The XRD study of N-chloro-N-methoxy-4-nitrobenzamide revealed the high pyramidality degree of its amide nitrogen atom in O–N–Cl moiety. N-Chloro-N-methoxy-4-nitrobenzamide reacts with AcONa in MeCN selectively forming N-acetoxy-N-methoxy-4-nitrobenzamide, whereas its methanolysis in the presence of AcONa yields N,N' bis(4-nitrobenzoyl)-N,N'-dimethoxyhydrazine

Kostyanovsky, R. G.

Mazepa, A. V.

Shishkin, O. V.

Shtamburg, V. G.

Shtamburg, V. V.

Tsygankov, A. V.

Uspensky, B. V.

Zubatyuk, R. I.

Library of National Technical University "Kharkiv Polytechnic Institute"

Mendeleev Commun., 2012, 22, 164–166
– 164 –© 2012 Mendeleev Communications. All rights reserved.
Mendeleev
Communications
As it was shown by S. A. Glover et al.,2–10 N-X-N-alkoxycarbox-
amides [X = OC(O)R, OAlk, Cl] represent a new unusual family 
of amides, or anomeric amides. The presence of two strongly 
electronegative substituents with lone electron pairs (Lp) should 
effect the pyramidality of the amide nitrogen atom which should 
be sp3 hybridized.2,10 In the O–N–X group of anomeric amides 
the N–X bond should be elongated and destabilized and N–OAlk 
bond should be shortened due to nO(Alk) ® s*N–X anomeric effect 
action.2–9
The high IR n values of C=O group in most of such amides 
was recognized as the argument for their nitrogen pyramidality,2,6 
which was later confirmed by XRD studies.9–15 However, XRD 
evidence for the case of N-chloro-N-alkoxybenzamides was lacking 
because of their lability.
Herein, we have fulfilled XRD study of N-chloro-N-methoxy-
4-nitrobenzamide which was synthesized by the chlorination of 
N-methoxy-4-nitrobenzamide (Scheme 1).‡ In fact, the inves tiga-
The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide†
Vasiliy G. Shtamburg,*a,b Alexander V. Tsygankov,c Oleg V. Shishkin,d Roman I. Zubatyuk,d  
Boris V. Uspensky,b Victor V. Shtamburg,b Alexander V. Mazepae and Remir G. Kostyanovsky*f
a
 Ukrainian State Chemico-Technological University, 49038 Dnepropetrovsk, Ukraine.  
E-mail: stamburg@gmail.com 
b
 National Technical University ‘Kharkov Polytechnical Institute’, 61002 Kharkov, Ukraine.  
E-mail: polytehnik@gmail.com
c
 State Flight Academy of Ukraine, 25005 Kirovograd, Ukraine. E-mail: geminalsystemsn@gmail.com
d
 STC ‘Institute for Single Crystals’, National Academy of Sciences of Ukraine, 61001 Kharkov, Ukraine. 
E-mail: shishkin@xray.isc.kharkov.com
e
 A. V. Bogatsky Physico-Chemical Institute, National Academy of Sciences of Ukraine, 65080 Odessa, 
Ukraine. E-mail: almazepa@rambler.ru
f
 N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow,  
Russian Federation. Fax: +7 499 137 8284; e-mail: kost@center.chph.ras.ru
05.019DOI: 10.1016/j.mencom.2012.
The XRD study of N-chloro-N-methoxy-4-nitrobenzamide revealed the high pyramidality degree of its amide nitrogen atom in O–N–Cl 
moiety. N-Chloro-N-methoxy-4-nitrobenzamide reacts with AcONa in MeCN selectively forming N-acetoxy-N-methoxy-4-nitrobenz-
amide, whereas its methanolysis in the presence of AcONa yields N,N'-bis(4-nitrobenzoyl)-N,N'-dimethoxyhydrazine.
†
 Geminal Systems. Part 62. For the previous communication, see ref. 1.
‡
 N-Methoxy-4-nitrobenzamide 1. 4-Nitrobenzoyl chloride (1.573 g, 
8.925 mmol) was added to the solution of methoxyamine (0.270 g, 
8.925 mmol) and 2,6-dimethylpyridine (0.956 g, 8.925 mmol) in MeCN 
(10 ml) at –22 °C, the reaction mixture was heated to 20 °C within 21 h 
and kept at 20 °C for 5 days, then it was evaporated in vacuo. The residue 
was washed with water (15 ml), dried in vacuo at 1 Torr, yielding 1.491 g 
(85%) of amide 1, yellow-white crystals, mp 176–179 °C (CHCl3). 1H NMR 
(500 MHz, DMSO-d6) d: 3.75 (s, 3 H, OMe), 7.99 (d, 2 H, C2H, C6H, 
3J 10.8 Hz), 8.32 (d, 2 H, C3H, C5H, 3J 10.8 Hz), 12.09 (br. s, 1H, NH). 
Found (%): N, 14.02. Calc. for C8H8N2O4 (%): N, 14.28.
 N-Chloro-N-methoxy-4-nitrobenzamide 2. The solution of ButOCl 
(0.455 g, 4.191 mmol) in CH2Cl2 (2 ml) was added to the mixture of 
N-methoxy-4-nitrobenzamide 1 (0.154 g, 0.785 mmol) and CH2Cl2 (5 ml) 
at –25 °C. The reaction mixture was kept at 5 °C for 2.5 h, then it was 
evaporated in vacuo. The residue was dissolved in CH2Cl2 (2 ml), and 
then hexane (8 ml) was added. After keeping at 5 °C the precipitate thus 
formed was filtered off, dried in vacuo, yielding 0.142 g (78%) of amide 2, 
white crystals, mp 93–95 °C (decomp.). 1H NMR (500 MHz, CDCl3) d: 
3.908 (s, 3 H, OMe), 7.933 (d, 2 H, C2H, C6H, 3J 9.5 Hz), 8.333 (d, 2 H, 
C3H, C5H, 3J 9.5 Hz). MS (FAB): 233 [M + H]+ (7.5), 231 [M + H]+ (22.5), 
197 (100).
MeO
NH
O
Ar
1
ButOCl
MeO
N
O
Ar
2
Cl
MeO
N
O
Ar
3
OAc
AcONa/
MeCN
MeOH
 
