Ethyl 1-butyl-6-methyl-2-phenyl-4-thioxo-1,4-dihydro­pyrimidine-5-carboxyl­ate

Sabino, J.R.; Vencato, I.; Bastos, R.M.; Cunha, S.

doi:10.1107/S1600536807019964

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Ethyl 1-butyl-6-methyl-2-phenyl-4-thioxo-1,4-dihydropyrimidine-5-carboxylate

J. R. Sabino, I. Vencato, R. M. Bastos and S. Cunha

The title compound, C₁₈H₂₂N₂O₂S, is of interest with respect to antibacterial and anticancer activity and it has shown good trypanocidal activity. The molecular packing lacks classical hydrogen bonds, being mediated only by weak van der Waals forces.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807019964/cf2100sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807019964/cf2100Isup2.hkl Contains datablock I

CCDC reference: 601660

checkCIF report

Key indicators

Single-crystal X-ray study
T = 297 K
Mean (C-C) = 0.005 Å
Disorder in main residue
R factor = 0.052
wR factor = 0.135
Data-to-parameter ratio = 9.5

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT220_ALERT_2_B Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.63 Ratio

Alert level C
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.79 Ratio
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C17
PLAT245_ALERT_2_C U(iso) H17B    Smaller than U(eq) C18B    by ...       0.03 AngSq
PLAT301_ALERT_3_C Main Residue  Disorder .........................       4.00 Perc.
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           67.13
           From the CIF: _reflns_number_total               2034
           Count of symmetry unique reflns         1764
           Completeness (_total/calc)            115.31%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       270
           Fraction of Friedel pairs measured     0.153
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

In continuation of our solid-state studies of bioactive thioxopyrimidine, we performed the crystallographic characterization of the title 4-thioxopyrimidine (I), which exhibited a lowered antifungal but enhanced trypanocidal activities compared to related compounds (Cunha et al., 2007).

The molecule of (I) is depicted in Fig. 1. This derivative differs from those of Parts 1 and 2 by a substituent on the ring atom N1, where (I) has a butyl group instead of a hydroxyethyl group. The conformation of compound (I) is defined by steric effects. The pyrimidine ring is planar with an r.m.s. deviation of 0.022 Å. With reference to this plane, the phenyl ring is rotated by 65.0 (1)°, approaching a gauche conformation. The torsion angles C4—C5—C14—O15 and C20—C19—N1—C6 are -99.3 (4)° and -92.9 (3)°, respectively. Bond lengths are within the expected ranges with the exception of the C2–C7 and C5–C14 bonds which are elongated by an average of 0.035 Å from the formal single bond distance.

It is interesting to note that the crystal packing of compound (I) is maintained by van der Waals forces only; it does not form dimers involving C═O···π-ring interactions as observed in the previous derivatives. It is supposed that the steric inaccessibility due to the long butyl substituent group prevents the pyrimidine ring stacking. The packing is shown in Fig. 2.

Related literature top

For the synthesis, see: Cunha et al. (2007). A butyl group on atom N1 in this structure replaces a hydroxyethyl group in the derivatives described in the preceding papers (Sabino, Lariucci et al., 2007; Sabino, Vencato et al., 2007). Owing to the different chemical nature of the butyl group, the title compound does not pack in the same manner and lacks the intermolecular hydrogen-bond contacts observed in the previous derivatives.

Experimental top

Compound (I) (m.p. 447.6–448.6 K) was prepared according to a known procedure (Cunha et al., 2007). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a solution in CHCl₃ at room temperature.

Structure description top

Computing details top

Data collection: CAD-4-PC (Enraf–Nonius, 1993); cell refinement: CAD-4-PC; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. The molecular structure of (I) with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitray radius.
	Fig. 2. Packing diagram of (I).

Ethyl 1-butyl-6-methyl-2-phenyl-4-thioxo-1,4-dihydropyrimidine-5-carboxylate top

Crystal data top

C₁₈H₂₂N₂O₂S	F(000) = 352
M_r = 330.45	D_x = 1.208 Mg m⁻³
Monoclinic, P2₁	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 10.9870 (18) Å	θ = 12.9–40.6°
b = 7.2840 (14) Å	µ = 1.66 mm⁻¹
c = 12.5885 (13) Å	T = 297 K
β = 115.591 (9)°	Prism, yellow
V = 908.6 (3) Å³	0.35 × 0.25 × 0.05 mm
Z = 2

