Synthesis of cyanamides from isoselenocyanates promoted by recyclable ionic liquid-supported (diacetoxyiodo)benzene

Article abstract of DOI:10.3184/174751915X14447479752475

One-pot synthesis of cyanamides from isoselenocyanates through deselenisation promoted by ionic liquid-supported hypervalent iodine(III) reagent 1-(4-diacetoxyiodobenzyl)-3-methylimidazolium tetrafluoroborate [dibmim BF₄ was developed. This approach provided a simple, mild and environmentally benign way to construct cyanamides in good yields. Moreover, powder Se and dibmim ⁺ BF₄ could be easily recycled. It was the first example of [dibmim] ⁺ [BF₄^- to be used as a deselenising agent.

Full text of DOI:10.3184/174751915X14447479752475

JOURNAL OF CHEMICAL RESEARCH 2015
VOL. 39 NOVEMBER, 631–634
RESEARCH PAPER 631
Synthesis of cyanamides from isoselenocyanates promoted by recyclable
ionic liquid-supported (diacetoxyiodo)benzene
Xue Lia, Yingyi Huanga, Bin Gana, Zhisheng Mib and Yuanyuan Xiea,b*
a Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, P.R. China
b College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P.R. China
One-pot synthesis of cyanamides from isoselenocyanates through deselenisation promoted by ionic liquid-supported hypervalent iodine(III)
reagent 1-(4-diacetoxyiodobenzyl)-3-methylimidazolium tetrafluoroborate ([dibmim]+[BF4]–) was developed. This approach provided a
simple, mild and environmentally benign way to construct cyanamides in good yields. Moreover, powder Se and [dibmim]+[BF4]– could be
easily recycled. It was the first example of [dibmim]+[BF4]– to be used as a deselenising agent.
Keywords: cyanamides, selenoureas, [dibmim]+[BF4]-, deselenisation, recyclable products
Table 1 Optimisation of reaction conditions for the conversion of
Due to their unique structure and reactivity, cyanamides
are widely used as intermediates to prepare biologically
important compounds such as minoxidil,1 tumour inhibitors2,3
and herbicides.4,5 This wide range of applications has created
considerable attention in their synthesis. The standard protocol
for the preparation of cyanamides generally involves the
reaction of cyanogen chloride/bromide with amines or imide
salts.6-8 The most widely used method for the synthesis of
cyanamides involves cyanation of amines with CN+ such as
1-cyanoimidazole,9 cyanogen azide,10 metal cyanide.11 In other
approaches, cyanamides have been obtained from hypervalent
iodine(V) reagents reacting with N,N′-disubstituted
glycylamide12 or (diacetoxyiodo)benzene reacting with
dithiocarbamate salt using aqueous ammonia or triethylamine
as the base,13 meanwhile, iodobenzene is obtained as the
byproduct. Theprocedures mentioned above have suffered from
strong alkaline conditions, expensive reagents and catalysts,
toxic reagents such as cyanogen halide, or high reaction
temperatures.
selenoureas to cyanamides
H
N
H
NH
N
2 oxidant, solvent
temp.
N
Se
1a
2a
Oxidants(1.0 equiv)
(1 equiv)
Entry Solvents
Temp./oC Time/ha Yield/%b
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
CH2Cl2
CH3CN
EtOH
THF
DMF
THF
THF
THF
THF
THF
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
I2
25
25
25
25
25
25
25
25
40
50
Reflux
25
Reflux
25
25
0.5
0.5
0.5
0.5
0.5
5.0
0.5
5.0
0.3
0.3
0.3
3.0
3.0
0.5
0.5
60
70
60
82
50
16
75
0
67
62
55
0c
DIB
–
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
[dibmim]+[BF4]-
We have examined the ionic liquid-supported hypervalent
THF
THF
THF
THF
iodine(III)
reagent
1-(4-diacetoxyiodobenzyl)-3-methyl-
imidazolium tetrafluoroborate ([dibmim]+[BF4]–)14-17 as
a
0c
80d
81e
deselenisating agent to promote the formation of cyanamides
from isoselenocyanates without a base at room temperature.
