Structural study of the acylation products of persubstituted para-nitrosophenols

Article abstract of DOI:10.1016/j.molstruc.2014.01.066

Acylation of potassium 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4- nitrosophenolate with acetic anhydride and benzoyl chloride gave previously unknown 10 derived acyl compounds. ¹H NMR spectroscopy and X-ray diffraction data have been used to show that the oxygen atom of the nitroso group undergoes acylation to form the quinoid products. X-ray powder crystal structure analysis of 1-acetoxymino-3,5-di(methoxycarbonyl)-2,6-dimethyl-1,4- benzoquinone, 1-acetoxymino-3,5-di(ethoxycarbonyl)-2,6-dimethyl-1,4-benzoquinone and 1-benzoyloxymino-3,5-di(propoxycarbonyl)-2,6-dimethyl-1,4-benzoquinon revealed a planar structure of the molecules with quinoid ring as the central moiety. Alkyloxycarbonyl groups rotate in the range 94-101 relative to the plane of the molecule. Typical hydrogen bonds are absent. Molecules fill the unit cell following the closest packing principle in the form of the columns. The ¹H NMR spectroscopic data indicates that the direction of acylation and type of structure for the other members of the series of the studied compounds are the same.

Full text of DOI:10.1016/j.molstruc.2014.01.066

Journal of Molecular Structure 1063 (2014) 341–350
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Structural study of the acylation products of persubstituted
para-nitrosophenols
D.Y. Leshok a, N.A. Fedorova b, D.G. Slaschinin b, M.S. Tovbis b, S.D. Kirik a,
⇑
a Siberian Federal University, Svobodni av., 79, 660041 Krasnoyarsk, Russia
b Siberian State Technological University, Mira av., 82, 660049 Krasnoyarsk, Russia
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
ꢀ
Ten new acyl derivatives of persubstituted para-nitrosophenols were synthesized.
The oxygen atom of nitroso group is subjected to acylation.
Quinonoid structure was proved for all products by NMR and X-ray diffraction.
The acylation products crystallize in molecular structure with stacking columns.
a r t i c l e i n f o
a b s t r a c t
Article history:
Acylation of potassium 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4-nitrosophenolate with acetic anhydride
and benzoyl chloride gave previously unknown 10 derived acyl compounds. 1H NMR spectroscopy and
X-ray diffraction data have been used to show that the oxygen atom of the nitroso group undergoes
acylation to form the quinoid products. X-ray powder crystal structure analysis of 1-acetoxymino-3,5-
di(methoxycarbonyl)-2,6-dimethyl-1,4-benzoquinone, 1-acetoxymino-3,5-di(ethoxycarbonyl)-2,6-dimethyl-
1,4-benzoquinone and 1-benzoyloxymino-3,5-di(propoxycarbonyl)-2,6-dimethyl-1,4-benzoquinon revealed
a planar structure of the molecules with quinoid ring as the central moiety. Alkyloxycarbonyl groups
rotate in the range 94–101° relative to the plane of the molecule. Typical hydrogen bonds are absent.
Molecules fill the unit cell following the closest packing principle in the form of the columns. The
1H NMR spectroscopic data indicates that the direction of acylation and type of structure for the other
members of the series of the studied compounds are the same.
Received 2 December 2013
Received in revised form 27 January 2014
Accepted 27 January 2014
Available online 2 February 2014
Keywords:
Persubstituted nitrosophenols
Quinonemonooximes
Acylation
X-ray powder diffraction crystal structure
analysis
1H NMR analysis
Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction
study of their reactivity. For conventional nitrosophenols, exist-
ing in two tautomeric forms as p-nitrosophenol and p-ben-
There are known a number of persubstituted nitrosophenols
existing as salts in monomeric nitrosoform [1]. Hydrogenation of
persubstituted nitrosophenols gives corresponding para-amino-
phenols [2]. Their some derivatives have been used in the pharma-
ceutical industry as anti-arrhythmic drugs [3]. Despite the
practical importance of these para-nitrosophenols, their chemical
properties are poorly understood. It is only known that they dimer-
ize in neutral and mildly acidic medium [4] and their oxidation by
hydrogen peroxide in alkaline medium leads to the formation of
nitrophenols [5]. Recently, on the example of a structure of the
product of alkylation it have been shown that alkylation brought
the alkylesters of para-benzoquinonemonooximes [6]. The
acylation of persubstituted nitrosophenols is interesting to further
zoquinonemonooxime (PQMO), the acylation may proceed both
onto the hydroxyl and onto the oxime group depending on the con-
ditions. For example, p-nitrosophenol in the reaction with benzoyl
chloride in dioxane gives the p-nitrosophenylbenzoat [7,8]. The
reaction of the potassium salt of p-nitrosophenol with acetic anhy-
dride in acetonitril in the presence of crown ether (18-crown-6)
proceeds similarly, giving p-nitrosophenylacetate [9]. At the same
time, the p-benzoquinonemonooxime acetate was obtained by ac-
tion of acetic anhydride on PQMO or acetyl chloride on the silver
salt of PQMO [10]. The same result was obtained at the acylation
of the series of substituted PQMO by acetyl chloride [11]. Similarly,
PQMO benzoylation with benzoyl chloride in pyridine occurs at the
oxime group with forming an ester [12] and in diethyl ether in the
presence of triethylamine [13]. Conclusion about the structure of
the acylation products was made using the of electronic spectros-
copy data. The nitroso group remains intact in the case of the
⇑
Corresponding author. Tel.: +7 8 10391 2495663.
