Application of bis-2-(trimethylsilyl)ethyl diselenide to the synthesis of selenium-containing amino acid derivatives

Article abstract of DOI:10.1016/j.tet.2017.09.004

Selenium-containing amino acids play a pivotal role as biomaterials for the synthesis of Se-dependent enzymes and repair proteins. Especially, selenocysteine and selenoglutathione are prominently involved in fundamental biological processes. In this study

Full text of DOI:10.1016/j.tet.2017.09.004

Accepted Manuscript
Application of bis-2-(trimethylsilyl)ethyl diselenide to the synthesis of selenium-
containing amino acid derivatives
Tsubasa Yonezawa, Masahito Yamaguchi, Masayuki Ninomiya, Mamoru Koketsu
PII:
S0040-4020(17)30917-1
10.1016/j.tet.2017.09.004
TET 28955
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 1 August 2017
Revised Date: 30 August 2017
Accepted Date: 4 September 2017
Please cite this article as: Yonezawa T, Yamaguchi M, Ninomiya M, Koketsu M, Application of
bis-2-(trimethylsilyl)ethyl diselenide to the synthesis of selenium-containing amino acid derivatives,
Tetrahedron (2017), doi: 10.1016/j.tet.2017.09.004.
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Application of bis-2-(trimethylsilyl)ethyl
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Tsubasa Yonezawaa, Masahito Yamaguchia, Masayuki Ninomiyaa,b and Mamoru Koketsua,b,
aDepartment of Materials Science and Technology, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
bDepartment of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan

1
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Tetrahedron
journal homepage: www.elsevier.com
Application of bis-2-(trimethylsilyl)ethyl diselenide to the synthesis of selenium-
containing amino acid derivatives
Tsubasa Yonezawaa, Masahito Yamaguchia, Masayuki Ninomiyaa,b and Mamoru Koketsua,b,
aDepartment of Materials Science and Technology, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
bDepartment of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
ARTICLE INFO
ABSTRACT
Article history:
Received
Selenium-containing amino acids play a pivotal role as biomaterials for the synthesis of Se-
dependent enzymes and repair proteins. Especially, selenocysteine and selenoglutathione are
Received in revised form
Accepted
Available online
prominently involved in fundamental biological processes. In this study, a series of
selenocysteine (Sec) and selenoglutathione (GSeH) derivatives were synthesized via 2-
(trimethylsilyl)ethylselenation as a key step. Our findings suggested the relevance and
application of a 2-(trimethylsilyl)ethylselenyl group to the Se-containing amino acid synthesis.
Keywords:
Selenation
Bis-2-(trimethylsilyl)ethyl diselenide
Selenium-containing amino acid
Selenocysteine
2017 Elsevier Ltd. All rights reserved
.
Selenoglutathione
———
Corresponding author. Tel./Fax: +81-58-293-2619; e-mail: koketsu@gifu-u.ac.jp

2
Tetrahedron
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1. Introduction
selenolate anion by reduction of selenocystine with NaBH4 and
reaction with 4-methoxybenzyl chloride.30 (2) In the other, the
substituted diselenide or selenol are needed to prepare with
respect to each functionality. Gieselman et al., reported the
synthetic procedure which involved nucleophilic displacement of
the O-tosyl moiety of l-serine derivatives by a 4-methoxybenzyl
selenolate anion generated from 4-methoxybenzyl diselenide.31 In
this study, we therefore planned to use bis-2-(trimethylsilyl)ethyl
(TSE) diselenide (TSE-Se-Se-TSE, 1) as a selenating reagent
which has two latent sites of reactivity. As outlined in Scheme 1,
the initial step commences with in situ generation of a TSE
selenolate anion (TSE-Se-) from bis-TSE diselenide (1) by
hydride reduction. This anion attack to β-halo alanine, resulting
in introduction of TSE selenyl moiety onto amino acid skeleton.
Second step involves Se-alkylation with alkyl halides using high
specificity and affinity between Si and F. Our approach never
goes through selenocystine or even offers to prepare the suitable
diselenide or selenol.
Since the element selenium was firstly discovered from
copper pyrites by the Swedish chemist Jöns Jacob Berzelius in
1817,1 it had been predicted as a dangerous component causing
livestock poisoning for over a century. In 1950s, Schwarz et al.,
reported its ability to serve interchangeably with vitamin E in the
prevention of vascular or muscular signs.2 Subsequently, it was
reported that the glutathione peroxidase (GPx) having Se in its
catalytic center spares vitamin E by Se.3 Owing to the discoveries
of several Se-dependent GPx forms,4-7 other selenoenzymes
(iodothyronine deiodinases,8-10 thioredoxin reductases,11,12 and
selenophosphate synthetase [7,13]), and specific selenoproteins
(SelH, SelI, SelK, SelN, SelM, SelO, SelP, SelR, SelS, SelT,
SelV, SelW, and Sep15),13-16 the selenium is now recognized to
be nutritionally essential for humans.
Selenocysteine (Sec) is often referred to as the 21st amino acid
found in 25 human selenoenzymes and selenoproteins. The GPxs
catalyze the reduction of harmful hydroperoxides through the
catalytic triad formation of the Sec residue at the active site with
tryptophan and glutamine.16 The key role of Sec in the overall
catalytic process is believed to arise from the powerful
nucleophilicity of Se. In general, selenoproteins are involved in a
variety of fundamental functions, most notably redox
homeostasis.17 With the exception of plasma selenoprotein P,
selenoproteins contain a single Sec residue, which is incorporated
by the co-translational modification of transfer RNA-bound
serine at certain loci coded by specific uracil-guanine-adenine
codons.18,19
Bis-TSE diselenide (1) was prepared as published previously;
following treatment of elemental selenium with sodium
borohydride (NaBH4), alkylation of the activated selenium with
2-(bromoethyl)trimethyl silane provided the desired selenating
reagent (1) in 73% yield.22,24 Under the Appel conditions,32 N-
[tert-butoxycarbonyl (Boc)]-3-iodo-
was prepared in 84 % yield starting from N-Boc-
L-alanine methyl ester (2)
L-serine methyl
ester (Scheme 2). It is noteworthy that treatment of 2 with bis-
TSE diselenide (1, 1.2 equiv.) in the presence of NaBH4 (1.2
equiv.) and EtOH (3.0 equiv.) in DMF for 1 h proceeded
swimmingly to afford the requisite Se-TSE-selenocysteine (3) in
89% yield. The characteristic 77Se NMR signal for the TSE
selenyl group appeared at 177.8 ppm.24 Subsequently, we
attempted Se-methylation of 3 by means of iodomethane (MeI,
5.0 equiv.) and tetrabutylammonium fluoride (TBAF, 3.0 equiv.)
at room temperature for 24 h, however, the reaction yielded an
unexpected α-methylated compound as a major product. It was
deemed that the basicity of TBAF was the cause of α-
methylation. In order to suppress of the bothersome side effect of
TBAF, AcOH was selected. Addition of AcOH (3.0 equiv.)
brought the role switching of TBAF in the reaction progress,
leading to facilitation of Se-methylation (4a, 43% yield). The
77Se NMR signal arising from 3 significantly sifted to the higher
Organoselenium chemistry has attracted a great deal of
attention due to the unique chemical behavior and potent
pharmacological efficacy of Se-containing compounds. Our
efforts have been directed to searching the possibilities of bis-2-
(trimethylsilyl)ethyl (TSE) diselenide as a selenating agent in the
synthesis of Se-containing biomolecules including sugars,20,21 β-
lactams,22,23 and nucleosides.24,25 Within the scope of our ongoing
program, we would like to report the application of TSE
diselenide to the Se-containing amino acid synthesis, particularly
Sec and selenoglutathione (GSeH) analogues.
