2,2,2-Tri­fluoro­ethyl 5-methyl-1H-pyrazole-3-carboxyl­ate

Bof de Oliveira, A.; Bortoluzzi, A.J.; Fabiani Claro Flores, A.

doi:10.1107/S2414314626000192

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 11| Part 1| January 2026| x260019

https://doi.org/10.1107/S2414314626000192

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2,2,2-Trifluoroethyl 5-methyl-1H-pyrazole-3-carboxylate

Adriano Bof de Oliveira,^a ^* Adailton João Bortoluzzi ^b and Alex Fabiani Claro Flores ^a

^aEscola de Química e Alimentos, Universidade Federal do Rio Grande, Campus Carreiros, 96203-900 Rio Grande-RS, Brazil, and ^bDepartamento de Química, Universidade Federal de Santa Catarina, Campus Universitário, 88035-972 Florianópolis-SC, Brazil
^*Correspondence e-mail: [email protected]

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 6 January 2026; accepted 8 January 2026; online 13 January 2026)

AOB would like to dedicate this publication to his academic mentor on the occasion of his 70th birthday and to his contributions to solid-state chemistry, honoring the scientific tradition and the academic genealogical tree of Professor Dr Dr h. c. Joachim Strähle (University of Tübingen/Germany) and Professor Dr Hartmut Bärnighausen (University of Karlsruhe, now The Karlsruhe Institute of Technology/Germany).

The title compound, C₇H₇F₃N₂O₂, which exhibits disorder over the terminal trifluoromethyl and methyl entities, is close to planar with the r.m.s. deviation for the non-H/-F atoms being 0.038 Å. In the crystal, the molecules are linked by N—H⋯N interactions into a [010] chain with a C₁¹(3) motif. The Hirshfeld surface fingerprint plot analysis indicates that the major contributions for the crystal packing are from H⋯F/F⋯H (31.2%), H⋯H (15.9%), H⋯O/O⋯H (15.3%) and H⋯N/N⋯H (10.1%) contacts.

Keywords: crystal structure; hydrogen-bonded chain; pyrazole.

CCDC reference: 2521414

Structure description

As part of our interest in pyrazole derivatives with potential application in medicinal chemistry (Gonçalves et al., 2016 ), we now report the crystal structure of the title compound, C₇H₇F₃N₂O₂ (I). For recent reports regarding pyrazole derivatives, see: Ameziane El Hassani et al. (2023 ), Ramajayam (2025 ) and Ríos & Portilla (2022 ).

There is one molecule in the asymmetric unit of (I), with all atoms being located in general positions (Fig. 1). The F atoms of the trifluoromethyl entity are disordered over two sets of sites in a 0.718 (11):0.282 (11) ratio and the H atoms of the C7 methyl group are statistically disordered. The molecule is close to planar, with the maximum deviations from the mean plane through the atoms being 0.0746 (17) Å for O1 [r.m.s.d. = 0.038 Å], excluding the hydrogen and the fluorine atoms. The side chain exhibits an extended conformation [C1A—C2—O1—C3 = −173.26 (19); C2—O1—C3—C4 = 178.48 (17)°].

Figure 1
The molecular structure of (I) showing displacement ellipsoids drawn at the 40% probability level.

In the crystal, the molecules are connected by N2—H2⋯N1 hydrogen bonds into a ribbon-like chain, which propagates along the b-axis direction (Table 1, Fig. 2). The crystal structure thus exhibits the supramolecular arrangement of a catemer with a C₁¹(3) motif (Alkorta et al., 2005 ; Foces-Foces et al., 2000 ): the ‘up' and ‘down' catemers are related by centers of inversion and no strong or relevant interactions are observed between the supramolecular chains (Fig. 3). There are two short C—F⋯H contacts (Table 1), but their structure-directing significance is not clear due to the disordered F atoms. The Hirshfeld surface analysis analysis of (I) was performed with Crystal Explorer 21 (Spackman et al., 2021 ). The surface mapped over d_norm shows the regions with the strongest contacts in red in the vicinities of H2 and N1 (Fig. 4), being in agreement with previous figures (Figs. 2 and 3). The fingerprint plots (Fig. 5) indicate that the H⋯F/F⋯H (31.2%), H⋯H (15.9%), H⋯O/O⋯H (15.3%) and H ⋯N/N⋯H (10.1%) contacts are the most relevant for the crystal cohesion of (I).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯N1ⁱ	0.86	2.13	2.922 (2)	153
C7—H7A⋯F2Aⁱⁱ	0.96	2.54	3.477 (7)	165
C7—H7D⋯F2Bⁱⁱⁱ	0.96	2.45	3.394 (11)	168
Symmetry codes: (i) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, y-{\script{3\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ .

Figure 2
Fragment of the extended structure of (I) showing N—H⋯N hydrogen bonds. Symmetry code: (i) −x + $[{1\over 2}]$ , y − $[{1\over 2}]$ , −z + $[{3\over 2}]$ ; minor disorder components omitted.

Figure 3
The packing of (I) as viewed along the b-axis direction.

Figure 4
The Hirshfeld surface of (I) mapped over d_norm in the range −0.49 to 1.62 a. u.

Figure 5
The two-dimensional fingerprint plots for (I) for different contact types.

A survey with the Cambridge Structural Database (CSD, accessed via WebCSD on January 2, 2026; Groom et al., 2016 ) revealed a similar structure, namely ethyl-5-methyl-1H-pyrazole-3-carboxylate, C₇H₁₀N₂O₂ (CSD refcode: FAQSAR02; Kusakiewicz-Dawid et al., 2019 ). The molecules of FAQSAR02 are linked by C—H⋯O and bifurcated N—H⋯(N,O) interactions into a two-dimensional tape-like supramolecular arrangement. Pyrazole derivatives show distinctive conformations in the solid state: it was pointed out by these authors that methyl and amino pyrazoles lead to structures with the amide or ester substituents and the N—H bond on the opposite side of the five-membered ring (compare C4 and N2 in this work, Fig. 1). This arrangement was observed in other structures, e.g. the derivatives with refcodes: HOKNON and HOKNUT. In contrast, nitro pyrazoles lead to the conformer with the N—H bond on the same side as the amide or carboxylate substituents, as observed in the structures with refcodes: HOKNED and HOKPIJ (Kusakiewicz-Dawid et al., 2019).

Synthesis and crystallization

The synthesis and spectroscopic characterization of (I) are already published in the literature (Gonçalves et al., 2016). For the single-crystal X-ray diffractometry reported here, colorless blocks of (I) were obtained from a dichloromethane solution by slow evaporation of the solvent at room temperature.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The F atoms of the –CF₃ group are disordered over two sets of sites in a 0.718 (11) (A suffix) to 0.282 (11) (B suffix) ratio. The H atoms of the C7 methyl group are statistically disordered over two sets of sites.

Table 2
Experimental details

Crystal data
Chemical formula	C₇H₇F₃N₂O₂
M_r	208.15
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	200
a, b, c (Å)	26.914 (6), 5.0133 (10), 18.693 (4)
β (°)	133.214 (2)
V (Å³)	1838.2 (7)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.15
Crystal size (mm)	0.40 × 0.26 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.603, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	10780, 2644, 1730
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.702

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.155, 1.04
No. of reflections	2644
No. of parameters	133
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.42, −0.60
Computer programs: APEX2 and SAINT (Bruker, 2014 ), SHELXT2014/5 (Sheldrick, 2015a ), SHELXL2019/2 (Sheldrick, 2015b ), DIAMOND (Brandenburg, 2006 ), Crystal Explorer 21 (Spackman et al., 2021) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 2521414

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314626000192/hb4551sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314626000192/hb4551Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314626000192/hb4551Isup3.cml

checkCIF report

Computing details top

2,2,2-Trifluoroethyl 5-methyl-1H-pyrazole-3-carboxylate top

Crystal data top

C₇H₇F₃N₂O₂	F(000) = 848
M_r = 208.15	D_x = 1.504 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 26.914 (6) Å	Cell parameters from 3527 reflections
b = 5.0133 (10) Å	θ = 3.0–29.6°
c = 18.693 (4) Å	µ = 0.15 mm⁻¹
β = 133.214 (2)°	T = 200 K
V = 1838.2 (7) Å³	Prismatic, colourless
Z = 8	0.40 × 0.26 × 0.12 mm

Data collection top

Bruker APEXII CCD diffractometer	2644 independent reflections
Radiation source: Fine-focus sealed tube	1730 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.033
φ and ω scans	θ_max = 29.9°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −37→37
T_min = 0.603, T_max = 0.746	k = −4→7
10780 measured reflections	l = −26→26

