A unique axially triacetyl­ated xylopyran­ose structure, methyl 6-­methoxy-2-methyl-1,3-dioxo-4-[(2,3,4-tri-O-acetyl-β-D-xylo­pyran­osyl)amino]-2,3-di­hydro-1H-pyrrolo­[3,4-c]­pyridine-7-carboxyl­ate

The title compound, C₂₂H₂₅N₃O₁₂, is unique amongst β-D-(tri-O-acetyl)­xylo­pyran­osyl compounds in having all three acetyl groups in axial positions.

S1. Comment

Our investigations of the use of hetero Diels-Alder reactions have resulted in the preparation of novel substituted nucleobases compounds containing acetylated xylopyranose substituents (Low et al., 1996; Cobo et al., 1996). In these compounds, all the substituent acetyl groups on the sugar rings were found to be equatorial. In the title compound (I), all acetyl groups are axial to the sugar ring, Figure 1. Relevant torsion angles are given in Table 1. \sch

It is well known that β-xylopyranosides tend to adopt a chair conformation with all four substituents occupying equatorial positions (⁴C₁ conformation). This is assumed to be the most stable of all possible conformations due to the relative low energy of the 1-equatorial:3-equatorial steric interactions between the hydroxyls (or functionalized hydroxyls) in comparison with the strong 1-axial:3-axial interaction found in the alternative chair conformation, the ¹C₄ conformation (Schwarz, 1973). The conformational features found in our previous work with β-D-(per-O-acetyl)xylopyranosylamino derivatives, cited above, are in agreement with the above statement, the ⁴C₁ conformation being found in the crystal structures. In solution (DMSO-d6) at 293 K, the ⁴C₁ conformation was also found for these compounds, as shown by the large values of the vicinal (³J) coupling constants between the hydrogen atoms of the pyranose rings measured in their 1H-NMR spectra; values around 10 Hz for the ³J_H,H coupling constants between 1'-2', 2'-3', 3'-4', and 4'-5'_ax are indicative of the all equatorial ⁴C₁ conformation (Widmalm, 1998).

It was thus surprising to find an all axial conformation in the crystal structure of the (I) because its structural formula closely resembles that of our previously studied xylopyranosides, and its ¹H-NMR data in CDCl₃ solution indicated absolutely, the preferred all equatorial ⁴C₁ conformation (see Experimental). After inspection of the Cambridge Structural Database (CSD; Allen & Kennard, 1993), no similar all axial conformation was found for any of the 15 β-D-(per-O-acetyl)xylopyranosides listed therein, thus confirming the unique features of the crystal structure described here. In fact, in all 15 β-D-xylopyranose structures listed in the CSD there is only one occurrence of an axial acetyl group, in 2,3,4-tri-O-acetyl-β-D-xylopyranosyl azide, (ACXPAZ10; Luger and Gyorgydeak, 1993).

The principal structural factors that contribute to explain the preference for a ¹C₄ conformation in compound (I) are: (i) the existence of a hydrogen bond between the 4-amino nitrogen atom and the oxygen atom of the acetate group at C3'; this leads to the formation of a six-membered ring which fixes the pyranoside ring in the ¹C₄ conformation. The same hydrogen atom participates in another intramolecular hydrogen bond involving a carbonyl oxygen of the pyrrolo[3,4-c]pyridine moiety (Fig. 1), which helps to block the free rotation around the N—C4 single bond and confers additional rigidity to the structure. The degree of planarity of the atoms involved in the N9–H9···O1,O3' hydrogen-bonding system can be seen when the O1···H4···O3' angle of 102° is considered in conjunction with the others at H4 (Table 1). The angle sum at H9 is 356° showing that the system is very close to being planar. ii) The anomeric effect (Eliel & Wilen, 1994), which favours the axial position of anomeric electronegative substituents. It is worth noting the absence of a type of called the exo-anomeric effect which usually operates in glycosylamine derivatives (Tvaroska & Carver, 1996). This is thought to be supported by the better electron-donor ability of the exocyclic nitrogen than that of the pyranose ring oxygen, thus cancelling the possibility of the 'anomeric effect' and favouring the equatorial conformation for the anomeric substituents on the base of steric reasons. However, no such effect can be found in (I) because the lone pair of the 4-amino nitrogen atom (directly linked to the anomeric position) is not available to help any exo-anomeric effect due to its large delocalization along the heterocyclic electron deficient π system. This delocalization is confirmed by the planar geometry found for the nitrogen atom and the short distance of its bond to the heterocyclic C4 atom (shorter than a common single bond, Table 1).