E-mail addresses: Tovbis@bk.ru (M.S. Tovbis), Kiriksd@yandex.ru (S.D. Kirik).
http://dx.doi.org/10.1016/j.molstruc.2014.01.066
0022-2860/Ó 2014 Elsevier B.V. All rights reserved.

342
D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
acylation reaction following the oxygen atom of the hydroxy
group. Nitroso group has a characteristic absorption at 680–
m/z (Irel., %): 337 (6) [M]+, 295 (20), 249 (6), 204 (5), 67 (13), 43
(100), 39 (5).
760 nm (n ?
p transition), causing the substance to be green
[14]. At the formation of the oxime type product similar absorption
band in the spectrum is missing. These data indicate the reactivity
of the two groups, which complicates the prediction of the acyla-
tion direction for persubstituted nitrosophenols: on the oxygen
atom of the hydroxy or nitroso groups.
2.1.4. (IIc) 1-Acetoxymino-3,5-di(propyloxycarbonyl)-2,6-dimetyl-
1,4-benzoquinone, C18H23NO7
Yield 53%, yellow crystals, mp 63–65 °C. 1H NMR spectrum
(CDCl3), d, ppm: 1.01 t (3H, COOC3H7), 1.02 t (3H, COOC3H7),
1.75–1.79 m (4H, 2 COOC3H7), 2.34 s (3H, PhCH3), 2.37 s (3H,
PhCH3), 2.47 s (3H, NOCOCH3), 4.30 t (2H, COOC3H7), 4.32 t (2H,
COOC3H7). Mass spectrum, m/z (Irel., %): 365 (9) [M]+, 323 (10),
203 (5), 121 (5), 67 (18), 43 (100), 41 (33), 39 (14).
In order to clarify the prefer directions of the carbonyl group
joining to the persubstituted nitrosophenols, we carried out the
reactions of the five potassium salts of 2,6-dialkoxycarbonyl-3,5-
dimethyl-4-nitrosophenols (Ia–Ie) with different alkyl groups:
methyl, ethyl, propyl, buthyl, amyl and acetic anhydride or benzoyl
chloride as the acylating agents. As the result 10 new compounds
were obtained: 1-acetoxymino-3,5-di(alkoxycarbonyl)-3,5-di-
methyl-1,4-benzoquinones (IIa–IIe) and 1-benzoiloxymino-3,5-
di(alkoxycarbonyl)-2,6-dimethyl-1,4-benzoquinones (IIIa–IIIe). In
this paper we present the results of syntheses, identification of
the products and some structural results obtained by X-ray powder
diffraction analysis. The individuality of the compounds is also
confirmed by 1H NMR spectroscopy and mass spectrometry.
2.1.5. (IId) 1-Acetoxymino-3,5-di(butyloxycarbonyl)-2,6-dimetyl-1,4-
benzoquinone, C20H27NO7
Yield 40%, yellow oil, fp 0–5 °C. 1H NMR spectrum (CDCl3), d,
ppm: 0.974 t (3H, COOC4H9), 0.975 t (3H, COOC4H9), 1.417–
1.480 m (4H, 2 COOC4H9), 1.702–1.750 m (4H, 2 COOC4H9), 2.33 s
(3H, PhCH3), 2.37 s (3H, PhCH3), 2.47 s (3H, NOCOCH3), 4.34 t
(2H, COOC4H9), 4.35 t (2H, COOC4H9). Mass spectrum, m/z (Irel., %):
393 (2) [M]+, 351 (7), 277 (23), 263 (11), 221 (20), 204 (11), 175
(7), 147 (13), 67 (21), 57 (59), 43 (83), 41 (100), 39 (22).