Moreover, the byproduct ionic liquid-supported iodobenzene
underwent oxidation with peracetic acid to form [dibmim]+[BF4]–,
which realised hypervalent iodine(III) reagent recycling.
THF
a Monitored by TLC.
b Isolated yield.
c Started from phenyl thiourea.
d Started from phenyl thiourea, aqueous ammonia was added as base.
e Aqueous ammonia was added as base.
Results and discussion
Phenyl selenourea 1a,18-22 which was obtained by phenyl
isoselenocyanate23,24 reacting with aqueous ammonia at room
temperature, was selected to optimise the reaction conditions
to form phenyl cyanamide 2a. We investigated the effects of
different solvents, reaction temperatures and oxidants. The
results are summarised in Table 1. THF proved to be the best
solvent, but the results might rely on the solubility and stability
of selenourea (Table 1, entries 1–5). Phenyl selenourea was
transformed to the corresponding phenyl cyanamide in very low
yield with stirring for 5 h using molecular iodine as the oxidant
(Table 1, entry 6). It is possible that the oxidation capacity
of molecular iodine was too weak to enable deselenisation.
Furthermore, [dibmim]+[BF4]- was more efficient in forming
phenyl cyanamide than was DIB (Table 1, entries 4 and 7). No
phenyl cyanamide was generated without using oxidants (Table
1, entry 8). For both phenyl selenourea and phenyl cyanamide
which might have low stability at high temperature, when the
reaction was carried out at 40 oC, 50 oC or reflux, the yield was
not improved but declined (Table 1, entries 9–11). Notably
phenyl cyanamide could not be formed from phenyl thiourea
reacting with [dibmim]+[BF4]- (Table 1, entries 12 and 13).
However, phenyl thiourea could convert to phenyl cyanamide
with the addition of aqueous ammonia as the base (Table 1,
entry 14). However, the addition of aqueous ammonia did not
improve the yield of phenyl cyanamide from phenyl selenourea
(Table 1, entries 4 and 15). So the optimal reaction condition
was when selenourea reacted with [dibmim]+[BF4]- in THF at
room temperature without using any base .
Subsequently, the scope of the reaction substrates was
investigated under the optimised conditions. In a one-pot
procedure, various aromatic selenoureas 1 were obtained by
isoselenocyanates 3 reacting with aqueous ammonia in CH2Cl2
* Correspondent. E-mail: xyycz@zjut.edu.cn

632 JOURNAL OF CHEMICAL RESEARCH 2015
which then further underwent oxidative deselenisation by
[dibmim]+[BF4]- to form corresponding cyanamides 2 in THF
at room temperature. The results are summarised in Table 2.
A variety of cyanamides were obtained in good to excellent
yields ranging from 61 to 92%. The nature of the different
R affected the reaction yields. Electron-withdrawing group
(Table 2, entries 5, 9–11, 14, and 15) substituted compounds
showed higher yields than electron-donating group (Table
2, entries 2–4, 6–8, and 16). When substituents attached to
the ortho position of the phenyl isoselenocyanate (Table 2,
entries 2–5), the reaction yields decreased slightly due to their
steric effect. Hindered and trisubstituted isoselenocyanates
gave corresponding cyanamides in good yields with 65–89%
(Table 2, entries 13–16). Moreover, naphthyl isoselenocyanate
also provided the desired product in 61% yield (Table 2, entry
17). Cyanamides were still obtained in excellent yields using
reproduced isoselenocyanates and [dibmim]+[BF4]- (Table 2,
entries 10 and 13).
filtrate was concentrated under vacuum and then the residue
was dissolved in ethyl acetate and precipitated by adding
petroleum ether. The ionic liquid-supported iodobenzene 7
was obtained by filtering and underwent further oxidation with
peracetic acid to form [dibmim]+[BF4]– 5. Therefore, selenium
powder and ionic liquid-supported hypervalent iodine (III)
could be recycled (Table 2, entries 10, 13), which realised the
goal of being environmentally benign.
