C. Parashiva Prabhu et al. / Journal of Organometallic Chemistry 745-746 (2013) 140e147
141
(DPPH), butylated hydroxytoluene (BHT), HPLC grade methanol
were obtained from commercial sources (Sigma/Aldrich). Amino
acids were obtained from local suppliers and were of analytical
grade. Sodium phenylselenolate was prepared by reduction of
diphenyl diselenide with stoichiometric quantity of sodium boro-
hydride in ethanol under a nitrogen atmosphere as a colorless so-
lution [29]. All the reactions were carried out under a nitrogen
atmosphere. The purity of organoselenium compounds was
initially tested by thin layer chromatography and compounds were
subsequently purified by column chromatography on a silica gel
(60/120 mesh size) using solvent mixtures as eluents.
(dmso-d6)
d
: 17.3 (CH3), 28.9 (SeCH2, J(77See13C) ¼ 66 Hz), 47.9
(NHCH2), 126.9 (Ph), 129.2 (Ph), 130.5 (Ph-Se), 131.5 (Ph), 168.9
(CONH), 174.1 (COOH); 77Se {1H} NMR (dmso-d6)
d: 306 ppm.
2.1.3. Preparation of [PhSeCH2CONHCH(CH2Ph)COOH] (3)
Prepared similar to 1 using phenyl alanine (2.4 g, 14.5 mmol),
sodium bicarbonate (3.65 g, 43.5 mmol) and chloroacetyl chloride
(1.97 g, 17.5 mmol) followed by treatment with sodium phenyl-
selenolate (sodium borohydride (540 mg, 14.2 mmol) and diphenyl
diselenide (2.26 g, 7.2 mmol) in ethanol). The product was column
chromatographed by using 30:70, 40:60 ratios of ethyl acetate and
hexane mixture. The faction eluting with 40:60 ratio on concen-
tration afforded a pale yellow powder of the title compound (yield
4.8 g, 91%), m.p. 156e158 ꢀC. Anal. for C17H17NO3Se; Calcd: C, 56.36;
H, 4.73; N, 3.87%. Found: C, 56.04; H, 4.17; N, 3.18%. UVeVis (in
Elemental analyses were carried out on a Thermo Fisher EA 1112
CHNS analyzer. Electronic spectra were recorded in methanol on a
Jasco UVeVis spectrometer model V-630 PC. IR spectra were
recorded on a JASCO FT IR-6100 spectrometer. NMR spectra were
recorded on a Bruker Avance-II 300 MHz spectrometer operating at
MeOH) (lmax in nm): 237, 275. IR in KBr (
y
cmꢂ1): 3290 (COOH),
: 2.82 (each, m,
300.13 (1H), 75.47 (13C {1H}) and 57.25 MHz (77Se {1H}). 1H and 13
C
1705 (CONH), 1600, 1555. 1H NMR (dmso-d6)
d
{1H} NMR chemical shifts were relative to internal dmso peak
CH2Ph); 2.88 (m, NHCH,1H); 3.07 (br, OH/NH); 3.59 (s, SeCH2); 4.44
(m, CH, 2H); 7.27 (m, Ph, 8H); 7.47 (d, 7.8 Hz, Ph, 2H); 8.47 (d, 7.8 Hz,
(d
¼ 2.49 ppm for 1H and
d
¼ 39.5 for 13C {1H} NMR). The 77Se {1H}
NMR chemical shifts were relative to external diphenyl diselenide
Ph, 1H). 13C {1H} NMR (dmso-d6) 28.7 (SeCH2, J(77See
d:
(Ph2Se2) in CDCl3
(d
463.0 ppm relative to Me2Se (0 ppm).
13C) ¼ 66 Hz), 36.6 (NHCH), 53.7 (PhCH2), 126.5 (Ph), 126.6 (Ph),
128.2 (Ph), 129.1 (Ph), 130.5 (SePh), 131.1 (Ph), 137.3 (Ph), 168.9
2.1. Synthesis
(CONH), 172.7 (COOH). 77Se {1H} NMR (dmso-d6)
d: 305 ppm.