2. Results and discussion
Table 1. Reactivity of 3 with various electrophiles.
Scheme 1. Synthetic strategy for the synthesis of alkylselenocysteine
derivatives.
Scheme 2. Synthesis of N-Boc-Se-methyl-L-selenocysteine methyl ester (4a).
For preparation of Sec derivatives, there are two general types
of synthetic approaches: (1) those employing a Sec selenolate
anion that attacks alkyl halides (RX), and (2) those using a
substituted selenolate anion (RSe-) that attacks β-halo alanine, O-
tosyl serine, or serine-β-lactone, to form RSec. (1) One of the
approaches utilizes selenocystine (dimeric Sec) as a precursor to
possible building of structures.26-28 By reference to a previous
magnetic side of 45.6 ppm in 4a.
Having successfully established Se-methylation of 3, we next
probed the generality of this protocol with a variety of
electrophiles. Results are summarized in Table 1. Although
reactions with MeI and EtI furnished the corresponding Se-
alkylated products (4a, 43% and 4b, 48%, Entries 1 and 2), 3 did
not react with i-PrI at all (Entry 3). Compared to these results,
treatment with allyl and propargyl bromides offered easy access
to
report,29
Koide
et
al.,
prepared
Se-4-
methoxybenzylselenocysteine through in situ formation of a Sec

3
Entry
1
R-X (equiv.)
Yield (%)
unsuccessful (Entry 22), and the instability of the produced acyl
selenide could explain it as a result of its hydrolysis.
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MeI (5.0)
43 (4a)
48 (4b)
0 (4c)
2
EtI (10)
Selenoglutathione (GSeH) appears to supply benefits by
acting as a redox tripeptide substrate comprising glutamic acid
(Glu), selenocysteine (Sec), and glycine (Gly).33,34 In light of the
above results, we shifted our focus to synthesize GSeH analogues
from 3 as the starting point. Due to their structural complexity,
their chemical synthesis is challenging. For conjugation of Gly
with Sec, the methyl ester (3) was converted to the free
carboxylate (5) under basic conditions (Scheme 3). Without
further purification by silica gel column chromatography, Gly
3
i-PrI (3.0)
4
CH2=CHCH2Br (3.0)
CH≡CCH2Br (5.0)
MeOCH2CH2Br (3.0)
N≡CCH2Br (3.0)
BnBr (2.0)
81 (4d)
78 (4e)
12 (4f)
34 (4g)
86 (4h)
73 (4i)
58 (4j)
46 (4k)
23 (4l)
58 (4m)
63 (4n)
59 (4o)
68 (4p)
87 (4q)
55 (4r)
50 (4s)
13 (4t)
0 (4u)
5
6
7
8
9
p-MeBnBr (3.0)
o-NO2BnBr (3.0)
m-NO2BnBr (3.0)
p-NO2BnBr (3.0)
o-ClBnBr (3.0)
m-ClBnBr (3.0)
p-ClBnBr (3.0)
Me(C=O)CH2Br (10)
Ph(C=O)CH2Br (3.0)
MeO(C=O)CH2Br (4.0)
tert-BuO(C=O)CH2Br (5.0)
o-NO2PhF (2.0)
p-NO2PhF (2.0)
BzCl (3.0)
methyl ester was inserted into
dimethylaminopropyl)carbodiimide
5
using 1-ethyl-3-(3-
(EDCI), 1-
10
11
12
13
14
15
16
17
18
19
20
21
22
hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine
(DIPEA), giving 6 in 60% yield with maintenance of the TSE
selenyl moiety. Under slightly modified conditions of Table 1,
Se-methylation and Se-benzylation actually succeeded in 60% for
7a and 68% for 7b. Acidic Boc-deprotection gave 8, which was
coupled with N-Boc-glutamic acid tert-butyl ester, to provide the
tripeptide analogues (9a, 91% and 9b, 85%). The final step was
deprotection of the both amino and carboxylate functionalities
which was effected in the same fashion, affording the targeted
GSeH derivatives (10a, 74% and 10b, 75% over two steps). The
multistep sequence from 3 depicted in Scheme 3 allowed to
construct the alkylselenyl Glu-Sec-Gly frameworks in overall
yields of 21% for 10a and 34% for 10b.
3. Conclusion
0 (4v)
We have demonstrated a concise route for the preparation of
Sec analogues by tuning the selenation step. Given the
convenient methodology presented herein was easily applicable
the products in good yields (4d, 81% and 4e, 78%, Entries 4 and
5). With 2-bromoethyl methyl ether and bromoacetonitrile, the
Scheme 3. Synthesis of Se-alkylated selenoglutathione derivatives.
yields were decreased considerably (Entries 6 and 7). In the
category of benzyl bromides bearing various functional groups
on the benzene ring, treatment with benzyl and p-methylbenzyl
bromides gave Se-benzylated products (4h and 4i) in 86% and
73% yields, respectively (Entries 8 and 9). With o-, m-, and p-
nitro substituted benzyl bromides, the yields were affected by
substitution patterns (Entries 10-12). In contrast, chloro-
substituted positions have little influence on the reaction progress
(Entries 13-15). When α-haloacyl reagents were used, the
reactions worked well (Entries 16-19). To further explore the
scope of our synthetic strategy, we tried nucleophilic aromatic
substitution and acylation. Although the reactivity of 3 with
nitrofluorobenzenes was low, the Se-arylated product (4t) was
obtained in 13% yield only by the reaction with o-
nitrofluorobenzene (Entry 20). The Se-benzoylation was
to the GSeH synthesis, it may be suited for the incorporation of
alkylselenyl moieties into peptide scaffolds. Our findings
highlight the great utility and versatility of
a
2-
(trimethylsilyl)ethylselenyl group. We believe that these results
will contribute to the better understanding of physiological roles
of selenopeptide-containing biomacromolecules.
4. Experimental section
4.1. General
All solvents and reagents were purchased from the suppliers
and used without further purification. IR spectra were recorded
on a JASCO FT/IR-460 Plus spectrophotometer. Optical
rotations were measured with a JASCO P-2300. MS spectra were
obtained using the Waters UPLC-MS system (Aquity UPLC
XevoQTof). NMR spectra were recorded with JEOL JNM-ECS

4
Tetrahedron
4.4.2. N-Boc-Se-allyl-L-selenocysteine methyl ester
400 and JNM-ECA 600 spectrometers with tetramethylsilane as
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an internal standard. 77Se chemical sifts were expressed in δ
values deshielded with respect to neat Me2Se. Silica gel column
chromatography (CC) was performed on silica gel N-60 (40-50
ꢀm). Thin-layer chromatography (TLC) spots on plates pre-
coated with silica gel 60 F254 were detected with a UV lamp (254
nm). Fractionations for all CCs were based on TLC analyses.