2. Experimental
2.1.6. (IIe) 1-Acetoxymino-3,5-di(amyloxycarbonyl)-2,6-dimetyl-1,4-
benzoquinone, C22H31NO7
2.1. Synthesis
Yield 70%, yellow oil. 1H NMR spectrum (CDCl3), d, ppm: 0.92 t
(6H, 2 COOC5H11), 1.36–1.38 m (8H, 2 COOC5H11), 1.72–1.74 m
(4H, 2 COOC5H11), 2.32 c (3H, PhCH3), 2.36 c (3H, PhCH3), 2.46 s
(3H, NOCOCH3), 4.32 t (4H, 2 COOC5H11). Mass spectrum, m/z (Irel., %):
421 (3) [M]+, 379 (10), 291 (27), 277 (6), 221 (26), 205 (13), 202
(23), 189 (11), 175 (8), 147 (23), 67 (34), 55 (40), 43 (100), 41
(85), 39 (27).
2.1.1. Acylation of the substituted 2,6-di(alkoxycarbonyl)-3,5-
dimethyl-4-nitrosophenols
Acylation of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4-nitros-
ophenols (Ia–Ie) were carried out at atmospheric pressure, stirring
and heating. Potassium salt of persubstituted p-nitrosophenol
(0.2 g) was suspended in absolute diethyl ether (2 ml) with addi-
tion acetic anhydride or benzoyl chloride in 1.1 fold molar excess
relative to the potassium salt of p-nitrosophenol. The reaction
was conducted in the presence of sulfuric acid. The reaction mix-
ture was heated in a round bottom flask with reflux condenser
and drying tube with stirring for 1.5–3 h. The product was passed
into the diethyl ether solution, the reaction mixture color changed
from green to yellow. Then the mixture was cooled to room tem-
perature, poured into 10–15 ml water and the aqueous layer was
separated from the organic in a separatory funnel. The aqueous
layer was extracted 3 times with 10 ml diethyl ether. The ether ex-
tracts were combined with the organic layer and washed with 10%
sodium carbonate solution, then with water. Ether was evaporated
and the solid residue was dried for 1 h under vacuum in a desicca-
tor over anhydrous sodium sulfate. Those products are isolated as
an oil, first had been triturated with hexane and then the resulting
crystals were dried under vacuum. The substances were purified
by recrystallization from petroleum ether. Some products were ob-
tained as yellow oil. Some of the individual physico-chemical prop-
erties of the synthesized compounds are presented below.
2.1.7. (IIIa) 1-Benzoyloxymino-3,5-di(methoxycarbonyl)-2,6-dimetyl-
1,4-benzoquinone, C19H19NO7
Yield 55%, yellow oil. 1H NMR spectrum (CDCl3), d, ppm: 2.44 s
(3H, PhCH3), 2.60 s (3H, PhCH3), 3.95 s (3H, COOCH3), 4.04 s (3H,
COOCH3), 7.57 m (2H, NOCOPh), 7.72 m (1H, NOCOPh), 8.11 m
(2H, NOCOPh). Mass spectrum, m/z (Irel., %): 371 (15) [M]+.
2.1.8. (IIIb) 1-Benzoyloxymino-3,5-di(ethoxycarbonyl)-2,6-dimetyl-
1
1,4-benzoquinone, C2 H23NO7
Yield 50%, yellow oil. 1H NMR spectrum (CDCl3), d, ppm: 1.38 t
(3H, COOC2H5), 1.39 t (3H, COOC2H5), 2.42 s (3H, PhCH3), 2.59 s
(3H, PhCH3), 4.40 q (4H, 2 COOC2H5), 7.56 m (2H, NOCOPh),
7.71 m (1H, NOCOPh), 8.10 m (2H, NOCOPh). Mass spectrum, m/z
(Irel., %): 399 (3) [M]+, 354 (6), 295 (7), 249 (6), 234 (6), 219 (22),
205 (18), 202 (12), 175 (8), 147 (22), 122 (30), 105 (65), 67 (66),
51 (60), 43 (22), 39 (32).
2.1.2. (IIa) 1-Acetoxymino-3,5-di(methoxycarbonyl)-2,6-dimetyl-1,4-
benzoquinone, C14H15NO7(Scheme 1)
O
C
O
O
C
Yield 60%, yellow crystals, mp 185–187 °C. 1H NMR spectrum
(CDCl3), d, ppm: 2.34 s (3H, PhCH3), 2.37 s (3H, PhCH3), 2.47 s
(3H, NOACOCH3), 3.93 s (6H, COOACH3). Mass spectrum, m/z (Irel., %):
309 (7) [M]+, 267 (8), 147 (5), 121 (7), 67 (16), 43 (100), 39 (9).
