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1.
Frank Seela Khalil Shaikh Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o489-o491
The title compound, C14H16N4O4, adopts the anti conformation at the glycosylic bond [χ−117.1 (5)°]. The sugar pucker of the 2′‐deoxyribofuranosyl moiety is C2′‐endo–C3′‐exo, 2T3 (S‐type). The orientation of the exocyclic C4′—C5′ bond is +sc (gauche). The propynyl group is linear and coplanar with the nucleobase moiety. The structure of the compound is stabilized by several hydrogen bonds (N—H⋯O and O—H⋯O), leading to the formation of a multi‐layered network. The nucleobases, as well as the propynyl groups, are stacked. This stacking might cause the extraordinary stability of DNA duplexes containing this compound. 相似文献
2.
Frank Seela Yunlong Zhang Kuiying Xu Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o60-o62
In the title compound, 4‐amino‐1‐(2‐deoxy‐β‐d ‐eythro‐pentofuranosyl)‐3‐vinyl‐1H‐pyrazolo[3,4‐d]pyrimidine monohydrate, C12H15N5O3·H2O, the conformation of the glycosyl bond is anti. The furanose moiety is in an S conformation with an unsymmetrical twist, and the conformation at the exocyclic C—C(OH) bond is +sc (gauche, gauche). The vinyl side chain is bent out of the heterocyclic ring plane by 147.5 (5)°. The three‐dimensional packing is stabilized by O—H·O, O—H·N and N—H·O hydrogen bonds. 相似文献
3.
Wenqing Lin Frank Seela Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(8):o566-o568
In the tricyclic nucleoside 7‐(β‐d ‐ribofuranosyl)‐7H‐imidazo[1,2‐c]pyrazolo[4,3‐e][1,2,3]triazine, C11H12N6O4, the conformation of the N‐glycosyl bond is intermediate between anti and high anti [χ = −103.5 (3)°]. The ribofuranose moiety adopts a 3T2 sugar pucker (S‐type sugar) and the conformation at the exocyclic C—C bond is ap (gauche–trans). Molecules of the title compound form a three‐dimensional network via three medium–strong intermolecular hydrogen bonds (one O—H⋯N and two O—H⋯O bonds). 相似文献
4.
Frank Seela Anup M. Jawalekar Simone Budow Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(9):o562-o564
In the title compound, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐6‐methylsulfanyl‐1H‐pyrazolo[3,4‐d]pyrimidine, C11H16N5O3S, the conformation of the glycosidic bond is between anti and high anti. The 2′‐deoxyribofuranosyl moiety adopts the C3′‐exo–C4′‐endo conformation (3T4, S‐type sugar pucker), and the conformation at the exocyclic C—C bond is +sc (+gauche). The exocyclic 6‐amine group and the 2‐methylsulfanyl group lie on different sides of the heterocyclic ring system. The molecules form a three‐dimensional hydrogen‐bonded network that is stabilized by O—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds. 相似文献
5.
Wen‐Qing Lin Xin Ming Henning Eickmeier Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):o379-o381
In the title compound [systematic name: 4‐amino‐7‐(β‐d ‐ribofuranosyl)‐7H‐pyrazolo[3,4‐d][1,2,3]triazine], C9H12N6O4, the torsion angle of the N‐glycosylic bond is high anti [χ = −83.2 (3)°]. The ribofuranose moiety adopts the C2′‐endo–C1′‐exo (2T1) sugar conformation (S‐type sugar pucker), with P = 152.4° and τm = 35.0°. The conformation at the C4′—C5′ bond is +sc (gauche,gauche), with the torsion angle γ = 52.0 (3)°. The compound forms a three‐dimensional network that is stabilized by several hydrogen bonds (N—H⋯O, O—H⋯N and O—H⋯O). 相似文献
6.