Examination of the structure with PLATON (Spek, 2000) showed that there were no solvent-accessible voids in the crystal lattice.

Related literature

For related literature, see: Allen & Kennard (1993); Cobo et al. (1996); Eliel & Wilen (1994); Low et al. (1996); Luger & Gyorgydeak (1993); Schwarz (1973); Spek (2000); Tvaroska & Carver (1996); Widmalm (1998).

S2. Experimental

Dimethyl acetylenedicarboxylate (1.28 g, 9.0 mmol) was added to a solution of 6-(tri-O-acetyl-β-D-xylopyranosylamino)-2-methoxy-3-methyl -4(3H)-pyrimidinone (1.85 g, 4.5 mmol) in acetonitrile (20 ml) containing a catalytic amount of trifluoroacetic acid (0.11 g, 1.2 mmol). The mixture was stirred in refluxing acetonitrile for 15.5 h. The solvent was evaporated under reduced pressure and the title compound was isolated by flash column chromatography on silica gel (toluene/acetone). Recrystallization from acetone afforded yellow crystals. It proved very difficult to obtain crystals of suitable quality for X-ray diffraction (m.p. 543 K). Analysis calculated for C₂₂H₂₅N₃O₁₂: C 50.5, H 4.8, N 8.0%; found: C 50.2, H 4.9, N 8.0%. ¹H-NMR (CDCl₃): 7.27 (d, 7.1 Hz, 1H, H—N), 5.58 (dd, 9.2 Hz, 8.4 Hz, 1H, H-1'), 5.38 (d, 8.6 Hz, 1H, H-3'), 5.08 (pst, 8.5 Hz, 1H, H-2'), 5.01 (m, 1H, H-4'), 4.15, (dd, 5.3 Hz, 11.8 Hz, 1H, H-5'eq), 4.03 (s, 3H, 6-OCH₃), 3.94 (s, 3H, 7-COOCH₃), 3.49 (dd, 9.3 Hz, 11.8 Hz, 1H, H-5'ax), 3.09 (s, 3H, N—CH₃), 2.07 (s, 3H, OAc), 2.08 (s, 3H, OAc), 2.14 (s, 3H, OAc).

S3. Refinement

Compound (I) crystallized in the monoclinic system; space group C2 was assumed, and confirmed by the analysis. H atoms were treated as riding atoms with C—H 0.98 to 1.00 Å, N—H 0.88 Å. Methyl H atoms atoms were placed in calculated positions and these positions checked against contoured difference maps calculated in the plane of the calculated H atoms following a structure-factor calculation with the H atoms present with a site occupation factor of 0.0001. This technique was also used to confirm the position of the amino hydrogen H9.

The high R factor for the title compound is probably due to non-merohedral twinning involving a small secondary component. This possibility is indicated by the strange location of the residual peaks and the large proportion of the 50 most disagreeable reflections being of the type l = 1 with F_obs² higher than F_calc². To check this, the diffraction images were examined and found to contain additional weak reflections and split faults in this direction. A symptom of these additional spots is the loss of 00 l reflections from the data file due to bad background during integration. Many of the twin reflections are close enough to the main reflections to contaminate the background and these will have been flagged as such and omitted from the final data set as unreliable. Due to the weak nature of the additional reflections, it is likely that the twin component is small and therefore a twin refinement was not attempted.