H3C
O
O
CH3
H3C
CH3
2.1.3. (IIb) 1-Acetoxymino-3,5-di(ethoxycarbonyl)-2,6-dimetyl-1,4-
benzoquinone, C16H19NO7
N
O
C
O
CH3
Yield 50%, yellow crystals, mp 123–125 °C. 1H NMR spectrum
(CDCl3), d, ppm: 1.371 t (3H, COOC2H5), 1.378 t (3H, COOC2H5),
2.34 t (3H, PhCH3), 2.37 s (3H, PhCH3), 2.47 s (3H, NOCOCH3),
4.397 q (2H, COOC2H5), 4.401 q (2H, COOC2H5). Mass spectrum,
Scheme 1. Structural formula for C14H15NO7 (IIa).

D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
343
2.1.9. (IIIc) 1-Benzoyloxymino-3,5-di(propyloxycarbonyl)-2,6-dimetyl-
1,4-benzoquinone, C23H25NO7
means of direct loading. The top of the excess was cut off with a
razor to prevent preferential orientation of the particles on the sur-
face. X-ray powder pattern registration was performed in range 3–
Yield 86%, yellow cystals, mp 75–76 °C. 1H NMR spectrum
(CDCl3), d, ppm: 1.01 t (3H, COOC3H7), 1.02 t (3H, COOC3H7),
1.79 m (4H, 2 COOC3H7), 2.43 s (3H, PhCH3), 2.60 s (3H, PhCH3),
4.32 t (4H, 2 COOC3H7), 7.57 m (2H, NOCOPh), 7.70 m (1H, NO-
COPh), 8.10 m (2H, NOCOPh). Mass spectrum, m/z (Irel., %): 427
(3) [M]+, 205 (23), 147 (6), 122 (25), 105 (100), 67(32), 51 (47),
43 (96), 41 (70), 39 (32).
90° 2h with step 0.026°,
registration is caused by the lack of diffraction picks in the far an-
D
t À 50c at T = 22 °C. The angular limit for
gle region.
There were three suitable substances for structure research:
(IIa) C14H15NO7, (IIb) C16H19NO7 and (IIIc) C23H25NO7. The unit cell
parameters were defined and refined using the programs described
in [15,16]. The space groups were chosen according to regular
reflection absence. The structural models were determined in the
direct space applying the ‘‘simulated annealing’’ approach (the
variety of Monte Carlo method) [17] with the program FOX [18].
In each case the complete molecule was taken as a molecular mod-
el with various substituents, in particular, with the addition of an
acyl or benzoyl moiety by nitroso- or phenol centers. The search
of a structure consisted in finding an optimal position of molecular
gravity center and orientation of the molecule in a unit cell. More
complete match of the calculated and experimental diffraction pat-
terns achieved by removing the molecular constrains, including the
substituents rotation regarding the plane of the benzene ring. The
most optimal structural models were refined by full-profile analy-
sis (Rietveld method) using the program FullProf [19]. Rigid and
soft constraints were impose on refined atomic coordinates [20]
using the weight coefficients and taking into account the average
values of corresponding distances and angles [21]. Optimization
of the structure was carried out by the gradual removal of restric-
tions and parallel refinement of the background and some of the
profile parameters. Thermal parameters of the atoms were refined
in the isotropic approximation. At the final refinement step hydro-
gen atoms were rigidly attached to the respective carbons [22]. The
resulting structural data have been deposited on CSD #CCDC
974561, #CCDC 974562.
2.1.10. (IIId) 1-Benzoyloxymino-3,5-di(butyloxycarbonyl)-2,6-dimetyl-
1,4-benzoquinone, C25H31NO7
Yield 55%, yellow oil. 1H NMR spectrum (CDCl3), d, ppm: 0.98 t
(3H, COOC4H9), 0.99 t (3H, COOC4H9), 1.45 m (4H, 2 COOC4H9),
1.74 m (4H, 2 COOC4H9), 2.43 s (3H, PhCH3), 2.60 s (3H, PhCH3),
4.36 t (4H,
2 COOC4H9), 7.55 m (2H, NOCOPh), 7.71 m (1H,
NOCOPh), 8.11 m (2H, NOCOPh). Mass spectrum, m/z (Irel., %):
455 (10) [M]+.
