Structure-activity studies of β-carbolines. 4. Crystal and molecular structures of t-butyl β-carboline-3-carboxylate and 2-(methoxycarbonyl)canthine-6-one

1988 ◽  
Vol 66 (12) ◽  
pp. 2981-2988 ◽  
Author(s):  
Penelope W. Codding ◽  
Maria B. Szkaradzinska ◽  
Aleksander W. Roszak ◽  
Lorraine J. Aha ◽  
Timothy J. Hagen ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Side Chain ◽  
Stacking Interactions ◽  
Lower Affinity ◽  
Space Group ◽  
High Affinity ◽  
Crystal And Molecular Structures ◽  
Structure Activity ◽  
The Difference

The crystal and molecular structures of two ligands for the benzodiazepine (BZ) receptor, t-butyl β-carboline-3-carboxylate, I (C16H16N2O2), and 2-(methoxycarbonyl)canthin-6-one, II (C16H10N2O3), are reported. The t-butyl β-carboline compound has high affinity for the receptor and is an antagonist; in contrast, the canthin-6-one has a 10-fold lower affinity for the receptor and no determinable in vivo activity. The space group for I is P21/c with a = 11.756(1), b = 11.2324(8), c = 11.964(1) Å, and β = 105.99(1)°. For II, the space group is also P21/c with a = 9.317(1), b = 7.964(1), c = 17.180(3) Å, and β = 104.173(7)°. The orientation of the alkyl-carboxylate side chain is different in the two molecules and may be related to the difference in affinity and in vivo activity of the ligands. In addition, the packing arrangements in the two structures are dominated by π-stacking interactions; and, in the case of the t-butyl compound, by hydrogen bonding.

Structure–activity studies of β-carbolines. 2. Crystal and molecular structures of N-ethyl-3-carbamoyl-β-carboline

1984 ◽  
Vol 62 (9) ◽  
pp. 1803-1806 ◽  
Author(s):  
Alastair K. S. Muir ◽  
Penelope W. Codding
Keyword(s):  
Molecular Conformation ◽  
Current Model ◽  
Benzodiazepine Receptor ◽  
Molecular Structures ◽  
Side Chain ◽  
Receptor Binding Site ◽  
Crystal And Molecular Structures ◽  
Structure Activity ◽  
Synthetic Ligand ◽  
Packing Arrangement

The crystal and molecular structures of N-ethyl-3-carbamoyl-β-carboline, C14H13N3O, a synthetic ligand of the benzodiazepine receptor are reported. The space group is C2/c with a = 16.220(4), b = 7.728(4), c = 19.623(6) Å, β = 104.16(1)°, Z = 8. The carboxyamide side chain assumes an extended conformation and is almost coplanar with the β-carboline skeleton. The observed molecular conformation is compared to the current model for the receptor binding site. Hydrogen bonding and aromatic ring stacking determine the molecular packing arrangement.

Synthesis and resolution of an asymmetric arsonium cation. Crystal and molecular structures of (R)-Benzyl(methyl)(4-methylphenyl)(naphthalen-1-yl)- arsonium bromide and hexafluorophosphate

1984 ◽  
Vol 37 (6) ◽  
pp. 1171 ◽  
Author(s):  
DG Allen ◽  
CL Raston ◽  
BW Skelton ◽  
AH White ◽  
SB Wild
Keyword(s):  
Ion Exchange ◽  
Absolute Configuration ◽  
Optically Active ◽  
Molecular Structures ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Ion Exchange Column ◽  
Optically Pure

