Schiff-base metal(II) complexes as new catalysts in the efficient, mild and regioselective conversion of 1,2-epoxyethanes to 2-hydroxyethyl thiocyanates with ammonium thiocyanate

Article abstract of DOI:10.1246/bcsj.76.137

A convenient and efficient procedure for the ring-opening of 1,2-epoxyethanes with ammonium thiocyanate in the presence of some Schiff-base complexes of metal(II) is described. The cleavage of the oxirane ring is found to proceed regioselectively under mild reaction conditions. Thus, several 2-hydroxyethyl thiocyanates, useful intermediates toward biological-active molecules, are easily obtained in very good yields.

Full text of DOI:10.1246/bcsj.76.137

c. Jpn.
e Chemical © 2003 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 76, 137–142 (2003)
137
ciety of Ja-
n
e Chemical
ciety of Ja-
n
Schiff-Base Metal(Ⅱ) Complexes as New Catalysts in the Efficient, Mild
and Regioselective Conversion of 1,2-Epoxyethanes to 2-Hydroxyethyl
Thiocyanates with Ammonium Thiocyanate
The Cleavage of Epoxides to Thiocyanohydrins
H. Sharghi et al.
0
7
2
3
Hashem Sharghi* and Mohammad Ali Nasseri
Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, I. R. Iran
SJA8
0
9-2673
(
Received January 28, 2002)
0
0
0
22
A convenient and efficient procedure for the ring-opening of 1,2- epoxyethanes with ammonium thiocyanate in the
2
2
presence of some Schiff-base complexes of metal(Ⅱ) is described. The cleavage of the oxirane ring is found to proceed
regioselectively under mild reaction conditions. Thus, several 2-hydroxyethyl thiocyanates, useful intermediates toward
biological-active molecules, are easily obtained in very good yields.
0.2
1
0
Thiocyanates are important intermediates in agricultural and
pharmaceutical chemistry. 2-Hydroxyethyl thiocyanates repre-
sent an interesting subclass having multiple modes of reactivi-
ty. Synthetic access by oxirane ring opening with thiocyanate
haloethanols with molecular halogen. Metal(Ⅱ)-salen com-
plexes can be readily synthesized from metal salts and salen
ligands, which are prepared by simply mixing 1 mol of ethyl-
enediamine and 2 mol of salicylaldehyde.
1
,2
has been limited by a further reaction to give thiiranes.
In this study, reactions of styrene oxide with ammonium
thiocyanate in the presence of some Schiff-base (SB) complex-
es of Co(Ⅱ) were carried out. In order to examine the effects of
ligands on the catalyst in the reaction, nine kinds of ligands
were employed (Scheme 1). It should be noted that the Schiff-
bases of complexes 2e–i behave as donor doubly-bidentate
ligands, and form dinuclear complexes (SB–M, 2:2) with
There are two methods reported in the literature for the synthe-
sis of 2-hydroxyethyl thiocyanates. In one method, 2-hy-
droxyethyl thiocyanates are prepared by the opening of a cy-
clic sulfate with NH SCN to form the corresponding β-sulfate,
4
which is hydrolyzed to the 2-hydroxyethyl thiocyanates. A
second method employs an addition to the 1,2-epoxyethanes of
3
17–19
thiocyanic acid generated in situ at low temperature. For
metal(Ⅱ) ions.
these syntheses, it has been reported that the presence of some
hydroquinone or DDQ is required to stabilize the produced 2-
hydroxyethyl thiocyanates, and to inhibit its conversion to thi-
To a mixture of styrene oxide and ammonium thiocyanate in
acetonitrile was added a solution of a catalyst in dichlo-
romethane; the mixture was stirred under reflux conditions.
Regarding the complex catalyst, a 0.01 molar amount of sty-
4
i
5
6
irane. Although reagents, such as Ti(O- Pr)
4
, Ph
3 2
P(SCN) ,
7
8
9
TiCl (or ZnCl ) , Pd(PPh ) and TMSNCS (Cat. TBAF), are
3 2 3 4
useful, they are limited to specific oxiranes, and are not appli-
cable as versatile reagents in the preparation of 2-hydroxyethyl
9
thiocyanates.
In conjunction with ongoing work in our laboratory on the
synthesis and complex formation of Schiff base-metal com-
1
0
plexes with different molecules, we found that these com-
plexes efficiently catalyzed the addition of ammonium thiocy-
anate to oxiranes to form 2-hydroxyethyl thiocyanates. Here,
we report on the reaction of some oxiranes with ammonium
thiocyanate in the presence of catalytic amounts of Schiff-base
complexes of metal(Ⅱ) wherein high yields are produced with
regioselectivity under mild reaction conditions.
