Dibromohydantoins as halogen bond (XB) donors: a route toward the introduction of chirality in halogen bonded systems. Issue 48 (24th November 2016)

• Record Type: Journal Article
• Authors: Nicolas, Irène; Jeannin, Olivier; Pichon, Delphine; Fourmigué, Marc
• Is Part Of: CrystEngComm. Volume 18:Issue 48(2016)
• Page Start: 9325
• Page End: 9333
• Publication Date: 2016-11-24
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c6ce02175a
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : N, N′ -Dibromohydantoins, also prepared in chiral form, act as powerful halogen bond donors toward 4-substituted pyridines. Abstract : 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–CO2 Me > 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.