The (�)-benzyl(methyl)(4-methylphenyl)(naphthalen-1-yl)arsonium cation has been synthesized and subsequently resolved by fractional crystallization of monohydrogen [R-(R*,R*)]-2,3-bis(benzoyloxy)- butanedioate salts. The separated diastereoisomers were converted into the corresponding optically active arsonium bromides by ion-exchange column chromatography. The absolute configuration of the arsonium cation exhibiting a positive rotation at 589 nm (sodium D line) has been established as (R) by single-crystal X-ray analysis of both the bromide and hexafluorophosphate salts. The arsonium bromide with [α]D + 54.8�(c, 0.62 in CH2Cl2) crystallizes in the orthorhombic space group P212121 (D24, No.19) with a 22.472(8), b 15.724(7), c 12.585(5) � and U 4447(3) �3. The corresponding hexafluorophosphate with [α]D + 19.3� (c, 0.5 in CH2Cl2) crystallizes in the same space group with a 23.56(2), b 16.40(1), c 13.12(1) � and U 5067(6) � 3. Benzylidene transfer to benzaldehyde from the arsonium ylide derived from either of the arsonium salts produced optically pure (–)-(S)-methyl(4-methylphenyl)(naphthalen-1-yl)arsine, [α]D - 115.9� (c, 0.593 in CHCl3), and partly resolved [R-(R*,R*)]-2,3-diphenyloxiran.

Synthesis of C-aryl-N-(2-hydroxyphenylmethyl)-nitrones and their reaction with diphenylborinic or carboxylic acid derivatives. Crystal and molecular structures of a free nitrone ligand and its diphenyl–boron chelate

1997 ◽  
Vol 75 (12) ◽  
pp. 1830-1843 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Carboxylic Acid ◽  
Electron Distribution ◽  
Direct Methods ◽  
Molecular Structures ◽  
State Structure ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
New Type ◽  
Boron Chelate ◽  
Diphenylboron Chelate

The syntheses of a number of aromatic aldonitrones of N-(2-hydroxyphenylmethyl)hydroxylamine and their subsequent reactions with diphenylborinic or carboxylic acid derivatives are reported. Crystals of 8-(4-dimethylaminophenylmethylene)-6,6-diphenyl-5,7-dioxa-8-azonia-6-borata-5H-6,7,8,9-tetrahydrobenzocycloheptene, 2b, are triclinic, a = 10.6802(8), b = 11.1809(4), c =10.1520(3) Å, α = 105.847(3)°, β = 92.567(4)°, γ = 84.610(5)°, Z = 2, space group PĪ, and those of C-(4-dimethylaminophenyl)-N-(2-hydroxyphenylmethyl)nitrone, 6e, are monoclinic, a = 12.2319(8), b = 7.071(1), c = 17.2005(9) Å, β = 107.520(4)°, Z = 4, space group P21/a. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.035 and 0.032 (Rw = 0.036 and 0.032) for 3379 and 1800 reflections with I ≥ 3σ(I), respectively. Compound 2b is representative of a new type of heterocyclic B,N-betaine. The solid state structure of 6e (the precursor to 2b) shows that only small topological changes, but significant changes in the electron distribution, occur upon the formation of the diphenylboron chelate. Keywords: aromatic aldonitrones, organoboron compounds, crystal structures.

Regulation of interaction of the iron-responsive element binding protein with iron-responsive RNA elements

1989 ◽  
Vol 9 (11) ◽  
pp. 5055-5061
Author(s):  
D J Haile ◽  
M W Hentze ◽  
T A Rouault ◽  
J B Harford ◽  
R D Klausner
Keyword(s):  
Binding Protein ◽  
Reduced Form ◽  
Scatchard Analysis ◽  
Stem Loop ◽  
Lower Affinity ◽  
Translational Repressor ◽  
High Affinity ◽  
Iron Responsive Element ◽  
Responsive Element