Result and Discussion
Metal(Ⅱ)-salen complexes have been recognized as being
among the most promising catalysts for various reactions.
These complexes show wide applicability, and are now used as
catalysts for a variety of enantioselective reactions, such as ox-
1
1
12
13
idation, aziridination, cyclopropanation, the Diels–Alder
1
4
15
reaction, the addition of TMSCN to aldehydes, the Stereck-
er reaction, and the conversion of 1,2-epoxyethanes to 2-
16
Scheme 1.

1
38 Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
The Cleavage of Epoxides to Thiocyanohydrins
Table 1. Reaction of Styrene Oxide with Ammonium Thio-
cyanate in the Presence of Various Co(Ⅱ)-Schiff Base
Table 2. Reaction Times and the Yields of 2-Hydroxy-2-
phenylethyl Thiocyanate in the Reactions of Styrene
Oxide and Ammonium Thiocyanate in the Presence of
Various Metal(Ⅱ)-Salen Complexes
Complexes as Catalysts in CH
3
CN under Reflux Condition
a)
Entry
Catalyst
Time/min
Yield/%
a)
Entry
Cat. M(Ⅱ)-Salen
Time/min
Yield/%
1
2
3
4
5
6
7
8
9
3a
3b
3c
3d
3e
3f
3g
3h
3i
35
45
50
50
25
45
60
55
50
93
80
70
85
95
90
90
75
83
1
2
3
4
5
6
Co(Ⅱ)
Ni(Ⅱ)
Mn(Ⅱ)
Zn(Ⅱ)
Cu(Ⅱ)
Fe(Ⅱ)
35
75
50
80
100
150
93
80
90
75
80
60
a) Determined by GC.
b)
c)
1
0
—
190
—
Table 3. Thiocyanative Cleavage of Styrene Oxide in the
Presence of 0.01 mol Catalyst 3e in Various Solvents
a) Determined by GC.
b) In the presence of excess of NH
4
SCN
c) A 35% of the corresponding thiirane was obtained.
a)
Entry
Solvent
CH CN
THF
CH COCH
Time/min
Yield/%
1
2
3
4
5
6
7
3
25
50
70
95
80
60
rene oxide was used. The reaction product was 2-hydroxy-2-
phenylethyl thiocyanate (2a), and the yield was determined by
GLC and TLC analyses. The results of the reactions of styrene
oxide with thiocyanate ion in the presence of the above-men-
tioned catalysts are summarized in Table 1. In each case,
cleavage of the oxirane ring occurred and upon a work-up, the
corresponding 2-hydroxyethyl thiocyanate was obtained.
Two-valent metal salen complexes are well-know to be oxi-
dized to their three-valent complexes upon exposure to oxy-
3
3
EtOH
CHCl
35
45
3
120
120
120
< 20
< 15
< 15
6 6
C H
DMF
a) Determined by GC.
bility, or their adducts with ammonium thiocyanate in refluxed
acetonitrile.
Next, we studied the catalytic effect of the first-row transi-
tion metal(Ⅱ) with the ligand of N,Nꢀ-disalicylideneethylenedi-
20
gen. In order to find whether a three-valent metal-salen com-
plex is also formed in the reactions under our studies, the
Co(Ⅱ)-salen complex was exposed to an excess amount of
ammonium thiocyanate for an appropriate time. Oxidation did
not occur and the Co(Ⅱ)-salen complex was isolated intact. It
therefore seems that the formation of three-valent metal salen
complexes under this condition is improbable. A comparison
of the electronic absorption spectra of the recovered Co(Ⅱ)-
salen complex for a reaction with Co(Ⅱ)-salen before the reac-
tion and Co(Ⅲ)-salen was also in accord with the above discus-
sion. The catalysts were easily recovered and could be reused
several times.
2
amine (or H salen ) on the formation of 2-hydroxy-2-phenyl-
ethyl thiocyanate (2a). In all of the used catalysts, ring open-
ing with a thiocyanato group of styrene oxide was carried out;
the corresponding results are summarized in Table 2. Among
the catalysts examined, the use of Co(Ⅱ)-salen gave the best re-
sults in the yields and reaction rates.
The results of a ring opening of styrene oxide with ammoni-
um thiocyanate by catalyst 3e in various aprotic solvents are
reported in Table 3. We found that these reactions appeared to
be largely dependent on the nature of the solvent.