/AcONa– Cl
–
– MeOH+
MeO
N
O
Ar
A
Ar = 4-O2NC6H4
MeO
N
O
Ar
4
N
OMe
O
Ar
Scheme 1
 N-Acetoxy-N-methoxy-4-nitrobenzamide 3. The solution of amide 2 
(0.198 g, 0.856 mmol) in MeCN (15 ml) and AcONa (0.246 g, 3.00 mmol) 
was stirred at 18–20 °C for 32 h. Then CH2Cl2 (8 ml) was added, the 
precipitate was filtered off, washed with CH2Cl2 (6 ml). The combined 
filtrate was evaporated in vacuo, the residue was extracted with CH2Cl2 
(8 ml), the extract was evaporated in vacuo, yielding 0.205 g (94%) of 
amide 3, firstly as viscous oil, which then converted into colourless 
crystals, mp 65–67 °C (CH2Cl2–C6H14). 1H NMR (500 MHz, CDCl3) d: 
2.175 (s, 3 H, NOAc), 3.966 (s, 3 H, NOMe), 7.937 (d, 2 H, C2H, C6H, 
3J 9.5 Hz), 8.316 (d, 2 H, C3H, C5H, 3J 9.5 Hz). MS (FAB, H+): 255 
[M + H]+ (2.5), 213 (5.5), 195 [M – AcO]+ (18), 150 (100). MS (FAB, K+): 
293 [M + K]+ (12), 195 [M – AcO]+ (19), 150 (100). Found (%): N, 10.85. 
Calc. for C10H10N2O6 (%): N, 11.02.
 N,N'-Bis(4-nitrobenzoyl)-N,N’-dimethoxyhydrazine 4. The solution 
of N-chloro-N-methoxy-4-nitrobenzamide 2 (0.086 g, 0.373 mmol) in 
THF (2 ml) was added to the solution of AcONa (0.100 g, 1.220 mmol) 
in MeOH (10 ml) at –23 °C, the reaction mixture was heated to 20 °C 
within 24 h, MeOH was evaporated in vacuo, the residue was extracted with 
CH2Cl2 (15 ml). The extract was evaporated in vacuo yielding 0.072 g 
(99%) of the product 4, white crystals, mp 86–88 °C (decomp.). 1H NMR 
(500 MHz, CDCl3) d: 4.001 (s, 6 H, NOMe), 8.233 (d, 4 H, C2H, C6H, 
3J 9.0 Hz), 8.311 (d, 4 H, C3H, C5H, 3J 9.0 Hz). MS (FAB, H+): 391 
[M + H]+ (7), 55 (100). MS (FAB, K+): 429 [M + K]+ (19.5), 192 (100). 
Found (%): N, 14.20. Calc. for C16H14N4O8 (%): N, 14.35.
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Mendeleev Commun., 2012, 22, 164–166
– 165 –
tions done confirmed amide N(1) nitrogen pyramidal configura-
tion (Figure 1). The sum of bond angles centered at this nitrogen 
atom (Sß) is 337.5(3)°, the deviation of N(1) atom from the 
plane of bonded with N(1) atoms (hN) is equal to 0.418(2) Å 
(for N-methoxy-4-nitrobenzamide 1 Sß is 354° as shown by the 
reference XRD study).
Thus, in compound 2 the nitrogen pyramidality degree is lower in 
comparison with that in N-chloro-N-methoxyurea12 [Sß = 329.0(2)°, 
hN = 0.500(1) Å]. Probably this is caused by the bigger degree of 
conjugation of Lp of N(1) atom with aroyl group in 2, than that 
takes place with carbamoyl group in N-chloro-N-methoxyurea. 
This conjugation increases p character of Lp(N1) and shortened 
Cl(1)–N(1) bond to 1.7288(14) Å. In N-chloro-N-methoxyurea 
the N–Cl bond is longer [1.7563(11) Å12], but in substituted 
N-chloro-N-(phenyl)acetamides the N–Cl bond is somewhat 
shorter (1.71–1.72 Å).16 The N–OMe bond lengths in amide 2 
[1.3967(17) Å] and in N-chloro-N-methoxyurea [1.3984(13) Å]12 
are similar to those in N-methoxy-N,N-bis(methoxycarbonyl) imide 
[1.396(1) Å]13 and in compound 1 [1.394(5) Å]. In the latter, the 
amide nitrogen atom has planar configuration as sp2 hybridized 
one. In amide 2 strong pyramidal N(1) atom is sp3 hybridized as 
it was predicted earlier.2 The length of Nsp3–OMe bond may be 
equal to that of Nsp2–OMe bond only if the former bond is addi-
tionally shortened. Evidently this shortening of Nsp3–OMe bond 
in amide 2 is caused by nO(Me) ® s*N–Cl anomeric effect action.
In compound 2 the amide N(1)–C(1) bond is shorter [1.408(2) Å] 
than proper amide N–C bond in N-acyloxy-N-alkoxybenzamides6 
