Isoselenocyanates derived from amino acid esters: an expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins

Abstract

An important class of organoselenium compounds-α-isoselenocyanato esters 4 has been prepared by a reaction of α-isocyano esters with elemental selenium powder. The reaction issimple, rapid and all the isoselenocyanates have been isolated as stable ones after chromatographic purification. These hitherto unreported classes of molecules would be useful building blocks for the preparation of variety of selenium containing peptidomimetics. In this study, the utility of the title molecules in the preparation of selenoureidopeptidomimetics 6, unsymmetrical selenoureas 8 and selenohydantoins 10 is demonstrated.

Synthesis of Isoselenocyanates

“…The direct addition of selenium to isocyanides using black, finely powdered, elemental selenium in an organic solvent is the most typical method for the synthesis of isoselenocyanates. 9,10,[34][35][36][37][38][39][40][41] In our previous research, we have obtained isoselenocyanates (bearing nitroxyl 25 and aryl 26 moieties) from isocyanides. Unfortunately, we observed unreproducible results when the addition of selenium to isocyanides with black, finely powdered, elemental selenium occurred either in chloroform or in tetrahydrofuran in the presence of triethylamine (see below).…”

Reactions of Nitroxides, Part 17. Synthesis, Fungistatic and Bacteriostatic Activity of Novel Five- and Six-Membered Nitroxyl Selenoureas and Selenocarbamates

“…Selenourea derivatives were synthesized from the following starting compounds—sources of selenium: isoselenocyanates and primary or secondary amines [27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44] selenoamides and nitrile oxides (generated in situ) [45], hydrogen selenide [46,47,48], lithium aluminum hydride (LiAlH 2 Se) [12,32,36,49,50,51,52,53], bis(dimethylaluminum) selenide [54], tetraethylammonium tetraselenotungstate [14], elemental selenium with an isonitrile and an amine [55], elemental selenium with an amine and triethylorthoformate [56], and elemental selenium with a secondary amine, a base, and dihalomethan derivatives [57,58].…”

Cysteine Isocyanide in Multicomponent Reaction: Synthesis of Peptido-Mimetic 1,3-Azoles

“… 19 In another report, ( R )-methyl 3-(benzythio)-2-isocyanopropanoate was described for the synthesis of corresponding isoselenocyanate. 20 However, benzyl protection for thiol is not promising for many postmodifications on sulfur. Very recently, we have synthesized the stable and enantiomerically pure chiral isocyanide derived from S -trityl protected cysteine and employed it for the preparation of disulfide bridged macrocycles.…”