2.1.11. (IIIe) 1-Benzoyloxymino-3,5-di(amyloxycarbonyl)-2,6-dimetyl-
1,4-benzoquinone, C27H35NO7
Yield 50%, yellow crystals, mp 45–47 °C. 1H NMR spectrum
(CDCl3), d, ppm: 0.943 t (3H, 2 COOAC5H11), 0.953 t (3H, 2 COOAC5H11),
1.39 m (8H, 2 COOAC5H11), 1.76 m (4H, 2 COOAC5H11), 2.43 s
(3H, PhCH3), 2.60 s (3H, PhCH3), 4.348 t (2H, 2 COOAC5H11), 4.359 t
(2H, 2 COOAC5H11), 7.58 m (2H, NOCOPh), 7.72 m (1H, NOCOPh),
8.10 m (2H, NOCOPh). Mass spectrum, m/z (Irel., %): 483 (3) [M]+,
105 (100), 77 (24), 51 (9), 43 (13).
2.2. Terms and conditions 1H NMR and mass spectra
All NMR data were collected in CDCl3 on Bruker Avance III 600
spectrometer system (14.1 T, Bruker) at 295 k. For proton NMR
experiments single p/2-pulse was applied. For proton NMR
analyses the relaxation delay were 3 s, 90° p/2-pulses of 13.7 ls,
spectral width 5071 Hz.
3. Results and discussion
Mass spectra were recorded on Finnigan MAT 8200 with
double-focusing Nier-Johnson geometry and electron impact as
ionization method. Range of recorded mass was set in the range
of 5–2000 amu.
The oxygen atoms of hydroxyl and nitroso group are two nucle-
ophilic centers in the anions of persubstituted nitrosophenols.
From the point of view of the of charge magnitude on the nucleo-
philic center the preferable direction for the attack of carbonyl
group of acylating agent is oxygen atom of hydroxyl-group of the
nitrosophenolate-ion (Scheme 2). Previously, we found that the
alkylation of persubstituted nitrosophenols by alkyl halides
in the diethyl ether went solely on the oxygen atom of the
nitroso-group to form alkyl esters of p-benzoquinonemonooximes
[6]. On this basis it was concluded that the reaction did not depend
on the charge, but the orbital control, which was well described by
the mechanism of nucleophilic substitution SN2. There are evi-
dences [14], that the acylation follows through the other two-stage
mechanism by attaching the nucleophile towards the carbonyl
2.3. X-ray powder diffraction study
Solid state samples, were analyzed for crystallinity, monophase
content and the possibility of crystal structure determination. For
this purpose the X-ray powder diffraction data were obtained.
X’Pert PRO diffractometer (PANalytical) with a PIXcel detector,
equipped with a graphite monochromator, was used. Cu Ka radia-
tion was applied. The sample for the survey was grinded up into an
agate mortar and placed in a cuvettee of 25 mm in diameter by
O
O
OCR1
O
ROOC
H3C
COOR
CH3
R1C
X
ROOC
H3C
COOR
CH3
- X-
NO
NO
X = Cl, OAc
Scheme 2. The preferable reaction between nitrosophenolate-ion and the acylating agent.

344
D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
O
OK
O
O
O
O
R-O-C
C-O-R
1) Ac2O
R-O-C
C-O-R
O
Cl
C
2)
H3
C
CH 3
H3
C
CH 3
C
H2SO 4
NO
N
O
R'
I
O
II -III
R = Me (IIa), Et (IIb), Pr (IIc),
Bu (IId) , Amy l (IIe), R'=Me
R = Me (Ia), Et (Ib), Pr (Ic),
Bu (Id) , Amyl (Ie)
R = Me (IIIa), Et (IIIb),
Pr (IIIc),Bu (IIId) ,
Amy l (IIIe), R'=Ph
Scheme 3. The reaction between persubstituted potassium para-nitrosophenolate and acetic anhydride or benzoyl chloride.
group, followed by elimination of the halogen anion for benzoyl
chloride or acetate ion in the case of acetic anhydride. To clarify
which of two nucleophilic centers the oxygen atom of the hydro-
xyl-group or nitroso-group of persubstituted nitrosophenols were
active, the potassium salt was introduced in the reaction with ace-
tic anhydride and benzoyl chloride in absolute ether in the pres-
ence of sulfuric acid.
acyloxime group. At the same time, the proton signals from of
the acyl substituent at the oxime group is not doubled, that indi-
cates their identical environment. In general, the 1H NMR data in
all cases consistent with the fact that the acylation goes on the
oxygen atom of the nitroso-group.