(1.4394–1.4414 Å, Sß = 323.51°, 324.14°) and in N,N-dialkoxy-
benzamides9,10 [1.45 Å in N-ethoxy-N-methoxy-4-nitrobenzamide 
and 1.42 Å in N-methoxy-N-(4-nitrobenzyloxy)benzamide]. In 
methyl N-(4-chlorobenzoyloxy)-N-methoxycarbamate the amide 
N–C bond is longer as well,11 1.423(2) Å (Sß is 334.1°, hN is 
0.426 Å). Shortening amide N–C bond in amide 2 compared with 
N–C bond in N-acyloxy-N-alkoxybenzamides,6 N,N-dialkoxy-
benzamides9 and N-acyloxy-N-alkoxycarbamates11 may resulted 
from decrease in the N(1) nitrogen pyramidality degree. However, 
in amide 1, containing the almost planar amide nitrogen atom, the 
proper N–C bond is substantially shorter [1.319(5) Å] compared 
with the N(1)–C(1) bond of compound 2.
In amide 2 the Lp(N1) is oriented perpendicular to the car-
bonyl group plane [the Lp(N1)–N(1)–C(1)–O(1) torsion angle is 
–100°]. The methyl group has sc-orientation toward Lp(N1) [the 
Lp(N1)–N(1)–O(2)–C(8) torsion angle is 31°], whereas the aryl 
group is slightly turned round to the carbonyl group plane [the 
O(1)–C(1)–C(2)–C(7) torsion angle is –30.4(2)°]. The nitro group is 
situated in the aryl substituent plane [the O(3)–N(2)–C(5)–C(6) 
torsion angle is 3.7(2)°].
As other N-chloro-N-alkoxybenzamides,17 compound 2 reacts 
with AcONa in MeCN selectively yielding N-acetoxy-N-methoxy-
4-nitrobenzamide 3 by nucleophilic substitution at amide nitro gen 
(see Scheme 1). Surprisingly, its methanolysis in the presence of 
AcONa afforded only N,N'-bis(4-nitrobenzoyl)-N,N'-dimethoxy-
hydrazine 4. Apparently, reduction of compound 2 by SET-mech-
anism produces aminyl radical A which then gives dimer 4. In 
the same manner, N-chloro-N-methoxy-N-tert-alkylamines yield 
azoxy compounds by alcoholysis in the presence of Et3N18 and in 
reactions with some amines.19 Analogously, methyl N-chloro-
N-methoxycarbamate yields N,N'-bis(methoxycarbonyl)-N,N'-
dimethoxyhydrazine during methanolysis.20,21 This duality of 
chemical properties of amide 2 towards the nucleophiles is similar 
to that of N-chloro-N-alkoxycarbamates.17,20,21
The structure of N-acetoxy-N-methoxy-4-nitrobenzamide 3§ 
has been investigated by XRD study (Figure 2). The amide 
N(1) atom has large pyramidality degree [Sß = 330.29°, hN = 
= 0.4550(15) Å] which is more compared with that in amide 2, 
but less than that in the known N-acyloxy-N-alkoxybenzamides.6 
Probably, the last decrease in pyramidality degree is caused by 
the action of the 4-nitro group (cf. ref. 6).
The O(1)–N(1) bond [1.3970(18) Å] is shorter than the 
O(5)–N(1) bond [1.4214(16) Å] due to nO(Me) ® s*N–O(Ac) anomeric 
effect action. This O(1)–N(1) bond length is similar to N–OMe 
bond lengths in amide 2, N-acetoxy-N-methoxyurea13 and N-meth-
oxy-N,N-bis(methoxycarbonyl)imide.13 However, in N-benzoyl-
oxy-N-benzyloxybenzamides these differences between lengths 
of N–OC(O)R bond and N–OAlk bond are larger.6 In the case 
of amide 3 the presence of 4-nitrobenzoyl group at N(1) atom 
reduces the action of the nO(Alk) ® s*N–OC(O)R anomeric effect.
The amide N(1)–C(1) bond in 3 is longer [1.4113(19) Å] than 
that bond in compound 2. The O(5)–C(9) bond is sp-oriented 
O(1)
O(2)
O(3)
O(4)
C(1)
C(8)
C(3)
C(2)
C(7)
C(6)
C(5)
C(4)
N(1)
N(2)
Cl(1)
Molecular structure of compound Figure 1 2. Selected bond lengths (Å) and 
bond angles (°): Cl(1)–N(1) 1.7288(14), O(2)–N(1) 1.3967(17), N(1)–C(1) 
1.408(2), O(1)–C(1) 1.2046(19), C(1)–C(2) 1.490(2); O(2)–N(1)–C(1) 
112.76(12), O(2)–N(1)–Cl(1) 110.84(10), C(1)–N(1)–Cl(1) 113.89(10).
