Synthesis and crystal structure of N1,N2-di­methyl­ethane­dihydrazide

Bibik, Y.S.; Khomenko, D.M.; Doroshchuk, R.O.; Raspertova, I.V.; Bargan, A.; Lampeka, R.D.

doi:10.1107/S2056989024000239

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Volume 80| Part 2| February 2024| Pages 148-151

https://doi.org/10.1107/S2056989024000239

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Synthesis and crystal structure of N¹,N²-dimethylethanedihydrazide

Yurii S. Bibik,^a ^* Dmytro M. Khomenko,^a,^b Roman O. Doroshchuk,^a,^b Ilona V. Raspertova,^a,^b Alexandra Bargan ^c and Rostyslav D. Lampeka ^a

^aDepartment of Chemistry, Kyiv National Taras Shevchenko University, Volodymyrska St 64, Kyiv, Ukraine, ^bEnamine Ltd., Winston Churchill St 78, Kyiv 02094, Ukraine, and ^c"Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania
^*Correspondence e-mail: yurii.bibik@knu.ua

Edited by L. Van Meervelt, Katholieke Universiteit Leuven, Belgium (Received 15 December 2023; accepted 7 January 2024; online 12 January 2024)

The title compound, N¹,N²-dimethylethanedihydrazide, C₄H₁₀N₄O₂, was obtained by the methylation of oxalyl dihydrazide protected with phthalimide. The molecule is essentially non-planar with a dihedral angle between the two planar hydrazide fragments of 86.5 (2)°. This geometry contributes to the formation of a multi-contact three-dimensional supramolecular network via C—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds.

Keywords: crystal structure; X-ray crystallography; hydrazide; hydrogen bonds.

CCDC reference: 2323887

1. Chemical context

For over a century, researchers have aimed to synthesize diverse heterocycles using well-established available methods. Currently, there is significant research interest in developing new methods for their synthesis, focusing on efficient and atom-economical routes (Favi, 2020 ; Pathan et al., 2020 ). Among these novel synthetic approaches, the utilization of hydrazides stands out as one of the most appealing methods for synthesizing heterocyclic compounds such as pyrazoles, triazoles, oxadiazoles and pyridazines (Majumdar et al., 2014 ; Mittersteiner et al., 2021 ; Hosseini & Bayat, 2018 ; Khomenko et al., 2022 ).

Organic acid hydrazides constitute a broad group of hydrazine derivatives containing the functional group –C(=O)NHNH₂. Therefore, this keen interest in hydrazide chemistry appears to arise not only from their diversity but also from the unique properties of these compounds. Acid hydrazides and their derivatives such as hydrazones possess biological activities including anticonvulsant (Angelova et al., 2016 ), antidepressant (Ergenç et al., 1998 ), anti-inflammatory (Kajal et al., 2014 ), antimalarial (Walcourt et al., 2004 ), antimycobacterial (Shalini et al., 2019 ), anticancer (Witusik-Perkowska et al., 2023 ; Küçükgüzel et al., 2015 ) and antimicrobial (Hiremathad et al., 2015 ; Popiołek et al., 2022 ; Berillo & Dyusebaeva, 2022 ; Popiołek, 2021 ). Hydrazides are also bidentate ligands that can form chelate complexes (Ju et al., 2023 ).

Considering the above, we report on the synthesis and crystal structure of a new alkylated oxalyl dihydrazide as an attractive synthon for the synthesis of biologically active organic compounds and metal complexes.

2. Structural commentary

The title compound crystalizes in the orthorhombic Sohncke space group P2₁2₁2₁ with four formula units per unit cell (Fig. 1). The crystal structure does not show other tautomeric forms. Bond lengths and angles are given in Table 1. The geometrical parameters are comparable to the values found in methylsemicarbazide (Szimhardt & Stierstorfer, 2018 ) and oxalyl dihydrazide (Quaeyhaegens et al., 1990 ). The methyl hydrazide core [–C(=O)N(—CH₃)NH₂] is almost planar (r.m.s. deviation = 0.022 Å). The torsion angles around the N1—C2 and N3—C3 bonds are N2—N1—C2—O1 = 175.1 (4)°, C1—N1—C2—O1 = −1.2 (5)°, N4—N3—C3—O2 = 174.8 (4)°, and C4—N3—C3—O2 = −1.4 (6)°. The methyl hydrazide fragments are almost perpendicular to each other [the dihedral angle between the two moieties is 86.5 (2)°]. The torsion angles around the C2—C3 bond are O1—C2—C3—O2 = 89.9 (4), O1—C2—C3—N3 = −81.4 (4), N1—C2—C3—O2 = −83.2 (4), and N1—C2—C3—N3 = 105.5 (4)°.