The 5' untranslated region of the ferritin heavy-chain mRNA contains a stem-loop structure called an iron-responsive element (IRE), that is solely responsible for the iron-mediated control of ferritin translation. A 90-kilodalton protein, called the IRE binding protein (IRE-BP), binds to the IRE and acts as a translational repressor. IREs also explain the iron-dependent control of the degradation of the mRNA encoding the transferrin receptor. Scatchard analysis reveals that the IRE-BP exists in two states, each of which is able to specifically interact with the IRE. The higher-affinity state has a Kd of 10 to 30 pM, and the lower affinity state has a Kd of 2 to 5 nM. The reversible oxidation or reduction of a sulfhydryl is critical to this switching, and the reduced form is of the higher affinity while the oxidized form is of lower affinity. The in vivo rate of ferritin synthesis is correlated with the abundance of the high-affinity form of the IRE-BP. In lysates of cells treated with iron chelators, which decrease ferritin biosynthesis, a four- to fivefold increase in the binding activity is seen and this increase is entirely caused by an increase in high-affinity binding sites. In desferrioxamine-treated cells, the high-affinity form makes up about 50% of the total IRE-BP, whereas in hemin-treated cells, the high-affinity form makes up less than 1%. The total amount of IRE-BP in the cytosol of cells is the same regardless of the prior iron treatment of the cell. Furthermore, a mutated IRE is not able to interact with the IRE-BP in a high-affinity form but only at a single lower affinity Kd of 0.7 nM. Its interaction with the IRE-BP is insensitive to the sulfhydryl status of the protein.

The Crystal and Molecular Structures of Bis(diethyldithiocarbamato)platinum(II) and Bis[di(2-hydroxyethyl)dithiocarbamato]platinum(II)

1992 ◽  
Vol 45 (2) ◽  
pp. 429 ◽  
Author(s):  
AT Baker ◽  
MT Emett
Keyword(s):  
Single Crystal ◽  
Bond Length ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Crystal And Molecular Structures

The structures of [Pt(S2CN(C2H5)2)2] (1) and [Pt(S2CN(C2H4OH)2)2] (2) have been determined by single-crystal X-ray diffractometry. Compound (1) crystallizes in the tetragonal space group P42/n, a 16.4692(10),c 6.2160(6) � (Z = 4); R was 0.029 for 1012 observed reflections. Compound (2) is monoclinic, space group Pc, a 6-0663(11), b 1.1784(15), c 12.5740(21) � ,β92.569(8)� (Z = 2); R was 0.019 for 1573 observed reflections. The presence of electron-withdrawing groups in the ligands of (2) appears to have little effect on the Pt-S distances but causes an increase in the C-N bond length, with the C-N bond lengths being significantly different at the 2 σ level.

Reaktionen von Oxo-Rhenium(VII und V)-Verbindungen mit Thiobenzoylhydrazin. Kristall- und Molekülstrukturen von Re(NHNC(S)Ph)3 · DMF, Re(NHNC(S)Ph)3 · OPPh3 und [Re(NHNC(S)Ph)(NHNHC(S)Ph)2]Cl · 1/3 C2H5OH · 1/3 H2O / Reactions of Oxorhenium(VII and V) Complexes with Thiobenzoylhydrazine. Crystal and Molecular Structures of Re(NHNC(S)Ph)3 · DMF, Re(NHNC(S)Ph)3 · OPPh3 and [Re(NHNC(S)Ph)(NHNHC(S)Ph)2]Cl · 1/3 C2H5OH · 1/3 H2O

1990 ◽  
Vol 45 (8) ◽  
pp. 1167-1176 ◽  
Author(s):  
Alfons Möhlenkamp ◽  
Rainer Mattes
Keyword(s):  
Unit Cell ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Chelating Ligands ◽  
Rhenium Atom ◽  
Coordination Polyhedra ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Ligand Structure

The reaction of NaReO4 with thiobenzoylhydrazine yields Re(NHNC(S)Ph)3- DMF (1). With ReOCl3(PPh3)2 thiobenzoylhydrazine reacts to give Re(NHNC(S)Ph)3 · OPPh3 (2) and in the presence of HCl to yield [Re(NHNC(S)Ph)(NHNHC(S)Ph),]Cl · 1/3 C2H5OH -1 /3 H2O (3). The structures of 1-3 have been determined. 1: monoclinic, space group P2,/c, a = 1150.1(9), b = 2050.0(9), c = 1181.0(8) pm, β = 109.62(5)°, Z = 4, 2980 reflections, R = 0.055; 2: trigonal, space group R 3, a = 1399.8(1), c = 1684.0(1) pm, Z = 3, 1419 reflections, R = 0.033; 3: monoclinic, space group P2,/c, a = 1446.8(3), b = 3220.7(5), c = 1727.1(4) pm, β = 108.42(2)°, Z = 12, 6112 reflections, R = 0.062. In 1 and 2 three N,S-chelating ligands NHNR (R = C(S)Ph) are coordinated to the central rhenium atom. The ligand structure is intermediate between a diazene and a hydrazido(2–) structure. In 3 each rhenium atom is coordinated by one NHNR and two NHNHR ligands, all N,S-chelating. The latter can be considered as protonated diazene ligands. The unit cell contains three isomeric coordination polyhedra.