Computing details

Data collection: Kappa-CCD server software (Nonius, 1997); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PRPKAPPA (Ferguson, 1999).

Figures

Fig. 1. The asymmetric unit of (I) showing the the atom-labelling scheme and the intramolecular hydrogen bonds. Displacement ellipsoids are drawn at the 30% probability level.

4-[β-D-(tri-O-acetyl)xylopyranosyl)amino-7-carbomethoxy-6-methyl- 5-methyoxy-1H-pyrrolo[3,4-c]pyridin-1,3(2H)-dione

Crystal data

C22H25N3O12	Dx = 1.479 Mg m^−3
Mr = 523.45	Melting point: 270 K
Monoclinic, C2	Mo Kα radiation, λ = 0.71073 Å
a = 30.594 (6) Å	Cell parameters from 2704 reflections
b = 10.285 (2) Å	θ = 2.7–27.6°
c = 7.474 (1) Å	µ = 0.12 mm^−1
β = 91.07 (3)°	T = 150 K
V = 2351.4 (7) Å^3	Plate, yellow
Z = 4	0.20 × 0.20 × 0.08 mm
F(000) = 1096

Data collection

Kappa-CCD diffractometer	2704 independent reflections
Radiation source: fine-focus sealed X-ray tube	1621 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.080
ϕ scans and ω scans with κ offsets	θmax = 27.6°, θmin = 2.7°
Absorption correction: multi-scan (SORTAV; Blessing, 1995, 1997)	h = −32→39
Tmin = 0.976, Tmax = 0.991	k = −12→13
7395 measured reflections	l = −8→8

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.082	H-atom parameters constrained
wR(F^2) = 0.226	w = 1/[σ^2(Fo^2) + (0.1363P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.042
2704 reflections	Δρmax = 0.42 e Å^−3
328 parameters	Δρmin = −0.35 e Å^−3
1 restraint	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.017 (4)