Conclusion
In conclusion, a facile and efficient one-pot synthesis of
cyanamides has been developed starting from isoselenocyanates
promoted by ionic liquid-supported hypervalent iodine(III)
reagent [dibmim]+[BF4]-. This is the first example of
[dibmim]+[BF4]– being employed as a deselenising agent.
Fortunately, both [dibmim]+[BF4]– and powder selenium can be
easily recovered and reused to achieve the economic and eco-
friendly synthesis of cyanamides.
A possible mechanism is proposed for the formation of
cyanamides in Scheme 1. First, phenyl selenourea 1a could be
provided by phenyl isoselenocyanate 3a reacting with aqueous
ammonia. Subsequently, 1a tended to transform to its resonant
form 4a which attacked the iodine (III) of [dibmim]+[BF4]- 5 to
give 6a more easily. Then the C–Se bond of 6a was broken to
form intermediate phenyl carbodiimide 9a. At the same time,
selenium powder 8 and ionic liquid-supported iodobenzene 7
were produced. Finally, phenyl carbodiimide 9a was converted
to stable phenyl cyanamide 2a.
Experimental
IR spectra were determined on a Nicolet Avatar-370 spectrometer
in KBr (ν in cm−1). Melting points were measured on a Büchi B-540
capillary melting point apparatus and are uncorrected. Mass spectra
(ESI-MS) were determined on a Thermo Finnigan LCQ-Advantage.
High resolution mass spectra (ESI-HRMS) were determined on an
Agilent 6210 TOF instrument. 1H and 13C NMR spectra were recorded
on Varian 400 spectrometer (chemical shifts in δ ppm) using TMS as
internal standard.
Preparation of cyanamides; general procedure
After the reaction was complete, the precipitate selenium 8
could be easily obtained by filtering, washing with CH2Cl2, and
was then reused for the preparation of isoselenocyanates. The
Phenyl isoselenocyanate 3a (0.182 g, 1 mmol) and aqueous ammonia
(25%, 0.168 g, 1.2 mmol) were added to CH2Cl2 (3 mL) with magnetic
Table 2 One-pot synthesis of cyanamide from isoselenocyanates and [dibmim]+[BF4]-
H
H
[dibmim]+[BF4]-
r.t.,THF
N
aq. NH3
N
NH2
Se
N
R
C
R
R
Se
r.t.,CH2Cl2
N
2
1
3
Entry
1
2
R
Producta
2a
2b
Yield/%b
79
75
(3a) C6H5
(3b) 2-CH3C6H4
3
4
5
(3c) 2-CH3OC6H4
(3d) 2-CH3CH2C6H4
(3e) 2-ClC6H4
2c
2d
2e
73
66
83
6
7
(3f) 3-CH3OC6H4
(3g) 4-CH3OC6H4
2f
2g
78
80
8
9
(3h) 4-CH3CH2OC6H4
(3i) 4-FC6H4
2h
2i
78
89
10
11
12
13
14
15
16
17
(3j) 4-ClC6H4
2j
2k
2l
2m
2n
2o
2p
2q
2r
90 88c
92
73
84 83c
89
87
65
61
(3k) 4-BrC6H4
(3l) 4-CNC6H4
(3m) 2-CH3-3-ClC6H3
(3n) 2,4-ClC6H3
(3o) 3,4-ClC6H3
(3p) 3,5-CH3C6H3
(3q) 1-Naphthyl
(3r)
18
72
H
F
3C
O
N
C
F
3C
S
O
N
S
Se
N
C
a Confirmed by IR, 1H, and 13C NMR.
b Isolated yield based on isoselenocyanates 3.
c Using reproduced isoselenocyanates and [dibmim]+[BF4]-.