Cyclische Diazastannylene, XVIII [1]Zur Frage der Bindungsbeschreibung in Polyedern des Typs Sn4X3Y:Die Kristall-und Molekülstrukturen von Sn4(NtBu)4 und Sn4(NtBu)3O / Cyclic Diazastannylenes, XVIII [1]Bonding Description in Polyhedra of the Sn4X3Y-Type:The Crystal and Molecular Structures of Sn4(NtBu)4 and Sn4(NtBu)3O

1983 ◽  
Vol 38 (9) ◽  
pp. 1054-1061 ◽  
Author(s):  
M. Veith ◽  
O. Recktenwald
Keyword(s):  
Van Der Waals ◽  
Structural Data ◽  
Van Der Waals Forces ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Structural Elements ◽  
Triclinic Space Group ◽  
Space Group ◽  
O 213.2 ◽  
Crystal And Molecular Structures

Abstract Crystals of Sn4(NtBu)4 (1) are monoclinic, space group P21/c, with cell constants a = 1038.9(4), b = 1468.3(5), c = 1698.8(5) pm, β = 91.6(1)° and Z = 4, while those of Sn4(NtBu)3O (2) are triclinic, space group P 1̄, with dimensions a = 1293.0(5), b = 1027.1(5), c = 1716.7(9) pm, α = 90.9(1), β = 102.5(1), γ = 107.0(1)° and Z = 4. The molecules 1 are held together by van-der-Waals forces, whereas two molecules 2 interact in the crystal by weak 0→Sn donor bonds (290-332 pm) forming dimers. The outstanding structural elements of 1 and 2 are the Sn4N4 and Sn4N3O polyhedra, which can be described by two interpenetrating tetrahedra of tin atoms and of nitrogen or nitrogen and oxygen atoms forming a distorted cube, which approaches 4̄3 m symmetry in the case of 1 and 3m for 2. Characteristic distances are in 1: Sn-N 220.2 pm, in 2: Sn-N 221.3 pm and Sn-O 213.2 pm. An almost ionic bonding model and two covalent models are discussed on the basis of the structural data including Sn4(NtBu)3OAlMe3.

C-(2-Hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones as regioselective bidentate ligands in boron chelate formation. Crystal and molecular structures of a diphenylboron complex and its parent ligand

1998 ◽  
Vol 76 (7) ◽  
pp. 1082-1092 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J Rettig ◽  
James Trotter
Keyword(s):  
Direct Methods ◽  
Acid Anhydride ◽  
Molecular Structures ◽  
Bidentate Ligands ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Chelate Formation ◽  
Boron Chelate ◽  
Parent Ligand

The C-(2-hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones 5 are synthesized by the condensation of variously substituted salicylaldehydes with N-(2-hydroxyphenylmethyl)-hydroxylamine. These nitrones react with diphenylborinic acid anhydride to form seven-membered diphenylboron chelates 6. Crystals of C-(4-diethylamino-2-hydroxyphenyl)-N-(2-hydroxyphenylmethyl)nitrone, 5d, are monoclinic, a = 6.911(2), b = 10.663(2), c = 22.951(1) Å, β = 97.33(1)°, Z = 4, space group P21/n, and those of 4-dimethylamino-8-(2-hydroxyphenylmethyl)-6,6-diphenyl-5,7-dioxa-8-azonia-6-borata-6,7-dihydro-5H-benzocycloheptene-ethanol, 6d·EtOH, are monoclinic, a = 9.069(2), b = 29.881(1), c = 11.1883(6) Å, β = 109.426(9)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.032 and 0.039 (R w = 0.031 and 0.036) for 2510 and 4162 reflections with I > 3σ(I), respectively. Key words : C-(2-hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones, organoboron compounds, crystal structures.