A comparison of the cleavage of the styrene oxide with
ammonium thiocyanate in the absence of a catalyst is given in
entry 10 of Table 1. As shown in Table 1, the yields of thiocy-
anation with this new methodology were quite good, and the
reaction time was very short. Without a catalyst, the reaction
required a much longer time; moreover, undesirable thiirane-
formation predominated. In these reactions, 3–10% of the cor-
responding thiiranes was also formed, which could be easily
isolated by column chromatography. It is of great importance
that the reaction is largely affected by the various ligands of
the complexes. The use of catalysts 3a and 3e was most effec-
tive, and the reactions were completed within 35 and 25 min,
respectively (Table 1, entries 1 and 5). In the presence of other
catalysts (3b, 3c, 3d, and 3f–i) the reaction times for thiocy-
anation were in the rang 45–60 min. On the other hand, be-
cause first-row transition metal(Ⅱ) complexes of simple Schiff
bases are known to be sparingly soluble in common organic
solvents, the difference in the activity between the complexes
used in this study may instead be attributed to their own solu-
To ascertain the scope and limitation of the present reaction,
several oxiranes were examined using catalyst 3e; these results
are summarized in Table 4. By comparison, a number of
5
–8
methods for the conversion of oxiranes to the corresponding
2-hydroxyethyl thiocyanates are given in entries 2–5 and 8
(Table 4). In all of the cases listed, the yields increased and the
regioselectivities were also enhanced. The optimum amount
of the catalyst was found to be 0.01 equiv vs oxiranes. How-
ever, other factors can exert a controlling influence, such as (1)
the steric hindrance of oxiranes, (2) the nature of the solvent,
and (3) electron-donating or withdrawing groups bonded to the
oxiranes. Each one can have a pronounced effect on the ob-
served ratio of 2-hydroxyethyl thiocyanate isomers and the
overall yield.
As shown in Table 4 (entry7), in which only the trans isomer
is given, the reactions are completely anti stereoselective. As
for the regioselectivity, an attack of the nucleophile preferen-
tially occurs at the less-substituted oxirane carbon. An anti-

H. Sharghi et al.
Table 4. Reaction of Epoxides with NH
Bull. Chem. Soc. Jpn., 76, No. 1 (2003) 139
SCN in the Presence of the Representative Catalyst
4
Catalyst
Reaction
Reaction
time/min
a)
Entry
1
Oxirane
Product(s)
Yield/%
(
0.01 mol amt.)
Conditions
NH
4
SCN/CH
Reflux/N
3
CN
3e
25
120
240
180
50
95 (4:1)
35
2
NH
4
SCN/N
2
8
2
3
4
5
Pd(PPh
3
)
4
THF/Reflux
NH SCN
4
i
5
Ti(O- Pr)
4
30
THF/Reflux
KSCN
THF/Reflux
7
ZnCl
2
60
NH
4
SCN/CH
Reflux
3
CN
CN
4
b
DDQ
3e
91 (1:8)
NH
4
SCN/CH
3
6
7
25
30
—
92
93
Reflux/N
2
NH
4
SCN/CH
Reflux/N
3
CN
3e
2
KSCN/H
3
PO
4
3
a
b)
8
9
H
2
Q
48
H
2
O/Et O
2
NH
NH
NH
NH
NH
4
SCN/CH
Reflux/N
3
CN
CN
CN
CN
CN
3e
3e
3e
3e
3e
55
50
40
45
45
85
75
2
4
SCN/CH
Reflux/N
3
3
3
3
1
1
1
1
0
1
2
3
2
4
SCN/CH
Reflux/N
85
2
4
SCN/CH
Reflux/N
83
2
4
SCN/CH
Reflux/N
93 (1:4)
2
a) Determined by GC. b) Hydroquinone has been used to stabilize 2-hydroxycyclohexyl thiocyanate
see Ref. 3a).
(
2
1
Markovnikov-type regioselectivity is generally observed in
these reactions, except for the reactions of styrene oxide (Table
4
1
using macrocyclic diamides as catalysts. In that paper, we sug-
gest that the conversion of 1,2-epoxyethane to 2-hydroxyethyl
thiocyanate occurs according to the following four-step mech-
anism. The first step involves the formation of a molecular
, entry1) and indene oxide (Table 4, entry13), which produced
7% and 20% of other regioisomer, respectively, the reaction
of other oxiranes were found to be highly regioselective, and
only one isomer was obtained. The above-mentioned regio-
chemical mode can be viewed as occurring via a nucleophilic
attack by a thiocyanate ion on the less sterically hindered
4
complex between macrocycle and NH SCN in which thiocy-
−
anate ion (SCN ) exists as a contact ion pair. In the second
−
step, this complex is further decomposed to release the SCN
−
ion into the solution. Therefore, in this way, the SCN ion is
oxirane carbon. This mechanism closely resembles the S
model for an aliphatic nucleophilic displacement.
