Literature DB >> 21583697

N-[2-(6-Methyl-4-oxo-4H-chromen-3-yl)-4-oxothia-zolidin-3-yl]furan-2-carbox-amide N,N-dimethyl-formamide solvate.

Abstract

The title mol-ecule, C(18)H(14)N(2)O(5)S·C(3)H(7)NO, comprises of a carboxamide group bonded to a furan ring and a distorted envelope-shaped 4-oxothia-zolidin-3-yl group which is connected to a substituted 6-methyl-4-oxo-4H-chromen-3-yl group. Extensive strong N-H⋯O and weak C-H⋯O inter-molecular hydrogen-bonding inter-actions occur between dimethyl-formamide (DMF), the crystallizing solvent, and the various heterocyclic groups within the compound, as well as additional weak C-H⋯O inter-actions between the heterocyclic groups themselves. The carboxyl group of the DMF solvent mol-ecule forms a trifurcated (four-center) acceptor hydrogen-bond inter-action with the carboxamide, furan and 6-methyl-4-oxo-4H-chromen-3-yl groups. The dihedral angles between the planar chromone group [maximum deviation = 0.0377 (18)°] and those of the furan and 4-oxothia-zolidin-3-yl groups are 89.4 (6) and 78.5 (1)°, respectively.

Entities: CellLine Chemical Disease Species

Year: 2009 PMID： 21583697 PMCID： PMC2977248 DOI： 10.1107/S1600536809029572

Source DB: PubMed Journal: Acta Crystallogr Sect E Struct Rep Online ISSN： 1600-5368

Related literature

For related structures, see: Zhou et al. (2005 ▶). For the preparation of the title compound, see: Zhou et al. (2008 ▶). For general background to glycoluril and its derivatives, see: Maliar et al. (2004 ▶), Zhou et al. (2007 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C18H14N2O5S·C3H7NO M = 443.48 Triclinic, a = 8.4141 (1) Å b = 11.5676 (14) Å c = 11.8382 (14) Å α = 87.138 (1)° β = 70.503 (2)° γ = 78.419 (2)° V = 1063.86 (18) Å3 Z = 2 Mo Kα radiation μ = 0.20 mm−1 T = 292 K 0.30 × 0.20 × 0.20 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer Absorption correction: multi-scan (SADABS; Sheldrick, 2008 ▶) T min = 0.934, T max = 0.962 7900 measured reflections 4568 independent reflections 3163 reflections with I > 2σ(I) R int = 0.043

Refinement

R[F 2 > 2σ(F 2)] = 0.049 wR(F 2) = 0.130 S = 0.96 4568 reflections 289 parameters H atoms treated by a mixture of independent and constrained refinement Δρmax = 0.25 e Å−3 Δρmin = −0.17 e Å−3 Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97. Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809029572/jj2002sup1.cif Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029572/jj2002Isup2.hkl Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C₁₈H₁₄N₂O₅S·C₃H₇NO	Z = 2
M_r = 443.48	F(000) = 464
Triclinic, P1	D_x = 1.384 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.4141 (1) Å	Cell parameters from 2421 reflections
b = 11.5676 (14) Å	θ = 2.5–26.7°
c = 11.8382 (14) Å	µ = 0.20 mm⁻¹
α = 87.138 (1)°	T = 292 K
β = 70.503 (2)°	Block, colorless
γ = 78.419 (2)°	0.30 × 0.20 × 0.20 mm
V = 1063.86 (18) Å³

Bruker SMART APEX CCD area-detector diffractometer	4568 independent reflections
Radiation source: fine-focus sealed tube	3163 reflections with I > 2σ(I)
graphite	R_int = 0.043
φ and ω scans	θ_max = 27.0°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008)	h = −10→10
T_min = 0.934, T_max = 0.962	k = −13→14
7900 measured reflections	l = −15→15

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.130	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ²(F_o²) + (0.0676P)²] where P = (F_o² + 2F_c²)/3
4568 reflections	(Δ/σ)_max < 0.001
289 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.16 e Å⁻³