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.155	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.050P)² + 3.1537P] where P = (F_o² + 2F_c²)/3
2644 reflections	(Δ/σ)_max < 0.001
133 parameters	Δρ_max = 0.42 e Å⁻³
0 restraints	Δρ_min = −0.60 e Å⁻³

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	Occ. (<1)
C2	0.32947 (11)	1.0880 (5)	0.64954 (16)	0.0445 (5)
H2A	0.309121	1.261903	0.637302	0.053*
H2B	0.326834	1.046331	0.596343	0.053*
C3	0.22953 (10)	0.8424 (4)	0.57173 (13)	0.0334 (4)
C4	0.19776 (9)	0.6313 (4)	0.58381 (13)	0.0298 (4)
C5	0.13094 (9)	0.5346 (4)	0.51236 (13)	0.0351 (5)
H5	0.097239	0.590858	0.447569	0.042*
C6	0.12582 (9)	0.3380 (4)	0.55871 (13)	0.0335 (4)
C7	0.06852 (11)	0.1606 (5)	0.52476 (17)	0.0483 (6)
H7A	0.085442	0.026166	0.573408	0.072*	0.5
H7B	0.048965	0.076990	0.464084	0.072*	0.5
H7C	0.034334	0.264684	0.514954	0.072*	0.5
H7D	0.027052	0.219061	0.461556	0.072*	0.5
H7E	0.063529	0.168237	0.570880	0.072*	0.5
H7F	0.078160	−0.019457	0.520010	0.072*	0.5
C1A	0.40082 (14)	1.0874 (6)	0.7439 (2)	0.0594 (7)*	0.718 (11)
F1A	0.4328 (3)	0.8643 (15)	0.7764 (6)	0.113 (2)	0.718 (11)
F2A	0.4018 (3)	1.1767 (14)	0.8164 (3)	0.0867 (16)	0.718 (11)
F3A	0.4367 (5)	1.253 (3)	0.7457 (9)	0.0838 (11)	0.718 (11)
C1B	0.40082 (14)	1.0874 (6)	0.7439 (2)	0.0594 (7)*	0.282 (11)
F1B	0.4233 (9)	0.839 (5)	0.7329 (14)	0.113 (2)	0.282 (11)
F2B	0.4209 (7)	1.060 (3)	0.8212 (8)	0.0867 (16)	0.282 (11)
F3B	0.4429 (15)	1.288 (8)	0.741 (2)	0.0838 (11)	0.282 (11)
N1	0.23275 (8)	0.5042 (4)	0.66983 (10)	0.0303 (4)
N2	0.18769 (7)	0.3269 (3)	0.65185 (10)	0.0307 (4)
H2	0.197260	0.217450	0.695247	0.037*
O1	0.29450 (7)	0.8889 (3)	0.65623 (10)	0.0399 (4)
O2	0.20159 (8)	0.9569 (3)	0.49600 (11)	0.0478 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C2	0.0536 (12)	0.0447 (14)	0.0480 (12)	−0.0159 (11)	0.0397 (11)	−0.0078 (10)
C3	0.0428 (10)	0.0333 (12)	0.0332 (9)	−0.0012 (9)	0.0295 (8)	−0.0024 (8)
C4	0.0354 (9)	0.0313 (11)	0.0277 (8)	−0.0008 (8)	0.0236 (7)	−0.0017 (7)
C5	0.0330 (9)	0.0402 (13)	0.0251 (8)	0.0027 (9)	0.0172 (7)	0.0028 (8)
C6	0.0306 (9)	0.0360 (12)	0.0298 (8)	−0.0005 (8)	0.0191 (8)	−0.0012 (8)
C7	0.0359 (10)	0.0500 (15)	0.0482 (12)	−0.0071 (10)	0.0246 (10)	−0.0014 (11)
F1A	0.054 (2)	0.089 (2)	0.130 (5)	0.0057 (18)	0.038 (3)	0.018 (4)
F2A	0.088 (3)	0.121 (4)	0.0569 (11)	−0.051 (3)	0.0515 (16)	−0.045 (2)
F3A	0.070 (2)	0.095 (4)	0.0957 (18)	−0.0487 (18)	0.0607 (14)	−0.012 (2)
F1B	0.054 (2)	0.089 (2)	0.130 (5)	0.0057 (18)	0.038 (3)	0.018 (4)
F2B	0.088 (3)	0.121 (4)	0.0569 (11)	−0.051 (3)	0.0515 (16)	−0.045 (2)
F3B	0.070 (2)	0.095 (4)	0.0957 (18)	−0.0487 (18)	0.0607 (14)	−0.012 (2)
N1	0.0332 (7)	0.0330 (9)	0.0267 (7)	−0.0038 (7)	0.0213 (6)	−0.0016 (6)
N2	0.0326 (7)	0.0330 (10)	0.0263 (7)	−0.0019 (7)	0.0200 (6)	0.0028 (6)
O1	0.0445 (8)	0.0450 (10)	0.0343 (7)	−0.0127 (7)	0.0286 (6)	−0.0036 (6)
O2	0.0564 (9)	0.0490 (11)	0.0391 (8)	−0.0020 (8)	0.0331 (7)	0.0102 (7)

