Zinc Chloride Mediated Nucleophilic Substitution: Amination and Thioetherification of Alcohols at Room Temperature

Full text of DOI:10.1080/00304948.2020.1716617

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
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Zinc Chloride Mediated Nucleophilic Substitution:
Amination and Thioetherification of Alcohols at
Room Temperature
Ashima Singh, Shruti Gupta & Jitender M. Khurana
To cite this article: Ashima Singh, Shruti Gupta & Jitender M. Khurana (2020): Zinc
Chloride Mediated Nucleophilic Substitution: Amination and Thioetherification of Alcohols
at Room Temperature, Organic Preparations and Procedures International, DOI:
10.1080/00304948.2020.1716617
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ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
https://doi.org/10.1080/00304948.2020.1716617
EXPERIMENTAL PAPER
Zinc Chloride Mediated Nucleophilic Substitution:
Amination and Thioetherification of Alcohols at Room
Temperature
Ashima Singh, Shruti Gupta, and Jitender M. Khurana
Department of Chemistry, University of Delhi, New Delhi, India
ARTICLE HISTORY Received 2 July 2019; Accepted 28 September 2019
Catalytic chemistry is one of the focal points for the development of environmentally
benign organic transformations. It is true that the employment of catalysts in organic
transformations comes with the advantages of increased efficiencies, selectivity, and
lower production costs; but the use of precious metals in either homogeneous or hetero-
geneous catalysis has been under scrutiny because of high cost, toxicity and the carbon
footprint of obtaining these materials. Aromatic secondary amines find their applicabil-
ity in pharmaceutical, agrochemical, photographic, pigment, and electronic indus-
tries.1–3. Amines are also important precursors of bioactive molecules, including many
natural products.4 In considering the preparation of the title compounds, numerous
methodologies have been reported for the synthesis of N-alkylamines. Some well-known
early protocols include the Hofmann N-alkylation reaction and the Gabriel synthesis.5,6
These procedures have their merits, but some are associated with such problems as tox-
icity of reagents, control of the degree of alkylation, requirement of large amounts of
base, low atom economy or reaction efficiency.7
Employing alcohols for amination has the advantages of low cost and easy availabilty.
Amination has been achieved by using a variety of nucleophiles such as urea, ammonia
and primary amines with catalysts.8 For example, Fujita and coworkers have reported
that Ir complexes catalyze an oxidation-imination-reduction sequence at relatively low
temperatures (90–120 ꢀC).8 A variety of Ru and Pd complexes have also been synthe-
sized for achieving the N-alkylation reaction employing various primary and secondary
amines and alcohols.8 All these successful methods nonetheless have such drawbacks as
catalyst–product separation, expensive metal complexes, toxic solvents, or high tempera-
tures. Jung and co-workers reported the application of CsOH as the base by taking
advantage of the “Cesium Effect.”9–11 However, the constraints of anhydrous conditions
and excess amounts of alkyl halides can make this a less desirable method for
some cases.
Thioethers are significant structural scaffolds for several drugs used against
Alzheimer’s, Parkinson’s, malaria, inflammation, HIV, and cancer.12 Methodologies
employed for C-S bond formation include deoxygenation of sulfoxides,13,14 transition
metal-catalyzed coupling between aryl halides and thiols,15,16 coupling reactions between
CONTACT Jitender M. Khurana
jmkhurana@chemistry.du.ac.in
Department of Chemistry, University of Delhi, New
Delhi, 110 007, India
ß 2020 Taylor & Francis Group, LLC

2
A. SINGH ET AL.
alkenyl silyl ethers and thiosilanes using BF3ꢁOEt2,17 and the addition of thiols to car-
bonyl compounds followed by the in situ reduction of the generated intermediate thio-
nium ion.18 Recent approaches for C-S bond formation involve the use of Lewis acid
catalysts,19 Ni-nanoparticles,20 and a heterogenous Pd-MgO system.21 Nonetheless, com-
plications of the aforementioned procedures include high temperature, hazardous and
corrosive alkylating agents, strong reducing agents, harsh reaction conditions, tedious
workup and low product yields. Considering the importance of N-alkylated amines and
aryl thioethers, the development of sustainable and practical synthetic protocols for C-N
and C-S bond formation using a suitable catalyst is highly desirable. In continuation of
our work on azidation of alcohols using trimethylsilylazide,22 we decided to investigate
these transformations using Lewis acid catalysts.
In this paper, we report a high yielding, waste-free, efficient synthesis of thioethers
and amines from secondary or tertiary alcohols and anilines or thiophenols in dichloro-
methane in the presence of ZnCl2 at room temperature. We deliberately focused our
initial experiments on low catalyst loading, short reaction times and room temperature
and did not investigate larger amounts of catalyst or higher temperatures. For the pre-
liminary investigation, benzhydrol (1.0 mmol) and aniline (1.0 mmol) were used as the
model substrates and the reaction was carried out using 10 mol% of ZnCl2 as catalyst in
anhydrous dichloromethane. The reaction was found to be complete in 20 min. After
workup, N-benzhydrylaniline (81%) was isolated (eq. 1) (Table 1, entry 1). On decreas-
ing the catalyst loading of ZnCl2 to 5 mol %, the reaction was observed to be incomplete
even after 24 h and yielded 72% of N-benhydrylaniline (entry 2). The reaction attempted
using another Lewis acid catalyst, AlCl3, did not proceed in DCM or DMF at all (entries
.
3, 4). The reaction carried out in the presence of 10 mol% of CuSO4 5H2O in DCM was
incomplete even after 24 h and gave a comparatively inferior yield of 40% of IIIa (entry
5). There was no reaction with ZnCl2 as catalyst in ethyl acetate and 1,4-dioxane
(entries 6,7). Thus, reaction of benzhydrol and aniline in the presence of 10 mol% of
ZnCl2 in DCM at room temperature were the best conditions we found in our direct
and pragmatic approach to the amination.
Table 1. Optimization of reaction conditions for amination reaction.a
Entry
Solvent
Catalyst
Catalyst Loading (mol%)
Time
%Yield (IIIa)
1.
2.
3.
4.
5.
6.
7.
DCM
DCM
DCM
DMF
DCM
ZnCl2
ZnCl2
AlCl3
10
5
10
10
10
10
10
20 min
24 h
–
24 h
24 h
24 h
24 h
81
72b
b
-
c
AlCl3
-
CuSO4ꢁ5H2O
40b
c
EtOAc
Dioxane
ZnCl2
-
c
ZnCl2
-
aReactions carried out using aniline (1.0 mmol) and benzhydrol (1.0 mmol) at room temperature.
bIncomplete reaction.
cNo reaction.

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
3
Subsequently, a variety of alcohols and amines were screened to study the general
applicability of the above optimized protocol. The reactions of equimolar alcohols and
amines were carried out in DCM in the presence of 10 mol% of ZnCl2 at room tem-
perature. All the reactions were complete in less than 30 min and gave the correspond-
ing N-aryl anilines in good yields with a convenient workup. The results have been
summarized in Table 2 and the reactions can be generalized as eq. 2.
Table 2. Synthesis of secondary amines from their corresponding alcohols.a
Entry
R1
R2
R3
R4
Product (III)
Time (min)
% Yield
1.
2.
3.
4.
5.
6.
7.
8.
H
H
H
4-Cl
4-Cl
4-Br
H
H
C6H5
CH3
CH3
CH3
CH3
C6H5
CH3
C6H5
C6H5
C6H5
CH3
C6H5
4-ClC6H4
4-BrC6H4
C6H5
4-ClC6H4
C6H5
1-Naphthyl
C6H5
C6H5
H
H
H
H
H
H
H
C6H5
H
H
IIIa
IIIb
IIIc
IIId
IIIe
IIIf
IIIg
IIIh
IIIi
20
30
20
15
20
20
25
15
20
20
20
81
80
82
84
75
79
70
81
86
88
85
9.
10.
11.