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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	U_iso*/U_eq
C1	0.2135 (3)	0.19985 (18)	0.1714 (2)	0.0722 (7)
H1A	0.1411	0.1794	0.1309	0.108*
H1B	0.2338	0.1381	0.2251	0.108*
H1C	0.3210	0.2097	0.1135	0.108*
C2	0.1263 (3)	0.31350 (16)	0.24164 (17)	0.0519 (5)
C3	−0.0211 (3)	0.31675 (18)	0.34263 (19)	0.0580 (6)
H3	−0.0598	0.2469	0.3680	0.070*
C4	−0.1099 (3)	0.41904 (17)	0.40512 (18)	0.0542 (5)
H4	−0.2082	0.4192	0.4713	0.065*
C5	−0.0502 (2)	0.52272 (16)	0.36769 (16)	0.0445 (4)
C6	0.0963 (2)	0.52416 (15)	0.26977 (15)	0.0420 (4)
C7	0.1832 (3)	0.41704 (16)	0.20822 (16)	0.0484 (5)
H7	0.2825	0.4164	0.1427	0.058*
C8	0.1533 (2)	0.63617 (16)	0.22977 (15)	0.0427 (4)
C9	0.0433 (2)	0.73858 (15)	0.30060 (15)	0.0414 (4)
C10	−0.0936 (2)	0.72643 (16)	0.39626 (16)	0.0467 (5)
H10	−0.1573	0.7941	0.4410	0.056*
C11	0.0758 (2)	0.86128 (16)	0.26908 (16)	0.0443 (4)
H11	−0.005	0.9161	0.3323	0.053*
C12	0.3611 (3)	0.89041 (15)	0.14565 (16)	0.0469 (5)
C13	0.2766 (3)	0.90147 (18)	0.05140 (17)	0.0573 (5)
H13A	0.3236	0.8335	−0.0027	0.069*
H13B	0.2968	0.9719	0.0052	0.069*
C14	0.2690 (2)	0.93551 (16)	0.43651 (15)	0.0415 (4)
C15	0.3436 (2)	0.89915 (16)	0.53174 (15)	0.0430 (4)
C16	0.4445 (3)	0.80082 (19)	0.55371 (19)	0.0593 (5)
H16	0.4843	0.7310	0.5086	0.071*
C17	0.4781 (3)	0.8243 (2)	0.6579 (2)	0.0678 (6)
H17	0.5443	0.7728	0.6952	0.081*
C18	0.3975 (3)	0.9337 (2)	0.69290 (19)	0.0650 (6)
H18	0.3986	0.9716	0.7600	0.078*
C19	0.7238 (4)	0.6242 (3)	0.1424 (3)	0.1048 (10)
H19A	0.6655	0.6544	0.0867	0.157*
H19B	0.8457	0.6078	0.1013	0.157*
H19C	0.6968	0.6818	0.2050	0.157*
C20	0.7468 (4)	0.4095 (3)	0.1255 (3)	0.1092 (11)
H20A	0.7150	0.3444	0.1756	0.164*
H20B	0.8696	0.4012	0.0976	0.164*
H20C	0.7074	0.4105	0.0581	0.164*
C21	0.5459 (3)	0.5218 (2)	0.2970 (2)	0.0710 (6)
H21	0.5136	0.4507	0.3256	0.085*
N1	0.2489 (2)	0.87432 (13)	0.25530 (13)	0.0442 (4)
N2	0.3049 (2)	0.85021 (14)	0.35237 (14)	0.0476 (4)
H2	0.361 (3)	0.7885 (19)	0.351 (2)	0.057*
N3	0.6696 (3)	0.51810 (17)	0.19314 (17)	0.0676 (5)
O1	0.28274 (17)	0.64100 (11)	0.14324 (11)	0.0563 (4)
O2	−0.14547 (16)	0.62410 (11)	0.43227 (11)	0.0507 (3)
O3	0.51047 (19)	0.89574 (13)	0.12709 (12)	0.0630 (4)
O4	0.18311 (18)	1.03252 (11)	0.43361 (11)	0.0534 (4)
O5	0.31260 (18)	0.98314 (12)	0.61700 (12)	0.0576 (4)
O6	0.4692 (2)	0.60997 (13)	0.35973 (14)	0.0764 (5)
S1	0.04994 (8)	0.91011 (5)	0.12526 (5)	0.0628 (2)

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.1061 (19)	0.0405 (12)	0.0708 (15)	−0.0139 (12)	−0.0301 (14)	−0.0033 (11)
C2	0.0703 (14)	0.0380 (11)	0.0530 (11)	−0.0120 (10)	−0.0274 (10)	0.0036 (9)
C3	0.0755 (15)	0.0429 (12)	0.0618 (13)	−0.0232 (11)	−0.0255 (11)	0.0115 (10)
C4	0.0597 (13)	0.0518 (12)	0.0518 (11)	−0.0213 (10)	−0.0150 (10)	0.0116 (10)
C5	0.0506 (11)	0.0418 (10)	0.0418 (10)	−0.0112 (9)	−0.0154 (8)	0.0037 (8)
C6	0.0508 (11)	0.0376 (10)	0.0395 (9)	−0.0110 (8)	−0.0163 (8)	0.0027 (8)
C7	0.0585 (12)	0.0419 (10)	0.0436 (10)	−0.0105 (9)	−0.0152 (9)	0.0012 (8)
C8	0.0508 (11)	0.0412 (10)	0.0370 (9)	−0.0129 (9)	−0.0136 (8)	0.0021 (8)
C9	0.0510 (11)	0.0369 (10)	0.0365 (9)	−0.0107 (8)	−0.0134 (8)	0.0014 (8)
C10	0.0516 (11)	0.0379 (10)	0.0460 (10)	−0.0071 (9)	−0.0109 (9)	−0.0015 (8)
C11	0.0529 (11)	0.0358 (10)	0.0403 (10)	−0.0075 (9)	−0.0110 (9)	−0.0008 (8)
C12	0.0619 (13)	0.0316 (10)	0.0436 (10)	−0.0142 (9)	−0.0098 (9)	0.0003 (8)
C13	0.0808 (15)	0.0505 (12)	0.0415 (10)	−0.0224 (11)	−0.0167 (10)	0.0060 (9)
C14	0.0460 (10)	0.0384 (10)	0.0368 (9)	−0.0152 (8)	−0.0053 (8)	−0.0005 (8)
C15	0.0456 (10)	0.0449 (11)	0.0371 (9)	−0.0163 (9)	−0.0071 (8)	−0.0004 (8)
C16	0.0659 (14)	0.0550 (13)	0.0594 (13)	−0.0103 (11)	−0.0244 (11)	−0.0015 (10)
C17	0.0738 (16)	0.0729 (16)	0.0672 (14)	−0.0154 (13)	−0.0374 (12)	0.0094 (12)
C18	0.0711 (15)	0.0889 (18)	0.0464 (12)	−0.0280 (14)	−0.0270 (11)	0.0023 (12)
C19	0.118 (3)	0.101 (2)	0.0788 (19)	−0.0156 (19)	−0.0172 (18)	0.0177 (17)
C20	0.137 (3)	0.094 (2)	0.0798 (19)	0.016 (2)	−0.0315 (19)	−0.0293 (17)
C21	0.0858 (18)	0.0557 (15)	0.0702 (16)	−0.0094 (13)	−0.0262 (14)	−0.0010 (12)
N1	0.0563 (10)	0.0408 (9)	0.0377 (8)	−0.0143 (7)	−0.0156 (7)	0.0006 (7)
N2	0.0655 (11)	0.0351 (9)	0.0426 (8)	−0.0052 (8)	−0.0206 (8)	−0.0017 (7)
N3	0.0767 (13)	0.0657 (12)	0.0566 (11)	0.0029 (10)	−0.0263 (10)	−0.0027 (10)
O1	0.0622 (9)	0.0481 (8)	0.0469 (7)	−0.0175 (7)	0.0017 (7)	−0.0035 (6)
O2	0.0532 (8)	0.0426 (8)	0.0469 (7)	−0.0117 (6)	−0.0030 (6)	0.0020 (6)
O3	0.0613 (10)	0.0649 (10)	0.0587 (9)	−0.0208 (8)	−0.0099 (7)	0.0031 (7)
O4	0.0688 (9)	0.0368 (7)	0.0531 (8)	−0.0047 (7)	−0.0206 (7)	−0.0056 (6)
O5	0.0661 (9)	0.0616 (9)	0.0465 (7)	−0.0110 (7)	−0.0197 (7)	−0.0101 (7)
O6	0.0965 (13)	0.0516 (9)	0.0663 (10)	0.0032 (9)	−0.0167 (9)	−0.0069 (8)
S1	0.0733 (4)	0.0633 (4)	0.0590 (3)	−0.0192 (3)	−0.0307 (3)	0.0198 (3)

C1—C2	1.508 (3)	C13—S1	1.797 (2)
C1—H1A	0.9600	C13—H13A	0.9700
C1—H1B	0.9600	C13—H13B	0.9700
C1—H1C	0.9600	C14—O4	1.212 (2)
C2—C7	1.370 (2)	C14—N2	1.354 (2)
C2—C3	1.401 (3)	C14—C15	1.470 (3)
C3—C4	1.367 (3)	C15—C16	1.347 (3)
C3—H3	0.9300	C15—O5	1.361 (2)
C4—C5	1.388 (2)	C16—C17	1.404 (3)
C4—H4	0.9300	C16—H16	0.9300
C5—O2	1.380 (2)	C17—C18	1.325 (3)
C5—C6	1.384 (2)	C17—H17	0.9300
C6—C7	1.404 (3)	C18—O5	1.363 (2)
C6—C8	1.473 (2)	C18—H18	0.9300
C7—H7	0.9300	C19—N3	1.430 (3)
C8—O1	1.230 (2)	C19—H19A	0.9600
C8—C9	1.450 (2)	C19—H19B	0.9600
C9—C10	1.344 (2)	C19—H19C	0.9600
C9—C11	1.504 (2)	C20—N3	1.438 (3)
C10—O2	1.344 (2)	C20—H20A	0.9600
C10—H10	0.9300	C20—H20B	0.9600
C11—N1	1.448 (2)	C20—H20C	0.9600
C11—S1	1.8349 (19)	C21—O6	1.224 (3)
C11—H11	0.9800	C21—N3	1.315 (3)
C12—O3	1.216 (2)	C21—H21	0.9300
C12—N1	1.356 (2)	N1—N2	1.378 (2)
C12—C13	1.498 (3)	N2—H2	0.77 (2)