(4d)
Colorless oil in 81% yield; [α]20 +6.7° (c 1.70, CHCl3); IR
D
(film): νmax 3377, 3082, 2978, 1714, 1632, 1165 cm-1; H NMR
1
t
(400 MHz, CDCl3): δ 1.43 (s, 9H, Bu), 2.92 (d, 2H, J = 5.0 Hz,
H-β), 3.19 (dd, 2H, J = 3.6 and 7.8 Hz, SeCH2CH=CH2), 3.76 (s,
3H, CO2Me), 4.60 (d, 1H, J = 7.8 Hz, H-α), 5.04 (d, 2H, J = 10.1
Hz, SeCH2CH=CH2), 5.37 (d, 1H, J = 7.3 Hz, NH), 5.85 (dt, 1H,
J = 10.1 and 27.0 Hz, SeCH2CH=CH2); 13C NMR (100 MHz,
CDCl3): δ 25.2, 26.8, 28.4, 52.6, 53.4, 80.1, 117.1, 134.4, 155.1,
171.7; 77Se NMR (113 MHz, CDCl3): δ 160.2; HRESITOFMS:
m/z 346.0524 [M+Na]+ (calcd for C12H21NO4SeNa, 346.0533).
4.2. Synthesis of N-Boc-Se-[2-(trimethylsilyl)ethyl]-
selenocysteine methyl ester (3)
L-
After stirring of bis-2-(trimethylsilyl)ethyl diselenide (1, 3.6
mmol), NaBH4 (3.6 mmol), and EtOH (9.0 mmol) in DMF (2 ml)
at 0oC for 30 min, N-Boc-3-iodo-
L-alanine methyl ester (2, 3.0
4.4.3. N-Boc-Se-propargyl-L-selenocysteine methyl
mmol) was added to the solution, and the reaction was continued
at rt for an additional 1 h. The resultant solution was poured into
distilled water, partitioned with EtOAc, and washed with brine.
The organic layer was dried over anhydrous Na2SO4 and
concentrated in vacuo. The residue was purified using silica gel
column chromatography eluted with n-hexane/EtOAc (15/1) to
ester (4e)
Yellow oil in 78% yield; [α]20 +15.2° (c 1.32, CHCl3); IR
D
(film): νmax 3377, 3292, 2978, 2114, 1744 cm-1; H NMR (400
1
t
MHz, CDCl3): δ 1.40 (s, 9H, Bu), 2.26 (s, 1H, SeCH2C≡CH),
3.12-3.18 (m, 4H, H-β and SeCH2C≡CH), 3.72 (s, 3H, CO2Me),
4.62 (d, 1H, J = 6.9 Hz, H-α), 5.37 (d, 1H, J = 6.9 Hz, NH); 13C
NMR (100 MHz, CDCl3): δ 8.0, 26.7, 28.4, 52.6, 53.4, 72.1,
80.2, 80.3, 155.1, 171.6; 77Se NMR (113 MHz, CDCl3): δ 219.7;
HRESITOFMS: m/z 344.0355
C12H19NO4SeNa, 344.0377).
afford 3 (89% yield) as a yellow oil; [α]20 +18.8° (c 1.02, CHCl3);
D
IR (film): νmax 3379, 2953, 1717 cm-1; H NMR (400 MHz,
1
CDCl3): δ 0.00 (s, 9H, TMS), 0.92 (dd, 2H, J = 7.1 and 11.2 Hz,
SeCH2CH2TMS), 1.44 (s, 9H, tBu), 2.62 (dt, 2H, J = 3.2 and 13.8
Hz, SeCH2CH2TMS), 2.99 (t, 2H, J = 4.6 Hz, H-β), 3.75 (s, 3H,
CO2Me), 4.63 (dt, 1H, J = 4.1 and 7.8 Hz, H-α), 5.37 (d, 1H, J =
7.8 Hz, NH); 13C NMR (100 MHz, CDCl3): δ -1.8, 18.7, 20.3,
26.0, 28.4, 52.6, 53.6, 80.2, 155.2, 171.8; 77Se NMR (113 MHz,
CDCl3): δ 177.8; HRESITOFMS: m/z 406.0906 [M+Na]+ (calcd
for C14H29NO4SeNa, 406.0929).
[M+Na]+ (calcd for
4.4.4. N-Boc-Se-methoxyethyl-
L
-selenocysteine
methyl ester (4f)
Colorless oil in 12% yield; [α]20 +8.91° (c 1.10, CHCl3); IR
D
(film): νmax 3376, 2978, 1746, 1502, 1166 cm-1; H NMR (400
1
t
MHz, CDCl3): δ 1.45 (s, 9H, Bu), 2.75 (dt, 2H, J = 2.8 and 6.4
Hz, SeCH2CH2OMe), 3.03 (t, 2H, J = 4.6 Hz, H-β), 3.37 (s, 3H,
4.3. Methylation of 3
SeCH2CH2OMe), 3.62 (dt, 2H,
J = 3.2 and 7.3 Hz,
SeCH2CH2OMe), 3.75 (s, 3H, CO2Me), 4.60 (d, 1H, J = 7.8 Hz,
H-α), 5.58 (d, 1H, J = 7.3 Hz, NH); 13C NMR (100 MHz,
CDCl3): δ 24.4, 26.6, 28.5, 52.7, 53.8, 58.8, 72.8, 80.2, 155.4,
171.8; 77Se NMR (113 MHz, CDCl3): δ 115.1; HRESITOFMS:
m/z 364.0659 [M+Na]+ (calcd for C12H23NO5SeNa, 364.0639).
TBAF (1.0 M in THF, 0.9 mmol), AcOH (0.9 mmol), and MeI
(1.5 mmol) were added to a solution of 3 (0.3 mmol) in DMF
(0.5 ml). After stirring at rt for 24 h, the resultant solution was
poured into distilled water, partitioned with EtOAc, and washed
with brine. The organic layer was dried over anhydrous Na2SO4
and concentrated in vacuo. The residue was purified using silica
gel column chromatography eluted with n-hexane/EtOAc (10/1)
4.4.5. N-Boc-Se-cyanomethyl-
methyl ester (4g)
L-selenocysteine
to afford N-Boc-Se-methyl-L-selenocysteine methyl ester 4a
Colorless oil in 34% yield; [α]20 +10.8° (c 1.20, CHCl3); IR
(43% yield) as a colorless oil; [α]20 +13.7° (c 1.40, CHCl3); IR
D
D
1
1
(film): νmax 3367, 2980, 2241, 1743, 1511 cm-1; H NMR (400
(film): νmax 3376, 2978, 1747, 1715 cm-1; H NMR (400 MHz,
t
MHz, CDCl3): δ 1.44 (s, 9H, Bu), 3.20-3.27 (m, 4H, H-β and
CDCl3): δ 1.43 (s, 9H, tBu), 2.00 (s, 3H, SeMe), 2.95 (d, 2H, J =
5.0 Hz, H-β), 3.74 (s, 3H, CO2Me), 4.58 (d, 1H, J = 7.3 Hz, H-
α), 5.35 (d, 1H, J = 4.0 Hz, NH); 13C NMR (100 MHz, CDCl3): δ
5.31, 27.7, 28.4, 52.6, 53.4, 80.2, 155.2, 171.8; 77Se NMR (113
MHz, CDCl3): δ 45.6; HRESITOFMS: m/z 320.0351 [M+Na]+
(calcd for C10H19NO4SeNa, 320.0377).