Special details

Geometry. Mean-plane data from the final SHELXL97 refinement run:-

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.0578 (2)	0.1076 (8)	0.1858 (9)	0.0284 (16)
O1	0.09636 (17)	0.1158 (6)	0.1454 (7)	0.0366 (13)
N2	0.0306 (2)	0.2164 (6)	0.2158 (10)	0.0340 (16)
C21	0.0460 (3)	0.3506 (8)	0.2140 (15)	0.049 (2)
C3	−0.0121 (3)	0.1794 (8)	0.2525 (10)	0.0303 (18)
O3	−0.0416 (2)	0.2536 (6)	0.2796 (9)	0.0432 (15)
C4	0.0414 (2)	−0.1373 (7)	0.1990 (9)	0.0265 (17)
N4	0.0815 (2)	−0.1803 (6)	0.1565 (8)	0.0282 (15)
C3A	0.0308 (2)	−0.0058 (7)	0.2104 (9)	0.0219 (16)
N5	0.01009 (19)	−0.2281 (6)	0.2283 (8)	0.0244 (13)
C6	−0.0302 (2)	−0.1892 (8)	0.2616 (9)	0.0275 (17)
O6	−0.06086 (16)	−0.2820 (5)	0.2887 (7)	0.0283 (12)
C61	−0.04713 (13)	−0.4137 (3)	0.2950 (4)	0.0319 (18)
C7	−0.04437 (14)	−0.0593 (3)	0.2727 (7)	0.0289 (18)
C71	−0.09176 (11)	−0.0283 (3)	0.3025 (5)	0.0292 (18)
O71	−0.09743 (12)	0.0415 (3)	0.4479 (4)	0.0356 (14)
C72	−0.14325 (11)	0.0777 (3)	0.4784 (6)	0.046 (2)
O72	−0.12016 (19)	−0.0648 (6)	0.2027 (8)	0.0457 (16)
C7A	−0.0116 (2)	0.0343 (7)	0.2491 (9)	0.0222 (15)
C1'	0.0929 (2)	−0.3159 (7)	0.1526 (9)	0.0257 (16)
C2'	0.1339 (2)	−0.3360 (7)	0.0402 (10)	0.0260 (17)
O2'	0.13422 (16)	−0.4742 (5)	0.0100 (7)	0.0292 (12)
C21'	0.1591 (3)	−0.5189 (9)	−0.1263 (10)	0.0345 (19)
O21'	0.18110 (19)	−0.4452 (6)	−0.2138 (7)	0.0379 (14)
C22'	0.1546 (3)	−0.6604 (9)	−0.1477 (15)	0.050 (2)
C3'	0.1763 (2)	−0.2994 (7)	0.1464 (10)	0.0258 (16)
O3'	0.17665 (17)	−0.1566 (5)	0.1448 (7)	0.0329 (13)
C31'	0.2116 (3)	−0.0984 (9)	0.0711 (11)	0.0380 (19)
O31'	0.2419 (2)	−0.1581 (6)	0.0122 (11)	0.0568 (19)
C32'	0.2081 (3)	0.0454 (9)	0.0775 (14)	0.047 (2)
C4'	0.1766 (2)	−0.3396 (7)	0.3397 (10)	0.0279 (17)
O4'	0.18377 (17)	−0.4781 (5)	0.3491 (7)	0.0309 (13)
C41'	0.2260 (3)	−0.5157 (9)	0.3775 (11)	0.036 (2)
O41'	0.2556 (2)	−0.4404 (7)	0.3852 (11)	0.070 (2)
C42'	0.2288 (4)	−0.6576 (10)	0.3994 (15)	0.056 (3)
C5'	0.1334 (3)	−0.3146 (9)	0.4250 (10)	0.0341 (19)
O5'	0.09722 (16)	−0.3686 (5)	0.3253 (6)	0.0275 (12)
H21A	0.0570	0.3745	0.3336	0.073*
H21B	0.0218	0.4084	0.1793	0.073*
H21C	0.0696	0.3592	0.1278	0.073*
H4	0.1016	−0.1228	0.1298	0.034*
H61A	−0.0386	−0.4417	0.1752	0.048*
H61B	−0.0712	−0.4682	0.3364	0.048*
H61C	−0.0221	−0.4222	0.3778	0.048*
H72A	−0.1577	0.0974	0.3635	0.069*
H72B	−0.1442	0.1545	0.5558	0.069*
H72C	−0.1583	0.0054	0.5361	0.069*
H1'	0.0683	−0.3629	0.0907	0.031*
H2'	0.1317	−0.2872	−0.0752	0.031*
H22A	0.1275	−0.6797	−0.2147	0.075*
H22B	0.1536	−0.7015	−0.0296	0.075*
H22C	0.1796	−0.6942	−0.2131	0.075*
H3'	0.2026	−0.3343	0.0852	0.031*
H32A	0.2133	0.0813	−0.0417	0.071*
H32B	0.2299	0.0799	0.1627	0.071*
H32C	0.1787	0.0700	0.1157	0.071*