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.047
ω/2θ scans	θ_max = 67.1°, θ_min = 3.9°
Absorption correction: ψ scan (North et al., 1968)	h = −13→11
T_min = 0.594, T_max = 0.922	k = −1→8
2129 measured reflections	l = 0→15
2034 independent reflections	2 standard reflections every 120 min
1907 reflections with I > 2σ(I)	intensity decay: 2%

Refinement top

Refinement on F²	w = 1/[σ²(F_o²) + (0.1111P)² + 0.0314P] where P = (F_o² + 2F_c²)/3
Least-squares matrix: full	(Δ/σ)_max < 0.001
R[F² > 2σ(F²)] = 0.052	Δρ_max = 0.28 e Å⁻³
wR(F²) = 0.136	Δρ_min = −0.44 e Å⁻³
S = 1.09	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
2034 reflections	Extinction coefficient: 0.034 (3)
214 parameters	Absolute structure: Flack (1983), 270 Friedel pairs
1 restraint	Absolute structure parameter: 0.10 (3)
H-atom parameters constrained

Crystal data top

C₁₈H₂₂N₂O₂S	V = 908.6 (3) Å³
M_r = 330.45	Z = 2
Monoclinic, P2₁	Cu Kα radiation
a = 10.9870 (18) Å	µ = 1.66 mm⁻¹
b = 7.2840 (14) Å	T = 297 K
c = 12.5885 (13) Å	0.35 × 0.25 × 0.05 mm
β = 115.591 (9)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1907 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.047
T_min = 0.594, T_max = 0.922	2 standard reflections every 120 min
2129 measured reflections	intensity decay: 2%
2034 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	H-atom parameters constrained
wR(F²) = 0.136	Δρ_max = 0.28 e Å⁻³
S = 1.09	Δρ_min = −0.44 e Å⁻³
2034 reflections	Absolute structure: Flack (1983), 270 Friedel pairs
214 parameters	Absolute structure parameter: 0.10 (3)
1 restraint

