The sense of the resulting handedness can be controlled byaddition of one enantiomer of a simple chiral amino acid, thealanine

Partial Sublimation of Enantioenriched Amino Acids at Low Temperature. Is it Coming From the Formation of a Euatmotic Composition of the Gaseous Phase?.

International audienceThe partial sublimation of enantioenriched amino acids was performed slowly at low temp. with the aim to det. the rules of sublimation of these compds. Although the formation of a euatmotic compn. of the gaseous phase starting from DL + L mixts. of Leu, Pro, and Phe can be deduced from the enantiomeric excess of sublimates, the behavior of the kinetic conglomerate explains the results for D + L mixts. of Ala, Leu, Val, and Pro. Consequently, the enantiomeric excess of the partial sublimate is dependent not only on the studied compd. but also on the compn. of the starting mixt. [on SciFinder(R)