Simone Budow Khalil I. Shaikh Henning Eickmeier Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(5):o246-o248
In the title compound, 2′‐deoxy‐7‐propynyl‐7‐deazaadenosine, C14H16N4O3, the torsion angle of the N‐glycosylic bond is anti [χ = −130.7 (2)°]. The sugar pucker of the 2′‐deoxyribofuranosyl moiety is C2′‐endo–C3′‐exo, 2T3 (S‐type), with P = 185.9 (2)° and τm = 39.1 (1)°, and the orientation of the exocyclic C4′—C5′ bond is −ap (trans). The 7‐substituted propynyl group is nearly coplanar with the heterocyclic base moiety. Molecules of the nucleoside form a layered network in which the heterocyclic bases are stacked head‐to‐tail with a closest distance of 3.197 (1) Å. The crystal structure of the nucleoside is stabilized by three intermolecular hydrogen bonds of types N—H⋯ O, O—H⋯ N and O—H⋯ O. 相似文献
7.
Simone Budow Henning Eickmeier Hans Reuter Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(12):o645-o648
The title compound, 1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐5‐(prop‐1‐ynyl)pyrimidin‐2,4(1H,3H)‐dione, C12H14N2O5, shows two conformations in the crystalline state: conformer 1 adopts a C2′‐endo (close to 2E; S‐type) sugar pucker and an anti nucleobase orientation [χ = −134.04 (19)°], while conformer 2 shows an S sugar pucker (twisted C2′‐endo–C3′‐exo), which is accompanied by a different anti base orientation [χ = −162.79 (17)°]. Both molecules show a +sc (gauche, gauche) conformation at the exocyclic C4′—C5′ bond and a coplanar orientation of the propynyl group with respect to the pyrimidine ring. The extended structure is a three‐dimensional hydrogen‐bond network involving intermolecular N—H...O and O—H...O hydrogen bonds. Only O atoms function as H‐atom acceptor sites. 相似文献
8.
Marcin Palusiak Izabela Janowska Janusz Zakrzewski Sawomir J. Grabowski 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):m55-m57
In the title compound, [Fe(C5H5)(C12H19NO)]I, the ferrocene moiety has an eclipsed conformation, with mean Fe—C bond lengths of 2.031 (4) and 2.020 (6) Å for the substituted and unsubstituted cyclopentadienyl rings. The pyrrolidinium heterocycle adopts an envelope conformation and has its 1‐ and 2‐substituents in a relative trans disposition. Strong (+/−)‐charge‐assisted N—H·I and C—H·I hydrogen bonds are present. The crystal structure is also stabilized by weak C—H·O interactions. 相似文献
9.
Frank Seela Yang He Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(4):o194-o196
In the title compound, 3‐amino‐2‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐6‐methyl‐1,2,4‐triazin‐5(2H)‐one, C9H14N4O4, the conformation of the N‐glycosidic bond is high‐anti and the 2‐deoxyribofuranosyl moiety adopts a North sugar pucker (2T3). The orientation of the exocyclic C—C bond between the –CH2OH group and the five‐membered ring is ap (gauche, trans). The crystal packing is such that the nucleobases lie parallel to the ac plane; the planes are connected via hydrogen bonds involving the five‐membered ring. 相似文献
10.
Dawei Jiang Simone Budow Virginie Glaon Henning Eickmeier Hans Reuter Yang He Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(4):o194-o197
The title compound, C10H12FN5O4·H2O, shows an anti glycosyl orientation [χ = −123.1 (2)°]. The 2‐deoxy‐2‐fluoroarabinofuranosyl moiety exhibits a major C2′‐endo sugar puckering (S‐type, C2′‐endo–C1′‐exo, 2T1), with P = 156.9 (2)° and τm = 36.8 (1)°, while in solution a predominantly N conformation of the sugar moiety is observed. The conformation around the exocyclic C4′—C5′ bond is −sc (trans, gauche), with γ = −78.3 (2)°. Both nucleoside and solvent molecules participate in the formation of a three‐dimensional hydrogen‐bonding pattern via intermolecular N—H...O and O—H...O hydrogen bonds; the N atoms of the heterocyclic moiety and the F substituent do not take part in hydrogen bonding. 相似文献
11.