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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)
S	0.77081 (9)	0.15710 (13)	0.75355 (7)	0.0651 (3)
N1	0.7310 (2)	0.5282 (3)	0.46126 (19)	0.0458 (5)
C2	0.7929 (2)	0.3596 (4)	0.4803 (2)	0.0423 (6)
N3	0.8080 (2)	0.2499 (4)	0.5663 (2)	0.0466 (5)
C4	0.7614 (3)	0.3022 (4)	0.6479 (2)	0.0463 (6)
C5	0.7055 (2)	0.4821 (4)	0.6357 (2)	0.0462 (6)
C6	0.6850 (3)	0.5898 (4)	0.5420 (2)	0.0476 (6)
C7	0.8475 (2)	0.2935 (4)	0.3973 (2)	0.0435 (6)
C8	0.7920 (3)	0.1380 (5)	0.3314 (2)	0.0508 (7)
H8	0.7191	0.0806	0.3365	0.061*
C9	0.8442 (3)	0.0673 (6)	0.2581 (3)	0.0632 (8)
H9	0.8066	−0.0378	0.2142	0.076*
C10	0.9521 (3)	0.1521 (7)	0.2496 (3)	0.0665 (9)
H10	0.9874	0.1041	0.2002	0.08*
C11	1.0069 (3)	0.3070 (7)	0.3139 (3)	0.0681 (10)
H11	1.0784	0.3652	0.3069	0.082*
C12	0.9574 (3)	0.3781 (5)	0.3895 (3)	0.0575 (8)
H12	0.997	0.4814	0.4346	0.069*
C13	0.6183 (4)	0.7740 (6)	0.5228 (3)	0.0734 (10)
H13A	0.542	0.7765	0.4471	0.11*
H13B	0.6814	0.8674	0.5259	0.11*
H13C	0.5888	0.7963	0.5832	0.11*
C14	0.6638 (3)	0.5473 (5)	0.7281 (3)	0.0556 (7)
O15	0.5505 (2)	0.5468 (6)	0.7192 (2)	0.0825 (9)
O16	0.7694 (2)	0.6091 (5)	0.82076 (18)	0.0664 (7)
C17	0.7489 (5)	0.6655 (11)	0.9216 (4)	0.1002 (18)
H17A	0.6863	0.7678	0.9003	0.12*
H17B	0.7103	0.565	0.9474	0.12*
C18A	0.8742 (8)	0.719 (3)	1.0149 (7)	0.154 (6)	0.807 (19)
H18A	0.8707	0.7003	1.089	0.231*	0.807 (19)
H18B	0.8908	0.8461	1.0063	0.231*	0.807 (19)
H18C	0.9455	0.6458	1.0122	0.231*	0.807 (19)
C18B	0.843 (4)	0.569 (11)	1.019 (3)	0.154 (6)	0.193 (19)
H18D	0.8499	0.625	1.0903	0.231*	0.193 (19)
H18E	0.93	0.573	1.0174	0.231*	0.193 (19)
H18F	0.815	0.4439	1.0157	0.231*	0.193 (19)
C19	0.7021 (3)	0.6331 (5)	0.3526 (2)	0.0546 (7)
H19A	0.778	0.6213	0.3329	0.066*
H19B	0.6928	0.762	0.367	0.066*
C20	0.5751 (3)	0.5694 (5)	0.2488 (2)	0.0565 (7)
H20A	0.4982	0.5836	0.2668	0.068*
H20B	0.5832	0.4404	0.2338	0.068*
C21	0.5532 (4)	0.6817 (7)	0.1401 (2)	0.0729 (10)
H21A	0.55	0.8108	0.1576	0.087*
H21B	0.6297	0.6638	0.1219	0.087*
C22	0.4257 (5)	0.6321 (9)	0.0332 (3)	0.0909 (13)
H22A	0.4174	0.7079	−0.032	0.136*
H22B	0.3493	0.6514	0.0499	0.136*
H22C	0.4293	0.5054	0.0137	0.136*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S	0.0847 (5)	0.0628 (5)	0.0606 (4)	0.0110 (4)	0.0435 (4)	0.0122 (4)
N1	0.0506 (11)	0.0397 (12)	0.0433 (11)	0.0013 (10)	0.0166 (9)	−0.0012 (10)
C2	0.0426 (11)	0.0394 (14)	0.0428 (12)	−0.0002 (10)	0.0163 (10)	−0.0022 (11)
N3	0.0534 (11)	0.0428 (13)	0.0476 (11)	0.0064 (11)	0.0255 (9)	0.0035 (11)
C4	0.0426 (12)	0.0493 (15)	0.0463 (13)	−0.0003 (12)	0.0186 (10)	−0.0024 (13)
C5	0.0388 (11)	0.0492 (16)	0.0475 (13)	−0.0005 (11)	0.0157 (9)	−0.0088 (12)
C6	0.0448 (12)	0.0441 (14)	0.0470 (13)	0.0032 (11)	0.0134 (10)	−0.0076 (12)
C7	0.0437 (12)	0.0437 (14)	0.0441 (12)	0.0013 (11)	0.0200 (9)	0.0026 (12)
C8	0.0529 (13)	0.0488 (17)	0.0592 (14)	−0.0056 (13)	0.0322 (11)	−0.0033 (14)
C9	0.0650 (16)	0.070 (2)	0.0627 (17)	−0.0080 (16)	0.0350 (14)	−0.0179 (18)
C10	0.0630 (16)	0.087 (3)	0.0629 (16)	0.008 (2)	0.0401 (13)	0.002 (2)
C11	0.0493 (14)	0.088 (3)	0.078 (2)	−0.0044 (17)	0.0380 (14)	0.005 (2)
C12	0.0467 (13)	0.0606 (18)	0.0642 (17)	−0.0108 (13)	0.0230 (12)	−0.0040 (16)
C13	0.086 (2)	0.057 (2)	0.068 (2)	0.026 (2)	0.0248 (17)	−0.0021 (18)
C14	0.0483 (13)	0.0607 (19)	0.0589 (15)	0.0017 (14)	0.0243 (11)	−0.0098 (15)
O15	0.0518 (11)	0.118 (3)	0.0857 (15)	0.0043 (14)	0.0368 (10)	−0.0215 (18)
O16	0.0597 (11)	0.0851 (18)	0.0565 (11)	−0.0044 (12)	0.0269 (9)	−0.0261 (12)
C17	0.096 (3)	0.136 (5)	0.077 (2)	−0.001 (3)	0.044 (2)	−0.045 (3)
C18A	0.100 (5)	0.269 (19)	0.080 (3)	−0.018 (7)	0.027 (3)	−0.099 (8)
C18B	0.100 (5)	0.269 (19)	0.080 (3)	−0.018 (7)	0.027 (3)	−0.099 (8)
C19	0.0628 (15)	0.0433 (16)	0.0532 (14)	0.0017 (13)	0.0208 (12)	0.0074 (14)
C20	0.0618 (15)	0.0568 (18)	0.0475 (14)	0.0066 (15)	0.0204 (11)	0.0068 (15)
C21	0.085 (2)	0.080 (3)	0.0484 (15)	−0.003 (2)	0.0241 (14)	0.0064 (18)
C22	0.109 (3)	0.093 (3)	0.0504 (16)	−0.009 (3)	0.0157 (17)	0.003 (2)