Geometric parameters (Å, º) top

C2—O1	1.435 (2)	C7—H7A	0.9600
C2—C1A	1.470 (4)	C7—H7B	0.9600
C2—C1B	1.470 (4)	C7—H7C	0.9600
C2—H2A	0.9700	C7—H7D	0.9600
C2—H2B	0.9700	C7—H7E	0.9600
C3—O2	1.201 (2)	C7—H7F	0.9600
C3—O1	1.351 (2)	C1A—F3A	1.256 (7)
C3—C4	1.472 (3)	C1A—F1A	1.283 (8)
C4—N1	1.343 (2)	C1A—F2A	1.412 (6)
C4—C5	1.401 (3)	C1B—F2B	1.155 (11)
C5—C6	1.380 (3)	C1B—F1B	1.46 (3)
C5—H5	0.9300	C1B—F3B	1.539 (18)
C6—N2	1.355 (2)	N1—N2	1.347 (2)
C6—C7	1.494 (3)	N2—H2	0.8600

O1—C2—C1A	106.9 (2)	C6—C7—H7E	109.5
O1—C2—C1B	106.9 (2)	H7A—C7—H7E	56.3
O1—C2—H2A	110.3	H7B—C7—H7E	141.1
C1A—C2—H2A	110.3	H7C—C7—H7E	56.3
O1—C2—H2B	110.3	H7D—C7—H7E	109.5
C1A—C2—H2B	110.3	C6—C7—H7F	109.5
H2A—C2—H2B	108.6	H7A—C7—H7F	56.3
O2—C3—O1	124.09 (19)	H7B—C7—H7F	56.3
O2—C3—C4	124.35 (18)	H7C—C7—H7F	141.1
O1—C3—C4	111.56 (16)	H7D—C7—H7F	109.5
N1—C4—C5	111.54 (17)	H7E—C7—H7F	109.5
N1—C4—C3	121.32 (16)	F3A—C1A—F1A	108.1 (8)
C5—C4—C3	127.14 (17)	F3A—C1A—F2A	104.8 (7)
C6—C5—C4	105.27 (16)	F1A—C1A—F2A	104.8 (4)
C6—C5—H5	127.4	F3A—C1A—C2	112.3 (6)
C4—C5—H5	127.4	F1A—C1A—C2	118.2 (4)
N2—C6—C5	105.83 (17)	F2A—C1A—C2	107.5 (3)
N2—C6—C7	121.63 (19)	F2B—C1B—F1B	101.1 (9)
C5—C6—C7	132.54 (18)	F2B—C1B—C2	127.5 (7)
C6—C7—H7A	109.5	F1B—C1B—C2	99.2 (7)
C6—C7—H7B	109.5	F2B—C1B—F3B	113.0 (14)
H7A—C7—H7B	109.5	F1B—C1B—F3B	99.9 (19)
C6—C7—H7C	109.5	C2—C1B—F3B	110.3 (13)
H7A—C7—H7C	109.5	C4—N1—N2	103.93 (15)
H7B—C7—H7C	109.5	N1—N2—C6	113.44 (16)
C6—C7—H7D	109.5	N1—N2—H2	123.3
H7A—C7—H7D	141.1	C6—N2—H2	123.3
H7B—C7—H7D	56.3	C3—O1—C2	114.79 (16)
H7C—C7—H7D	56.3