JOURNAL OF CHEMICAL RESEARCH 2015 633
H
N
NH2
SeH
NH2
N
N
aq. NH3
Ph
Ph
C
Ph
Se
Se
a
3
a
1
a
4
OAc
NH
N
I
BF4
OAc
-HOAc
NH2
5
7
N
N
N
I
BF4
Ph
Se
I
Ph
Ph
N
N
N
BF4
-HOAc
NH
N
C
NH
2a
OAc
9a
6a
Se
8
Scheme 1 A mechanism for the formation of 3a.
aq. NH3
NH2
NH
N
Ph
Ph
C
3a
Se
1a Se
BF4
OAc
2a
N
NH
I
NH
OAc
5
Ph
N
PhNHCHO,BTC,Et3N
Se
H
H
C
3COOO
8
N
N
I
BF4
7
Scheme 2 Recovery and recycling of selenium powder 8 and ionic liquid-supported iodobenzene 7.
stirring for 30 min at room temperature. Phenyl selenourea 1a was
confirmed by TLC. The reaction mixture was concentrated under
vacuum to remove CH2Cl2, then [dibmim]+[BF4]- 5 (0.504 g, 1 mmol)
and THF (5 mL) were added and stirred at room temperature. Brick-
red selenium powder 8 unfixed out rapidly. The reaction was
complete in 30 min as monitored by TLC, then the selenium powder
was filtered off and washed with CH2Cl2 (20 mL). The recovery rate
of selenium powder was about 97% (0.077 g). The combined filtrate
was concentrated under vacuum and then the residue was dissolved
in ethyl acetate (2 mL) and precipitated by adding petroleum ether
(10 mL). The ionic liquid-supported iodobenzene 7 (0.311 g, 80%
yield) was obtained through filtration. The filtrate was evaporated,
and the residue was purified through column chromatography on
silica gel (petroleum ether /EtOAc = 8:1) to give the pure product
phenylcyanamide 2a (0.093 g, yield 79%) as oil.
1144, 752 cm-1; 1H NMR (400 MHz, CDCl3): δ = 7.22– 7.17 (m, 2H,
ArH), 7.13 (d, J = 7.6 Hz, 1H, ArH),7.01–6.97 (m, 1H, ArH), 6.30 (brs,
1H, NH), 2.23 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3): δ 135.4,
130.8, 127.2, 124.3, 123.4, 115.3, 112.0, 17.2.
(2-Methoxypheny)lcyanamide (2c): Oil (lit.13); IR (KBr): νmax = 3194,
2938, 2852, 2222, 1603, 1514, 1452, 1262, 1220, 1031, 759, 737 cm-1;
1H NMR (400 MHz, CDCl3): δ = 7.16 (dd, J = 1.6 Hz, 7.6 Hz, 1H,
ArH), 7.04–6.94 (m, 2H, ArH), 6.86 (dd, J = 1.6 Hz, 7.6 Hz, 1H, ArH),
6.30 (brs, 1H, NH), 3.87 (s, 3H, OCH3); 13C NMR (100 MHz, CDCl3):
δ 146.2, 126.3, 123.1, 120.9, 114.3, 110.4, 110.3, 55.5.
(2-Ethylphenyl)cyanamide (2d): White solid; m.p. 117–119 oC;
IR (KBr): νmax = 3189, 2970, 2227, 1589, 1509, 1434, 1252, 748 cm-1;
1H NMR (400 MHz, CDCl3): δ 7.24–7.19 (m, 2H, ArH), 7.15 (d,
J = 7.6 Hz, 1H, ArH), 7.05–7.01 (m, 1H, ArH), 6.43 (brs, 1H, NH), 2.55
(q, J = 7.6 Hz, 2H, CH2), 1.25 (t, J = 7.6 Hz, 3H, CH3); 13C NMR (100
MHz, CDCl3): δ 134.8, 130.2, 128.9, 127.2, 123.8, 115.8, 111.9, 23.8,
13.7. MS (ESI): m/z (%) = 147 ([M+H]+, 100). HRMS-ESI: calcd for
C9H10N2Na (M+Na)+ 169.0742; found: 169.0736.
Phenylcyanamide (2a): Oil13; IR (KBr): νmax = 3320, 2924, 2212,
1
1607, 1497, 1257, 752, 691 cm-1; H NMR (400 MHz, CDCl3):
δ = 7.35–7.31 (m, 2H, ArH), 7.08 (t, J = 7.6 Hz, 1H, ArH), 7.01–6.99 (m,
2H, ArH), 5.98 (brs, 1H, NH). 13C NMR (100 MHz, CDCl3): δ 137.2,
129.5, 123.3, 115.2, 111.2. MS (ESI): m/z (%) = 119 ([M+H]+, 100).
HRMS-ESI: calcd for C7H7N2 (M+H)+ 119.0609; found: 119.0604.
(2-Methylphenyl)cyanamide (2b): White solid; m.p. 76–77 oC (lit. 25
76–78 oC); IR (KBr): νmax = 3234, 2964, 2244, 1591, 1500, 1427, 1257,
(2-Chlorophenyl)cyanamide (2e): White solid; m.p. 102–103 oC
o
(lit. 13 101–103 C); IR (KBr): νmax = 3172, 2243, 1597, 1509, 1426,
1296, 1049, 747 cm-1; 1H NMR (400 MHz, CDCl3): δ = 7.37–7.26 (m,
3H, ArH), 7.05–7.01 (m, 1H, ArH), 6.39 (brs, 1H, NH); 13C NMR (100
MHz, CDCl3): δ 134.0, 129.6, 128.2, 124.2, 120.2, 116.0, 109.7.

634 JOURNAL OF CHEMICAL RESEARCH 2015
(3-Methoxyphenyl)cyanamide (2f): Oil (lit.13); IR (KBr): νmax = 3167,
2922, 2221, 1606, 1491, 1287, 1207, 1042, 915, 768 cm-1, 1H NMR (400
MHz, CDCl3): δ = 7.22–7.18 (t, J = 8.0Hz, 1H, ArH), 6.93 (brs, 1H,
NH), 6.61–6.55 (m, 3H, ArH), 3.78 (s, 3H, OCH3); 13C NMR (100
MHz, CDCl3): δ 160.6, 138.3, 130.5, 111.2, 109.1, 107.7, 101.5, 55.4.
(4-Methoxyphenyl)cyanamide (2g): White solid; m.p. 86–87 oC
(lit. 26 86–89 oC); IR (KBr): νmax = 3066, 2936, 2836, 2212, 1604, 1511,
1456, 1252, 1181, 1031, 825 cm-1; 1H NMR (400 MHz, DMSO-d6):
δ = 9.83 (brs, 1H, NH), 6.91 (d, J = 8.8 Hz, 2H, ArH), 6.87 (d, J = 8.8
Hz, 2H, ArH), 3.70 (s, 3H, OCH3); 13C NMR (100 MHz, DMSO-d6):
δ 154.6, 131.3, 115.9, 114.8, 112.4, 55.2.
(1-Naphthyl)cyanamide (2q): White solid; m.p. 134–135 oC
(lit.31 133–134 oC); IR (KBr): νmax = 3183, 3052, 2944, 2234, 1584, 1529,
1479, 1402, 1344, 1258, 786, 759 cm-1; 1H NMR (400 MHz, CDCl3):
δ = 7.88–7.86 (m, 1H, ArH), 7.76–7.74 (m, 1H, ArH), 7.61 (d, J = 8.0
Hz, 1H, ArH), 7.57–7.51 (m, 2H, ArH), 7.45 (t, J = 7.6 Hz, 1H, ArH),
7.38 (d, J = 7.6 Hz, 1H, ArH), 6.78 (brs,1H,NH); 13C NMR (100 MHz,
DMSO-d6): δ 134.0, 133.6, 128.0, 126.3, 125.8, 125.6, 123.0, 122.9,
120.7, 112.4, 111.0.
N-(3-Methyl-4-(4-(trifluoromethylthio)phenoxy)phenyl)cyanamide
(2r): Oil; IR(KBr): νmax = 3288, 2926, 2226, 1611, 1590, 1486, 1284,
1255, 1233, 1205, 1118, 1805, 1011, 857, 832, 755 cm-1; 1H NMR (400
MHz, CDCl3): δ = 7.54 (d, J = 8.8 Hz, 2H, ArH), 6.96–6.94 (m, 2H,
ArH), 6.86–6.82 (m, 3H, ArH), 6.42 (brs, 1H, NH), 2.17 (s, 3H, CH3);
13C NMR (100 MHz, CDCl3): δ 160.4, 148.9, 138.3, 134.0, 132.5, 132.4
(1JCF = 303 Hz), 122.2, 118.3, 117.0, 116.7, 114.3, 111.1, 16.4; MS (ESI):
m/z (%) = 323 ([M-H]-,100); HRMS-ESI: calcd for C15H10F3N2OS (M-
H)-: 323.0466; found: 323.0471.
o
(4-Ethoxyphenyl)cyanamide (2h): White solid; m.p. 84–86 C (lit. 27
87 oC); IR (KBr): νmax=3170, 2979, 2214, 1602, 1511, 1238, 1116, 1047,
823 cm-1;1H NMR (400 MHz, CDCl3):δ = 6.92 (d, J = 8.8 Hz, 2H, ArH),
6.84 (d, J = 8.8 Hz, 2H, ArH), 6.16 (br s, 1H, NH), 3.98 (q, J = 6.8 Hz,
2H, CH2), 1.40 (t, J = 6.8 Hz, 3H, CH3); 13C NMR (100 MHz, CDCl3):
δ 130.8, 130.2, 116.7, 116.2, 115.5, 64.0, 14.8.
(4-(4-Isoselenocyanato-2-methylphenoxy)phenyl)(trifluoromethyl)
sulfane (3r): Oil; IR(KBr): νmax = 2922, 2108, 1601, 1589, 1487, 1280,
(4-Fluorophenyl)cyanamide (2i): White solid; m.p. 122–124 oC;
IR (KBr): νmax = 3177, 2968, 2237, 1616, 1511, 1231, 1097, 819 cm-1;
1H NMR (400 MHz, CDCl3): δ = 7.05–7.01 (m, 2H, ArH), 6.98–6.95
(m, 2H, ArH), 6.60 (brs, 1H, NH); 13C NMR (100 MHz, CDCl3):
1
1258, 1233, 1207, 1120, 1808, 1010, 854, 830, 751 cm-1; H NMR (400
MHz, DMSO-d6): δ 7.59 (d, J = 8.4 Hz, 2H, ArH), 7.22 (d, J = 2.4 Hz,
1H, ArH), 7.12 (dd, J1 = 1.2 Hz, J2 = 8.8Hz, 1H, ArH), 6.91-6.88 (m, 3H,
ArH), 2.22 (s, 3H, CH3); 13C NMR (100 MHz, DMSO): δ 153.5, 148.5,
1
3
2
δ 158.8(d, JCF = 241 Hz), 133.1, 117.2 (d, JCF = 8Hz), 116.3 (d, JCF
=
23Hz), 111.8. MS (ESI): m/z (%) = 135 ([M-H]-, 100). HRMS-ESI:
1
138.2, 134.9, 132.8 ( JCF = 305 Hz), 131.6, 131.2, 121.8, 121.5, 117.8,
calcd for C7H5FN2 (M-H)- 135.0358; found: 135.0355.