SeCH2CN), 3.79 (s, 3H, CO2Me), 4.67 (d, 1H, J = 4.6 Hz, H-α),
5.37 (s, 1H, NH); 13C NMR (100 MHz, CDCl3): δ 3.2, 28.4, 53.0,
53.4, 80.7, 117.2, 155.2, 171.2; 77Se NMR (113 MHz, CDCl3): δ
224.1; HRESITOFMS: m/z 345.0357 [M+Na]+ (calcd for
C11H18N2O4SeNa, 345.0329).
4.4.6. N-Boc-Se-benzyl-L-selenocysteine methyl
4.4. Various alkylation of 3
ester (4h)
Reaction parameters are given in Table 1. The operation
procedures are exactly the same with the section of Methylation
of 3.
Yellow oil in 86% yield; [α]2D0 -2.0° (c 1.30, CHCl3); IR
1
(film): νmax 3388, 2978, 1714, 1601, 1496 cm-1; H NMR (400
MHz, CDCl3): δ 1.47 (s, 9H, tBu), 2.91 (s, 2H, H-β), 3.74 (s, 3H,
CO2Me), 3.80 (s, 2H, SeBn), 4.61 (d, 1H, J = 7.3 Hz, H-α), 5.29
(d, 1H, J = 6.9 Hz, NH), 7.21-7.29 (m, 5H, Ar); 13C NMR (100
MHz, CDCl3): δ 26.0, 28.0, 28.4, 52.7, 53.4, 80.3, 127.1, 128.7,
129.0, 138.9, 155.2, 171.8; 77Se NMR (113 MHz, CDCl3): δ
219.1; HRESITOFMS: m/z 396.0676 [M+Na]+ (calcd for
C16H23NO4SeNa, 396.0690).
4.4.1. N-Boc-Se-ethyl-L-selenocysteine methyl ester
(4b)
Colorless oil in 48% yield; [α]20 +10.6° (c 1.60, CHCl3); IR
D
(film): νmax 3365, 2977, 1715, 1166 cm-1; H NMR (400 MHz,
1
t
CDCl3): δ 1.37 (t, 3H, J = 7.3 Hz, SeEt), 1.44 (s, 9H, Bu), 2.58
(dd, 2H, J = 7.8 and 15.6 Hz, SeEt), 2.99 (d, 2H, J = 5.0 Hz, H-
β), 3.75 (s, 3H, CO2Me), 4.60 (d, 1H, J = 8.2 Hz, H-α), 5.36 (d,
1H, J = 7.3 Hz, NH); 13C NMR (100 MHz, CDCl3): δ 15.8, 18.4,
25.5, 28.4, 52.6, 53.5, 80.2, 155.2, 171.8; 77Se NMR (113 MHz,
CDCl3): δ 157.2; HRESITOFMS: m/z 334.0533 [M+Na]+ (calcd
for C11H21NO4SeNa, 334.0555).
4.4.7. N-Boc-Se-(p-methylbenzyl)-L-selenocysteine
methyl ester (4i)
White amorphous powder in 73% yield; [α]2D0 -3.51° (c 1.10,
CHCl3); IR (film): νmax 3377, 2977, 1746, 1614, 1513 cm-1; H
1
t
NMR (400 MHz, CDCl3): δ 1.45 (s, 9H, Bu), 2.30 (s, 3H,
SeCH2PhMe), 2.91 (s, 2H, H-β), 3.73 (s, 5H, SeCH2PhMe and
CO2Me), 4.60 (d, 1H, J = 4.1 Hz, H-α), 5.31 (d, 1H, J = 3.9 Hz,

5
NH), 7.07-7.17 (m, 4H, Ar); 13C NMR (100 MHz, CDCl3): δ
21.2, 25.8, 27.7, 28.4, 52.6, 53.4, 80.1, 128.8, 129.3, 135.6,
136.6, 155.1, 171.7; 77Se NMR (113 MHz, CDCl3): δ 218.3;
3H, Ar), 7.29 (s, 1H, Ar); 13C NMR (100 MHz, CDCl3): δ 26.2,
ACCEPTED MANUSCRIPT
27.2, 28.4, 52.7, 53.5, 80.4, 127.2, 127.3, 129.1, 129.9, 134.4,
141.0, 155.2, 171.7; 77Se NMR (113 MHz, CDCl3): δ 225.1;
HRESITOFMS: m/z 410.0858 [M+Na]+ (calcd
for
HRESITOFMS: m/z 430.0311
[M+Na]+ (calcd for
C17H25NO4SeNa, 410.0846).
C16H22ClNO4SeNa, 430.0300).
4.4.8. N-Boc-Se-(o-nitrobenzyl)-
L
-selenocysteine
4.4.13. N-Boc-Se-(p-chlorobenzyl)-L-selenocysteine
methyl ester (4j)
methyl ester (4o)
Yellow oil in 58% yield; [α]2D0 -25.8° (c 1.00, CHCl3); IR
Colorless oil in 59% yield; [α]20 -4.20° (c 1.20, CHCl3); IR
D
(film): νmax 3376, 2978, 1744, 1608, 1525, 1365 cm-1; H NMR
(400 MHz, CDCl3): δ 1.42 (s, 9H, Bu), 2.92-2.96 (m, 2H, H-β),
(film): νmax 3371, 2978, 1745, 1491, 776 cm-1; H NMR (400
MHz, CDCl3): δ 1.46 (s, 9H, Bu), 2.89 (dd, 2H, J = 5.5 and 9.2
1
1
t
t
3.71 (s, 3H, CO2Me), 4.19 (dd, 2H, J = 6.2 and 11.9 Hz,
SeCH2PhNO2), 4.58 (d, 1H, J = 3.7 Hz, H-α), 5.36 (d, 1H, J =
3.7 Hz, NH), 7.37 (t, 2H, J = 3.9 Hz, Ar), 7.51 (dt, 1H, J = 0.7
and 3.9 Hz, Ar), 8.08 (d, 1H, J = 4.1 Hz, Ar); 13C NMR (100
MHz, CDCl3): δ 25.0, 26.6, 28.3, 52.7, 53.6, 80.3, 125.8, 128.2,
132.0, 133.4, 135.4, 147.8, 155.1, 171.5; 77Se NMR (113 MHz,
CDCl3): δ 236.2; HRESITOFMS: m/z 441.0563 [M+Na]+ (calcd
for C16H22N2O6SeNa, 441.0541).
Hz, H-β), 3.74 (s, 3H, CO2Me), 3.75 (s, 2H, SeCH2PhCl), 4.61
(d, 1H, J = 7.3 Hz, H-α), 5.31 (d, 1H, J = 10.0 Hz, NH), 7.20-
7.26 (m, 4H, Ar); 13C NMR (100 MHz, CDCl3): δ 26.1, 27.1,
28.4, 52.7, 53.5, 80.3, 128.8, 130.3, 132.8, 137.4, 155.2, 171.7;
77Se NMR (113 MHz, CDCl3): δ 225.1; HRESITOFMS: m/z
430.0305 [M+Na]+ (calcd for C16H22ClNO4SeNa, 430.0300).