O(3)
O(2)
O(5)
O(6)
O(1)C(3)
C(8)
C(9)
C(10)
C(2)
C(1)
C(4)
O(4)
C(5)
C(6)
C(7)
N(2)
N(1)
Molecular structure of compound Figure 2 3. Selected bond lengths (Å) and 
bond angles (°): O(1)–N(1) 1.3970(18), O(5)–N(1) 1.4214(16), O(2)–C(1) 
1.2035(18), N(1)–C(1) 1.4113(19), O(6)–C(9) 1.1863(19), C(1)–C(2) 1.493(2); 
O(1)–N(1)–O(5) 107.99(11), O(1)–N(1)–C(1) 112.04(13), C(1)–N(1)–O(5) 
110.26(11).
§
 Crystal data for 1: crystals were grown from CH2Cl2 at –20 °C, 
C8H8N2O4, monoclinic, space group Pc, a = 3.8578(5), b = 11.8168(16) 
and c = 9.6848(12) Å, b = 100.297(11)°, V = 434.38(9) Å3, F(000) = 204, 
dcalc = 1.500 g cm–3, Z = 2, m = 0.123 mm–1, M = 196.16.
 Crystal data for 2: crystals were grown from CH2Cl2 at –20 °C, 
C8H7N2O4Cl, triclinic, space group P1
–
, a = 6.7596(4), b = 7.8452(6) and 
c = 9.6412(6) Å, a = 72.614(6)°, b = 84.737(5)°, g = 73.358(6)°, V = 
= 467.47(5) Å3, F(000) = 236, dcalc = 1.638 g cm–3, Z = 4, m = 0.404 mm–1, 
M = 230.61. 
 Crystal data for 3: crystals were grown from CH2Cl2–C6H14 at –20 °C, 
C10H10N2O6, triclinic, space group P1
–
, a = 6.2863(4), b = 8.7528(7) and 
c = 11.5095(8) Å, a = 68.848(7)°, b = 84.283(6)°, g = 75.474(6)°, V = 
= 571.71(7) Å3, F(000) = 264, dcalc = 1.477 g cm–3, Z = 2, m = 0.124 mm–1, 
M = 254.20.
 Data were measured using an Xcalibur 3 diffractometer [T = 100 K (1 
and 2), 180 K (3), graphite-monochromated MoKa radiation, 2q/q scan, 
2qmax = 58.04° (1), 65.4° (2), 57.72° (3)]. The structures were solved by 
direct method using the SHELXTL PLUS program package.22 Refine-
ment against F2 in an anisotropic approximation (the hydrogen atoms 
isotropic in the riding model) by a full matrix least-squares method for 
1195 reflections was carried out to wR2 = 0.106 [R1 = 0.054 for 969 reflec-
tions with F > 4s(F), S=1.06] for 1, for 3069 reflections was carried out 
to wR2 = 0.112 [R1 = 0.042 for 2597 reflections with F > 4s(F), S = 1.08] 
for 2, and for 2588 reflections was carried out to wR2 = 0.095 [R1 = 0.045 
for 1713 reflections with F > 4s(F), S = 0.99] for 3. 
 CCDC 857730–857732 contain the supplementary crystallographic data 
for this paper. These data can be obtained free of charge from The Cambridge 
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. 
For details, see ‘Notice to Authors’, Mendeleev Commun., Issue 1, 2012.
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Mendeleev Commun., 2012, 22, 164–166
– 166 –
towards Lp(N1) [the Lp(N1)–N(1)–O(5)–C(9) torsion angle is 
–2°], whereas the C(9)–O(6) carbonyl has sp-orientation towards 
N(1)–O(5) bond [the O(6)–C(9)–O(5)–N(1) torsion angle is 
–3.4(4)°]. As in compound 2, the O(1)–C(8) bond is sp-oriented 
towards Lp(N1) [the Lp(N1)–N(1)–O(1)–C(8) torsion angle is 
26°]. The C(1)=O(2) carbonyl group has perpendicular orienta-
tion towards Lp(N1) [the Lp(N1)–N(1)–C(1)–O(2) torsion angle 
is –100°]. The aryl group is some turned round to the C(1)=O(2) 
carbonyl group [the O(2)–C(1)–C(2)–C(7) torsion angle is 
–41.7(2)°].
To sum up, XRD study of a representative of N-chloro-N-alk oxy-
benzamide confirmed the high degree of pyramidality of its amide 
nitrogen atom. The influence of electron-withdrawing 4-nitro 
substituent in benzoyl group of N-chloro-N-alkoxybenzamides 
and N-acyloxy-N-alkoxybenzamides on their structure parameters 
and chemical properties has been demonstrated.
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The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide

Electronic National Technical University &quot;Kharkiv Polytechnic Institute&quot; Institutional Repository (eNTUKhPIIR)

Mendeleev Commun., 2012, 22, 164–166– 164 –© 2012 Mendeleev Communications. All rights reserved.MendeleevCommunicationsAs it was shown by S. A. Glover et al.,2–10 N-X-N-alkoxycarbox-amides [X = OC(O)R, OAlk, Cl] represent a new unusual family of amides, or anomeric amides. The presence of two strongly electronegative substituents with lone electron pairs (Lp) should effect the pyramidality of the amide nitrogen atom which should be sp3 hybridized.2,10 In the O–N–X group of anomeric amides the N–X bond should be elongated and destabilized and N–OAlk bond should be shortened due to nO(Alk) ® s*N–X anomeric effect action.2–9The high IR n values of C=O group in most of such amides was recognized as the argument for their nitrogen pyramidality,2,6 which was later confirmed by XRD studies.9–15 However, XRD evidence for the case of N-chloro-N-alkoxybenzamides was lacking because of their lability.Herein, we have fulfilled XRD study of N-chloro-N-methoxy-4-nitrobenzamide which was synthesized by the chlorination of N-methoxy-4-nitrobenzamide (Scheme 1).‡ In fact, the inves tiga-The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide†Vasiliy G. Shtamburg,*a,b Alexander V. Tsygankov,c Oleg V. Shishkin,d Roman I. Zubatyuk,d  Boris V. Uspensky,b Victor V. Shtamburg,b Alexander V. Mazepae and Remir G. Kostyanovsky*fa Ukrainian State Chemico-Technological University, 49038 Dnepropetrovsk, Ukraine.  E-mail: stamburg@gmail.com b National Technical University ‘Kharkov Polytechnical Institute’, 61002 Kharkov, Ukraine.  E-mail: polytehnik@gmail.comc State Flight Academy of Ukraine, 25005 Kirovograd, Ukraine. E-mail: geminalsystemsn@gmail.comd STC ‘Institute for Single Crystals’, National Academy of Sciences of Ukraine, 61001 Kharkov, Ukraine. E-mail: shishkin@xray.isc.kharkov.come A. V. Bogatsky Physico-Chemical Institute, National Academy of Sciences of Ukraine, 65080 Odessa, Ukraine. E-mail: almazepa@rambler.ruf N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow,  Russian Federation. Fax: +7 499 137 8284; e-mail: kost@center.chph.ras.ru05.019DOI: 10.1016/j.mencom.2012.The XRD study of N-chloro-N-methoxy-4-nitrobenzamide revealed the high pyramidality degree of its amide nitrogen atom in O–N–Cl moiety. N-Chloro-N-methoxy-4-nitrobenzamide reacts with AcONa in MeCN selectively forming N-acetoxy-N-methoxy-4-nitrobenz-amide, whereas its methanolysis in the presence of AcONa yields N,N'-bis(4-nitrobenzoyl)-N,N'-dimethoxyhydrazine.† Geminal Systems. Part 62. For the previous communication, see ref. 1.‡ N-Methoxy-4-nitrobenzamide 1. 4-Nitrobenzoyl chloride (1.573 g, 8.925 mmol) was added to the solution of methoxyamine (0.270 g, 8.925 mmol) and 2,6-dimethylpyridine (0.956 g, 8.925 mmol) in MeCN (10 ml) at –22 °C, the reaction mixture was heated to 20 °C within 21 h and kept at 20 °C for 5 days, then it was evaporated in vacuo. The residue was washed with water (15 ml), dried in vacuo at 1 Torr, yielding 1.491 g (85%) of amide 1, yellow-white crystals, mp 176–179 °C (CHCl3). 1H NMR (500 MHz, DMSO-d6) d: 3.75 (s, 3 H, OMe), 7.99 (d, 2 H, C2H, C6H, 3J 10.8 Hz), 8.32 (d, 2 H, C3H, C5H, 3J 10.8 Hz), 12.09 (br. s, 1H, NH). Found (%): N, 14.02. Calc. for C8H8N2O4 (%): N, 14.28. N-Chloro-N-methoxy-4-nitrobenzamide 2. The solution of ButOCl (0.455 g, 4.191 mmol) in CH2Cl2 (2 ml) was added to the mixture of N-methoxy-4-nitrobenzamide 1 (0.154 g, 0.785 mmol) and CH2Cl2 (5 ml) at –25 °C. The reaction mixture was kept at 5 °C for 2.5 h, then it was evaporated in vacuo. The residue was dissolved in CH2Cl2 (2 ml), and then hexane (8 ml) was added. After keeping at 5 °C the precipitate thus formed was filtered off, dried in vacuo, yielding 0.142 g (78%) of amide 2, white crystals, mp 93–95 °C (decomp.). 1H NMR (500 MHz, CDCl3) d: 3.908 (s, 3 H, OMe), 7.933 (d, 2 H, C2H, C6H, 3J 9.5 Hz), 8.333 (d, 2 H, C3H, C5H, 3J 9.5 Hz). MS (FAB): 233 [M + H]+ (7.5), 231 [M + H]+ (22.5), 197 (100).MeONHOAr1ButOClMeONOAr2ClMeONOAr3OAcAcONa/MeCNMeOH /AcONa– Cl–– MeOH+MeONOArAAr = 4-O2NC6H4MeONOAr4NOMeOArScheme 1 N-Acetoxy-N-methoxy-4-nitrobenzamide 3. The solution of amide 2 (0.198 g, 0.856 mmol) in MeCN (15 ml) and AcONa (0.246 g, 3.00 mmol) was stirred at 18–20 °C for 32 h. Then CH2Cl2 (8 ml) was added, the precipitate was filtered off, washed with CH2Cl2 (6 ml). The combined filtrate was evaporated in vacuo, the residue was extracted with CH2Cl2 (8 ml), the extract was evaporated in vacuo, yielding 0.205 g (94%) of amide 3, firstly as viscous oil, which then converted into colourless crystals, mp 65–67 °C (CH2Cl2–C6H14). 