Fig. 2 shows the 1H NMR spectrum one of the benzoylation
products C27H35NO7 (IIIe).
Yellow crystalline or oily products were obtained in all con-
ducted reactions of acylation. Supposed formation scheme of per-
substituted para-nitrosophenols acyl derivatives is presented in
Scheme 3. Important information about the structure of the acyla-
tion products was obtained by 1H NMR spectroscopy. Fig. 1 shows
the spectra of (IIa) C14H15NO7.
The spectrum shows signals of the aromatic ring protons of
benzoyl substituent in
a weak field with chemical shift
d = 8.1 ppm for two protons in the ortho-position, for one proton
in the para-position with chemical shift d = 7.72 ppm and for two
protons in the meta-position with chemical shift d = 7.58 ppm.
The spectrum also contains signals of the ester group protons of
benzoyl substituent’s: four protons of methylene groups are close
to the oxygen atom in the form of the triplet in the weaker field
with the chemical shift d = 4.34–4.36 ppm. The triplet splitting is
due to the different environment of alkoxycarbonyl groups because
of syn- or anti-location relative to the benzoyloxime group. Six
protons of the methyl groups in a strong field are in the form of
According to 1H NMR data 1-acyloxymino-3,5-di(alcoxycarbon-
yl)-2,6-dimethyl-1,4-benzoquinones were formed in all cases. The
protons of the methyl groups in the ring and the ester substituent’s
are not equal. 1H NMR spectrum contains double bands with the
same intensity of the components of the methyl groups protons
corresponding syn- or anti-location of the substituents relative to
Fig. 1. 1H NMR spectrum of 1-acetoxymino-3,5-di(methoxycarbonyl)-2,6-dimetyl-1,4-benzoquinone (IIa).

D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
345
Fig. 2. 1H NMR spectrum of 1-benzoyloxymino-3,5-di(amyloxycarbonyl)-2,6-dimetyl-1,4-benzoquinone (IIIe).
a ‘‘doubling’’ triplet with chemical shifts d = 0.95–0.96 ppm. The
other protons of the methylene groups are in the form of the
multiplets (d = 1.39–1.74 ppm). Six protons of the methyl groups
of the ring give signals with chemical shifts d = 2.43 ppm and
d = 2.60 ppm in the form of ‘‘doubling’’ singlets for the reason given
above. A similar situation consistent with the quinoneoxime
structure of the acylation products was observed in the spectra
of all other acyl derivatives.
by X-ray powder diffraction analysis. Other substances had
consistence unsuitable for X-ray diffraction analysis due to the
low melting temperature. Their structure modeling was carried
out using the initial knowledge about the structure of the original
moieties, based on the method of synthesis, chemical analysis,
mass spectrometry and NMR data. Orientation alkyloxycarbonyl
groups to the ring were refined independently. Thus, overall orien-
tation of the molecule in the unit cell, center of acylation and ori-
entation of alkyloxycarbonyl groups were determined. Two
molecular configurations of the acylation products on the hydroxyl
or nitroso group were subsequently analyzed. It was found that the
shift of the acylation center on the hydroxyl group leads to the sig-
nificant difference between the experimental and calculated dif-
fraction patterns with increasing Rwp of about 15.00% for (IIa).
Crystal data and structure characteristics after verifying are pre-
sented in Table 1. Figs. 3 and 4 show final convergence of experi-
mental and calculated X-ray diffraction patterns for (IIa) and
(IIb) correspondently.
The crystal structures (IIa) C14H15NO7, (IIb) C16H19NO7 and the
most likely structural model (IIIc) C23H25NO7 were determined
Table 1
Crystallographic parameters and details of powder X-ray diffraction structure
determination for (IIa), (IIb) and (IIIc).
Chemical formula
Molecular weight
Space group
a, Å
C14H15NO7
309.27
P À 1
C16H19NO7
337.32
P – 1
11.529(1)
10.085(1)
9.018(1)
105.87(1)
111.28(1)
102.44(1)
880.08
C23H25NO7
440.32
P21/a
17.459(1)
16.795(1)
7.671(1)
90
91.50(1)
90
2248.27
4
11.896(1)
9.080(1)
8.245(1)
109.22(1)
98.46(1)
108.97(1)
762.37
2
The crystal structures of investigated substances (IIa)
b, Å
c, Å
C14H15NO7, (IIb) C16H19NO7 and (IIIc) C23H25NO7 are of molecular
a
, (o)
type. The molecules of (IIa) and (IIb) are shown in Fig. 5, have a
planar configuration. Non-hydrogen atoms of the molecules are
substantially coplanar. The central fragment is the quinonoid ring.