We have already reported on the related reaction of oxiranes
and ammonium thiocyanate to 2-hydroxyethyl thiocyanates
N
2
produced as a nucleophilic species in the presence of a suitable
macrocycle and, in the third step, this ion participates in the
ring-opening reaction of oxiranes. Finally, in step (4) the cata-
2
2
lyst is reproduced and is used in the first step again.

1
40 Bull. Chem. Soc. Jpn., 76, No. 1 (2003)
The Cleavage of Epoxides to Thiocyanohydrins
Table 5. The Formation Constants K (mol− dm ) for Com-
1
3
−
plexation of SCN with Some Co(Ⅱ)-Schiff Bases at 25C°
in Acetonitril Solution
Catalyst
K
3
3
2
3
a
1.74(± 0.1) × 10
1(± 0.06) × 10
2.5(± 0.11) × 10
3.7(± 0.2) × 10
Fig. 1.
3
3
d
3
e
2
3
f
3
g
1.53(± 0.1) × 10
shown in Fig. 2; the resulting stability constants are summa-
rized in Table 5. Figure 2 shows that the addition of a reagent
results in an increasing absorbance of 3e at 315 and 625 nm,
while decreasing the intensity of the 400 nm bands. The ob-
servation of a clear isosbestic point in the spectra supports the
occurrence of a simple 1:1 complexation in solution. The data
given in Table 1 clearly indicate the formation of the most sta-
ble complexes between ammonium thiocyanate and 3a and 3e
in the series. This obviously supports the increased reaction
yield with these two catalysts as well as the predominance of
the mechanism (Scheme 2) in solution.
Scheme 2.
Given that salen complexes are remarkably effective for the
2
3
epoxidation of simple olefins, it has been considered whether
similar systems could be useful in oxirane ring-opening reac-
tions. Thus, the elements of the stereochemical interaction be-
tween the substrate and the ligand in olefin oxidation (Fig.
Moreover, based on the experimental results, it can be con-
cluded that the reaction rate in the present reaction should be
2
4
1
a) might apply to oxirane activation by a metal-(salen) com-
4
affected not only by complexation of NH SCN with M(Ⅱ)-
2
5
plex (e.g., Figs. 1, b or c).
−
Schiff base complexes, but also by dissociation of the SCN
anion from the adduct and the solubility of M(Ⅱ)-Schiff base
complex or the adduct in acetonitrile.
1
0
26
Based on our previous studies and other work on the ring
opening of oxirane with different nucleophiles in the presence
of some Schiff base-metal complexes, a general mechanism
was suggested for ring-opening with a thiocyanato group of
oxiranes, as Shown in Scheme 2.
It is noteworthy that the operation is quite simple and the re-
action conditions are sufficiently mild to operate several sensi-
tive functionalities, and that the salen catalysts can be recycled
and reusable.
The use of catalysts 3a and 3e resulted in the highest reac-
tion yield in the series (Table 1). This was most probably due
to the formation of the most stable complexes between
Experimental
NH
lyst sites). In order to obtain a clue about the stability of the
:1 complexes of ammonium thiocyanate with all of the cata-
lysts tested, a spectrophotometric procedure in an acetonitrile
4
SCN and catalysts 3a and 3e (i.e. the largest number cata-
General. Some 1,2-epoxyethanes and other chemical materi-
als were purchased from Fluka and Merck in high purity. The
Schiff-base complexes were prepared by reported procedures, and
their spectroscopic and physical data were compared with the lit-
1
2
7
1
7,19,28
solution was performed. Sample absorption spectra of 3e in
the presence of increasing concentrations of NH SCN are
erature.
4
General Procedure for the Conversion of 1,2-Epoxyethanes
to 2-Hydroxyethyl Thiocyanate Using Schiff-Base Complexes
of Metal(Ⅱ) as a Catalyst. To a mixture of 1,2-epoxyethanes
(
10 mmol) and NH
4
SCN (10 mmol, 0.76 g) in acetonitrile (30
Cl (5 mL) was add-
mL), a solution of catalyst (0.1 mmol) in CH
2
2
ed, and the mixture was stirred under reflux for 25–150 min (in the
case of Fe, Co, Mn, metals, under nitrogen atmosphere). The re-
action was monitored by TLC or GC. After completion of the re-
action, the mixture was filtered and the solvent was evaporated.
