Internally stabilized selenocysteine derivatives: syntheses, 77Se NMR and biomimetic studies

Abstract

Selenocystine ([Sec]2) and aryl-substituted selenocysteine (Sec) derivatives are synthesized, starting from commercially available amino acid l-serine. These compounds are characterized by a number of analytical techniques such as NMR (1H, 13C and 77Se) and TOF mass spectroscopy. This study reveals that the introduction of amino/imino substituents capable of interacting with selenium may stabilize the Sec derivatives. This study further suggests that the oxidation-elimination reactions in Sec derivatives could be used for the generation of biologically active selenols having internally stabilizing substituents.

Catalytic application of selenium and tellurium compounds as glutathione peroxidase enzyme mimetics

“…28 Their results supported that amino groups in close proximity to selenium could increase the stability of 31 derivatives by intramolecular Se•••N interactions. These interactions appear to modulate the reactivity of selenium toward the GPx reaction conditions.…”

“…Mugesh et al 28 proposed the synthesis of aryl-substituted L-selenocysteine derivative 31 containing a basic amino group, Figure 7. 28 Their results supported that amino groups in close proximity to selenium could increase the stability of 31 derivatives by intramolecular Se•••N interactions.…”

Improved synthetic routes to the selenocysteine derivatives useful for Boc-based peptide synthesis with benzylic protection on the selenium atom

“…The obtained colorless oil was purified by silica gel column chromatography (hexane:EtOAc = 1:1) to give 5 as a colorless oil (1.24 g, 93%). The spectral data of 5 were identical to the literature, 25 and the purity was confirmed by 1 …”

“…[20][21][22] Later, more reactive bromoalanines were utilized for the synthesis of Sec derivatives. 15,[23][24][25][26] 12 the amino group of L-serine (3) was protected with Boc, and the obtained carbamate 4 was converted into methyl ester 5 (Scheme 1). The Ser derivative thus protected was tosylated to 6 and then selenated to 7 by reaction with a selenolate, which was generated from di(p-methylbenzyl) diselenide (MBnSeSeMBn) and NaBH 4 in MeOH, according to a similar procedure reported by Braga.…”

Synthesis of chiral Nβ-protected amino diselenides from the corresponding amino alkyl iodides using NaBH2Se3 as a selenating reagent and their conversion to seleninic acids

“…Scheme 2 Synthesis of N β -protected amino diselenides 2 Woollin's reagent but the protocol is restricted to N-acetyl protection 45 and the activation through tosylates, 46 halides, 47,48,44 β-lactones, 49 or sulfamidates 21 using conventional selenating reagents is also known. But these protocols often suffer from several limitations, which include harsh reaction conditions, 5 longer reaction duration, use of expensive reagents, inseparable byproducts formation, difficulty in workup, incompatibility with base sensitive groups, etc.…”