Table 1
Selected geometric parameters (Å, °)

O1—C2	1.231 (4)	N3—N4	1.414 (4)
O2—C3	1.233 (4)	N3—C3	1.319 (4)
N1—N2	1.412 (4)	N3—C4	1.460 (4)
N1—C1	1.460 (4)	C2—C3	1.511 (5)
N1—C2	1.331 (4)

N2—N1—C1	119.9 (3)	O1—C2—N1	123.8 (3)
C2—N1—N2	117.6 (3)	O1—C2—C3	118.2 (3)
C2—N1—C1	122.4 (3)	N1—C2—C3	117.7 (3)
N4—N3—C4	120.5 (3)	O2—C3—N3	124.1 (4)
C3—N3—N4	117.3 (3)	O2—C3—C2	118.7 (3)
C3—N3—C4	122.1 (4)	N3—C3—C2	116.5 (3)

Figure 1
The molecular structure of the title compound with atom labeling and displacement ellipsoids drawn at the 50% probability level.

3. Supramolecular features

In the crystal, each molecule forms chains along the a-axis direction with two neighboring ones via N—H⋯O hydrogen bonds (Table 2, Fig. 2). Neighboring chains form a 3D supramolecular network via C—H⋯O, N—H⋯O and N—H⋯N hydrogen-bonding contacts (Table 2, Fig. 3).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1C⋯O1ⁱ	0.96	2.58	3.042 (4)	110
N2—H2A⋯O2ⁱⁱ	0.87 (5)	2.13 (5)	2.977 (4)	164 (4)
N2—H2B⋯O2ⁱⁱⁱ	0.90 (3)	2.35 (3)	3.182 (4)	155 (3)
N4—H4A⋯O1^iv	0.79 (4)	2.30 (4)	3.075 (5)	169 (4)
N4—H4B⋯N2^v	0.99 (5)	2.38 (5)	3.367 (5)	170 (4)
Symmetry codes: (i) $[x-{\script{1\over 2}}, -y-{\script{3\over 2}}, -z-1]$ ; (ii) ; (iii) $[x-{\script{1\over 2}}, -y-{\script{1\over 2}}, -z-1]$ ; (iv) $[-x-1, y+{\script{1\over 2}}, -z-{\script{1\over 2}}]$ ; (v) $[-x-1, y-{\script{1\over 2}}, -z-{\script{1\over 2}}]$ .

Figure 2
One-dimensional chains along the a-axis direction formed by N—H⋯O hydrogen bonding.

Figure 3
A view normal to plane (100) of the crystal structure of the title compound, showing the three-dimensional supramolecular hydrogen-bonding network.

4. Database survey

A search of the Cambridge Structural Database (CSD, version 5.43, last update November 2021; Groom et al., 2016 ) confirmed that the title compound has not previously been published. A search for the N—N—C(=O)—C(=O)—N—N fragment gave oxalyl dihydrazide (CSD refcode VIPKIO; Quaeyhaegens et al., 1990), its salts: EREQOK (Wu, 2021 ), NEXMIP (Xu et al., 2018 ), MIDNOG (Devi et al., 2018 ), VUHYUU and VUHZAB (Fischer et al., 2014 ), ZIBBIX and ZIBDAR (Fischer et al., 2013 ), and Schiff bases derived from it as the closest analogues: CUQPAF (Drexler et al., 1999 ), HIRHIB (Singh et al., 2013 ), IYACUH (Ran et al., 2011 ), KUTREX (Kaluderović et al., 2010 ), LORQEP (Bi et al., 2009 ), NAJWUT (Singh et al., 2016 ), NEQQOQ (Zhu et al., 2006 ), RIRTET (Singh et al., 2014 ), SUYWUG (Galvão et al., 2016 ), UMIZUN (El-Asmy et al., 2015 ), ZOLQUP and ZOLRAW (Fries et al., 2019 ). For compound ZOLQOJ (Fries et al., 2019), the fragment is part of a ring structure. Notably, a strictly planar structure is observed for the molecules oxalyl dihydrazide VIPKIO and dimethyl oxalate DMEOXA (Dougill & Jeffrey, 1953 ).