The difference between the lengths of CAC bonds in the ring, in
particular, d(C2AC3) = 1.41(8) Å and d(C3AC4) = 1.34(4) Å, the
short connections: d(C2AO1) = 1.17(0) Å and d(C5AN10) =
1.35(8) Å corresponding to the double bonds between the atoms,
b, (o)
, (o)
Vun,cell, Å3
c
Z
2
V/Z, Å3
381.185
1.347
0.936
440.04
1.273
0.853
562.07
q
l
calc., g/cm3
, mmÀ1
295
295
295
T, R
indicate the quinonoid structure with p-conjugation. Substituents:
Diffractometer
Radiation
k, Å
X’Pert PRO
X’Pert PRO
X’Pert PRO
Cu Ka
k1 = 1.54056,
k2 = 1.54439
3.013–80.909
Cu K
a
Cu K
a
@O, ACH3, @N are located in the plane of the benzene ring. Planes
of alkyloxycarbonyl groups are substantially perpendicular to the
quinonoid ring. The torsion angles of the opposite alkyloxycarbon-
yl groups relatively to plane of the quinonoid ring in (IIa) and (IIb)
differ by 10°. The orientation of these groups relative to the plane
of the ring is bilateral, which seems to be associated with the en-
ergy gain, realized at molecule packing in the unit cell volume.
Acetoximine groups in both compounds are located in the plane
of quinonoid ring. Some structural characteristics for the molecules
k1 = 1.54056,
k2 = 1.54439
3.039–80.935
2996
1219
5.51
k1 = 1.54056,
k2 = 1.54439
3.013–80.909
2996
1102
8.90
Scanning area, 2h (o)
Number of points
Number of reflections
Rp, %
Rwp, %
7.18
11.8
Rexp, %
3.28
7.76
S = Rwp/Rexp
2.19
1.52

346
D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
Fig. 3. X-ray diffraction patterns for (IIa) C14H15NO7: the experimental (dots) and calculated (solid line), the difference (solid line), position of calculated reflections in
bottom. The zoomed high angle part is shown in the insertion.
13000
12000
11000
10000
0
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
40
50
60
70
80
2 Theta (deg.)
-1000
10
20
30
40
50
60
70
80
2 Theta (deg.)
Fig. 4. X-ray diffraction patterns for (IIb) C16H19NO7: the experimental (dots) and calculated (solid line), the difference (solid line), position of calculated reflections in
bottom. The zoomed high angle part is shown in the insertion.
(IIa), (IIb) and (IIIc) are presented in Tables 2 and 3. Unit cells of
(IIa) and (IIb) contain two asymmetrical molecules in parallel
planes related via the symmetry center (Fig. 6). The pairs are
stacked along translational vector at a distance of 3.71(9) and
3.59(2) Å between the planes of the rings. The centers of the
quinonoid rings of each pair are spaced apart by distances
4.09(1) and 4.39(2) Å correspondently. Relative to each other pairs
shifted by 6.07 and 3.01 Å. Formation of such pairs in the unit cell
can be explained by steric effect of alkyloxycarbonyl substituent
during the crystallization of compounds (IIa) and (IIb). Thus cen-
trosymmetrical arrangement of the molecules is likely to lead to
the achievement of the dense packing of the molecules in the crys-
tals (Fig. 7).
The discussed compounds have no ‘‘classical’’ hydrogen bonds,
so the supramolecular structure is regulated by the molecule forms
and their packing. It results in formation of stacks of the planar
molecules along the c axis. In the stacks centrosymmetrically re-
lated molecules arranged in pairs at angles of 60.2° and 86.9° to
the column axis, respectively. There are no association of mole-
cules from different columns in the layer (Fig. 8):
1-Benzoyloxymino-3,5-di(propyloxycarbonyl)-2,6-dimetyl-1,4-
benzoquinone (IIIc) in contrast to the above-described compounds

D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
347
Fig. 5. Molecular structure of (IIa) C14H15NO7 and (IIb) C16H19NO7.
Table 2
The most important interatomic distances and angles for (IIa) C14H15NO7.