4.4.14. N-Boc-Se-(2-oxopropyl)-L-selenocysteine
methyl ester (4p)
Yellow oil in 68% yield; [α]20 +16.0° (c 1.20, CHCl3); IR
4.4.9. N-Boc-Se-(m-nitrobenzyl)-L-selenocysteine
D
(film): νmax 3365, 2978, 1745, 1701, 1513 cm-1; H NMR (400
1
methyl ester (4k)
Yellow oil in 46% yield; [α]2D0 -0.6° (c 1.20, CHCl3); IR
MHz, CDCl3): δ 1.45 (s, 9H, tBu), 2.32 (s, 3H, SeCH2(C=O)Me),
2.98-3.02 (m, 2H, H-β), 3.28 (s, 2H, SeCH2(C=O)Me), 3.77 (s,
3H, CO2Me), 4.59 (d, 1H, J = 5.5 Hz, H-α), 5.40 (d, 1H, J = 7.3
Hz, NH); 13C NMR (100 MHz, CDCl3): δ 26.8, 27.7, 28.3, 32.4,
52.7, 53.4, 80.3, 155.2, 171.5, 203.6; 77Se NMR (113 MHz,
CDCl3): δ 163.3; HRESITOFMS: m/z 362.0455 [M+Na]+ (calcd
for C12H21NO5SeNa, 362.0483).
1
(film): νmax 3390, 2978, 1745, 1581, 1529, 1365 cm-1; H NMR
t
(400 MHz, CDCl3): δ 1.42 (s, 9H, Bu), 2.88-2.92 (m, 2H, H-β),
3.73 (s, 3H, CO2Me), 3.84 (s, 2H, SeCH2PhNO2), 4.59 (d, 1H, J
= 3.7 Hz, H-α), 5.31 (d, 1H, J = 3.1 Hz, NH), 7.44 (t, 1H, J = 4.1
Hz, Ar), 7.61 (d, 1H, J = 3.9 Hz, Ar), 8.06 (dd, 1H, J = 0.5 and
4.1 Hz, Ar), 8.13 (s, 1H, Ar); 13C NMR (100 MHz, CDCl3): δ
26.4, 26.8, 28.4, 52.8, 53.5, 80.4, 122.1, 123.8, 129.6, 135.1,
141.2, 148.4, 155.2, 171.5; 77Se NMR (113 MHz, CDCl3): δ
233.6; HRESITOFMS: m/z 441.0569 [M+Na]+ (calcd for
C16H22N2O6SeNa, 441.0541).
4.4.15. N-Boc-Se-(2-oxo-2-phenylethyl)-L-
selenocysteine methyl ester (4q)
Yellow oil in 87% yield; [α]20 +22.1° (c 1.00, CHCl3); IR
D
(film): νmax 3365, 2978, 1744, 1668, 1597, 1511 cm-1; H NMR
1
t
4.4.10. N-Boc-Se-(p-nitrobenzyl)-L-selenocysteine
(400 MHz, CDCl3): δ 1.44 (s, 9H, Bu), 3.04-3.09 (m, 2H, H-β),
methyl ester (4l)
3.73 (s, 3H, CO2Me), 3.86 (s, 2H, SeCH2(C=O)Ph), 4.63 (d, 1H,
J = 5.5 Hz, H-α), 5.46 (d, 1H, J = 7.3 Hz, NH), 7.46 (t, 2H, J =
7.8 Hz, Ar), 7.57 (t, 1H, J = 7.8 Hz, Ar), 7.94 (d, 2H, J = 7.3 Hz,
Ar); 13C NMR (100 MHz, CDCl3): δ 27.2, 27.5, 28.4, 52.7, 53.6,
80.2, 128.8, 133.5, 135.1, 155.2, 171.6, 195.0; 77Se NMR (113
MHz, CDCl3): δ 179.1; HRESITOFMS: m/z 424.0639 [M+Na]+
(calcd for C17H23NO5SeNa, 424.0639).
Yellow oil in 23% yield; [α]2D0 -4.21° (c 0.96, CHCl3); IR
1
(film): νmax 3384, 2978, 1744, 1598, 1520, 1366 cm-1; H NMR
t
(400 MHz, CDCl3): δ 1.45 (s, 9H, Bu), 2.90-2.95 (m, 2H, H-β),
3.75 (s, 3H, CO2Me), 3.85 (s, 2H, SeCH2PhNO2), 4.63 (d, 1H, J
= 3.7 Hz, H-α), 5.31 (d, 1H, J = 3.2 Hz, NH), 7.45 (d, 2H, J = 4.4
Hz, Ar), 8.16 (d, 2H, J = 4.3 Hz, Ar); 13C NMR (100 MHz,
CDCl3): δ 26.4, 26.8, 28.4, 52.8, 53.6, 80.5, 124.0, 129.8, 147.0,
147.0, 155.2, 171.5; 77Se NMR (113 MHz, CDCl3): δ 237.5;
4.4.16. N-Boc-Se-(2-methyl-2-oxoethyl)-L-
selenocysteine methyl ester (4r)
HRESITOFMS: m/z 441.0560 [M+Na]+ (calcd
for
Colorless oil in 55% yield; [α]20 +7.60° (c 1.10, CHCl3); IR
D
C16H22N2O6SeNa, 441.0541).
(film): νmax 3375, 2978, 1738, 1715, 1513 cm-1; H NMR (400
1
t
4.4.11. N-Boc-Se-(o-chlorobenzyl)-L-selenocysteine
MHz, CDCl3): δ 1.41 (s, 9H, Bu), 3.05-3.10 (m, 2H, H-β), 3.18
methyl ester (4m)
(s, 2H, SeCH2(C=O)OMe), 3.69 (s, 3H, SeCH2(C=O)OMe),3.73
(s, 3H, CO2Me), 4.61 (d, 1H, J = 6.9 Hz, H-α), 5.40 (d, 1H, J =
7.3 Hz, NH); 13C NMR (100 MHz, CDCl3): δ 22.9, 27.4, 28.4,
52.6, 52.7, 53.5, 80.3, 155.2, 171.5, 171.7; 77Se NMR (113 MHz,
CDCl3): δ 184.5; HRESITOFMS: m/z 378.0439 [M+Na]+ (calcd
for C12H21NO6SeNa, 378.0432).
Colorless oil in 58% yield; [α]20 -5.10° (c 1.00, CHCl3); IR
D
(film): νmax 3370, 2978, 1745, 1500, 757 cm-1; H NMR (400
1
t
MHz, CDCl3): δ 1.44 (s, 9H, Bu), 2.98 (dd, 2H, J = 3.0 and 4.4
Hz, H-β), 3.73 (s, 3H, CO2Me), 3.88 (s, 2H, SeCH2PhCl), 4.63
(d, 1H, J = 3.4 Hz, H-α), 5.33 (d, 1H, J = 3.7 Hz, NH), 7.16 (t,
1H, J = 1.6 Hz, Ar), 7.18 (t, 1H, J = 2.1 Hz, Ar), 7.27 (dd, 1H, J
= 2.3 and 5.7 Hz, Ar), 7.34 (dd, 1H, J = 1.3 and 4.7 Hz, Ar); 13C
NMR (100 MHz, CDCl3): δ 25.6, 26.5, 28.4, 52.7, 53.6, 80.3,
127.0, 128.5, 130.1, 130.7, 133.9, 136.9, 155.2, 171.7; 77Se NMR
(113 MHz, CDCl3): δ 208.5; HRESITOFMS: m/z 430.0311
[M+Na]+ (calcd for C16H22ClNO4SeNa, 430.0300).