Frank Seela Khalil I. Shaikh Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(3):o151-o153
In the title compound, 2‐amino‐7‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐3,7‐dihydropyrrolo[2,3‐d]pyrimidin‐4‐one, C11H14N4O4, the N‐glycosylic bond torsion angle, χ, is anti [−106.5 (3)°]. The 2′‐deoxyribofuranosyl moiety adopts the 3T4 (N‐type) conformation, with P = 39.1° and τm = 40.3°. The conformation around the exocyclic C—C bond is ap (trans), with a torsion angle, γ, of −173.8 (3)°. The nucleoside forms a hydrogen‐bonded network, leading to a close‐packed multiple‐layer structure with a head‐to‐head arrangement of the bases. The nucleobase interplanar O=C—C⋯NH2 distance is 3.441 (1) Å. 相似文献
12.
Xiaohua Peng Hans Reuter Henning Eickmeier Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(10):o593-o595
In 4‐chloro‐7‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐7H‐pyrrolo[2,3‐d]pyrimidine‐2,4‐diamine, C11H14ClN5O3, the conformation of the N‐glycosylic bond is between anti and high‐anti [χ = −102.5 (6)°]. The 2′‐deoxyribofuranosyl unit adopts the C3′‐endo‐C4′‐exo (3T4) sugar pucker (N‐type) with P = 19.6° and τm = 32.9° [terminology: Saenger (1989). Landolt‐Börnstein New Series, Vol. 1, Nucleic Acids, Subvol. a, edited by O. Madelung, pp. 1–21. Berlin: Springer‐Verlag]. The orientation of the exocyclic C4′—C5′ bond is +ap (trans) with a torsion angle γ = 171.5 (4)°. The compound forms a three‐dimensional network that is stabilized by four intermolecular hydrogen bonds (N—H⋯O and O—H⋯N) and one intramolecular hydrogen bond (N—H⋯Cl). 相似文献
13.
Dawei Jiang Yang He Simone Budow Zygmunt Kazimierczuk Henning Eickmeier Hans Reuter Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(11):o561-o564
The title compound, C9H12N6O3, shows a syn‐glycosylic bond orientation [χ = 64.17 (16)°]. The 2′‐deoxyfuranosyl moiety exhibits an unusual C1′‐exo–O4′‐endo (1T0; S‐type) sugar pucker, with P = 111.5 (1)° and τm = 40.3 (1)°. The conformation at the exocyclic C4′—C5′ bond is +sc (gauche), with γ = 64.4 (1)°. The two‐dimensional hydrogen‐bonded network is built from intermolecular N—H...O and O—H...N hydrogen bonds. An intramolecular bifurcated hydrogen bond, with an amino N—H group as hydrogen‐bond donor and the ring and hydroxymethyl O atoms of the sugar moiety as acceptors, constrains the overall conformation of the nucleoside. 相似文献
14.
Frank Seela Xin Ming Simone Budow Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(5):o293-o295
The title compound [systematic name: 4‐amino‐5‐fluoro‐7‐(β‐d ‐ribofuranosyl)‐7H‐pyrrolo[2,3‐d]pyrimidine], C11H13FN4O4, exhibits an anti glycosylic bond conformation, with a χ torsion angle of −124.7 (3)°. The furanose moiety shows a twisted C2′‐endo sugar pucker (S‐type), with P = 169.8 (3)° and τm = 38.7 (2)°. The orientation of the exocyclic C4′—C5′ bond is +sc (gauche, gauche), with a γ torsion angle of 59.3 (3)°. The nucleobases are stacked head‐to‐head. The extended crystal structure is a three‐dimensional hydrogen‐bond network involving O—H...O, O—H...N and N—H...O hydrogen bonds. The crystal structure of the title nucleoside demonstrates that the C—C bonds nearest the F atom of the pyrrole system are significantly shortened by the electronegative halogen atom. 相似文献
15.
Xiaohua Peng Frank Seela Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(2):o96-o98
In the title compound [systematic name: 7‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐2‐fluoro‐7H‐pyrrolo[2,3‐d]pyrimidin‐2‐amine], C11H13FN4O3, the conformation of the N‐glycosylic bond is between anti and high‐anti [χ = −110.2 (3)°]. The 2′‐deoxyribofuranosyl unit adopts the N‐type sugar pucker (4T3), with P = 40.3° and τm = 39.2°. The orientation of the exocyclic C4′—C5′ bond is −ap (trans), with a torsion angle γ = −168.39 (18)°. The nucleobases are arranged head‐to‐head. The crystal structure is stabilized by four intermolecular hydrogen bonds of types N—H⋯N, N—H⋯O and O—H⋯O. 相似文献
16.