116.9, 116.3,16.4; MS (EI): m/z (%) = 390 ([M+H]+,100); HRMS-ESI:
(4-Chlorophenyl)cyanamide (2j): White solid; m.p. 95–97 C (lit. 13
o
calcd for C15H11F3NOSSe (M+H)+: 389.9679; found: 389.9683.
95 oC); IR (KBr): νmax = 3147, 2957, 2233, 1602, 1500, 1254, 1092 cm-1;
1H NMR (400 MHz, CDCl3): δ = 7.28 (d, J = 8.8 Hz, 2H, ArH), 6.94
(d, J = 8.8 Hz, 2H, ArH), 6.89 (brs, 1H, NH); 13C NMR (100 MHz,
CDCl3): δ 135.6, 129.7, 128.9, 116.6, 110.8.
Received 14 August 2015; accepted 29 September 2015
Paper 150344 doi: 10.3184/174751915X14447479752475
Published online: 1 November 2015
(4-Bromophenyl)cyanamide (2k): White solid; m.p. 111–112 oC
(lit.28 110–111 oC); IR (KBr): νmax = 3154, 2959, 2230, 1596, 1494, 1252,
1074, 814 cm-1; 1H NMR (400 MHz, CDCl3): δ = 7.43 (d, J = 8.8 Hz,
2H, ArH), 6.89 (d, J = 8.8 Hz, 2H, ArH), 6.61 (brs, 1H, NH); 13C NMR
(100 MHz, CDCl3): δ 136.3, 132.5, 117.0, 116.1, 111.0.
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2, 795.
IR (KBr): νmax = 3195, 2966, 2228, 1609, 1514, 1407, 1264, 1172, 829;
1H NMR (400 MHz, DMSO-d6): δ = 10.81 (brs, 1H, NH), 7.74 (d,
J = 8.8 Hz, 2H, ArH), 7.04 (d, J = 8.8 Hz, 2H, ArH); 13C NMR (100
MHz, DMSO-d6): δ 142.9, 133.9, 118.5, 115.5, 110.4, 104.4. MS (ESI):
m/z (%) = 142 ([M-H]-, 100). HRMS-ESI: calcd for C8H6N3 (M+H)+
144.0562; found: 144.0556.
5
6
7
(2-Methyl-3-chlorophenyl)cyanamide (2m): White solid; m.p.
135–136 oC; IR (KBr): νmax = 3205, 2926, 2240, 1586, 1491, 1458, 1116,
8
9
1
770 cm-1; H NMR (400 MHz, CDCl3): δ = 7.16–7.11 (m, 3H, ArH),
6.08 (brs, 1H, NH), 2.29 (s, 3H,CH3); 13C NMR (100 MHz, DMSO-d6):
δ 138.0, 134.2, 127.5, 123.2, 122.8, 114.1, 111.9, 13.8. MS (ESI): m/z
(%) = 165 ([M-H]-, 100), 167 ([M-H]-, 100). HRMS-ESI: calcd for
C8H7ClN2Na (M+Na)+ 189.0195; found: 189.0190.
10 M.E. Hermes and F.D. Marsh, J. Org. Chem., 1972, 37, 2969.
11 T.V. Hughes, S.D. Hammond and M.P. Cava, J. Org. Chem., 1998, 63, 401.
12 K.H. Chaudhuri, U.S. Mahajan, D.S. Bhalerao and K.G. Akamanchi, Synlett.,
2007, 2815.
13 G. Harisadhan, Y. Ramesh, R.A. Abdur, K.S. Santosh and K.P. Bhisma,
Tetrahedron Lett., 2009, 50, 2407.
(2,4-Dichlorophenyl)cyanamide (2n): Needle crystal; m.p.
162–163 oC (lit. 29 162–163 oC); IR (KBr): νmax = 3197, 2920, 2238, 1581,
14 W.X. Qian, E. Jin, W.L. Bao and Y.M. Zhang, Angew. Chem. Int. Ed., 2005,
44, 952.