Geometric parameters (Å, º) top

S—C4	1.666 (3)	C14—O15	1.201 (3)
N1—C2	1.374 (4)	C14—O16	1.319 (4)
N1—C6	1.390 (4)	O16—C17	1.442 (4)
N1—C19	1.477 (4)	C17—C18B	1.40 (6)
C2—N3	1.297 (4)	C17—C18A	1.424 (10)
C2—C7	1.492 (4)	C17—H17A	0.97
N3—C4	1.385 (3)	C17—H17B	0.97
C4—C5	1.427 (4)	C18A—H18A	0.96
C5—C6	1.353 (4)	C18A—H18B	0.96
C5—C14	1.499 (4)	C18A—H18C	0.96
C6—C13	1.498 (5)	C18B—H18D	0.96
C7—C8	1.381 (4)	C18B—H18E	0.96
C7—C12	1.396 (4)	C18B—H18F	0.96
C8—C9	1.380 (4)	C19—C20	1.515 (4)
C8—H8	0.93	C19—H19A	0.97
C9—C10	1.382 (5)	C19—H19B	0.97
C9—H9	0.93	C20—C21	1.522 (4)
C10—C11	1.367 (7)	C20—H20A	0.97
C10—H10	0.93	C20—H20B	0.97
C11—C12	1.384 (5)	C21—C22	1.508 (5)
C11—H11	0.93	C21—H21A	0.97
C12—H12	0.93	C21—H21B	0.97
C13—H13A	0.96	C22—H22A	0.96
C13—H13B	0.96	C22—H22B	0.96
C13—H13C	0.96	C22—H22C	0.96

C2—N1—C6	118.0 (2)	C18B—C17—O16	106.8 (16)
C2—N1—C19	121.1 (2)	C18A—C17—O16	109.9 (4)
C6—N1—C19	120.6 (2)	C18B—C17—H17A	142.5
N3—C2—N1	124.9 (2)	C18A—C17—H17A	109.7
N3—C2—C7	116.1 (2)	O16—C17—H17A	109.7
N1—C2—C7	119.0 (2)	C18B—C17—H17B	66.2
C2—N3—C4	119.7 (2)	C18A—C17—H17B	109.7
N3—C4—C5	116.9 (3)	O16—C17—H17B	109.7
N3—C4—S	120.2 (2)	H17A—C17—H17B	108.2
C5—C4—S	122.9 (2)	C17—C18A—H18A	109.5
C6—C5—C4	121.9 (2)	C17—C18A—H18B	109.5
C6—C5—C14	120.1 (3)	H18A—C18A—H18B	109.5
C4—C5—C14	118.0 (3)	C17—C18A—H18C	109.5
C5—C6—N1	118.3 (3)	H18A—C18A—H18C	109.5
C5—C6—C13	123.1 (3)	H18B—C18A—H18C	109.5
N1—C6—C13	118.6 (3)	C17—C18B—H18D	109.5
C8—C7—C12	119.4 (3)	C17—C18B—H18E	109.5
C8—C7—C2	118.6 (2)	H18D—C18B—H18E	109.5
C12—C7—C2	121.9 (3)	C17—C18B—H18F	109.5
C9—C8—C7	120.3 (3)	H18D—C18B—H18F	109.5
C9—C8—H8	119.8	H18E—C18B—H18F	109.5
C7—C8—H8	119.8	N1—C19—C20	112.9 (3)
C8—C9—C10	120.2 (4)	N1—C19—H19A	109
C8—C9—H9	119.9	C20—C19—H19A	109
C10—C9—H9	119.9	N1—C19—H19B	109
C11—C10—C9	119.7 (3)	C20—C19—H19B	109
C11—C10—H10	120.1	H19A—C19—H19B	107.8
C9—C10—H10	120.1	C19—C20—C21	109.8 (3)
C10—C11—C12	120.9 (3)	C19—C20—H20A	109.7
C10—C11—H11	119.6	C21—C20—H20A	109.7
C12—C11—H11	119.6	C19—C20—H20B	109.7
C11—C12—C7	119.4 (3)	C21—C20—H20B	109.7
C11—C12—H12	120.3	H20A—C20—H20B	108.2
C7—C12—H12	120.3	C22—C21—C20	113.5 (4)
C6—C13—H13A	109.5	C22—C21—H21A	108.9
C6—C13—H13B	109.5	C20—C21—H21A	108.9
H13A—C13—H13B	109.5	C22—C21—H21B	108.9
C6—C13—H13C	109.5	C20—C21—H21B	108.9
H13A—C13—H13C	109.5	H21A—C21—H21B	107.7
H13B—C13—H13C	109.5	C21—C22—H22A	109.5
O15—C14—O16	124.3 (3)	C21—C22—H22B	109.5
O15—C14—C5	125.3 (3)	H22A—C22—H22B	109.5
O16—C14—C5	110.3 (2)	C21—C22—H22C	109.5
C14—O16—C17	117.6 (3)	H22A—C22—H22C	109.5
C18B—C17—C18A	48 (3)	H22B—C22—H22C	109.5