4.4.17. N-Boc-Se-(2-tert-butoxy-2-oxoethyl)-L-
selenocysteine methyl ester (4s)
Colorless oil in 50% yield; [α]20 +7.90° (c 1.20, CHCl3); IR
D
(film): νmax 3367, 2979, 1717, 1512 cm-1; H NMR (400 MHz,
1
CDCl3): δ 1.43 (s, 9H, tBu), 1.45 (s, 9H, SeCH2(C=O)OtBu), 3.10
(s, 2H, SeCH2(C=O)OtBu), 3.09-3.13 (m, 2H, H-β), 3.75 (s, 3H,
CO2Me), 4.62 (d, 1H, J = 6.9 Hz, H-α), 5.45 (d, 1H, J = 7.8 Hz,
NH); 13C NMR (100 MHz, CDCl3): δ 24.8, 27.0, 28.0, 28.4, 52.7,
53.6, 81.8, 155.3, 170.5, 171.6; 77Se NMR (113 MHz, CDCl3): δ
180.2; HRESITOFMS: m/z 420.0921 [M+Na]+ (calcd for
C15H27NO6SeNa, 420.0901).
4.4.12. N-Boc-Se-(m-chlorobenzyl)-L-selenocysteine
methyl ester (4n)
Colorless oil in 63% yield; [α]20 -3.70° (c 0.90, CHCl3); IR
D
(film): νmax 3377, 2978, 1745, 1502, 784 cm-1; H NMR (400
1
t
MHz, CDCl3): δ 1.43 (s, 9H, Bu), 2.91 (dd, 2H, J = 2.8 and 7.6
Hz, H-β), 3.75 (s, 3H, CO2Me), 3.88 (s, 2H, SeCH2PhCl), 4.62
(d, 1H, J = 3.7 Hz, H-α), 5.32 (d, 1H, J = 3.7 Hz, NH), 7.18 (m,

6
Tetrahedron
ACCEPTED MANUSCRIPT
Yellow oil in 60% yield; [α]20 -9.50° (c 1.23, CHCl3); IR
4.4.18. N-Boc-Se-(o-nitrophenyl)-L-selenocysteine
D1
(film): νmax 3320, 2975, 1747 cm-1; H NMR (600 MHz, CDCl3):
δ 1.46 (s, 9H, tBu), 2.05 (s, 3H, SeMe), 2.91-2.96 (m, 2H, H-β of
Sec), 3.77 (s, 3H, CO2Me), 4.04-4.08 (m, 2H, CH2 of Gly), 4.41
(s, 1H, H-α of Sec), 5.48 (s, 1H, NH), 7.00 (s, 1H, NH); 13C
NMR (150 MHz, CDCl3): δ 5.3, 27.4, 28.4, 41.4, 52.5, 53.9,
80.6, 155.5, 170.0, 171.1; 77Se NMR (113 MHz, CDCl3): δ
46.5; HRESITOFMS: m/z 377.0619 [M+Na]+ (calcd for
C12H22N2O5SeNa, 377.0592).
methyl ester (4t)
Yellow oil in 13% yield; [α]2D0 +22.8° (c 0.77, CHCl3); IR
(film): νmax 3383, 2979, 1712, 1567, 1514, 1333 cm-1; H NMR
(400 MHz, CDCl3): δ 1.42 (s, 9H, Bu), 3.31-3.37 (m, 2H, H-β),
1
t
3.73 (s, 3H, CO2Me), 4.70 (d, 1H, J = 6.9 Hz, H-α), 5.32 (d, 1H,
J = 7.4 Hz, NH), 7.33 (t, 1H, J = 8.7 Hz, Ar), 7.51 (dt, 1H, J =
1.4 and 9.6 Hz, Ar), 7.62 (d, 1H, J = 7.8 Hz, Ar), 8.25 (dd, 1H, J
= 1.4 and 8.7 Hz, Ar); 13C NMR (100 MHz, CDCl3): δ 27.7, 28.3,
52.9, 53.4, 80.2, 125.9, 126.6, 129.5, 132.0, 133.8, 143.0, 155.2,
171.2; 77Se NMR (113 MHz, CDCl3): δ 324.3; HRESITOFMS:
m/z 427.0363 [M+Na]+ (calcd for C15H20N2O6SeNa, 427.0384).
4.7.2. N-Boc-Se-benzyl-L-selenocysteinyl-glycine
methyl ester (7b)
White amorphous powder in 68% yield; [α]2D0 +10.2° (c 0.19,
CHCl3); IR (film): νmax 3323, 2957, 1718, 1495 cm-1; H NMR
1
4.5. Demethylation of 3
(600 MHz, CDCl3): δ 1.46 (s, 9H, tBu), 2.85-2.90 (m, 2H, H-β of
Sec), 3.75 (s, 3H, CO2Me), 3.81 (s, 2H, SeBn), 4.01-4.05 (m, 2H,
CH2 of Gly), 4.06 (s, 1H, H-α of Sec), 5.27 (d, 1H, J = 6.4 Hz,
NH), 6.81 (s, 1H, NH), 7.22-7.30 (m, 5H, Ar); 13C NMR (150
MHz, CDCl3): δ 25.7, 28.0, 28.4, 41.4, 52.6, 54.0, 80.6, 127.1,
128.7, 129.1, 139.0, 155.5, 170.0, 171.1; 77Se NMR (113 MHz,
CDCl3): δ 221.8; HRESITOFMS: m/z 453.0910 [M+Na]+ (calcd
for C18H26N2O5SeNa, 453.0905).
1N NaOH aq. (3.9 mmol) was added to a solution of 3 (1.3
mmol) in MeOH (3 ml). After stirring at rt for 1 h, the resultant
solution was diluted with iced CHCl3, adjusted to pH 1 using 1N
HCl, and partitioned with CHCl3 twice. The organic layer was
concentrated
in
vacuo
to
afford
N-Boc-Se-[2-
(trimethylsilyl)ethyl]-L-selenocysteine 5 (quantitative yield) as a
yellow oil; [α]20 +12.3° (c 0.15, CHCl3); IR (film): νmax 3434,
D
1
2953, 1715 cm-1; H NMR (400 MHz, CDCl3): δ 0.00 (s, 9H,
4.8. Boc-Deprotection of 7
TMS), 0.92 (dd, 2H, J = 7.8 and 11.4 Hz, SeCH2CH2TMS), 1.44
(s, 9H, tBu), 2.65 (dt, 2H, J = 2.6 and 16.0 Hz, SeCH2CH2TMS),
2.96 (m, 2H, H-β), 4.64 (d, 1H, J = 6.9 Hz, H-α), 5.38 (d, 1H, J =
7.8 Hz, NH), 10.28 (br s, 1H, CO2H); 13C NMR (100 MHz,
CDCl3): δ -1.7, 18.7, 20.5, 28.3, 28.4, 53.5, 80.6, 155.5, 171.6;
77Se NMR (113 MHz, CDCl3): δ 178.6; HRESITOFMS: m/z
392.0777 [M+Na]+ (calcd for C13H27NO4SiSeNa, 392.0772).