A search for the methyl hydrazide moiety gave methylsemicarbazide (XIBFEW; Szimhardt & Stierstorfer, 2018). Its geometric parameters agree well with those of the title compound. Further searches also revealed two structural analogues with a second non-hydrogen substituent at the amide-nitrogen atom: N,N,N′,N′-tetramethyloxamide and N,N,N′,N′-tetramethylmonothiooxamide (TMOXAM and TMTHOX, respectively; Adiwidjaja & Voss, 1977 ). These two crystal structures have a different packing and belong to monoclinic space groups. However, they exhibit very similar geometries in terms of the rotation of the molecule fragments around the central C—C bond. The O=C—C=O(S) torsion angles are 105.1 (2) and 89.6 (2)°, respectively.

5. Synthesis and crystallization

The title compound (5) was obtained according to the reaction scheme shown in Fig. 4.

Figure 4
Synthesis of the title compound.

N,N'-bis(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)ethanediamide (3): compound 3 was synthesized from the commercially available precursors (Enamine Ltd.) according to the following method: 12.45 g (84 mmol, 2 eq.) of phthalic anhydride (2) were dissolved in 125 ml of DMF and 4.96 g (42 mmol, 1 eq.) of oxalyl dihydrazide (1) were added to the boiling solution. The obtained mixture was refluxed for 5 h. Upon cooling, precipitation of the product was observed. It was filtered off and dried. White powder; yield 73%. ¹H NMR (400 MHz, DMSO-d₆): δ 8.05–8.15 (m, 4H, 4-Ph), 11.57 (br, 1H, NH).

N¹,N²-dimethylethanedihydrazide (5): 11.0 g (79.7 mmol, 3 eq.) of K₂CO₃ and 3.65 ml (58.6 mmol, 2.2 eq.) of CH₃I were added to a solution containing 10.0 g (26.5 mmol, 1 eq.) of compound 3 in 50 ml DMF. The reaction mixture was stirred for 6 h at room temperature. The inorganic precipitate was filtered off, the filtrate was evaporated and the residue was stirred in water, filtered off and dried in air. Yield: 9.9 g.

The crude precipitate of 4 (4 g, 9.8 mmol, 1 eq.) obtained from the previous step was refluxed with 1.1 ml (20.6 mmol, 2.1 eq.) of methylhydrazine in ethanol for 6 h. The precipitate was filtered off, ethanol was evaporated and the residue was recrystallized from 2-propanol and dried in air. The title compound was isolated as a white solid. Crystals suitable for X-ray analysis were obtained during the recrystallization. White powder; yield 84%. LC–MS (ESI) m/z 147 (MH⁺) . IR (ATR, ν, cm⁻¹) : ν 3290, 3214, 1672, 1616, 1414, 1386, 1234, 1066, 1014, 870, 782, 762. ¹H NMR (400 MHz, DMSO-d₆): δ 2.90*, 2.95 and 3.00* (s, 3H, CH₃), 4.68, 4.85* and 4.93* (s, 2H, NH₂). *Minor signals indicate hindered rotation about the (O)C—N bond.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. For the NH₂ group, the hydrogen atoms were placed from a difference-Fourier map and refined freely. The CH₃ hydrogen atoms were placed geometrically and refined as riding with C—H = 0.96 Å and U_iso(H) = 1.5U_eq(C).