1H NMR (500 MHz, CDCl3) d: 2.175 (s, 3 H, NOAc), 3.966 (s, 3 H, NOMe), 7.937 (d, 2 H, C2H, C6H, 3J 9.5 Hz), 8.316 (d, 2 H, C3H, C5H, 3J 9.5 Hz). MS (FAB, H+): 255 [M + H]+ (2.5), 213 (5.5), 195 [M – AcO]+ (18), 150 (100). MS (FAB, K+): 293 [M + K]+ (12), 195 [M – AcO]+ (19), 150 (100). Found (%): N, 10.85. Calc. for C10H10N2O6 (%): N, 11.02. N,N'-Bis(4-nitrobenzoyl)-N,N’-dimethoxyhydrazine 4. The solution of N-chloro-N-methoxy-4-nitrobenzamide 2 (0.086 g, 0.373 mmol) in THF (2 ml) was added to the solution of AcONa (0.100 g, 1.220 mmol) in MeOH (10 ml) at –23 °C, the reaction mixture was heated to 20 °C within 24 h, MeOH was evaporated in vacuo, the residue was extracted with CH2Cl2 (15 ml). The extract was evaporated in vacuo yielding 0.072 g (99%) of the product 4, white crystals, mp 86–88 °C (decomp.). 1H NMR (500 MHz, CDCl3) d: 4.001 (s, 6 H, NOMe), 8.233 (d, 4 H, C2H, C6H, 3J 9.0 Hz), 8.311 (d, 4 H, C3H, C5H, 3J 9.0 Hz). MS (FAB, H+): 391 [M + H]+ (7), 55 (100). MS (FAB, K+): 429 [M + K]+ (19.5), 192 (100). Found (%): N, 14.20. Calc. for C16H14N4O8 (%): N, 14.35.Authr’s persoal copyMendeleev Commun., 2012, 22, 164–166– 165 –tions done confirmed amide N(1) nitrogen pyramidal configura-tion (Figure 1). The sum of bond angles centered at this nitrogen atom (Sß) is 337.5(3)°, the deviation of N(1) atom from the plane of bonded with N(1) atoms (hN) is equal to 0.418(2) Å (for N-methoxy-4-nitrobenzamide 1 Sß is 354° as shown by the reference XRD study).Thus, in compound 2 the nitrogen pyramidality degree is lower in comparison with that in N-chloro-N-methoxyurea12 [Sß = 329.0(2)°, hN = 0.500(1) Å]. Probably this is caused by the bigger degree of conjugation of Lp of N(1) atom with aroyl group in 2, than that takes place with carbamoyl group in N-chloro-N-methoxyurea. This conjugation increases p character of Lp(N1) and shortened Cl(1)–N(1) bond to 1.7288(14) Å. In N-chloro-N-methoxyurea the N–Cl bond is longer [1.7563(11) Å12], but in substituted N-chloro-N-(phenyl)acetamides the N–Cl bond is somewhat shorter (1.71–1.72 Å).16 The N–OMe bond lengths in amide 2 [1.3967(17) Å] and in N-chloro-N-methoxyurea [1.3984(13) Å]12 are similar to those in N-methoxy-N,N-bis(methoxycarbonyl) imide [1.396(1) Å]13 and in compound 1 [1.394(5) Å]. In the latter, the amide nitrogen atom has planar configuration as sp2 hybridized one. In amide 2 strong pyramidal N(1) atom is sp3 hybridized as it was predicted earlier.2 The length of Nsp3–OMe bond may be equal to that of Nsp2–OMe bond only if the former bond is addi-tionally shortened. Evidently this shortening of Nsp3–OMe bond in amide 2 is caused by nO(Me) ® s*N–Cl anomeric effect action.In compound 2 the amide N(1)–C(1) bond is shorter [1.408(2) Å] than proper amide N–C bond in N-acyloxy-N-alkoxybenzamides6 (1.4394–1.4414 Å, Sß = 323.51°, 324.14°) and in N,N-dialkoxy-benzamides9,10 [1.45 Å in N-ethoxy-N-methoxy-4-nitrobenzamide and 1.42 Å in N-methoxy-N-(4-nitrobenzyloxy)benzamide]. In methyl N-(4-chlorobenzoyloxy)-N-methoxycarbamate the amide N–C bond is longer as well,11 1.423(2) Å (Sß is 334.1°, hN is 0.426 Å). Shortening amide N–C bond in amide 2 compared with N–C bond in N-acyloxy-N-alkoxybenzamides,6 N,N-dialkoxy-benzamides9 and N-acyloxy-N-alkoxycarbamates11 may resulted from decrease in the N(1) nitrogen pyramidality degree. However, in amide 1, containing the almost planar amide nitrogen atom, the proper N–C bond is substantially shorter [1.319(5) Å] compared with the N(1)–C(1) bond of compound 2.In amide 2 the Lp(N1) is oriented perpendicular to the car-bonyl group plane [the Lp(N1)–N(1)–C(1)–O(1) torsion angle is –100°]. The methyl group has sc-orientation toward Lp(N1) [the Lp(N1)–N(1)–O(2)–C(8) torsion angle is 31°], whereas the aryl group is slightly turned round to the carbonyl group plane [the O(1)–C(1)–C(2)–C(7) torsion angle is –30.4(2)°]. The nitro group is situated in the aryl substituent