2-Benzothiazolyl
H
H
C2H5
4-O2NC6H4
IIIj
IIIk
H
aReactions carried out using aromatic amines (1.0 mmol) and alcohol (1.0 mmol) in DCM using ZnCl2 (10 mol%) at r.t.
It can be inferred from the results that secondary and tertiary benzylic alcohols could be
converted to their corresponding N-alkyl anilines (entries 1-10). Amines with substitution
(chloro, bromo) and heteroaromatic amines also gave smoothly the desired N-aryl prod-
ucts but reaction of 4-nitroaniline with benzhydrol and reactions of primary benzylic alco-
hols (benzyl alcohol, 2,5-dimethoxybenzyl alcohol), aliphatic secondary alcohols
(cyclohexanol) and phenols with aniline did not proceed under these conditions.
The scope of the above protocol was also investigated for the thioetherification of
alcohols (eq. 3). The reactions of equimolar amounts of alcohols and thiols were carried
out in DCM in the presence of 10 mol% of ZnCl2 at room temperature. All the
reactions proceeded smoothly and gave the corresponding thioethers in excellent yields
(82-98%) in 15-30 min. It can be inferred from the results in Table 3 that secondary
benzylic alcohols and tertiary aromatic/aliphatic alcohols (entries 8-11) could be con-
verted to their corresponding thioethers in high yields. However, in the case of primary
benzylic alcohols (benzyl alcohol, 2,5-dimethoxybenzyl alcohol), aliphatic secondary
alcohols (cyclohexanol), and aromatic heterocyclic alcohols (9H-xanthen-9-ol, fluoren-9-
ol), no reaction was observed.
Encouraged by these results, the present method was evaluated for gram scale synthe-
sis. The reaction of 3 g of benzhydrol (1a) was attempted with aniline and thiophenol
using ZnCl2 (10 mol%) in DCM at room temperature (Scheme 1). The reaction fur-
nished the corresponding products in 79% (3.77 g) and 96% (4.36 g) yield respectively.
Thus, this procedure can be used for gram scale synthesis of anilines and thioethers.

4
A. SINGH ET AL.
Table 3. Synthesis of thioethers from their corresponding alcohols.a
Entry
R1
R2
R3
R4
Product (V)
Time (min)
% Yield
1.
2.
3.
4.
5.
6.
7.
8.
C6H5
3-MeOC6H4
C6H5
C6H5
C6H5
3-MeOC6H4
C6H5
C6H5
3-MeOC6H4
C6H5
3-MeOC6H4
n-hexyl
C6H5
C6H5
CH3
CH3
CH3
CH3
–
C6H5
C6H5
CH3
CH3
C6H5
C6H5
C6H5
C6H5
H
H
H
H
H
Va
Vb
Vc
Vd
Ve
Vf
Vg
Vh
Vi
20
30
20
20
15
20
20
25
20
15
25
15
98
95
88
94
84
82
81
88
83
87
91
95
4-ClC6H4
1-Naphthyl
1-Naphthyl
Fluorenonyl
C6H5
H
–
C6H5
C6H5
CH3
CH3
H
9.
C6H5
CH3
CH3
C6H5
10.
11.
12.
Vj
Vk
Vl
aReactions carried out using alcohol (1.0 mmol) and thiophenol (1.0 mmol) in DCM using ZnCl2 (10 mol%) at r.t.
Scheme 1. Gram-scale syntheses of amine and thioether IIIa and Va.
Figure 1. Recyclability of the catalyst.
The recycling of catalyst has also been investigated for the synthesis of IIIa and Va
(Fig. 1). The yields changed from 81% to 74% in the case of IIIa and 98% to 92% in
case of Va after 5 cycles.
In conclusion, we have developed an efficient methodology for the synthesis of
amines and thioethers from alcohols with the recyclable Lewis acid ZnCl2 as a catalyst

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
5
in DCM at room temperature. High yield of products, recyclability of the catalyst, scal-
ability to gram scale and short reaction times are the striking features of this protocol.