Chromatography of the crude product was performed on a column
of silica gel eluted first with hexane for the separation of thiirane,
6 2 2
followed by using C H14/CH Cl (1:1) for the separation of 2-
hydroxyethyl thiocyanate as a pale-yellow liquid. Then, the Schiff
base metal(Ⅱ) complex was recovered by elution with methanol.
4
, 6, 9
Selected Spectral Data for 2-Hydroxyethyl Thiocyanates.
(
a) 2-Hydroxy-2-phenylethyl Thiocyanate:
IR (neat)
−
1 1
ν(SCN) 2160 cm ; H NMR (CDCl
5.0 (1H, dd), 3.1–3.3 (2H, m), 2.4–2.9 (1H, brs). C NMR
3
, 250 MHz) δ 7.3(5H, m),
−
4
13
Fig. 2. Absorption spectra of catalyst 3e (8 × 10 M) in the
presence of different concentrations of NH SCN at 25 °C
4
(CDCl
42.4.
3
, 62.9 MHz) δ 135.8, 129.5, 128.3, 126.2, 113.0, 72.9,
−
4
−4
in acetonitril: (1) 0, (2) 1.5 × 10 , (3) 2.5 × 10 , (4) 3.5
−
4
−4
−4
−4
×
10 , (5) 4.5 × 10 , (6) 5.5 × 10 , (7) 7.5 × 10 M.
(b) 3-Phenoxy-2-hydroxypropyl Thiocyanate: IR (neat)

H. Sharghi et al.
Bull. Chem. Soc. Jpn., 76, No. 1 (2003) 141
−
1 1
ν(SCN) 2163 cm ; H NMR (CDCl
.92 (3H, m), 5.0 (1H, m), 4.2 (2H, d), 3.64 (2H, d). C NMR
CDCl , 62.9 MHz) δ 158.0, 130.0, 122.0, 115.1, 114.9, 78.2,
7.2, 33.6.
c) 2-Hydroxycyclohexyl Thiocyanate: IR (neat) ν(SCN)
3
, 250 MHz) δ 7.27 (2H, m),
Trans.1, 1981, 1577.
A. Olszewski-Ortar, P. Gros, and Y. Fort, Tetrahedron Lett.,
38, 8699 (1997).
13
6
(
6
7
3
8
B. M. Choudary, S. Shobha, and M. L. Kantam, Synth.
(
Commun., 20, 2313 (1990).
−
1
1
2
165 cm ; H NMR (CDCl
1H, m), 2.15 (1H, s), 1.80 (2H, m), 1.65 (2H, m), 1.20–1.50
3
, 250 MHz) δ 2.95 (1H, m), 2.35
9
Y. Tanabe, K. Mori, and Y. Yoshida, J. Chem. Soc., Perkin
(
(
3
Trans.1, 1997, 671.
10 H. Sharghi, and H. Naeimi, Bull. Chem. Soc. Jpn., 72, 1525
(1999).
1
3
4H, m). C NMR (CDCl
2.5, 30.5, 27.0.
d) 2-Hydroxy-3-isopropoxypropyl Thiocyanate: IR (neat)
3
, 62.9 MHz) δ 110.0, 72.0, 55.0, 34.5,
(
11 a) T. Katsuki, J. Mol. Cat. A, 113, 87 (1996). b) E. N.
Jacobsen, “Catalytic Asymmetric Synthesis,” ed by I. Ojima, VCH
Publishers, Inc., New York (1993), pp. 159–202.
12 a) K. Noda, N. Hosoya, R. Irie, Y. Ito, and T. Katsuki,
Synlett, 1993, 469. b) H. Nishikori, and T. Katsuki, Tetrahedron
Lett., 37, 9245 (1996). c) K. Hori, H. Sugihara, N. Ito, and T.
Katsuki, Tetrahedron Lett., 40, 5207 (1999).
13 a) T. Fukuda, and T. Katsuki, Synlett, 1995, 825. b) T.
Fukuda, and T. Katsuki, Tetrahedron, 53, 7201 (1997). c) B. Saha,
T. Uchida, and T. Katsuki, Synlett, 2001, 114.
14 a) Y. Yamashita, and T. Katsuki, Synlett, 1995, 829. b) S. E.