Organolanthanoids. XI. The Crystal and Molecular Structures of Two Tris(η5-cyclopentadienyl)(pyridine) lanthanoid(III) Compounds

1987 ◽  
Vol 40 (5) ◽  
pp. 907 ◽  
Author(s):  
GB Deacon ◽  
BM Gatehouse ◽  
SN Platts ◽  
DL Wilkinson
Keyword(s):  
Crystal Structures ◽  
Coordination Number ◽  
Unit Cell ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Crystal And Molecular Structures

The crystal structures of tris (η5-cyclopentadienyl) (pyridine) samarium(III), monoclinic, space group P21/c, a 10.906(4), b 8.636(2), c 17.825(3) �, β 96.44(2)�, Z 4, R 0.027 and Rw 0.032 for 3619 'observed' reflections, and tris (η5-cyclopentadienyl)(pyridine)neodymium(III), monoclinic, space group P21 / c, a 14-206(4), b 8.619(2), c 15.190(7) �, β 107.38(2)�, Z 4, R 0.035 and R, 0.039 for 2677 'observed' reflections have been determined. Both compounds have pseudotetrahedral geometry with a coordination number of 10 for the lanthanoid metal but there is a difference in the coordination of pyridine and in unit cell packing between the two structures.

Aromatic aldonitrones of 2-(hydroxyamino)benzyl alcohol and their cyclic isomers. Crystal and molecular structures of a 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine, a boron chelate, and its parent nitrone ligand

1998 ◽  
Vol 76 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Benzyl Alcohol ◽  
Crystal Structures ◽  
Direct Methods ◽  
Molecular Structures ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Independent Molecules ◽  
Boron Chelate

The synthesis of a series of C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 5 (that can also exist under certain conditions as isomeric 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, 8), via 2-(hydroxyamino)benzyl alcohol, 4, and their subsequent reactions with oxybis(diphenylborane), (Ph2B)2O, leading to the 5-(arylmethylene)-7,7-diphenyl-6,8-dioxa- 5-azonia-7-borata-5H-6,7,8,9-tetrahydrobenzocyclo- heptenes 6 are described. Crystals of 1-hydroxy-2- (4-methoxyphenyl)- 1,2-dihydro-4H-3,1-benzoxazine, 8b, are monoclinic, a = 9.379(2), b = 10.699(2), c = 12.9392(7) Å, β = 99.916(2)°, Z = 4 (two independent molecules), space group Pa; those of C-[4-(dimethylamino)phenyl]-N-[(2-hydroxymethyl)phenyl]nitrone, 5c, are monoclinic, a = 7.687(1), b = 7.891(1), c = 11.5053(9) Å, β = 92.781(9)°, Z = 2, space group P21; and those of 5-[4-(dimethylamino)phenylmethylene]-7,7-diphenyl-6,8-dioxa-5-azonia-7-borata-5H-6,7,8,9- tetrahydro-benzocycloheptene, 6a, are monoclinic, a = 10.771(1), b = 13.1057(9), c = 16.8724(7) Å, β = 90.005(5)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R(F2) = 0.120 (Rw(F2) = 0.135) for all 3149 reflections (R(F) = 0.071, Rw(F) = 0.063 for 1500 reflections with I >3 σ (I)) for 8b and R(F) = 0.035 and 0.036 (Rw(F) = 0.031 and 0.038) for 1071 and 3594 reflections with I >3 σ (I), respectively, for 5c and 6a. Compound 8b is the first structurally characterized 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine derivative and 6a features a relatively rare seven-membered boron-containing heterocycle.Key words: C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, organoboron compounds, crystal structures

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