H4'	0.2004	−0.2927	0.4069	0.033*
H42A	0.2574	−0.6881	0.3600	0.084*
H42B	0.2057	−0.6992	0.3271	0.084*
H42C	0.2251	−0.6800	0.5256	0.084*
H5'A	0.1339	−0.3522	0.5470	0.041*
H5'B	0.1291	−0.2195	0.4366	0.041*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.020 (4)	0.026 (4)	0.039 (4)	0.001 (3)	0.003 (3)	0.002 (3)
O1	0.020 (3)	0.035 (3)	0.055 (3)	−0.004 (2)	0.005 (2)	0.004 (3)
N2	0.025 (4)	0.017 (4)	0.060 (4)	0.000 (3)	0.004 (3)	0.003 (3)
C21	0.029 (5)	0.016 (4)	0.101 (7)	−0.003 (4)	0.014 (5)	−0.003 (4)
C3	0.025 (4)	0.023 (4)	0.043 (5)	0.002 (3)	0.009 (3)	0.005 (3)
O3	0.029 (3)	0.028 (3)	0.074 (4)	0.009 (3)	0.012 (3)	−0.004 (3)
C4	0.022 (4)	0.025 (4)	0.032 (4)	0.001 (3)	−0.001 (3)	0.003 (3)
N4	0.015 (3)	0.025 (4)	0.045 (4)	0.003 (3)	0.009 (3)	0.001 (3)
C3A	0.012 (4)	0.020 (4)	0.034 (4)	0.004 (3)	0.003 (3)	−0.001 (3)
N5	0.011 (3)	0.025 (3)	0.037 (3)	0.007 (3)	0.003 (2)	0.000 (2)
C6	0.014 (4)	0.040 (5)	0.029 (4)	0.002 (3)	0.006 (3)	−0.002 (3)
O6	0.019 (3)	0.020 (3)	0.046 (3)	0.003 (2)	0.003 (2)	0.003 (2)
C61	0.022 (4)	0.021 (4)	0.053 (5)	0.004 (3)	−0.001 (3)	−0.005 (3)
C7	0.020 (4)	0.039 (5)	0.028 (4)	0.007 (3)	0.002 (3)	−0.002 (3)
C71	0.022 (4)	0.028 (4)	0.037 (4)	0.005 (3)	0.006 (3)	0.004 (3)
O71	0.020 (3)	0.048 (4)	0.040 (3)	0.010 (3)	0.004 (2)	−0.007 (3)
C72	0.040 (5)	0.045 (6)	0.052 (5)	0.022 (5)	0.014 (4)	0.003 (4)
O72	0.022 (3)	0.049 (4)	0.066 (4)	0.002 (3)	−0.005 (3)	−0.017 (3)
C7A	0.015 (4)	0.021 (4)	0.030 (4)	0.004 (3)	−0.001 (3)	0.003 (3)
C1'	0.021 (4)	0.025 (4)	0.032 (4)	0.000 (3)	0.005 (3)	−0.002 (3)
C2'	0.021 (4)	0.019 (4)	0.038 (4)	0.003 (3)	0.002 (3)	−0.004 (3)
O2'	0.025 (3)	0.020 (3)	0.043 (3)	−0.002 (2)	0.006 (2)	−0.005 (2)
C21'	0.022 (4)	0.042 (5)	0.039 (4)	−0.005 (4)	0.001 (3)	−0.002 (4)
O21'	0.035 (3)	0.040 (3)	0.039 (3)	0.010 (3)	0.009 (2)	0.001 (2)
C22'	0.037 (5)	0.027 (5)	0.087 (7)	0.004 (4)	0.009 (5)	−0.017 (5)
C3'	0.014 (4)	0.018 (4)	0.045 (4)	0.000 (3)	−0.003 (3)	0.000 (3)
O3'	0.023 (3)	0.018 (3)	0.059 (3)	−0.003 (2)	0.011 (2)	−0.003 (2)
C31'	0.029 (5)	0.031 (5)	0.055 (5)	−0.002 (4)	0.010 (4)	0.008 (4)
O31'	0.037 (4)	0.027 (4)	0.108 (5)	−0.005 (3)	0.038 (4)	−0.005 (3)
C32'	0.032 (5)	0.035 (5)	0.075 (6)	−0.005 (4)	0.012 (4)	−0.004 (4)
C4'	0.015 (4)	0.025 (4)	0.043 (4)	0.000 (3)	−0.005 (3)	−0.006 (3)
O4'	0.025 (3)	0.019 (3)	0.048 (3)	0.004 (2)	−0.003 (2)	−0.001 (2)
C41'	0.023 (5)	0.041 (5)	0.046 (5)	0.013 (4)	−0.001 (3)	−0.001 (4)
O41'	0.028 (4)	0.055 (5)	0.125 (6)	0.008 (3)	−0.008 (4)	−0.012 (4)
C42'	0.052 (7)	0.032 (5)	0.084 (7)	0.019 (5)	0.000 (5)	0.009 (5)
C5'	0.029 (5)	0.042 (5)	0.031 (4)	0.008 (4)	−0.005 (3)	−0.006 (3)
O5'	0.017 (3)	0.027 (3)	0.039 (3)	−0.006 (2)	0.004 (2)	0.003 (2)