plane [the O(3)–N(2)–C(5)–C(6) torsion angle is 3.7(2)°].As other N-chloro-N-alkoxybenzamides,17 compound 2 reacts with AcONa in MeCN selectively yielding N-acetoxy-N-methoxy-4-nitrobenzamide 3 by nucleophilic substitution at amide nitro gen (see Scheme 1). Surprisingly, its methanolysis in the presence of AcONa afforded only N,N'-bis(4-nitrobenzoyl)-N,N'-dimethoxy-hydrazine 4. Apparently, reduction of compound 2 by SET-mech-anism produces aminyl radical A which then gives dimer 4. In the same manner, N-chloro-N-methoxy-N-tert-alkylamines yield azoxy compounds by alcoholysis in the presence of Et3N18 and in reactions with some amines.19 Analogously, methyl N-chloro-N-methoxycarbamate yields N,N'-bis(methoxycarbonyl)-N,N'-dimethoxyhydrazine during methanolysis.20,21 This duality of chemical properties of amide 2 towards the nucleophiles is similar to that of N-chloro-N-alkoxycarbamates.17,20,21The structure of N-acetoxy-N-methoxy-4-nitrobenzamide 3§ has been investigated by XRD study (Figure 2). The amide N(1) atom has large pyramidality degree [Sß = 330.29°, hN = = 0.4550(15) Å] which is more compared with that in amide 2, but less than that in the known N-acyloxy-N-alkoxybenzamides.6 Probably, the last decrease in pyramidality degree is caused by the action of the 4-nitro group (cf. ref. 6).The O(1)–N(1) bond [1.3970(18) Å] is shorter than the O(5)–N(1) bond [1.4214(16) Å] due to nO(Me) ® s*N–O(Ac) anomeric effect action. This O(1)–N(1) bond length is similar to N–OMe bond lengths in amide 2, N-acetoxy-N-methoxyurea13 and N-meth-oxy-N,N-bis(methoxycarbonyl)imide.13 However, in N-benzoyl-oxy-N-benzyloxybenzamides these differences between lengths of N–OC(O)R bond and N–OAlk bond are larger.6 In the case of amide 3 the presence of 4-nitrobenzoyl group at N(1) atom reduces the action of the nO(Alk) ® s*N–OC(O)R anomeric effect.The amide N(1)–C(1) bond in 3 is longer [1.4113(19) Å] than that bond in compound 2. The O(5)–C(9) bond is sp-oriented O(1)O(2)O(3)O(4)C(1)C(8)C(3)C(2)C(7)C(6)C(5)C(4)N(1)N(2)Cl(1)Molecular structure of compound Figure 1 2. Selected bond lengths (Å) and bond angles (°): Cl(1)–N(1) 1.7288(14), O(2)–N(1) 1.3967(17), N(1)–C(1) 1.408(2), O(1)–C(1) 1.2046(19), C(1)–C(2) 1.490(2); O(2)–N(1)–C(1) 112.76(12), O(2)–N(1)–Cl(1) 110.84(10), C(1)–N(1)–Cl(1) 113.89(10).O(3)O(2)O(5)O(6)O(1)C(3)C(8)C(9)C(10)C(2)C(1)C(4)O(4)C(5)C(6)C(7)N(2)N(1)Molecular structure of compound Figure 2 3. Selected bond lengths (Å) and bond angles (°): O(1)–N(1) 1.3970(18), O(5)–N(1) 1.4214(16), O(2)–C(1) 1.2035(18), N(1)–C(1) 1.4113(19), O(6)–C(9) 1.1863(19), C(1)–C(2) 1.493(2); O(1)–N(1)–O(5) 107.99(11), O(1)–N(1)–C(1) 112.04(13), C(1)–N(1)–O(5) 110.26(11).§ Crystal data for 1: crystals were grown from CH2Cl2 at –20 °C, C8H8N2O4, monoclinic, space group Pc, a = 3.8578(5), b = 11.8168(16) and c = 9.6848(12) Å, b = 100.297(11)°, V = 434.38(9) Å3, F(000) = 204, dcalc = 1.500 g cm–3, Z = 2, m = 0.123 mm–1, M = 196.16. Crystal data for 2: crystals were grown from CH2Cl2 at –20 °C, C8H7N2O4Cl, triclinic, space group P1–, a = 6.7596(4), b = 7.8452(6) and c = 9.6412(6) Å, a = 72.614(6)°, b = 84.737(5)°, g = 73.358(6)°, V = = 467.47(5) Å3, F(000) = 236, dcalc = 1.638 g cm–3, Z = 4, m = 0.404 mm–1, M = 230.61.  Crystal data for 3: crystals were grown from CH2Cl2–C6H14 at –20 °C, C10H10N2O6, triclinic, space group P1–, a = 6.2863(4), b = 8.7528(7) and c = 11.5095(8) Å, a = 68.848(7)°, b = 84.283(6)°, g = 75.474(6)°, V = = 571.71(7) Å3, F(000) = 264, dcalc = 1.477 g cm–3, Z = 2, m = 0.124 mm–1, M = 254.20. Data were measured using an Xcalibur 3 diffractometer [T = 100 K (1 and 2), 180 K (3), graphite-monochromated MoKa radiation, 2q/q scan, 2qmax = 58.04° (1), 65.4° (2), 57.72° (3)]. The structures were solved by direct method using the SHELXTL PLUS program package.22 Refine-ment against F2 in an anisotropic approximation (the hydrogen atoms isotropic in the riding model) by a full matrix least-squares method for 1195 reflections was carried out to wR2 = 0.106 [R1 = 0.054 for 969 reflec-tions with F > 4s(F), S=1.06] for 1, for 3069 reflections was carried out to wR2 = 0.112 [R1 = 0.042 for 2597 reflections with F > 4s(F), S = 1.08] for 2, and for 2588 reflections was carried out to wR2 = 0.095 [R1 = 0.045 for 1713 reflections with F > 4s(F), S = 0.99] for 3.  