4N HCl/EtOAc (3.0 mmol) was added to a solution of 7 (0.3
mmol) in DCM (3 ml) at 0oC. After stirring at rt for 1 h, the
resultant solution was diluted with Et2O (30 ml) and further
decanted to afford 8.
4.8.1. N-Boc-Se-methyl-L-selenocysteinyl-glycine
(8a)
4.6. Conjugation of Gly with 5
White amorphous powder in 88% yield; [α]2D0 +13.9° (c 0.68,
MeOH); IR (film): νmax 3434, 1635 cm-1; H NMR (600 MHz,
1
Gly methyl ester HCl salt (2.0 mmol), EDCI (2.0 mmol), and
HOBt (2.0 mmol) were added to a solution of 5 (1.4 mmol) in
DMF (5 ml). After stirring at rt for 1 min, DIPEA (6.5 mmol)
was added and the reaction mixture was stirred for 3 h. The
resultant solution was poured into distilled water, partitioned
with EtOAc, and washed with brine. The organic layer was dried
over anhydrous Na2SO4 and concentrated in vacuo. The residue
was purified using silica gel column chromatography eluted with
D2O): δ 2.02 (s, 3H, SeMe) , 2.98-3.03 (m, 2H, H-β of Sec), 3.71
(s, 3H, CO2Me), 4.05 (s, 2H, CH2 of Gly), 4.23 (t, 1H, J = 6.9
Hz, H-α of Sec); 13C NMR (150 MHz, D2O): δ 4.6, 24.2, 41.2,
52.4, 52.9, 169.3, 171.6; 77Se NMR (113 MHz, D2O): δ
42.1; HRESITOFMS: m/z 277.0079 [M+Na]+ (calcd for
C7H14N2O3SeNa, 277.0067).
4.8.2. N-Boc-Se-benzyl-L-selenocysteinyl-glycine
n-hexane/EtOAc
(5/1)
to
afford
N-Boc-Se-[2-
(8b)
(trimethylsilyl)ethyl]-
L-selenocysteinyl-glycine methyl ester 6
White amorphous powder in 95% yield; [α]2D0 +15.1° (c 0.79,
(60% yield) as a white amorphous powder; [α]20 -4.29° (c 0.34,
1
-1D
1
MeOH); IR (film): νmax 3435, 1633, 1495, 1454 cm-1; H NMR
CHCl3); IR (film): νmax 3325, 2954, 1722 cm ; H NMR (600
MHz, CDCl3): δ 0.00 (s, 9H, TMS), 0.94 (dt, 2H, J = 3.7 and
11.9 Hz, SeCH2CH2TMS), 1.45 (s, 9H, Bu), 2.60-2.66 (m, 2H,
SeCH2CH2TMS), 2.93-2.97 (m, 2H, H-β of Sec), 3.75 (s, 3H,
CO2Me), 4.00-4.05 (m, 2H, CH2 of Gly), 4.39 (d, 1H, J = 4.6 Hz,
H-α of Sec), 5.37 (s, 1H, NH), 6.85 (s, 1H, NH); 13C NMR (150
MHz, CDCl3): δ -1.7, 18.7, 20.4, 25.7, 28.4, 41.4, 52.6, 54.2,
80.6, 155.5, 170.1, 171.2; 77Se NMR (113 MHz, CDCl3): δ
177.5; HRESITOFMS: m/z 463.1166 [M+Na]+ (calcd for
C16H32N2O5SiSeNa, 463.1143).
(600 MHz, D2O): δ 2.93-2.97 (m, 2H, H-β of Sec), 3.60 (s, 3H,
CO2Me), 3.87 (d, 2H, J = 3.4 Hz, SeBn), 4.00 (d, 2H, J = 2.1 Hz,
CH2 of Gly), 4.09 (t, 1H, J = 6.2 Hz, H-α of Sec), 7.28 (dt, 1H, J
= 4.1 and 13.2 Hz, Ar), 7.30-7.37 (m, 4H, Ar); 13C NMR (150
MHz, D2O): δ 22.5, 27.6, 41.2, 52.7, 52.9, 127.4, 128.9, 129.0,
t
138.9, 169.0, 171.5; 77Se NMR (113 MHz, D2O):
δ
214.8; HRESITOFMS: m/z 353.0392 [M+Na]+ (calcd for
C13H18N2O3SeNa, 353.0380).
4.9. Conjugation of Glu with 8
4.7. Se-Alkylation of 6
The operation procedures are exactly the same with the
section of Conjugation of Gly with 5.
TBAF (1.0 M in THF, 0.18 mmol), AcOH (0.18 mmol), and
MeI (0.3 mmol) or BnBr (0.18 mmol) were added to a solution of
6 (0.06 mmol) in DMF (3 ml). After stirring at rt for 24 h, the
resultant solution was poured into distilled water, partitioned
with EtOAc, and washed with brine. The organic layer was dried
over anhydrous Na2SO4 and concentrated in vacuo. The residue
was purified using silica gel column chromatography eluted with
n-hexane/EtOAc (2/1) to afford 7.
4.9.1. N-(Se-methyl-L-selenocysteinyl)-glycine
methyl ester hydrochloride (9a)
White amorphous powder in 91% yield; [α]2D0 -21.2° (c 0.67,
CHCl3); IR (film): νmax 3433, 1644 cm-1; H NMR (600 MHz,
1
t
t
CDCl3): δ 1.44 (s, 9H, Bu), 1.47 (s, 9H, Bu), 2.00-2.05 (m, 2H,
CH2 of Glu), 2.04 (s, 3H, SeMe), 2.33-2.39 (m, 2H, CH2 of Glu),
2.94 (d, 2H, J = 6.9 Hz, H-β of Sec), 3.75 (s, 3H, CO2Me), 4.05
(t, 2H, J =5.5 Hz, CH2 of Gly), 4.23 (d, 1H, J = 4.8 Hz, H-α of
Sec), 4.74 (d, 1H, J = 6.9 Hz, CH of Glu), 5.42 (d, 1H, J = 8.3
Hz, NH), 7.14 (d, 1H, J = 7.6 Hz, NH), 7.41 (s, 1H, NH); 13C
4.7.1. N-Boc-Se-methyl-L-selenocysteinyl-glycine
methyl ester (7a)

7
7. Arthur, J. R. Cell. Mol. Life Sci., 2000, 57, 1825–1835.
8. Arthur, J. R.; Nicol, F.; Beckett, G. J. Biochem. J., 1990, 272,
NMR (150 MHz, CDCl3): δ 5.1, 26.7, 28.0, 28.3, 28.9, 32.4,
41.3, 52.4, 53.4, 53.5, 79.9, 82.2, 155.8, 170.0, 171.0, 171.5,
172.4; 77Se NMR (113 MHz, CDCl3): δ 54.5; HRESITOFMS:
m/z 562.1672 [M+Na]+ (calcd for C21H37N3O8SeNa, 562.1644).