C2—C1—H1A	109.5	C12—C13—H13B	110.1
C2—C1—H1B	109.5	S1—C13—H13B	110.1
H1A—C1—H1B	109.5	H13A—C13—H13B	108.4
C2—C1—H1C	109.5	O4—C14—N2	123.15 (17)
H1A—C1—H1C	109.5	O4—C14—C15	123.24 (16)
H1B—C1—H1C	109.5	N2—C14—C15	113.61 (17)
C7—C2—C3	117.65 (18)	C16—C15—O5	109.77 (17)
C7—C2—C1	122.10 (19)	C16—C15—C14	134.79 (17)
C3—C2—C1	120.22 (18)	O5—C15—C14	115.37 (16)
C4—C3—C2	122.26 (18)	C15—C16—C17	106.6 (2)
C4—C3—H3	118.9	C15—C16—H16	126.7
C2—C3—H3	118.9	C17—C16—H16	126.7
C3—C4—C5	118.60 (18)	C18—C17—C16	106.9 (2)
C3—C4—H4	120.7	C18—C17—H17	126.5
C5—C4—H4	120.7	C16—C17—H17	126.5
O2—C5—C6	121.90 (15)	C17—C18—O5	110.6 (2)
O2—C5—C4	116.58 (16)	C17—C18—H18	124.7
C6—C5—C4	121.52 (18)	O5—C18—H18	124.7
C5—C6—C7	117.91 (16)	N3—C19—H19A	109.5
C5—C6—C8	120.29 (16)	N3—C19—H19B	109.5
C7—C6—C8	121.76 (16)	H19A—C19—H19B	109.5
C2—C7—C6	122.04 (18)	N3—C19—H19C	109.5
C2—C7—H7	119.0	H19A—C19—H19C	109.5
C6—C7—H7	119.0	H19B—C19—H19C	109.5
O1—C8—C9	123.67 (16)	N3—C20—H20A	109.5
O1—C8—C6	122.18 (17)	N3—C20—H20B	109.5
C9—C8—C6	114.14 (15)	H20A—C20—H20B	109.5
C10—C9—C8	120.52 (16)	N3—C20—H20C	109.5
C10—C9—C11	117.78 (16)	H20A—C20—H20C	109.5
C8—C9—C11	121.69 (15)	H20B—C20—H20C	109.5
O2—C10—C9	125.11 (17)	O6—C21—N3	126.2 (2)
O2—C10—H10	117.4	O6—C21—H21	116.9
C9—C10—H10	117.4	N3—C21—H21	116.9
N1—C11—C9	113.96 (16)	C12—N1—N2	120.45 (16)
N1—C11—S1	103.67 (11)	C12—N1—C11	120.75 (16)
C9—C11—S1	113.20 (12)	N2—N1—C11	117.91 (14)
N1—C11—H11	109.0	C14—N2—N1	119.57 (15)
C9—C11—H11	109.0	C14—N2—H2	125.4 (17)
S1—C11—H11	109.0	N1—N2—H2	114.9 (17)
O3—C12—N1	124.01 (19)	C21—N3—C19	120.1 (2)
O3—C12—C13	124.74 (17)	C21—N3—C20	121.3 (2)
N1—C12—C13	111.25 (17)	C19—N3—C20	118.6 (2)
C12—C13—S1	108.00 (13)	C10—O2—C5	117.98 (14)
C12—C13—H13A	110.1	C15—O5—C18	106.03 (16)
S1—C13—H13A	110.1	C13—S1—C11	93.51 (9)