Experimental section
All of the compounds are known and were identified by matching their spectrometric
features with those in the literature references that are cited. In the case of solids, melt-
ing points matched the literature values.
General procedure for the synthesis of N-aryl anilines (IIIa-k) from alcohols
A mixture of alcohol (1.0 mmol), aniline (1.0 mmol), ZnCl2 (10 mol%) and anhydrous
DCM (3 mL) was placed in a 50 mL round-bottomed flask. The reaction contents were
stirred magnetically at room temperature for the appropriate time as mentioned in
Table 2. The progress of the reaction was monitored by TLC (silica gel; eluent: ethyl
acetate/petroleum ether, 10/90, v/v). After completion of the reaction as indicated by
TLC, it was quenched with water (5 mL). The reaction mixture was extracted with
DCM (3 ꢂ 5 mL). The combined organic layer was dried over anhydrous Na2SO4, fil-
tered, and the solvent removed under vacuum to get crude product, which was purified
by column chromatography using (silica gel; eluent: ethyl acetate/petroleum ether, 1/99,
v/v) to give the corresponding product as shown in Table 2. Reactions failed with pri-
mary benzylic alcohols (benzyl alcohol, 2,5-dimethoxybenzyl alcohol), aliphatic second-
ary alcohols (cyclohexanol) and phenols.
General procedure for the synthesis of thoiethers (Va-l) from alcohols
A mixture of alcohol (1.0 mmol), thiol (1.0 mmol), ZnCl2 (10 mol%) and anhyd. DCM
(3 mL) was placed in a 50 mL round-bottomed flask. The reaction contents were stirred
magnetically at room temperature for the appropriate time as mentioned in Table 3.
The progress of the reaction was monitored by TLC (silica gel; eluent: ethyl acetate/pet-
roleum ether, 10/90, v/v). After completion of the reaction as indicated by TLC, it was
quenched with water (5 mL). The reaction mixture was extracted with DCM (3 ꢂ 5 mL),
The combined organic layer was dried over anhydrous Na2SO4, filtered, and the solvent
removed under vacuum to get crude product, which was purified by column chroma-
tography using (silica gel; eluent: ethyl acetate/petroleum ether, 1/99, v/v) to give the
corresponding product in good yield as mentioned in Table 3. Reactions failed with pri-
mary benzylic alcohols (benzyl alcohol, 2,5-dimethoxybenzyl alcohol), aliphatic second-
ary alcohols (cyclohexanol), and aromatic heterocyclic alcohols (9H-xanthen-9-ol,
fluoren-9-ol).
N-Benzhydrylaniline (IIIa)23
1
Oil, Yield: 81%. IR ꢀmax (DCM/cmꢃ1): 3383, 1490, 1448. H-NMR (400 MHz, CDCl3) d
7.37-7.16 (m, 12H, ArH), 6.79-6.77 (m, 1H, ArH), 6.77-6.65(m, 2H, ArH), 5.78 (s, 1H,

6
A. SINGH ET AL.
CH), 3.11 (s, 1H, NH). 13C-NMR (100 MHz, CDCl3) 146.11, 143.76, 129.18, 128.38,
127.42, 126.45, 118.57, 115.14, 76.04.
N-(1-(4-Chlorophenyl)ethyl)aniline (IIIb)24
1
Oil, Yield: 80%. IR ꢀmax (DCM/cmꢃ1): 3348, 2974, 1492. H-NMR (400 MHz, CDCl3) d
7.31-7.09 (m, 7H, ArH), 6.75-6.64 (m, 2H, ArH), 4.83 (q, J ¼ 6.4 Hz, 1H, CH), 2.75 (s,
1H), 1.44 (d, J ¼ 6.4 Hz, 3H, CH3). 13C-NMR (100 MHz, CDCl3) 146.07, 144.20, 132.83,
129.19, 128.44, 126.71, 118.61, 69.51, 25.14.