ACCEPTED MANUSCRIPT
537–540.
9. Davey, J. C.; Becker, K. B.; Schneider, M. J.; St. Germain, D. L.;
Galton, V. A. J. Biol. Chem., 1995, 270, 26786–26789.
10. Bianco, A. C.; Salvatore, D.; Gereben, B.; Berry, M. J.; Larsen, P.
R. Endocr. Rev., 2002, 23, 38–89.
11. Tamura, T.; Stadtman, T. C. Proc. Natl. Acad. Sci. USA, 1996, 93,
1006–1011.
4.9.2. N-(Se-benzyl-L-selenocysteinyl)-glycine
methyl ester hydrochloride (9b)
White amorphous powder in 85% yield; [α]2D0 -17.3° (c 0.81,
1
CHCl3); IR (film): νmax 3434, 1644, 1453 cm-1; H NMR (600
12. Arnér, E. S. J. Biochim. Biophys. Acta, 2009, 1790, 495–526.
13. Guimaraes, M. J.; Peterson, D.; Vicari, A.; Cocks, B. G.;
Copeland, N. G.; Gilbert, D. J.; Jenkins, N. A.; Ferrick, D. A.;
Kastelein, R. A.; Bazan, J. F.; Zlotnik, A. Proc. Natl. Acad. Sci.
USA, 1996, 93, 15086–15091.
14. Sunde, R. A. Annu. Rev. Nutr., 1990, 10, 451–474.
15. Behne, D.; Kyriakopoulos, A. Annu. Rev. Nutr., 2001, 21, 453–
473.
t
t
MHz, CDCl3): δ 1.43 (s, 9H, Bu), 1.45 (s, 9H, Bu), 1.99-2.04
(m, 2H, CH2 of Glu), 2.27 (t, 2H, J = 7.6 Hz, CH2 of Glu), 2.87-
2.90 (m, 2H, H-β of Sec), 3.72 (s, 3H, CO2Me), 3.80 (s, 2H,
SeBn), 3.99-4.03 (m, 2H, CH2 of Gly), 4.19 (d, 1H, J = 4.8 Hz,
H-α of Sec), 4.69 (d, 1H, J = 6.9 Hz, CH of Glu), 5.41 (d, 1H, J
= 8.3 Hz, NH), 6.83 (d, 1H, J = 7.6 Hz, NH), 7.21 (t, 1H, J = 6.9
Hz, Ar), 7.26-7.31 (m, 4H, Ar), 7.30 (s, 1H, NH); 13C NMR (150
MHz, CDCl3): δ 25.2, 27.9, 28.3, 28.3, 32.3, 41.2, 52.3, 52.6,
53.5, 79.8, 82.1, 126.9, 128.6, 128.9, 139.1, 155.8, 170.0, 171.0,
16. Labunskyy, V. M.; Hatfield, D. L.; Gladyshev, V. N. Physiol.
Rev., 2014, 94, 739–777.
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Signal., 2007, 9, 775–806.
171.5, 172.4; 77Se NMR (113 MHz, CDCl3):
δ
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20. Kawai, Y.; Ando, H.; Ozeki, H.; Koketsu, M.; Ishihara, H. Org.
Lett., 2005, 7, 4653–4656.
228.9; HRESITOFMS: m/z 638.1927 [M+Na]+ (calcd for
C27H41N3O8SeNa, 638.1957).
21. Nanami, M.; Ando, H.; Kawai, Y.; Koketsu, M.; Ishihara, H.
Tetrahedron Lett., 2007, 48, 1113–1116.
4.10. Full deprotection of 9
22. Garud, D. R.; Ando, H.; Kawai, Y.; Ishihara, H.; Koketsu, M.
Org. Lett., 2007, 9, 4455–4458.
23. Ninomiya, M.; Garud, D. R.; Koketsu, M. Coord. Chem. Rev.,
2011, 255, 2968–2990.
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9417.
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834.
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Andrade, F. M. Synthesis, 2010, 3131–3137.
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2481
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1239.
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The operation procedures are exactly the same with the
sections of Demethylation of 3 and Boc-Deprotection of 7.
4.10.1. Se-Methyl-selenoglutathione (10a)
Yellow amorphous powder in 74% yield; [α]2D0 -17.2° (c 0.64,
1
MeOH); IR (film): νmax 3434, 1634 cm-1; H NMR (600 MHz,
D2O): δ 1.95 (s, 3H, SeMe), 2.13-2.18 (m, 2H, CH2 of Glu), 2.51
(t, 2H, J = 6.8 Hz, CH2 of Glu), 2.82-2.86 (m, 2H, H-β of Sec),
3.94-4.03 (m, 3H, CH2 of Gly and CH of Glu), 4.50 (dd, 1H, J =
4.8 and 8.9 Hz, H-α of Sec); 13C NMR (150 MHz, D2O): δ 4.3,
25.3, 25.5, 30.9, 41.2, 52.8, 53.4, 171.8, 173.3, 174.3; 77Se NMR
(113 MHz, D2O): δ 53.2; HRESITOFMS: m/z 392.0355 [M+Na]+
(calcd for C11H19N3O6SeNa, 392.0337).
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Soda, K.; Fujii, N. Chem. Pharm Bull., 1993, 41, 502–506.
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3, 1331–1334.
4.10.2. Se-Benzyl-selenoglutathione (10b)
Orange amorphous powder in 75% yield; [α]2D0 -18.7° (c 0.71,
1
MeOH); IR (film): νmax 3435, 1634 cm-1; H NMR (600 MHz,
32. Trost, B. M.; Rudd, M. T. Org. Lett., 2003, 5, 4599–4602.
33. Beld, J.; Woycechowsky, K. J.; Hilvert, D. Biochemistry, 2007,
46, 5382–5390.
34. Yoshida, S.; Kumakura, F.; Komatsu, I.; Arai, K.; Onuma, Y.;
Hojo, H.; Singh, B. G.; Priyadarsini, K. I.; Iwaoka, M. Angew.
Chem. Int. Ed. Engl., 2011, 50, 2125–2128.
D2O): δ 2.09-2.14 (m, 2H, CH2 of Glu), 2.41 (t, 2H, J = 6.2 Hz,
CH2 of Glu), 2.76-2.81 (m, 2H, H-β of Sec), 3.64 (s, 2H, SeBn),
3.74-3.78 (m, 1H, CH of Glu), 3.87-3.90 (m, 2H, CH2 of Gly),
4.30-4.34 (m, 1H, H-α of Sec), 7.20-7.27 (m, 5H, Ar); 13C NMR
(150 MHz, D2O): δ 24.0, 25.5, 27.3, 30.9, 41.2, 52.8, 53.4, 127.1,
128.9, 139.4, 170.1, 171.7, 173.0, 174.0; 77Se NMR (113 MHz,
D2O): δ 228.4; HRESITOFMS: m/z 468.0671 [M+Na]+ (calcd for
C17H23N3O6SeNa, 468.0650).
Acknowledgments
This work was supported by a Grant-in-Aid for Science
Research from the Ministry of Education, Culture, Sports,
Science and Technology of Japan (No. 15K07856) to which we
are grateful.
References and notes
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