C7—C2—C3—C4	1.8 (3)	N2—C14—C15—C16	2.3 (3)
C1—C2—C3—C4	−176.30 (19)	O4—C14—C15—O5	−1.2 (2)
C2—C3—C4—C5	−0.8 (3)	N2—C14—C15—O5	178.98 (14)
C3—C4—C5—O2	178.99 (17)	O5—C15—C16—C17	0.1 (2)
C3—C4—C5—C6	−0.3 (3)	C14—C15—C16—C17	177.0 (2)
O2—C5—C6—C7	−178.88 (16)	C15—C16—C17—C18	−0.1 (2)
C4—C5—C6—C7	0.4 (3)	C16—C17—C18—O5	0.1 (3)
O2—C5—C6—C8	−1.3 (3)	O3—C12—N1—N2	−7.0 (3)
C4—C5—C6—C8	178.01 (17)	C13—C12—N1—N2	173.40 (15)
C3—C2—C7—C6	−1.7 (3)	O3—C12—N1—C11	−175.98 (17)
C1—C2—C7—C6	176.35 (18)	C13—C12—N1—C11	4.4 (2)
C5—C6—C7—C2	0.6 (3)	C9—C11—N1—C12	109.33 (18)
C8—C6—C7—C2	−176.91 (17)	S1—C11—N1—C12	−14.16 (19)
C5—C6—C8—O1	180.00 (18)	C9—C11—N1—N2	−59.9 (2)
C7—C6—C8—O1	−2.5 (3)	S1—C11—N1—N2	176.57 (11)
C5—C6—C8—C9	−0.4 (2)	O4—C14—N2—N1	2.9 (3)
C7—C6—C8—C9	177.10 (16)	C15—C14—N2—N1	−177.28 (14)
O1—C8—C9—C10	−178.07 (19)	C12—N1—N2—C14	105.6 (2)
C6—C8—C9—C10	2.3 (3)	C11—N1—N2—C14	−85.1 (2)
O1—C8—C9—C11	3.0 (3)	O6—C21—N3—C19	−1.2 (4)
C6—C8—C9—C11	−176.62 (16)	O6—C21—N3—C20	−178.0 (2)
C8—C9—C10—O2	−2.8 (3)	C9—C10—O2—C5	1.0 (3)
C11—C9—C10—O2	176.18 (16)	C6—C5—O2—C10	1.1 (3)
C10—C9—C11—N1	127.95 (18)	C4—C5—O2—C10	−178.26 (16)
C8—C9—C11—N1	−53.1 (2)	C16—C15—O5—C18	−0.1 (2)
C10—C9—C11—S1	−113.90 (17)	C14—C15—O5—C18	−177.62 (15)
C8—C9—C11—S1	65.1 (2)	C17—C18—O5—C15	0.0 (2)
O3—C12—C13—S1	−171.45 (16)	C12—C13—S1—C11	−13.78 (14)
N1—C12—C13—S1	8.17 (19)	N1—C11—S1—C13	15.17 (13)
O4—C14—C15—C16	−177.9 (2)	C9—C11—S1—C13	−108.82 (14)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O6	0.77 (2)	2.10 (2)	2.856 (2)	169 (2)
C4—H4···O6ⁱ	0.93	2.50	3.421 (3)	172
C10—H10···O4ⁱⁱ	0.93	2.49	3.332 (2)	151
C11—H11···O5ⁱⁱ	0.98	2.50	3.267 (2)	135 (1)
C13—H13B···O3ⁱⁱⁱ	0.97	2.55	3.441 (2)	153
C16—H16···O6	0.93	2.36	3.193 (3)	150
C18—H18···O3^iv	0.93	2.47	3.342 (3)	157
C20—H20C···O1^v	0.96	2.46	3.361 (3)	157

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯O6	0.77 (2)	2.10 (2)	2.856 (2)	169 (2)
C4—H4⋯O6ⁱ	0.93	2.50	3.421 (3)	172
C10—H10⋯O4ⁱⁱ	0.93	2.49	3.332 (2)	151
C11—H11⋯O5ⁱⁱ	0.98	2.50	3.267 (2)	135 (1)
C13—H13B⋯O3ⁱⁱⁱ	0.97	2.55	3.441 (2)	153
C16—H16⋯O6	0.93	2.36	3.193 (3)	150
C18—H18⋯O3^iv	0.93	2.47	3.342 (3)	157
C20—H20C⋯O1^v	0.96	2.46	3.361 (3)	157

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

3 in total

N-[2-(6-Methyl-4-oxo-4H-chromen-3-yl)-4-oxothia-zolidin-3-yl]furan-2-carbox-amide N,N-dimethyl-formamide solvate.

Related literature

Experimental

Crystal data

Data collection

Refinement

1. A short history of SHELX.

2. Structural aspects of flavonoids as trypsin inhibitors.

3. Structure validation in chemical crystallography.