N-(1-(4-Bromophenyl)ethyl)aniline (IIIc)25
1
Oil; Yield: 82%. IR ꢀmax (DCM/cmꢃ1): 3334, 2972, 1487. H-NMR (400 MHz, CDCl3) d
7.47-7.45 (m, 2H, ArH), 7.26-7.22 (m, 2H, ArH), 7.18-7.14 (m, 2H, ArH), 6.79-6.75 (m,
1H, ArH), 6.69-6.67 (m, 2H, ArH), 4.83 (q, J ¼ 6.4 Hz, 1H, CH), 2.97 (s, 1H, CH), 1.46
(m, 3H, CH3). 13C-NMR (100 MHz, CDCl3) 146.10, 144.76, 131.39, 129.18, 127.07,
120.95, 118.59, 115.16, 69.54, 25.12.
4-Chloro-N-(1-phenylethyl)aniline (IIId)24
1
Oil; Yield: 84%. IR ꢀmax (DCM/cmꢃ1): 3366, 2973, 1480. H-NMR (400 MHz, CDCl3) d
7.29-7.06 (m, 7H, ArH), 6.59-6.52 (m, 2H, ArH), 4.84 (q, J ¼ 6.4 Hz, 1H), 3.40 (s, 1H,
NH), 1.44 (d, J ¼ 6.4 Hz, 3H). 13C-NMR (100 MHz, CDCl3) 144.87, 144.81, 144.76,
144.22, 129.54, 129.52, 129.05, 127.93, 127.27, 116.65, 116.63, 115.81, 69.55, 25.67.
4-Chloro-N-(1-(4-chlorophenyl)ethyl)aniline (IIIe)24
1
Oil; Yield: 75%. IR ꢀmax (DCM/cmꢃ1): 3356, 2974, 1490. H-NMR (400 MHz, CDCl3) d
7.30-7.25 (m, 4H, ArH), 7.08-7.06 (m, 2H, ArH), 6.59-6.55 (m, 2H, ArH), 4.83 (q,
J ¼ 6.4 Hz, 1H), 3.40 (s, 1H, NH), 1.44 (d, J ¼ 6.4 Hz, 3H). 13C-NMR (100 MHz,
CDCl3) 144.87, 144.81, 144.76, 144.22, 129.54, 129.52, 129.05, 127.93, 127.27, 116.65,
116.63, 115.81, 69.55, 25.67.
4-Bromo-N-(1-phenylethyl)aniline (IIIf)25
Oil, Yield: 79%. IR ꢀmax (DCM/cmꢃ1): 3385, 2924, 1490.1H-NMR (400 MHz, CDCl3) d
7.37-7.23 (m, 14H, ArH), 5.40 (s, 1H, CH), 1.54 (s, 1H, NH), 13C-NMR (100 MHz,
CDCl3) 145.23, 143.75, 142.08, 131.85, 128.36, 128.30, 127.42, 127.35, 127.30, 127.16,
126.45, 116.65, 114.99 110.10, 79.91.
N-(1-Phenylethyl)aniline (IIIg)23
1
Oil; Yield: 70%. IR ꢀmax (DCM/cmꢃ1): 3340, 1510, 1444. H-NMR (400 MHz, CDCl3) d
8.03-7.97 (m, 2H, ArH), 7.88-7.59 (m, 5H, ArH), 7.51-7.34 (m, 5H, ArH), 5.39 (q,
J ¼ 6.4 Hz,1H, CH), 1.66 (d, J ¼ 6.4 Hz,1H, CH). 13C-NMR (100 MHz, CDCl3) 140.08,

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
7
139.80, 133.95, 133.74, 128.76, 128.53, 127.80, 127.47, 125.64, 125.61, 125.58, 125.42,
125.23, 123.64, 123.39, 71.85, 23.09.