O2—C3—C4—N1	177.56 (19)	O1—C2—C1B—F1B	73.5 (9)
O1—C3—C4—N1	−1.6 (3)	O1—C2—C1B—F3B	177.7 (17)
O2—C3—C4—C5	−1.9 (3)	C5—C4—N1—N2	0.3 (2)
O1—C3—C4—C5	178.99 (18)	C3—C4—N1—N2	−179.26 (16)
N1—C4—C5—C6	0.0 (2)	C4—N1—N2—C6	−0.5 (2)
C3—C4—C5—C6	179.51 (19)	C5—C6—N2—N1	0.5 (2)
C4—C5—C6—N2	−0.3 (2)	C7—C6—N2—N1	−178.95 (18)
C4—C5—C6—C7	179.1 (2)	O2—C3—O1—C2	−0.6 (3)
O1—C2—C1A—F3A	179.1 (8)	C4—C3—O1—C2	178.48 (17)
O1—C2—C1A—F1A	52.1 (5)	C1A—C2—O1—C3	−173.26 (19)
O1—C2—C1A—F2A	−66.1 (4)	C1B—C2—O1—C3	−173.26 (19)
O1—C2—C1B—F2B	−38.3 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N1ⁱ	0.86	2.13	2.922 (2)	153
C7—H7A···F2Aⁱⁱ	0.96	2.54	3.477 (7)	165
C7—H7D···F2Bⁱⁱⁱ	0.96	2.45	3.394 (11)	168

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

Hydrogen-bond geometry (Å, °) and selected torsion angles (°) for the ethyl 5-methyl-1H-pyrazole-3-carboxylate derivative (Figs. 11 and 12; refcode: FAQSAR02; Kusakiewicz-Dawid et al., 2019) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4C···O1ⁱ	0.96	2.66	3.5453 (19)	153.9
N1—H1···N2ⁱⁱ	0.86	2.17	2.9852 (18)	157.2
N1—H1···O2ⁱⁱ	0.86	2.48	3.0998 (16)	129.3

Atom chains	Torsion angles		Atom chains	Torsion angles
C1/C2/C3/C4	179.66 (16)		C2/C1/C5/O1	-5.5 (3)
C1/C5/O2/C6	-179.37 (12)		C2/C1/C5/O2	173.72 (14)
C1/N2/N1/C3	-0.54 (16)		C5/O2/C6/C7	174.94 (12)

Symmetry codes: (i) -x+1/2, y+1/2, -z+1/2; (ii) -x+3/2, y+1/2, -z+1/2.

Acknowledgements

ABO is deeply grateful to his academic mentor, Prof Johannes Beck (University of Bonn), for the long-time support, e.g. the access to the X-ray diffractometer facility and fruitful discussions.

Funding information

Funding for this research was provided by: CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/Brazilian Federal Agency for Support and Evaluation of Graduate Education), from the Brazilian Federal Ministry of Education; CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico/National Council for Scientific and Technological Development) and FINEP (Financiadora de Estudos e Projetos/Brazilian Innovation Agency), from the Brazilian Federal Ministry of Innovation, Science and Technology.

References

Alkorta, I., Elguero, J., Foces-Foces, C. & Infantes, L. (2005). Arkivoc ii, 15–30. Web of Science CrossRef Google Scholar
Ameziane El Hassani, I., Rouzi, K., Assila, H., Karrouchi, K. & Ansar, M. (2023). Reactions 4, 478–504. Web of Science CrossRef CAS Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2014). APEX2 SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Foces-Foces, C., Alkorta, I. & Elguero, J. (2000). Acta Cryst. B56, 1018–1028. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gonçalves, H. A., Pereira, B. A., Teixeira, W. K. O., Moura, S., Flores, D. C. & Flores, A. F. C. (2016). J. Fluor. Chem. 187, 40–45. 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
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Kusakiewicz-Dawid, A., Porada, M., Dziuk, B. & Siodłak, D. (2019). Molecules 24, 2632–0000. Web of Science PubMed Google Scholar
Ramajayam, R. (2025). J. Heterocycl. Chem. 62, 1424–1462. Web of Science CrossRef CAS Google Scholar
Ríos, M.-C. & Portilla, J. (2022). Chemistry 4, 940–968. Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006–1011. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar