27534-88-9Relevant articles and documents
Dibromohydantoins as halogen bond (XB) donors: a route toward the introduction of chirality in halogen bonded systems
Nicolas, Irène,Jeannin, Olivier,Pichon, Delphine,Fourmigué, Marc
, p. 9325 - 9333 (2016)
N,N′-Dibromohydantoins, known as electrophilic bromination reagents, are successfully used here as halogen bond (XB) donors, as demonstrated in their crystalline adducts with para-substituted pyridines acting as halogen bond acceptors. 1:1 adducts of the achiral 5,5-dimethyl-N,N′-dibromohydantoin (DBH) are crystallized with methylisonicotinate, 4-trifluoromethylpyridine and 4-cyanopyridine, while both nitrogen atoms of pyrazine are engaged in halogen bonding in the 2:1 adduct (DBH)2·(pyrazine). A strengthening of the XB interaction between the imidic N-Br group of DBH and the pyridinic nitrogen atom is observed with the more electron rich pyridines in the order Py-CO2Me > Py-CF3 > Py-CN > pyrazine. Chiral hydantoins and their N,N′-dibromo derivatives are obtained in good yields from different amino acids (phenylglycine, phenylalanine, valine and leucine). The ability of such enantiopure N-iodoimide derivatives to act as halogen-bond donors is demonstrated in the 1:1 methylisonicotinate adduct with (S)-5-isobutyl-N,N′-dibromohydantoin.
Mechanochemical preparation of hydantoins from amino esters: Application to the synthesis of the antiepileptic drug phenytoin
Konnert, Laure,Reneaud, Benjamin,De Figueiredo, Renata Marcia,Campagne, Jean-Marc,Lamaty, Frdric,Martinez, Jean,Colacino, Evelina
, p. 10132 - 10142 (2015/02/19)
The eco-friendly preparation of 5- and 5,5-disubstituted hydantoins from various amino ester hydrochlorides and potassium cyanate in a planetary ball-mill is described. The one-pot/two-step protocol consisted in the formation of ureido ester intermediates, followed by a base-catalyzed cyclization to hydantoins. This easy-handling mechanochemical methodology was applied to a large variety of α- and β-amino esters, in smooth conditions, leading to hydantoins in good yields and with no need of purification steps. As an example, the methodology was applied to the "green" synthesis of the antiepileptic drug Phenytoin, with no use of any harmful organic solvent.