C6—N1—C2—N3	2.4 (4)	N3—C2—C7—C12	−112.8 (3)
C19—N1—C2—N3	−171.8 (3)	N1—C2—C7—C12	67.4 (4)
C6—N1—C2—C7	−177.8 (2)	C12—C7—C8—C9	−0.3 (5)
C19—N1—C2—C7	8.0 (3)	C2—C7—C8—C9	−176.8 (3)
N1—C2—N3—C4	−0.9 (4)	C7—C8—C9—C10	−0.3 (5)
C7—C2—N3—C4	179.3 (2)	C8—C9—C10—C11	−0.2 (6)
C2—N3—C4—C5	−3.6 (3)	C9—C10—C11—C12	1.3 (6)
C2—N3—C4—S	175.89 (19)	C10—C11—C12—C7	−1.9 (6)
N3—C4—C5—C6	7.1 (4)	C8—C7—C12—C11	1.4 (5)
S—C4—C5—C6	−172.4 (2)	C2—C7—C12—C11	177.7 (3)
N3—C4—C5—C14	−175.5 (2)	C6—C5—C14—O15	78.1 (5)
S—C4—C5—C14	5.0 (3)	C4—C5—C14—O15	−99.3 (4)
C4—C5—C6—N1	−5.7 (4)	C6—C5—C14—O16	−100.7 (3)
C14—C5—C6—N1	176.9 (2)	C4—C5—C14—O16	81.8 (4)
C4—C5—C6—C13	175.9 (3)	O15—C14—O16—C17	5.4 (7)
C14—C5—C6—C13	−1.5 (4)	C5—C14—O16—C17	−175.8 (4)
C2—N1—C6—C5	1.0 (4)	C14—O16—C17—C18B	126 (3)
C19—N1—C6—C5	175.2 (2)	C14—O16—C17—C18A	177.0 (9)
C2—N1—C6—C13	179.5 (3)	C2—N1—C19—C20	81.1 (3)
C19—N1—C6—C13	−6.3 (4)	C6—N1—C19—C20	−92.9 (3)
N3—C2—C7—C8	63.6 (3)	N1—C19—C20—C21	−179.2 (3)
N1—C2—C7—C8	−116.2 (3)	C19—C20—C21—C22	−177.8 (4)

Experimental details

Crystal data
Chemical formula	C₁₈H₂₂N₂O₂S
M_r	330.45
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	297
a, b, c (Å)	10.9870 (18), 7.2840 (14), 12.5885 (13)
β (°)	115.591 (9)
V (Å³)	908.6 (3)
Z	2
Radiation type	Cu Kα
µ (mm⁻¹)	1.66
Crystal size (mm)	0.35 × 0.25 × 0.05

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.594, 0.922
No. of measured, independent and observed [I > 2σ(I)] reflections	2129, 2034, 1907
R_int	0.047
(sin θ/λ)_max (Å⁻¹)	0.598

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.136, 1.09
No. of reflections	2034
No. of parameters	214
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.28, −0.44
Absolute structure	Flack (1983), 270 Friedel pairs
Absolute structure parameter	0.10 (3)

Computer programs: CAD-4-PC (Enraf–Nonius, 1993), CAD-4-PC, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), WinGX (Farrugia, 1999).

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