N-Benzhydrylbenzo[d]thiazol-2-amine (IIIh)26
Gray solid, Yield: 81%. m.p: 157–159 ꢀC, lit m.p: 160-161 ꢀC. IR ꢀmax (DCM/cmꢃ1):
1
3290, 1531, 1448. H-NMR (400 MHz, CDCl3) d 7.63-7.49 (m, 2H, ArH), 7.41-7.23 (m,
11H, ArH), 7.18-7.06 (m, 1H, ArH), 5.69 (s, 1H, NH), 5.40 (s, 1H, CH). 13C-NMR
(100 MHz, CDCl3) 166.71, 151.53, 142.09, 130.99, 128.73, 128.74, 128.32, 127.50, 127.36,
127.15, 125.91, 122.15, 120.82, 118.75, 79.90.
N-Tritylaniline (IIIi)27
White solid, Yield: 86%. m.p: 146-150 ꢀC, lit m.p: 148-149 ꢀC. IR ꢀmax (DCM/cmꢃ1):
1
373 1496, 1456. H-NMR (400 MHz, CDCl3) d 7.32–7.22 (m, 18H, ArH), 7.21 (s, 1H,
ArH), 6.58-6.65 (d, J ¼ 8.4 Hz, 2H, ArH), 2.85 (s, 1H, NH). 13C-NMR (100 MHz,
CDCl3) 147.21, 146.84, 132.05, 131.12, 127.90, 127.31, 127.24, 125.70, 114.18, 82.01.
N-(1-Phenylpropyl)aniline (IIIj)24
1
Oil; Yield: 88%. IR ꢀmax (DCM/cmꢃ1): 3377, 1602, 1498. H -NMR (400 MHz, CDCl3)
d 7.48-7.16 (m, 7H, ArH), 6.91-6.77 (m, 1H, ArH), 6.76-6.63 (m, 2H, ArH), 4.56 (t, J ¼
6.6 Hz, 1H), 3.41 (s, 1H), 1.91-1.66 (m, 2H), 0.96 (t, J ¼ 7.6 Hz, 3H). 13C-NMR
(400 MHz, CDCl3) d 146.01, 144.53, 128.97, 128.03, 127.04, 125.79 (1C), 118.37, 115.05,
75.46, 31.59, 9.89.
N-(1-(4-Nitrophenyl)ethyl)aniline (IIIk)28
1
Oil, Yield: 85%, . IR ꢀmax (DCM/cmꢃ1): 3466, 1489, 1442. H -NMR (400 MHz, CDCl3)
d 8.23-8.12 (m, 2H, ArH), 7.51 (d, J ¼ 8.2 Hz, 2H, ArH), 7.27-7.18 (m, 2H, ArH), 6.88-
6.81 (m, 1H, ArH), 6.73 (dd, J ¼ 8.5, 1.1 Hz, 2H, ArH), 4.96 (q, J ¼ 6.4 Hz, 1H), 3.86
(s, 1H), 1.51 (d, J ¼ 6.4 Hz, 3H). 13C-NMR (400 MHz, CDCl3) d 153.33, 146.38, 145.80,
128.83, 125.72, 123.13, 118.33, 115.05, 68.65, 24.84 .
Benzhydryl (phenyl) sulfane (Va)29
White solid, Yield: 98%. m.p: 77-79 ꢀC, lit m.p 78.5 ꢀC. IR ꢀmax (DCM/cmꢃ1): 1582,
1
1485, 696. H-NMR (400 MHz, CDCl3) d 7.42 (d, J ¼ 7.6 Hz, 4H), 7.33-7.12 (m, 11H),
5.55 (s, 1H), 13C-NMR (100 MHz, CDCl3) d 140.93, 136.09, 130.40, 129.36, 129.07,
128.71, 128.52, 128.36, 127.23, 126.52, 57.33.
Benzhydryl (3-methoxyphenyl) sulfane (Vb)29
1
Oil, Yield: 95%. IR ꢀmax (DCM/cmꢃ1): 1587, 1477, 626. H-NMR (400 MHz, CDCl3) d
7.55-7.46 (m, 4H), 7.37-7.23 (m, 6H), 7.12 (t, J ¼ 8.0 Hz, 1H), 6.94-6.87 (m, 1H), 6.81

8
A. SINGH ET AL.
(d, J ¼ 1.4 Hz, 1H), 6.72 (dd, J ¼ 8.2, 2.3 Hz, 1H), 5.63 (s, 1H), 3.65 (s, 3H), 13C-NMR
(100 MHz, -CDCl3) 159.47, 140.88, 137.39, 129.45, 128.51, 128.34, 128.21, 127.22,
122.33, 115.08, 112.61, 57.15, 55.01
Phenyl (1-phenylethyl) sulfane (Vc)29
1
Oil, Yield: 88%. IR ꢀmax (DCM/cmꢃ1): 1581, 1483, 1444. H-NMR (400 MHz, CDCl3) d
7.46-7.23 (m, 9H), 4.42 (q, J ¼ 7.0 Hz, 1H), 1.71 (d, J ¼ 6.9 Hz, 3H), 13C-NMR
(100 MHz, CDCl3)
47.81, 22.23.
d 143.06, 135.03, 132.29, 128.55, 128.26, 127.14, 1207.00,
(1-(4-Chlorophenyl)ethyl) phenyl sulfane (Vd)29
1
Oil, Yield: 94%. IR ꢀmax (DCM/cmꢃ1): 1581, 1487, 1442. H-NMR (400 MHz, CDCl3) d
7.41-7.21 (m, 9H), 4.35 (q, J ¼ 7.0 Hz, 1H), 1.65 (d, J ¼ 7.3 Hz, 3H), 13C-NMR
(100 MHz, CDCl3) d 141.73, 134.46, 132.57, 128.66, 128.51, 128.36, 127.53, 127.26,
47.25, 22.09.
(1-(Naphthalen-2-yl)ethyl) phenyl sulfane (Ve)29
White solid, Yield: 84%. m.p: 57-60 ꢀC, lit. m.p. 57.5–59.2 ꢀC. IR ꢀmax (DCM/cmꢃ1):
1
1583, 1509, 773. H-NMR (400 MHz, CDCl3) d 8.15 (d, J ¼ 9.2 Hz, 1H), 7.79 (d, J ¼
7.6 Hz, 1H), 7.67 (d, J ¼ 8.4 Hz, 1H), 7.59-7.29 (m, 4H), 7.27-7.08 (m, 5H), 5.09 (q, J ¼
6.9 Hz, 1H), 1.70 (d, J ¼ 7.6 Hz, 3H), 13C-NMR (100 MHz, CDCl3) 138.09, 135.17,
133.88, 132.10, 130.79, 129.35, 128.98, 128.72, 127.86, 127.42, 127.02, 126.10, 125.54,
125.37, 124.35, 123.04, 42.79, 22.02.
(3-Methoxyphenyl) (1-(naphthalen-2-yl)ethyl)sulfane (Vf)29
1
Oil, Yield: 82%. IR ꢀmax (DCM/cmꢃ1): 1582, 1473, 683. H-NMR (400 MHz, CDCl3) d
8.32 (d, J ¼ 8.4 Hz, 1H), 7.96 (d, J ¼ 8.4 Hz, 1H), 7.84 (d, J ¼ 8.4 Hz, 1H), 7.73-7.46
(m, 4H), 7.22 (t, J ¼ 7.6 Hz, 1H), 7.04-6.75 (m, 4H), 5.29 (q, J ¼ 7.1 Hz, 1H), 3.70 (s,
3H), 1.88 (d, J ¼ 6.9 Hz, 3H), 13C-NMR (100 MHz, CDCl3) 159.48, 138.15, 136.52,
133.85, 131.91, 130.77, 129.88, 129.47, 128.96, 127.84, 126.12, 125.55, 125.41, 125.25,
124.30, 123.82, 122.97, 121.59, 116.57, 114.62, 112.98, 111.39, 55.04, 42.57, 22.06.
(9H-Fluoren-9-yl) (phenyl) sulfane (Vg)30
White solid, Yield: 81%, m.p: 210-214 ꢀC, lit m.p 215 ꢀC ꢀmax (DCM/cmꢃ1): 1583, 1509,
773.1H-NMR (400 MHz, CDCl3) d 7.65 (q, J ¼ 7.6 Hz, 2H), 7.60-7.48 (m, 2H), 7.39-7.21
(m, 7H), 7.20-7.11 (m, 2H), 5.27 (s, 1H), 13C-NMR (100 MHz, CDCl3) 144.29, 140.43,
133.26, 132.91, 129.35, 129.05, 128.46, 127.98, 127.66, 127.42, 127.26, 127.10, 125.57,
125.35,119.85, 51.71.

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
9
Phenyl trityl sulfane (Vh)31
White solid, Yield: 88%. m.p: 100-103 ꢀC, lit m.p 106 ꢀC. IR ꢀmax (DCM/cmꢃ1): 1583,
1
1482, 623. H-NMR (400 MHz, CDCl3) d 7.52-7.47 (m, 1H), 7.44-7.39 (m, 9H), 7.33-
7.27 (m, 1H), 7.26-7.16 (m, 13H), 7.12-7.07 (m, 1H), 7.02-6.94 (m, 5H), 13C-NMR
(100 MHz, CDCl3) 144.49, 134.46, 134.42, 129.97, 129.05, 128.04, 127.63, 127.45, 127.12,
126.63, 70.73.
3-Methoxyphenyl trity) sulfane (Vi)32
1
Oil, Yield: 83%. IR ꢀmax (DCM/cmꢃ1): 1583, 1477, 620. H-NMR (400 MHz, CDCl3) d
7.45-7.38 (m, 6H), 7.27-7.16 (m, 9H), 6.94 (t, J ¼ 8.0 Hz, 1H), 6.67 (dd, J ¼ 8.0, 1.9 Hz,
2H), 6.42 (t, J ¼ 1.9 Hz, 1H), 3.47 (s, 3H), 13C-NMR (100 MHz, CDCl3) 158.82, 144.44,
135.68, 129.96, 128.76, 127.64, 126.67, 126.48, 118.35, 114.52, 70.60, 54.97.
tert-Butyl pheny sulfane (Vj)33
Oil, Yield: 87%. IR ꢀmax (DCM/cmꢃ1): 1583, 1477, 623.1H-NMR (400 MHz, CDCl3) d
7.47 (dd, J ¼ 7.6, 1.6 Hz, 2H), 7.33-7.18 (m, 3H), 1.21 (s, 9H).13C-NMR (100 MHz,
CDCl3) 137.37, 132.60, 128.54, 128.33, 45.66, 30.87.
tert-Butyl 3-methoxyphenyl sulfane (Vk)34
Oil, Yield: 91%. IR ꢀmax (DCM/cmꢃ1): 1583, 1471, 754.1H-NMR (400 MHz, CDCl3) d
7.29-7.07 (m, 3H), 6.95-6.87 (1H), 3.80 (s, 3H), 1.31 (s, 9H). 13C-NMR (100 MHz,
CDCl3) 159.21, 133.69, 129.68, 129.10, 55.28, 45.97, 30.99.
Benzhydryl hexyl sulfane (Vl)35
Oil, Yield: 95%, IR ꢀmax (DCM/cmꢃ1): 1580, 779, 623.1H-NMR (400 MHz, CDCl3) 1H-
NMR (400 MHz, CDCl3) d 7.48 (d, J ¼ 5.5 Hz, 4H), 7.40-7.18 (m, 6H), 5.20 (s, 1H),
2.43 (td, J ¼ 7.1, 2.0 Hz, 2H), 1.67-1.55 (m, 2H), 1.44-1.23 (m, 6H), 0.98-0.89 (m,
3H).13C-NMR (100 MHz, CDCl3) 141.53, 128.41, 128.21, 54.07, 32.24, 31.30, 28.91,
28.47, 22.43,13.98.
Acknowledgments
AS thanks UGC, New Delhi, for financial assistance (grant no. 2016-2017/PDFWM-2015-17-
UTT-32744). SG thanks UGC, New Delhi, for a Junior Research Fellowship and a Senior
Research Fellowship.
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