Xiaomei Zhang Simone Budow Peter Leonard Henning Eickmeier Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o79-o81
In the title compound, 4‐amino‐2‐(2‐O‐methyl‐β‐d ‐ribofuranosyl)‐2H‐pyrazolo[3,4‐d]pyrimidine monohydrate, C11H15N5O4·H2O, the conformation of the N‐glycosylic bond is syn [χ = 20.1 (2)°]. The ribofuranose moiety shows a C3′‐endo (3T2) sugar puckering (N‐type sugar), and the conformation at the exocyclic C4′—C5′ bond is −ap (trans). The nucleobases are stacked head‐to‐head. The three‐dimensional packing of the crystal structure is stabilized by hydrogen bonds between the 2′‐O‐methylribonucleosides and the solvent molecules. 相似文献
17.
Dasharath Kondhare Simone Budow-Busse Constantin Daniliuc Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(5):513-523
The positional change of nitrogen‐7 of the RNA constituent guanosine to the bridgehead position‐5 leads to the base‐modified nucleoside 5‐aza‐7‐deazaguanosine. Contrary to guanosine, this molecule cannot form Hoogsteen base pairs and the Watson–Crick proton donor site N3—H becomes a proton‐acceptor site. This causes changes in nucleobase recognition in nucleic acids and has been used to construct stable `all‐purine' DNA and DNA with silver‐mediated base pairs. The present work reports the single‐crystal X‐ray structure of 7‐iodo‐5‐aza‐7‐deazaguanosine, C10H12IN5O5 ( 1 ). The iodinated nucleoside shows an anti conformation at the glycosylic bond and an N conformation (O4′‐endo) for the ribose moiety, with an antiperiplanar orientation of the 5′‐hydroxy group. Crystal packing is controlled by interactions between nucleobase and sugar moieties. The 7‐iodo substituent forms a contact to oxygen‐2′ of the ribose moiety. Self‐pairing of the nucleobases does not take place. A Hirshfeld surface analysis of 1 highlights the contacts of the nucleobase and sugar moiety (O—H…O and N—H…O). The concept of pK‐value differences to evaluate base‐pair stability was applied to purine–purine base pairing and stable base pairs were predicted for the construction of `all‐purine' RNA. Furthermore, the 7‐iodo substituent of 1 was functionalized with benzofuran to detect motional constraints by fluorescence spectroscopy. 相似文献
18.
G. Mazumdar M. De A. Mukhopadhyay S. K. Mazumdar N. Mazumder A. K. Das Edward E. Knaus 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):494-495
In the title compound, C14H19IN2O8, an almost planar heterocyclic base is oriented anti with respect to the puckered sugar moiety. The sugar pucker is C2′‐endo/C3′‐exo, the N‐glycosidic torsion angle is 166.4 (4)° and the conformation of O5′ is +sc. The molecules are linked by hydrogen bonds of the types N—H?O and O—H?O. 相似文献
19.
Frank Seela Helmut Rosemeyer Alexander Melenewski Eva‐Maria Heithoff Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o142-o144
In the monohydrate of 2‐amino‐8‐(2‐deoxy‐α‐d ‐erythro‐pentofuranosyl)‐8H‐imidazo[1,2‐a][1,3,5]triazin‐4‐one, C10H13N5O4·H2O, denoted (I) or αZd, the conformation of the N‐glycosylic bond is in the high‐anti range [χ = 87.5 (3)°]. The 2′‐deoxyribofuranose moiety adopts a C2′‐endo,C3′‐exo(2′T3′) sugar puckering (S‐type sugar) and the conformation at the C4′—C5′ bond is ?sc (trans). 相似文献
20.
Mustafa Odabaolu idem Albayrak Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):o240-o242
Molecules of the title compound, C8H9NO2, are linked into sheets by a combination of C—H·N, O—H·N and O—H·O hydrogen bonds and C—H·π interactions. The hydrogen bonds are arranged as described by the graph‐set ring notations R22(7) and R33(5), and a C8 chain motif. There are two planar symmetry‐independent molecules in the asymmetric unit, with a dihedral angle of 19.24 (5)° between their least‐squares mean planes. 相似文献