Schaus, J. Branalt, and E. N. Jacobsen, J. Org. Chem., 63, 403
(1998).
15 a) Y. Belokon, M. Flego, and M. Tasinazzo, J. Chem. Soc.,
Perkin Trans. 1, 1997, 1293. b) Y. Belokon, N. Ikonnikov, and L.
Yashkina, Tetrahedron: Asymmetry, 7, 851 (1996).
16 M. S. Sigman, and E. N. Jacobsen, J. Am. Chem. Soc., 120,
5315 (1998).
17 a) G. Mohan, R. C. Sharma, and R. K. Parashar, Pol. J.
Chem., 66, 929 (1992). b) B. B. Mahapatra, and D. Panda, Transi-
tion Met. Chem., 9, 280 (1984).
18 K. H. Reddy, and Y. Sreenivasulu, Pol. J. Chem., 67, 637
(1993).
19 a) B. B. Mahapatra, M. Raval, A. Behera, and A. K. Das, J.
Indian Chem. Soc., 72, 161 (1995). b) A. Ramachandraiah, P. N.
Rao, and M. Ramaiah, Indian J. Chem.,Sect. A, 28, 309 (1989).
20 a) S. J. Titus, W. M. Barr, and L. T. Taylor, Inorg. Chim.
Acta, 32, 103 (1979). b) C. J. Boreham, and B. Chiswell, Inorg.
Chim. Acta, 24, 77 (1977).
−
1 1
ν(SCN) 2170 cm ; H NMR (CDCl
3
, 250 MHz) δ 3.74 (1H, m),
3
.57 (3H, m), 3.33 (2H, d), 3.17 (1H, brs), 1.1 (6H, d, J = 6 Hz).
13
C NMR (CDCl
2.0.
3
, 62.9 MHz) δ 114.5, 79.4, 73.2, 67.6, 38.2, 23.0,
2
(
e) 3-Allyloxy-2-hydroxypropyl Thiocyanate:
IR (neat)
−
1 1
ν(SCN) 2158 cm ; H NMR (CDCl
3
, 250 MHz) δ 5.81 (1H, m),
5
(
7
.1–5.25 (2H, m), 4.7 (1H, brs), 3.98 (3H, m), 3.6 (2H, d), 3.36
1
3
2H, d). C NMR (CDCl
2.9, 69.2, 32.5.
f) 3-Chloro-2-hydroxypropyl Thiocyanate:
3
, 62.9 MHz) δ 134.2, 118.0, 117.0, 80.2,
(
IR (neat)
−
1 1
ν(SCN) 2168 cm ; H NMR (CDCl
3
, 250 MHz) δ 4.1 (1H, m),
1
3
3
7
.7 (4H, m), 2.64 (1H, brs). C NMR (CDCl
1.2, 46.1, 43.4.
3
, 62.9 MHz) δ 117.8,
(
g) 2-Hydroxyoctyl Thiocyanate: IR (neat) ν(SCN) 2162
cm ; H NMR (CDCl
13, J = 3.5 Hz), 2.95 (1H, dd, J = 13, 7.5 Hz), 2.69 (1H, brs),
−
1 1
3
, 250 MHz) δ 3.91 (1H, m), 3.15 (1H, dd, J
=
1
1
1
3
.2–1.6 (10H, m), 0.88 (3H, m). C NMR (CDCl
13.2, 70.6, 41.5, 36.3, 32.0, 29.4, 25.8, 22.9, 14.4.
h) 2-Hydroxy-1-indanyl Thiocyanate: IR (neat) ν(SCN)
3
, 62.9 MHz) δ
(
−
1 1
2
(
160 cm ; H NMR (CDCl , 250 MHz) δ 7.2–7.5 (4H, m), 5.0
3
13
1H, d), 4.8 (1H, m), 3.55 (2H, d), 3.2–3.5 (1H, brs). C NMR
CDCl , 62.9 MHz) δ 139.0, 130.0, 128.0, 126.0, 124.0, 120.0,
12.4, 83.7, 50.1, 39.4.
(
3
1
We gratefully acknowledge support of this work by the
Shiraz University Research Council and Professor M.
Shamsipur, Dr. B. Hemmateenejad and Dr. A. Soleymanpour
for their helpful comments.
2
1
P. B. D. DE la mare, and R. Bolton, “Electrophilic Addition
to Unsaturated Systems,” Elsevier Scientific, Amsterdam (1996),
p. 132.
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8