Table 3
Experimental details

Crystal data
Chemical formula	C₄H₁₀N₄O₂
M_r	146.16
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	293
a, b, c (Å)	6.0356 (5), 7.6501 (6), 15.7851 (14)
V (Å³)	728.84 (10)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.25 × 0.2 × 0.15

Data collection
Diffractometer	Xcalibur, Eos
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2021 $[Rigaku, OD (2021). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
T_min, T_max	0.975, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	2356, 1279, 1014
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.093, 1.04
No. of reflections	1279
No. of parameters	107
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.14, −0.12
Absolute structure	Flack x determined using 280 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.7 (10)
Computer programs: CrysAlis PRO (Rigaku OD, 2021 $[Rigaku, OD (2021). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), SHELXT (Sheldrick, 2015a ), SHELXL2018/3 (Sheldrick, 2015b ), and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC reference: 2323887

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989024000239/vm2294sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989024000239/vm2294Isup4.hkl

checkCIF report

Computing details top

N¹,N²-Dimethylethanedihydrazide top

Crystal data top

C₄H₁₀N₄O₂	D_x = 1.332 Mg m⁻³
M_r = 146.16	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 809 reflections
a = 6.0356 (5) Å	θ = 2.6–21.5°
b = 7.6501 (6) Å	µ = 0.11 mm⁻¹
c = 15.7851 (14) Å	T = 293 K
V = 728.84 (10) Å³	Prism, clear light colourless
Z = 4	0.25 × 0.2 × 0.15 mm
F(000) = 312

Data collection top

Xcalibur, Eos diffractometer	1279 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	1014 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.027
Detector resolution: 8.0797 pixels mm^-1	θ_max = 25.0°, θ_min = 2.6°
ω scans	h = −4→7
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2021)	k = −6→9
T_min = 0.975, T_max = 1.000	l = −17→18
2356 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: difference Fourier map
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.050	w = 1/[σ²(F_o²) + (0.0311P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.093	(Δ/σ)_max < 0.001
S = 1.04	Δρ_max = 0.14 e Å⁻³
1279 reflections	Δρ_min = −0.11 e Å⁻³
107 parameters	Absolute structure: Flack x determined using 280 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
6 restraints	Absolute structure parameter: −0.7 (10)
Primary atom site location: dual

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	−0.3495 (5)	−0.6601 (3)	−0.39158 (16)	0.0534 (8)
O2	−0.1053 (4)	−0.3057 (4)	−0.38063 (17)	0.0565 (8)
N1	−0.5715 (5)	−0.4389 (3)	−0.43410 (17)	0.0356 (8)
N2	−0.6265 (6)	−0.2617 (4)	−0.4206 (2)	0.0390 (8)
N3	−0.2831 (5)	−0.3723 (4)	−0.2592 (2)	0.0418 (8)
N4	−0.4758 (7)	−0.4508 (6)	−0.2252 (2)	0.0510 (10)
C1	−0.7056 (7)	−0.5453 (5)	−0.4913 (2)	0.0520 (11)
H1A	−0.703336	−0.494920	−0.546990	0.078*
H1B	−0.855356	−0.549500	−0.470930	0.078*
H1C	−0.646056	−0.661570	−0.493510	0.078*
C2	−0.4040 (6)	−0.5050 (5)	−0.3896 (2)	0.0357 (9)
C3	−0.2571 (6)	−0.3787 (4)	−0.3421 (2)	0.0359 (9)
C4	−0.1283 (7)	−0.2793 (5)	−0.2043 (3)	0.0661 (13)
H4C	−0.188175	−0.166675	−0.190369	0.099*
H4D	0.010785	−0.264855	−0.232939	0.099*
H4E	−0.105945	−0.345315	−0.153239	0.099*
H2A	−0.763 (8)	−0.255 (5)	−0.404 (2)	0.061 (14)*
H4A	−0.537 (7)	−0.378 (5)	−0.199 (2)	0.053 (15)*
H2B	−0.621 (6)	−0.208 (5)	−0.471 (2)	0.056 (14)*
H4B	−0.432 (9)	−0.548 (7)	−0.187 (3)	0.12 (2)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0640 (19)	0.0427 (15)	0.0536 (18)	0.0182 (15)	−0.0038 (16)	−0.0062 (13)
O2	0.0318 (15)	0.084 (2)	0.0542 (18)	−0.0106 (15)	0.0054 (15)	0.0102 (15)
N1	0.0346 (17)	0.0386 (16)	0.0335 (17)	0.0029 (15)	−0.0068 (15)	−0.0064 (14)
N2	0.0321 (19)	0.0372 (18)	0.048 (2)	0.0026 (17)	0.0011 (18)	0.0011 (17)
N3	0.0361 (18)	0.051 (2)	0.0377 (19)	−0.0037 (18)	−0.0046 (16)	−0.0015 (15)
N4	0.058 (3)	0.056 (2)	0.039 (2)	−0.002 (2)	0.0052 (19)	−0.002 (2)
C1	0.060 (3)	0.055 (2)	0.041 (2)	−0.005 (2)	−0.013 (2)	−0.011 (2)
C2	0.037 (2)	0.043 (2)	0.0267 (19)	0.0058 (19)	0.0072 (19)	−0.0023 (17)
C3	0.029 (2)	0.044 (2)	0.035 (2)	0.0081 (19)	−0.0022 (18)	0.0048 (18)
C4	0.057 (3)	0.084 (3)	0.057 (3)	−0.008 (3)	−0.017 (3)	−0.015 (3)

