[2+4] and [2+2] Cycloaddition Reactions of N-Sulfinyl Carboxylic Acid Amides with (CF3)2BNMe2. Crystal Structure ofcyclo-(CF3)2B-NMe2-S(=O)-N=C(p-CH3C6H4)-O

2002 ◽  
Vol 628 (11) ◽  
pp. 2299-2302 ◽  
Author(s):  
David J. Brauer ◽  
Hans Bürger ◽  
Gottfried Pawelke ◽  
Jürgen Rothe
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Cycloaddition Reactions ◽  
Carboxylic Acid Amides

Pigments of Fungi. XLVII. Cardinalic Acid, a New Anthraquinone Carboxylic Acid from the New Zealand Toadstool Dermocybe cardinalis and the Synthesis and X-Ray Crystal Structure of Methyl 1,7,8-Tri-O-methylcardinalate

1998 ◽  
Vol 51 (3) ◽  
pp. 213 ◽  
Author(s):  
Melvyn Gill ◽  
Peter M. Morgan ◽  
Jin Yu ◽  
Jonathan M. White
Keyword(s):  
Crystal Structure ◽  
New Zealand ◽  
Carboxylic Acid ◽  
Single Crystal ◽  
Natural Product ◽  
Carboxylic Acids ◽  
Structure Analysis ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
X Ray

Cardinalic acid (1,7,8-trihydroxy-6-methoxy-3-methyl-9,10-dioxoanthracene-2-carboxylic acid) (4) and the known anthraquinone carboxylic acids endocrocin (1), dermolutein (2) and cinnalutein (3) have been isolated from the New Zealand toadstool Dermocybe cardinalis. Methyl 1,7,8-tri-O-methylcardinalate (5) has been prepared both by permethylation of the natural product (4) and from 2,6-dichloro-1,4-benzoquinone by two consecutive regioselective Diels–Alder cycloaddition reactions. A single-crystal X-ray structure analysis of the ester (5) corroborates the structure of the natural product (4) and confirms the outcome of both cycloaddition reactions.

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

Crystal structure of tofacitinib dihydrogen citrate (Xeljanz®), (C16H21N6O)(H2C6H5O7)

2021 ◽  
pp. 1-8
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Acid Group ◽  
Dimensional Network ◽  
Van Der Waals Contacts ◽  
Citrate Anion

The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

A MOF based on a lead(II) 2-oxido-6-methylpyridine-4-carboxylate network

2020 ◽  
Vol 75 (4) ◽  
pp. 365-369
Author(s):  
Long Tang ◽  
Yu Pei Fu ◽  
Na Cui ◽  
Ji Jiang Wang ◽  
Xiang Yang Hou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Carboxylic Acid ◽  
Thermogravimetric Analysis ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
X Ray ◽  
Connected Node ◽  
Metal Organic ◽  
Solid State Fluorescence

AbstractA new metal-organic framework, [Pb(hmpcaH)2]n (1), has been hydrothermally synthesized from Pb(OAc)2 · 3H2O and 2-hydroxy-6-methylpyridine-4-carboxylic acid (hmpcaH2; 2), and characterized by IR spectroscopy, elemental and thermogravimetric analysis, and single-crystal X-ray diffraction. In complex 1, each hmpcaH− ligand represents a three-connected node to combine with the hexacoordinated Pb(II) ions, generating a 3D binodal (3,6)-connected ant network. The crystal structure of 2 was determined. The solid-state fluorescence properties of 1 and 2 were investigated.

Allosteric N-acetamide-indole-6-carboxylic acid thumb pocket 1 inhibitors of hepatitis C virus NS5B polymerase — Acylsulfonamides and acylsulfamides as carboxylic acid replacements

2013 ◽  
Vol 91 (1) ◽  
pp. 66-81 ◽  
Author(s):  
Pierre L. Beaulieu ◽  
René Coulombe ◽  
James Gillard ◽  
Christian Brochu ◽  
Jianmin Duan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Carboxylic Acid ◽  
Allosteric Inhibitors ◽  
Subgenomic Replicon ◽  
Structure Activity ◽  
Hcv Ns5b ◽  
Acid Function ◽  
Ns5b Polymerase

Acylsulfonamide and acylsulfamide as surrogates for the carboxylic acid function of N-acetamide-indole-6-carboxylic acids were evaluated as allosteric inhibitors of hepatitis C virus (HCV) NS5B polymerase. Several analogs displayed excellent antiviral potency against both 1a and 1b HCV genotypes in cell-based subgenomic replicon assays. Structure–activity relationships (SAR) are discussed in the context of the crystal structure of an inhibitor − NS5B polymerase complex. Absorption, distribution, metabolism, and excretion pharmacokinetic (ADME-PK) properties of this class of inhibitors are also described.

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