1
1490, 1431, 1390, 1288, 1101, 1051, 867, 847, 810 cm-1; H NMR (400
15 S.T. Handy and M. Okello, J. Org. Chem., 2005, 70, 2874.
16 W.X. Qian and L. Pei, Synlett., 2006, 709.
17 C. Fang, W.X. Qian and W.L. Bao, Synlett., 2008, 2529.
18 G.L. Sommen, A. Linden and H. Heimgartner, Eur. J. Org. Chem., 2005, 3128.
19 D.R. Garud, M. Makimura, H. Ando, H. Ishihara and M. Koketsu, Tetrahedron
Lett., 2007, 48, 7764.
20 D.R. Garud and M. Koketsu, Org. Lett., 2008, 10, 3319.
21 D.R. Garud, Y. Toyoda and M. Koketsu, Tetrahedron Lett., 2009, 50, 3035.
22 G.L. Sommen, A. Linden and H. Heimgartner, Tetrahedron, 2006, 62, 3344.
23 J.G. Fernández-Bolaños, Ó. López, V. Ulgar, I. Maya and J. Fuentes,
Tetrahedron Lett., 2004, 45, 4081.
24 Ó. López, S. Maza and V. Ulgar, Tetrahedron, 2009, 65, 2556.
25 F.F. Wong, Synlett., 2006, 4, 559.
26 N. Jayashree and K.P. Bhisma, Green Chem., 2009, 11, 1503.
27 J. Haginiwa, Yakugaku Zasshi., 1949, 69, 565.
28 K. Sahoo, Adv. Synth. Catal., 2010, 352, 2538.
29 B. Johnson, J. Am. Chem. Soc., 1939, 61, 176.
MHz, DMSO-d6): δ 10.10 (br s,1H,NH), 7.65 (d, J = 2.4 Hz, 1H, ArH),
7.45 (m, 1H, ArH), 7.19 (d, J = 8.8 Hz, 1H, ArH); 13C NMR (100 MHz,
DMSO-d6): δ 134.5, 129.3, 128.4, 126.8, 120.7, 117.8, 111.2.
(3,4-Dichlorophenyl)cyanamide
(2o):
White
solid;
m.p.
o
o
124.5–125.5 C (lit.30 121–124 C); IR (KBr): νmax = 3148, 2359, 2341,
2233, 1599, 1496, 1474, 1290, 1134, 1032 cm-1; H NMR (400 MHz,
1
CDCl3): δ = 7.39 (d, J = 8.8 Hz, 1H, ArH), 7.12 (d, J = 2.8 Hz, 1H,
ArH), 6.87 (dd, J = 2.8 Hz, 8.8 Hz, 1H, ArH), 6.39 (brs, 1H, NH);
13C NMR (100 MHz, DMSO-d6): δ 138.8, 131.8, 131.4, 124.1, 116.4,
115.3, 110.9.
(3,5-Dimethylphenyl)cyanamide (2p).White solid; m.p. 116-117 oC; IR
(KBr): νmax = 3159, 2924, 2228, 1602, 1526, 1458, 1308, 1196, 1033, 929,
832 cm-1; 1H NMR (400 MHz, CDCl3): δ = 6.69 (s, 1H, ArH), 6.62 (s,
2H, ArH), 2.28 (s, 6H, CH3×2); 13C NMR (100 MHz, CDCl3): δ 139.8,
137.3, 125.5, 113.4, 111.9, 21.5. MS (ESI): m/z (%) = 147 ([M+H]+, 100).
HRMS-ESI: calcd for C9H10N2Na (M+Na)+ 169.0742; found: 169.0736.
30 K, Engelbert , DE 1968, 1,261,498; Chem. Abstr. 1968, 69, 35679].
31 S.V. Voitekhovich, Chem. Heterocycl. Com., 2005, 41, 999.