Geometric parameters (Å, º) top

O1—C2	1.231 (4)	N4—H4A	0.79 (4)
O2—C3	1.233 (4)	N4—H4B	0.99 (5)
N1—N2	1.412 (4)	C1—H1A	0.9599
N1—C1	1.460 (4)	C1—H1B	0.9601
N1—C2	1.331 (4)	C1—H1C	0.9600
N2—H2A	0.87 (4)	C2—C3	1.511 (5)
N2—H2B	0.89 (4)	C4—H4C	0.9600
N3—N4	1.414 (4)	C4—H4D	0.9600
N3—C3	1.319 (4)	C4—H4E	0.9601
N3—C4	1.460 (4)

N2—N1—C1	119.9 (3)	H1A—C1—H1B	109.5
C2—N1—N2	117.6 (3)	H1A—C1—H1C	109.5
C2—N1—C1	122.4 (3)	H1B—C1—H1C	109.5
N1—N2—H2A	109 (3)	O1—C2—N1	123.8 (3)
N1—N2—H2B	108 (2)	O1—C2—C3	118.2 (3)
H2A—N2—H2B	106 (4)	N1—C2—C3	117.7 (3)
N4—N3—C4	120.5 (3)	O2—C3—N3	124.1 (4)
C3—N3—N4	117.3 (3)	O2—C3—C2	118.7 (3)
C3—N3—C4	122.1 (4)	N3—C3—C2	116.5 (3)
N3—N4—H4A	107 (3)	N3—C4—H4C	109.4
N3—N4—H4B	109 (3)	N3—C4—H4D	109.6
H4A—N4—H4B	109 (4)	N3—C4—H4E	109.4
N1—C1—H1A	109.6	H4C—C4—H4D	109.5
N1—C1—H1B	109.5	H4C—C4—H4E	109.5
N1—C1—H1C	109.4	H4D—C4—H4E	109.5

O1—C2—C3—O2	89.9 (4)	N4—N3—C3—O2	174.8 (4)
O1—C2—C3—N3	−81.4 (4)	N4—N3—C3—C2	−14.4 (5)
N1—C2—C3—O2	−83.2 (4)	C1—N1—C2—O1	−1.2 (5)
N1—C2—C3—N3	105.5 (4)	C1—N1—C2—C3	171.6 (3)
N2—N1—C2—O1	175.1 (4)	C4—N3—C3—O2	−1.4 (6)
N2—N1—C2—C3	−12.2 (4)	C4—N3—C3—C2	169.4 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1C···O1ⁱ	0.96	2.58	3.042 (4)	110
N2—H2A···O2ⁱⁱ	0.87 (5)	2.13 (5)	2.977 (4)	164 (4)
N2—H2B···O2ⁱⁱⁱ	0.90 (3)	2.35 (3)	3.182 (4)	155 (3)
N4—H4A···O1^iv	0.79 (4)	2.30 (4)	3.075 (5)	169 (4)
N4—H4B···N2^v	0.99 (5)	2.38 (5)	3.367 (5)	170 (4)

Symmetry codes: (i) x−1/2, −y−3/2, −z−1; (ii) x−1, y, z; (iii) x−1/2, −y−1/2, −z−1; (iv) −x−1, y+1/2, −z−1/2; (v) −x−1, y−1/2, −z−1/2.