CCDC 857730–857732 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. For details, see ‘Notice to Authors’, Mendeleev Commun., Issue 1, 2012.Author’s persal copyMendeleev Commun., 2012, 22, 164–166– 166 –towards Lp(N1) [the Lp(N1)–N(1)–O(5)–C(9) torsion angle is –2°], whereas the C(9)–O(6) carbonyl has sp-orientation towards N(1)–O(5) bond [the O(6)–C(9)–O(5)–N(1) torsion angle is –3.4(4)°]. As in compound 2, the O(1)–C(8) bond is sp-oriented towards Lp(N1) [the Lp(N1)–N(1)–O(1)–C(8) torsion angle is 26°]. The C(1)=O(2) carbonyl group has perpendicular orienta-tion towards Lp(N1) [the Lp(N1)–N(1)–C(1)–O(2) torsion angle is –100°]. The aryl group is some turned round to the C(1)=O(2) carbonyl group [the O(2)–C(1)–C(2)–C(7) torsion angle is –41.7(2)°].To sum up, XRD study of a representative of N-chloro-N-alk oxy-benzamide confirmed the high degree of pyramidality of its amide nitrogen atom. The influence of electron-withdrawing 4-nitro substituent in benzoyl group of N-chloro-N-alkoxybenzamides and N-acyloxy-N-alkoxybenzamides on their structure parameters and chemical properties has been demonstrated.ReferencesV. G. Shtamburg, A. V. Tsygankov, O. V. Shishkin, R. I. Zubatyuk, V. V. 1 Shtamburg, M. V. Gerasimenko, A. V. Mazepa and R. G. Kostyanovsky, Mendeleev Commun., 2012, 22, 92.S. A. Glover, 2 Tetrahedron, 1998, 54, 7229.R. G. Gerdes, S. A. Glover, J. F. ten Have and C. A. Rowbottom, 3 Tetrahedron Lett., 1989, 30, 2649.A. Rauk and S. A. Glover, 4 J. Org. Chem., 1996, 61, 2337.S. A. Glover and A. Rauk, 5 J. Org. Chem., 1999, 64, 2340.A.-M. E. Gillson, S. A. Glover, D. J. Tucker and P. Turner, 6 Org. Biomol. Chem., 2003, 1, 3430.S. A. Glover, A. Rauk, J. M. Buccigross, J. J. Campbell, G. P. Hammond, 7 G. Mo, L. E. Andrews and A.-M. E. Gillson, Can. J. Chem., 2005, 83, 1492.K. L. Cavanagh, S. A. Glover, H. L. Price and R. R. Schumacher, 8 Aust. J. Chem., 2009, 62, 700.K. M. Digianantonio, S. A. Glover, J. P. Johns and A. A. Rosser, 9 Biomol. Chem., 2011, 9, 4116.S. A. Glover, J. M. White, A. A. Rosser and K. M. Digianantonio, 10 J. Org. Chem., 2011, 76, 9757.O. V. Shishkin, R. I. Zubatyuk, V. G. Shtamburg, A. V. Tsygankov, E. A. 11 Klots, A. V. Mazepa and R. G. Kostyanovsky, Mendeleev Commun., 2006, 222.V. G. Shtamburg, O. V. Shishkin, R. I. Zubatyuk, S. V. Kravchenko, A. V. 12 Tsygankov, A. V. Mazepa, E. A. Klots and R. G. Kostyanovsky, Mendeleev Commun., 2006, 323.O. V. Shishkin, V. G. Shtamburg, R. I. Zubatyuk, D. A. Olefir, A. V. 13 Tsygankov, A. V. Prosyanik, A. V. Mazepa and R. G. Kostyanovsky, Chirality, 2009, 21, 642.V. G. Shtamburg, O. V. Shishkin, R. I. Zubatyuk, S. V. Kravchenko, A. V. 14 Tsygankov, V. V. Shtamburg, V. B. Distanov and R. G. Kostyanovsky, Mendeleev Commun., 2007, 17, 178.V. G. Shtamburg, A. V. Tsygankov, M. V. Gerasimenko, O. V. Shishkin, 15 R. I. Zubatyuk, A. V. Mazepa and R. G. Kostyanovsky, Mendeleev Commun., 2011, 21, 50.S.-Q. Dou, B. T. Gowda, H. Paulus and A. Weiss, 16 Z. Naturforsch., A: Phys. Sci., 1994, 49, 1136.V. G. Shtamburg, E. A. Klots, A. P. Pleshkova, V. I. Avramenko, S. P. 17 Ivonin, A. V. Tsygankov and R. G. Kostyanovsky, Izv. Akad. Nauk, Ser. Khim., 2003, 2132 (Russ. Chem. Bull., Int. Ed., 2003, 52, 2251).R. G. Kostyanovsky, V. F. Rudchenko, V. G. Shtamburg, I. I. Chervin and 18 Sh. S. Nasibov, Tetrahedron, 1981, 37, 4245.V. G. Shtamburg, V. F. Rudchenko, Sh. S. Nasibov, I. I. Chervin and 19 R. G. Kostyanovsky, Izv. Akad. Nauk SSSR, Ser. Khim., 1981, 2327 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1981, 30, 1914).V. G. Shtamburg, V. F. Rudchenko, Sh. S. Nasibov, I. I. Chervin and 20 R. G. Kostyanovsky, Izv. Akad. Nauk SSSR, Ser. Khim., 1981, 449 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1981, 30, 423).V. G. Shtamburg, V. M. Grinev, E. A. Klots and A. V. Tsygankov, 21 Visnyk Dnipropetrovsk. Univ., Ser. Khimiya, 2005, 11, no. 7, 104 (in Russian).G. M. Sheldrick, 22 Acta Crystallogr., 2008, A64, 112.16th December 2011; Com. 11/3850Received: Author’s personal cpy

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The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide

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The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide

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