Geometric parameters (Å, º)

C1—O1	1.226 (9)	C1'—C2'	1.538 (10)
C1—N2	1.415 (10)	C1'—H1'	1.0000
C1—C3A	1.443 (11)	C2'—O2'	1.439 (9)
N2—C3	1.393 (10)	C2'—C3'	1.553 (10)
N2—C21	1.459 (11)	C2'—H2'	1.0000
C21—H21A	0.9800	O2'—C21'	1.364 (9)
C21—H21B	0.9800	C21'—O21'	1.212 (10)
C21—H21C	0.9800	C21'—C22'	1.470 (13)
C3—O3	1.203 (10)	C22'—H22A	0.9800
C3—C7A	1.492 (11)	C22'—H22B	0.9800
C4—N4	1.349 (9)	C22'—H22C	0.9800
C4—N5	1.357 (10)	C3'—O3'	1.468 (9)
C4—C3A	1.393 (11)	C3'—C4'	1.503 (11)
N4—C1'	1.438 (10)	C3'—H3'	1.0000
N4—H4	0.8800	O3'—C31'	1.351 (9)
C3A—C7A	1.396 (10)	C31'—O31'	1.203 (10)
N5—C6	1.323 (9)	C31'—C32'	1.483 (13)
C6—O6	1.357 (9)	C32'—H32A	0.9800
C6—C7	1.408 (9)	C32'—H32B	0.9800
O6—C61	1.419 (6)	C32'—H32C	0.9800
C61—H61A	0.9800	C4'—O4'	1.443 (9)
C61—H61B	0.9800	C4'—C5'	1.501 (11)
C61—H61C	0.9800	C4'—H4'	1.0000
C7—C7A	1.404 (8)	O4'—C41'	1.362 (9)
C7—C71	1.505 (2)	C41'—O41'	1.191 (11)
C71—O72	1.195 (7)	C41'—C42'	1.471 (13)
C71—O71	1.3163 (18)	C42'—H42A	0.9800
O71—C72	1.4723 (13)	C42'—H42B	0.9800
C72—H72A	0.9800	C42'—H42C	0.9800
C72—H72B	0.9800	C5'—O5'	1.434 (9)
C72—H72C	0.9800	C5'—H5'A	0.9900
C1'—O5'	1.403 (9)	C5'—H5'B	0.9900
O1—C1—N2	123.7 (7)	C2'—C1'—H1'	107.3
O1—C1—C3A	130.0 (7)	O2'—C2'—C1'	103.0 (6)
N2—C1—C3A	106.3 (6)	O2'—C2'—C3'	108.2 (6)
C3—N2—C1	111.8 (6)	C1'—C2'—C3'	111.7 (6)
C3—N2—C21	124.4 (7)	O2'—C2'—H2'	111.2
C1—N2—C21	123.8 (7)	C1'—C2'—H2'	111.2
N2—C21—H21A	109.5	C3'—C2'—H2'	111.2
N2—C21—H21B	109.5	C21'—O2'—C2'	117.1 (6)
H21A—C21—H21B	109.5	O21'—C21'—O2'	121.0 (8)
N2—C21—H21C	109.5	O21'—C21'—C22'	127.7 (8)
H21A—C21—H21C	109.5	O2'—C21'—C22'	111.2 (7)
H21B—C21—H21C	109.5	C21'—C22'—H22A	109.5
O3—C3—N2	124.7 (7)	C21'—C22'—H22B	109.5
O3—C3—C7A	130.2 (8)	H22A—C22'—H22B	109.5
N2—C3—C7A	105.1 (6)	C21'—C22'—H22C	109.5
N4—C4—N5	117.4 (7)	H22A—C22'—H22C	109.5