Acknowledgements

We are grateful to the Ministry of Education and Science of Ukraine and to the Ministry of Research, Innovation and Digitization of Romania for financial support.

Funding information

Funding for this research was provided by: Ministry of Education and Science of Ukraine (grant for the perspective development of the scientific direction `Mathematical sciences and natural sciences' and grant No. 22BF037-06 at the Taras Shevchenko National University of Kyiv); Ministry of Research, Innovation and Digitization (Romania), CCCDI - UEFISCDI, project number PN-III-P2-2.1-PED-2021-3900, within PNCDI III, Contract PED 698/2022 (AI-Syn-PPOSS).

References

Adiwidjaja, G. & Voss, J. (1977). Chem. Ber. 110, 1159–1166. CSD CrossRef CAS Web of Science Google Scholar
Angelova, V., Karabeliov, V., Andreeva–Gateva, P. A. & Tchekalarova, J. (2016). Drug Dev. Res. 77, 379–392. Web of Science CrossRef CAS PubMed Google Scholar
Berillo, D. A. & Dyusebaeva, M. A. (2022). Saudi Pharm. J. 30, 1036–1043. Web of Science CrossRef CAS PubMed Google Scholar
Bi, W.-T., Hu, N.-L. & Bi, J.-H. (2009). Acta Cryst. E65, o782. Web of Science CSD CrossRef IUCr Journals Google Scholar
Devi, A., Dharavath, S. & Ghule, V. D. (2018). ChemistrySelect, 3, 4501–4504. Web of Science CSD CrossRef CAS Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Dougill, M. W. & Jeffrey, G. A. (1953). Acta Cryst. 6, 831–837. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Drexler, K., Dehne, H. & Reinke, H. (1999). CSD Communication (CCDC 137595, refcode CUQPAF). CCDC, Cambridge, England. Google Scholar
El-Asmy, A., Jeragh, B. & Ali, M. (2015). Chem. Cent. J. 9, 69. Web of Science PubMed Google Scholar
Ergenç, N., Günay, N. S. & Demirdamar, R. (1998). Eur. J. Med. Chem. 33, 143–148. Google Scholar
Favi, G. (2020). Molecules, 25, 10–13. Web of Science CrossRef Google Scholar
Fischer, D., Klapötke, T. M. & Stierstorfer, J. (2014). J. Energetic Mater. 32, 37–49. Web of Science CSD CrossRef CAS Google Scholar
Fischer, N., Klapötke, T. M., Reymann, M. & Stierstorfer, J. (2013). Eur. J. Inorg. Chem. pp. 2167–2180. Web of Science CSD CrossRef Google Scholar
Fries, M., Mertens, M., Teske, N., Kipp, M., Beyer, C., Willms, T., Valkonen, A., Rissanen, K., Albrecht, M. & Clarner, T. (2019). ACS Omega, 4, 1685–1689. Web of Science CSD CrossRef CAS Google Scholar
Galvão, A. M., Carvalho, M. F. N. N. & Ferreira, A. S. D. (2016). J. Mol. Struct. 1108, 708–716. Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Hiremathad, A., Patil, M. R., Chand, K., Santos, M. A. & Keri, R. S. (2015). RSC Adv. 5, 96809–96828. Web of Science CrossRef CAS Google Scholar
Hosseini, H. & Bayat, M. (2018). Cyanoacetohydrazides. In Synthesis of Heterocyclic Compounds. Cham, Switzerland: Springer International Publishing. Google Scholar
Ju, H., Zhu, Q. L., Zuo, M., Liang, S., Du, M., Zheng, Q. & Wu, Z. L. (2023). Chem. Eur. J. 29, e202300969. Web of Science CrossRef PubMed Google Scholar
Kajal, A., Bala, S., Sharma, N., Kamboj, S. & Saini, V. (2014). Int. J. Med. Chem. 2014, 1–11. Google Scholar