Distance, Å
Angle, °
Torsion, °
C2AC3
C3AC4
1.41(1)
1.34(1)
1.54(1)
1.35(1)
1.40(1)
1.44(1)
1.47(1)
1.20(1)
1.30(1)
1.38(1)
1.17(1)
O1AC2AC3
C2AC3AC4
C3AC4AC9
C4AC5AN10
C5AN10AO17
N10AO17AC20
O13AC8AO14
C8AO14AC19
C2AC3AC8
118.5(1)
121.2(1)
121.4(1)
116.0(1)
125.0(1)
112.8(1)
120.1(1)
119.3(1)
119.9(1)
O1AC2AC3AC4
À177.5(1)
C2AC3AC8AO13
C2AC7AC12AO15
O13AC8AO14AC19
C2AC3AC4AC9
C3AC4AC5AN10
C4AC5AN10AO17
C5AN10AO17AC20
À91.4(1)
101.3(1)
C6AC11
C5AN10
N10AO17
C20AC21
C3AC8
C8AO13
C8AO14
O14AC19
C2AO1
À0.8(1)
À179.1(0)
À176.7(1)
À173.2(1)
179.9(1)
Table 3
The most important interatomic distances and angles for (IIb) C16H19NO7.
Distance, Å
Angle, °
Torsion, °
C2AC3
C3AC4
1.44(1)
1.34(1)
1.48(1)
1.32(1)
1.50(1)
1.51(1)
1.52(1)
1.24(1)
1.45(1)
1.48(1)
1.19(1)
O1AC2AC3
C2AC3AC4
C3AC4AC9
C4AC5AN10
C5AN10AO17
N10AO17AC20
O13AC8AO14
O16AC18AC23
O14AC19AC24
120.1(1)
120.4(1)
121.1(1)
120.8(1)
125.0(1)
110.9(1)
121.4(1)
120.8(1)
128.5(1)
O1AC2AC3AC4
À179.2(1)
À94.0(1)
110.8(1)
À20.0(1)
À179.6(1)
À179.7(1)
À176.8(1)
174.8(1)
C2AC3AC8AO13
C2AC7AC12AO15
O13AC8AO14AC19
C2AC3AC4AC9
C3AC4AC5AN10
C4AC5AN10AO17
C5AN10AO17AC20
C6AC11
C5AN10
C18AC23
C20AC21
C19AC24
C8AO13
C8AO14
O14AC19
C2AO1
has two benzene rings which planes are tuned to each other on an-
gle 18.6(1)°. It crystallizes in monoclinic lattice with Space group
P21/a that directly affects on mutual orientation of the molecules
in the unit cell (Fig. 9). A proposed molecule arrangement in the
unit cell is shown in Fig. 10. The crystal structure was only partially
determined. However it allows to suggest the molecular parking
scheme (Figs. 10 and 11). The calculated X-ray powder pattern
demonstrates some differences with experimental one which at
the moment are not explained. The estimation of the molecular
and unit cell volume allows assumption the existence of solvent
molecules in the unit cell. Taking into account non-hydrogen atom
for C23H25NO7. It is possible to get the difference in volume of
about 100 Å3. The solvent molecules may be present either be-
tween the base molecules or partially replace them. Fig. 11 shows
a partially filled cell cavities which can hold solvent.
Thus, 10 new acetyl and benzoyl derivatives were obtained by
the reaction of acetic anhydride and benzoyl chloride with per-
substituted para-nitrosophenols. 1H NMR data in all cases consis-
tent with the fact that the acylation goes on the oxygen atom of
the nitroso-group. The crystal structure investigation of several

348
D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
Fig. 6. The molecule orientation in the unit cell for (IIa) and (IIb).
Fig. 7. The arrangement of the molecules (IIa) and (IIb) in the columns.
Fig. 8. The arrangement of columns in the crystal structures (IIa) and (IIb).

D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
349
Fig. 9. Molecular structure (a) and orientation of the molecules in unit cell (b) for C23H25NO7 (IIIc).
Fig. 10. Packing of molecules (IIIc) in plane (ab) in the unit cell volume.
products was carried out using X-Ray powder diffraction
technique. The molecular crystal structure for (IIa), (IIb) and (IIIc)
compounds shows that molecules have a generally planar configu-
ration with the quinonoid ring as the central moiety. Alkyloxycar-
bonyl substituents are asymmetric and out of the ring plane.
Arrangement of the molecules in the absence of hydrogen bonds
obeys the principles of the closest packing, which is realized in
the form of columns. The sectional shape of the column is different
from the cylindrical and caused the presence of substituents. Voids,
formed by stacking the columns can be filled with solvent.

350
D.Y. Leshok et al. / Journal of Molecular Structure 1063 (2014) 341–350
Fig. 11. Packing of molecules (IIIc) along c-axis with partial filling of the unit cell volume.
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Acknowledgement
The investigation were carried out with financial support
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