N4—C4—C3A	123.1 (7)	H22B—C22'—H22C	109.5
N5—C4—C3A	119.5 (7)	O3'—C3'—C4'	106.4 (6)
C4—N4—C1'	123.0 (6)	O3'—C3'—C2'	104.2 (6)
C4—N4—H4	118.5	C4'—C3'—C2'	114.5 (6)
C1'—N4—H4	118.5	O3'—C3'—H3'	110.5
C4—C3A—C7A	121.1 (7)	C4'—C3'—H3'	110.5
C4—C3A—C1	130.0 (7)	C2'—C3'—H3'	110.5
C7A—C3A—C1	108.8 (6)	C31'—O3'—C3'	116.9 (6)
C6—N5—C4	119.0 (6)	O31'—C31'—O3'	122.9 (8)
N5—C6—O6	117.7 (7)	O31'—C31'—C32'	125.2 (8)
N5—C6—C7	126.0 (7)	O3'—C31'—C32'	111.8 (7)
O6—C6—C7	116.3 (6)	C31'—C32'—H32A	109.5
C6—O6—C61	118.1 (5)	C31'—C32'—H32B	109.5
O6—C61—H61A	109.5	H32A—C32'—H32B	109.5
O6—C61—H61B	109.5	C31'—C32'—H32C	109.5
H61A—C61—H61B	109.5	H32A—C32'—H32C	109.5
O6—C61—H61C	109.5	H32B—C32'—H32C	109.5
H61A—C61—H61C	109.5	O4'—C4'—C3'	108.5 (6)
H61B—C61—H61C	109.5	O4'—C4'—C5'	106.4 (6)
C7A—C7—C6	114.9 (5)	C3'—C4'—C5'	111.8 (6)
C7A—C7—C71	124.5 (3)	O4'—C4'—H4'	110.0
C6—C7—C71	120.6 (4)	C3'—C4'—H4'	110.0
O72—C71—O71	125.5 (3)	C5'—C4'—H4'	110.0
O72—C71—C7	122.2 (5)	C41'—O4'—C4'	115.5 (6)
O71—C71—C7	112.3 (3)	O41'—C41'—O4'	122.7 (8)
C71—O71—C72	113.97 (6)	O41'—C41'—C42'	126.7 (8)
O71—C72—H72A	109.5	O4'—C41'—C42'	110.5 (8)
O71—C72—H72B	109.5	C41'—C42'—H42A	109.5
H72A—C72—H72B	109.5	C41'—C42'—H42B	109.5
O71—C72—H72C	109.5	H42A—C42'—H42B	109.5
H72A—C72—H72C	109.5	C41'—C42'—H42C	109.5
H72B—C72—H72C	109.5	H42A—C42'—H42C	109.5
C3A—C7A—C7	119.4 (6)	H42B—C42'—H42C	109.5
C3A—C7A—C3	108.0 (6)	O5'—C5'—C4'	112.9 (6)
C7—C7A—C3	132.5 (6)	O5'—C5'—H5'A	109.0
O5'—C1'—N4	112.0 (6)	C4'—C5'—H5'A	109.0
O5'—C1'—C2'	112.7 (6)	O5'—C5'—H5'B	109.0
N4—C1'—C2'	110.0 (6)	C4'—C5'—H5'B	109.0
O5'—C1'—H1'	107.3	H5'A—C5'—H5'B	107.8
N4—C1'—H1'	107.3	C1'—O5'—C5'	112.8 (6)
O1—C1—N2—C3	177.5 (7)	C71—C7—C7A—C3A	−175.7 (6)
C3A—C1—N2—C3	−1.8 (8)	C6—C7—C7A—C3	−179.2 (8)
O1—C1—N2—C21	−4.3 (12)	C71—C7—C7A—C3	2.6 (11)
C3A—C1—N2—C21	176.4 (8)	O3—C3—C7A—C3A	179.7 (8)