2.1.1. Preparation of [(PhSeCH2CONHCH2COOH] (1)
2.1.4. Preparation of [PhSeCH2CONHCH(CH2C6H4OH-4)COOH] (4)
Prepared similar to 1 using tyrosine (1.8 g, 9.9 mmol), sodium
bicarbonate (2.49 g, 29.6 mmol) and chloroacetyl chloride (1.83 g,
16.2 mmol) followed by treatment with sodium phenylselenolate
(sodium borohydride (370 mg, 9.7 mmol) and diphenyl diselenide
(1.54 g, 4.9 mmol) in ethanol). The product was column chroma-
tographed by using ethyl acetate - hexane mixture (40:60 ratio) and
recrystallized from ethyl acetate as white crystals (yield 0.8 g, 21%),
m.p. 175e178 ꢀC. Anal. for C17H17NO4Se; Calcd: C, 53.98; H, 4.53; N,
3.70%. Found: UVeVis (in MeOH) (lmax in nm): 216. IR in KBr
To a clear solution of glycine (2.0 g, 26.6 mmol) in distilled water
(40 ml) was added sodium bicarbonate (6.7 g, 79.8 mmol) and stirred
for 15 min and cooled to 0e5 ꢀC. To this solution chloroacetyl chloride
(2.97 g (2.11 ml), 26.3 mmol) was added drop wise and stirred for 1 h.
This solution was mixed to an ice cold sodium phenylselenolate
(prepared by adding sodium borohydride (1.0 g, 26.3 mmol) to an ice
cold ethanol (20 ml) solution of diphenyl diselenide (4.15 g,
13.3 mmol) under a nitrogen atmosphere) and the contents were
stirred for 2 h at room temperature. The solvents were evaporated in-
vacuo to give a white precipitate which was suspended in water
(50 ml) and acidified to pH 6 followed by extraction with chloroform
(30 ml ꢁ 5). The combined organic fractions were washed with
distilled water and the organic layer was dried over sodium sulfate
and concentrated in-vacuo. The crude residue was column chroma-
tographed using 30:70 ethyl acetate and hexane mixture, which on
slow evaporation gave colorless crystals of the title compound (yield
4.67 g, 65%), m.p. 139e141 ꢀC. Anal. for C10H11NO3Se, Calcd: C, 44.13;
H, 4.07; N, 5.15%; Found: C, 44.26; H, 4.41; N, 5.10%. UVeVis (in
(y
cmꢂ1): 3185 (COOH), 1750 (CONH), 1590 (COOH). 1H NMR (dmso-
d6) : 2.07e2.93 (m, distereotopic, CH2C6H4OH); 3.46 (br, NH and
d
COOH); 3.60 (s, SeCH2); 4.30e4.37 (m, CHeCOOH); 6.63, 6.99 (each
d, 8.4 Hz, C6H4); 7.25 (m); 7.47 (m), 8.39 (d, 7.8 Hz) [Ph]; 9.26 (br,
C6H4OH). 13C {1H} NMR (dmso-d6)
d:
28.8 (SeCH2, J(77See
13C) ¼ 66 Hz), 36.1 (NHCH), 54.1 (CH2C6H4); 115.0,127.3,131.2,156.0
(C6H4OH); 126.7, 127.3, 129.2, 130.1 (Ph); 168.9 (CONH), 172.9
(COOH). 77Se {1H} NMR (dmso-d6)
d: 303 ppm.