Kaluderović, G. N., Mohamad Eshkourfu, R. O., Gómez-Ruiz, S., Mitić, D. & Andelković, K. K. (2010). Acta Cryst. E66, o904–o905. Web of Science CSD CrossRef IUCr Journals Google Scholar
Khomenko, D. M., Doroshchuk, R. O., Ohorodnik, Y. M., Ivanova, H. V., Zakharchenko, B. V., Raspertova, I. V., Vaschenko, O. V., Dobrydnev, A. V., Grygorenko, O. O. & Lampeka, R. D. (2022). Chem. Heterocycl. C. 58, 116–128. Web of Science CrossRef CAS Google Scholar
Küçükgüzel, G. Ş., Koç, D., Çıkla–Süzgün, P., Özsavcı, D., Bingöl–Özakpınar, Ö., Mega–Tiber, P., Orun, O., Erzincan, P., Sağ–Erdem, S. & Şahin, F. (2015). Arch. Pharm. 348, 730–742. Google Scholar
Majumdar, P., Pati, A., Patra, M., Behera, R. K. & Behera, A. K. (2014). Chem. Rev. 114, 2942–2977. Web of Science CrossRef CAS PubMed Google Scholar
Mittersteiner, M., Bonacorso, H. G., Martins, M. A. P. & Zanatta, N. (2021). Eur. J. Org. Chem. pp. 3886–3911. Web of Science CrossRef Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Pathan, S. I., Chundawat, N. S., Chauhan, N. P. S. & Singh, G. P. (2020). Synth. Commun. 50, 1251–1285. Web of Science CrossRef CAS Google Scholar
Popiołek, Ł. (2021). Int. J. Mol. Sci. 22, 9389. Web of Science PubMed Google Scholar
Popiołek, Ł., Tuszyńska, K. & Biernasiuk, A. (2022). Biomed. Pharmacother. 153, 113302. Web of Science PubMed Google Scholar
Quaeyhaegens, F., Desseyn, H. O., Bracke, B. & Lenstra, A. T. H. (1990). J. Mol. Struct. 238, 139–157. CSD CrossRef CAS Web of Science Google Scholar
Ran, X., Zhang, P., Qu, S., Wang, H., Bai, B., Liu, H., Zhao, C. & Li, M. (2011). Langmuir, 27, 3945–3951. Web of Science CSD CrossRef CAS PubMed Google Scholar
Rigaku, OD (2021). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England. Google Scholar
Shalini, Johansen, M. D., Kremer, L. & Kumar, V. (2019). Chem. Biol. Drug Des. 94, 1300–1305. Web of Science CrossRef CAS PubMed Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Singh, D. P., Allam, B. K., Singh, K. N. & Singh, V. P. (2014). RSC Adv. 4, 1155–1158. Web of Science CSD CrossRef CAS Google Scholar
Singh, D. P., Allam, B. K., Singh, R., Singh, K. N. & Singh, V. P. (2016). RSC Adv. 6, 15518–15524. Web of Science CSD CrossRef CAS Google Scholar
Singh, D. P., Raghuvanshi, D. S., Singh, K. N. & Singh, V. P. (2013). J. Mol. Catal. A Chem. 379, 21–29. Web of Science CSD CrossRef CAS Google Scholar
Szimhardt, N. & Stierstorfer, J. (2018). Chem. A Eur. J. 24, 2687–2698. Web of Science CSD CrossRef CAS Google Scholar
Walcourt, A., Loyevsky, M., Lovejoy, D. B., Gordeuk, V. R. & Richardson, D. R. (2004). Int. J. Biochem. & Cell. Biol. 36, 401–407. Web of Science CrossRef CAS Google Scholar
Witusik-Perkowska, M., Głowacka, P., Pieczonka, A. M., Świderska, E., Pudlarz, A., Rachwalski, M., Szymańska, J., Zakrzewska, M., Jaskólski, D. J. & Szemraj, J. (2023). Cells, 12, 1906. Web of Science PubMed Google Scholar
Wu, B. (2021). CSD Communication (CCDC 2079326, refcode EREQOK). CCDC, Cambridge, England. Google Scholar
Xu, Y., Lin, Q., Wang, P. & Lu, M. (2018). Chem. Asian J. 13, 924–928. Web of Science CSD CrossRef CAS PubMed Google Scholar
Zhu, L.-N., Li, C.-Q., Li, X.-Z. & Li, R. (2006). Acta Cryst. E62, o4603–o4605. Web of Science CSD CrossRef IUCr Journals Google Scholar