C1—N2—C3—O3	−178.7 (8)	N2—C3—C7A—C3A	−0.2 (8)
C21—N2—C3—O3	3.2 (13)	O3—C3—C7A—C7	1.2 (15)
C1—N2—C3—C7A	1.2 (8)	N2—C3—C7A—C7	−178.7 (7)
C21—N2—C3—C7A	−176.9 (8)	C4—N4—C1'—O5'	−73.3 (8)
N5—C4—N4—C1'	−4.1 (10)	C4—N4—C1'—C2'	160.5 (6)
C3A—C4—N4—C1'	177.1 (7)	O5'—C1'—C2'—O2'	68.8 (7)
N4—C4—C3A—C7A	177.9 (6)	N4—C1'—C2'—O2'	−165.4 (5)
N5—C4—C3A—C7A	−0.9 (10)	O5'—C1'—C2'—C3'	−47.2 (8)
N4—C4—C3A—C1	−1.4 (12)	N4—C1'—C2'—C3'	78.6 (7)
N5—C4—C3A—C1	179.8 (7)	C1'—C2'—O2'—C21'	161.8 (6)
O1—C1—C3A—C4	1.7 (13)	C3'—C2'—O2'—C21'	−79.7 (8)
N2—C1—C3A—C4	−179.1 (8)	C2'—O2'—C21'—O21'	2.4 (10)
O1—C1—C3A—C7A	−177.7 (7)	C2'—O2'—C21'—C22'	−177.1 (7)
N2—C1—C3A—C7A	1.5 (8)	O2'—C2'—C3'—O3'	171.0 (5)
N4—C4—N5—C6	−176.7 (6)	C1'—C2'—C3'—O3'	−76.2 (7)
C3A—C4—N5—C6	2.1 (10)	O2'—C2'—C3'—C4'	−73.1 (8)
C4—N5—C6—O6	179.4 (6)	C1'—C2'—C3'—C4'	39.6 (8)
C4—N5—C6—C7	−1.0 (10)	C4'—C3'—O3'—C31'	117.5 (7)
N5—C6—O6—C61	5.3 (8)	C2'—C3'—O3'—C31'	−121.1 (7)
C7—C6—O6—C61	−174.3 (6)	C3'—O3'—C31'—O31'	−1.7 (12)
N5—C6—C7—C7A	−1.3 (10)	C3'—O3'—C31'—C32'	180.0 (7)
O6—C6—C7—C7A	178.3 (6)	O3'—C3'—C4'—O4'	−170.4 (5)
N5—C6—C7—C71	177.0 (6)	C2'—C3'—C4'—O4'	75.1 (8)
O6—C6—C7—C71	−3.5 (9)	O3'—C3'—C4'—C5'	72.6 (8)
C7A—C7—C71—O72	120.0 (7)	C2'—C3'—C4'—C5'	−41.9 (9)
C6—C7—C71—O72	−58.1 (7)	C3'—C4'—O4'—C41'	95.4 (7)
C7A—C7—C71—O71	−60.2 (6)	C5'—C4'—O4'—C41'	−144.2 (6)
C6—C7—C71—O71	121.7 (5)	C4'—O4'—C41'—O41'	−3.6 (11)
O72—C71—O71—C72	−2.2 (5)	C4'—O4'—C41'—C42'	175.3 (7)
C7—C71—O71—C72	178.0	O4'—C4'—C5'—O5'	−66.5 (8)
C4—C3A—C7A—C7	−1.5 (10)	C3'—C4'—C5'—O5'	51.8 (9)
C1—C3A—C7A—C7	177.9 (6)	N4—C1'—O5'—C5'	−66.1 (7)
C4—C3A—C7A—C3	179.8 (7)	C2'—C1'—O5'—C5'	58.6 (8)
C1—C3A—C7A—C3	−0.8 (8)	C4'—C5'—O5'—C1'	−61.4 (8)
C6—C7—C7A—C3A	2.5 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4···O1	0.88	2.46	3.081 (7)	128
N4—H4···O3′	0.88	2.32	2.924 (8)	126