MeOH) (lmax in nm): 235, 271. IR in KBr (
(CONH),1590,1550.1H NMR (dmso-d6)
: 3.64 (s, SeCH2, 2H); 3.76 (d,
6 Hz, NHCH2, 2H); . 7.28 (m, Ph, 2H); 7.53 (d, 8.4 Hz, Ph, 2H); 8.47 (t,
y
cmꢂ1): 3325 (COOH), 1715
2.1.5. Preparation of [PhSeCH2CONHCH(CH2OH)COOH] (5)
d
Prepared similar to 1 using serine (3.66 g, 34.8 mmol), sodium
bicarbonate (8.77 g, 104.4 mmol), chloroacetyl chloride (3.81 g,
33.7 mmol) and sodium phenylselenolate, (sodium borohydride
(1.32 g, 34.8 mmol) and diphenyl diselenide (5.43 g, 17.4 mmol) in
ethanol). The product was column chromatographed by using
30:70 of ethyl acetate - hexane mixture followed by concentration
to give a white powder which was recrystallized from ethyl acetate
- chloroform mixture (30:70) (yield 4.6 g, 43%), m.p. 112e115 ꢀC.
Anal. for C11H13NO4Se; Calcd: C, 43.72; H, 4.34; N, 4.64%. Found: C,
43.41; H, 5.11; N, 4.41%. UVeVis (in MeOH) (lmax in nm): 237, 269.
5.4 Hz, Ph, 1H). 13C {1H} NMR (dmso-d6) : 28.8 (SeCH2; J(77See
d
13C) ¼ 65 Hz); 41.0 (NHCH2), 126.8 (Ph), 129.2, 130.5 (Se-Ph), 131.3,
169.5 (CONH), 171.2 (COOH); 77Se {1H} NMR (dmso-d6)
d: 304 ppm.
2.1.2. Preparation of [PhSeCH2CONHCH(Me)COOH] (2)
Prepared similar to 1 using alanine (1.5 g, 16.8 mmol), sodium
bicarbonate (4.24 g, 50.5 mmol) and chloroacetyl chloride (1.83 ml,
16.2 mmol) followed by treatment with sodium phenylselenolate,
(sodium borohydride (640 mg, 16.8 mmol) in ice cold ethanol
(20 ml) and diphenyl diselenide (2.25 g, 7.2 mmol) in ethanol). The
product was column chromatographed by using ratios of ethyl ac-
etate and hexane mixture in a sequence 20:80, 30:70, 40:60 (v/v).
The fractions eluting in the last ratio was dried to yield a white solid
(yield 3.3 g, 79%), m.p. 95e97 ꢀC. Anal. for C11H13NO3Se; Calcd: C,
46.17; H, 4.58; N, 4.89%; Found: C, 45.93; H, 4.76; N, 4.75%. UVevis
IR in KBr (
NMR (dmso-d6)
SeCH2); 4.25e4.30 (m, CH); 7.23e7.31 (m), 7.53 (d, 7.8 Hz); 8.36 (d,
y
cmꢂ1): 3630 (CH2OH), 1735 (COOH), 1600 (CONH). 1H
: 3.56e3.72 (m, CH2OH, NH/COOH); 3.68 (s,
d
7.8 Hz) [Ph]. 13C {1H} NMR (dmso-d6)
d: 17.3 (NHCH3), 28.8 (SeCH2,
J(77See13C) ¼ 66 Hz), 47.8 (CH2OH), 126.8, 129.2, 130.4, 131.4 (Ph),
168.8 (CONH), 174.0 (COOH). 77Se {1H} NMR (dmso-d6)
d: 303 ppm.
(in MeOH) (lmax in nm): 237, 271. IR in KBr (
y
cmꢂ1): 3330 (COOH),
2.1.6. Preparation of [PhSeCH2COOH] (6)
1720 (CONH) 1595, 1539. 1H NMR (CDCl3)
d: 1.34 (d, 7.2 Hz, CHCH3,
An ethanolic solution (10 ml) of iodoacetic acid (1.71 g,
9.1 mmol) was added to a stirred ice cold solution of sodium phe-
nylselenolate (from sodium borohydride (520 mg, 13.6 mmol) and
3H); 3.56 (s, SeCH2, 2H); 4.51 (m, 7.2 Hz, NHCH, 1H); 6.98 (d, 7.1 Hz,
Ph, 1H); 7.27 (m, 8.1 Hz, Ph, 2H); 7.52 (m, Ph, 2H); 13C {1H} NMR