Reaction of ferrocenecarboxylic acid with N,N′-disubstituted carbodiimides: synthesis, spectroscopic and X-ray crystallographic analysis of N,N′-disubstituted N-ferrocenoylureas and identification of a one-pot coupling reagent for the formation of ferrocenecarboxamides in a non-aqueous solvent

2004 ◽  
Vol 689 (9) ◽  
pp. 1472-1480 ◽  
Author(s):  
Bernd Schetter ◽  
Bernd Speiser
Keyword(s):  
Crystallographic Analysis ◽  
One Pot ◽  
X Ray ◽  
Coupling Reagent ◽  
Aqueous Solvent ◽  
Ferrocenecarboxylic Acid

A Base-Promoted One-Pot Asymmetric Friedel–Crafts Alkylation/Michael Addition of 4-Substituted Indoles

Synthesis ◽  
2019 ◽  
Vol 52 (08) ◽  
pp. 1215-1222
Author(s):  
Robert Connon ◽  
Laura Carroll ◽  
Patrick J. Guiry
Keyword(s):  
Michael Addition ◽  
Crystallographic Analysis ◽  
Indole Derivatives ◽  
One Pot ◽  
X Ray ◽  
Excellent Yield ◽  
Tricyclic Core ◽  
Cyclobutane Derivative

Herein, we report a base-promoted Zn(II)–bis(oxazoline)-catalyzed one-pot Friedel–Crafts alkylation/Michael addition of 3-(indol-4-yl)acrylonitrile derivatives with trans-β-nitrostyrenes to yield the tricyclic core of the ergoline skeleton in up to 71% yield and 85% ee. During the purification of 3-(indol-4-yl)acrylonitrile, the key substrate for catalytic studies, a novel trans-cis-trans-cyclobutane derivative, thought to be formed via a [2+2] light-promoted cycloaddition, was identified by X-ray crystallographic analysis. Finally, a novel class of 4-substituted bis(indole)methane derivatives were serendipitously prepared in excellent yield by reacting 4-substituted indole derivatives with 4-nitrobenzaldehyde. One bis(indole)methane was characterized by X-ray crystallographic analysis.

A One-Pot Intramolecular Tandem Michael–Aldol Annulation Reaction for the Synthesis of Chiral Pentacyclic Terpenes

Synthesis ◽  
2019 ◽  
Vol 51 (21) ◽  
pp. 3964-3972
Author(s):  
Jianyu Lu ◽  
Serkan Koldas ◽  
Huafang Fan ◽  
John Desper ◽  
Victor W. Day ◽  
...  
Keyword(s):  
Michael Addition ◽  
Aldol Condensation ◽  
Crystallographic Analysis ◽  
Side Chain ◽  
One Pot ◽  
X Ray ◽  
Double Ring ◽  
Stereogenic Centers

A chiral tricyclic terpene possessing a 6,6,6-tricyclic framework and a 3,3-dimethyl-7-oxooctylidenyl side chain undergoes a double ring-closing reaction to give two chiral pentacyclic terpenes in a ratio of 4:3 via an intramolecular Michael addition followed by aldol condensation under basic conditions. Three new stereogenic centers are introduced in the initial Michael annulation reaction. Stereoselective installation of an ethoxycarbonyl group at C17 of the two pentacyclic terpenes separately gives the corresponding highly functionalized pentacyclic terpenoids with seven stereogenic centers. The structures and stereochemistry of key intermediates and products are established through X-ray crystallographic analysis. A mechanism is proposed for explaining the stereochemistry in the Michael annulation reaction.

Design and synthesis of novel pyridinium nitrate-bearing substituted anilines via one-pot tandem reactions

2017 ◽  
Vol 41 (7) ◽  
pp. 384-389 ◽  
Author(s):  
Yang Huijuan ◽  
Ren Yujie ◽  
Xu Wenqian ◽  
Li Ren
Keyword(s):  
Formation Mechanism ◽  
Crystallographic Analysis ◽  
Tandem Reactions ◽  
Substituted Anilines ◽  
One Pot ◽  
X Ray ◽  
Design And Synthesis ◽  
Potential Formation

Thirty-two novel 2-amino-1-[3-oxo-3-(substituted-anilino)propyl]pyridinium nitrate derivatives were designed and prepared via one-pot tandem reactions. The structure of the 2-methylanilino derivative was characterised by X-ray crystallographic analysis. In addition, a potential formation mechanism is proposed.

Structural studies of organoboron compounds LXIII. Reaction of ketoximes with aldehydes and diphenylborinic acid, and the crystal and molecular structures of two different types of boron chelates and one of the precursor aldehyde adducts

1995 ◽  
Vol 73 (6) ◽  
pp. 835-845 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ulf Riebe ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Chelate Ring ◽  
Direct Methods ◽  
Crystallographic Analysis ◽  
Molecular Structures ◽  
Boron Compounds ◽  
One Pot ◽  
Boron Chelates ◽  
Space Group ◽  
X Ray ◽  
Diphenylboron Chelates

The diphenylboron chelates of ketoxime adducts to formaldehyde and trichloroacetaldehyde (chloral) have been synthesized. The reactions were carried out as three-component one-pot reactions, and also as two-step reactions for the ketoxime chloral adducts, which were isolated and characterized before reaction with oxybis(diphenylborane) to form the diphenylboron chelates. One of the intermediate adducts and two of the diphenylboron chelates have been characterized by X-ray crystallographic analysis. Crystals of O-(2,2,2-trichloro-1-hydroxyethyl)-2-propanonoxime, 8d, are monoclinic, a = 7.010(2), b = 11.832(3), c = 11.684(2) Å, β = 90.48(2)°, Z = 4, space group P21/c; those of 4-isopropylidene-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 9a, are orthorhombic, a = 11.098(2), b = 15.364(1), c = 8.715(2) Å, Z = 4, space group P212121; and those of 5-trichloromethyl-2-isopropylidene-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclopentane, 10d, are monoclinic, a = 9.164(2), b = 15.304(3), c = 13.859(2) Å, β = 105.28(1)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037, 0.044, and 0.040 (Rw = 0.041, 0.016, and 0.042) for 1082, 1256, and 3062 reflections with I ≥ 3σ(F2), respectively. The X-ray analyses show that the products from the reaction between acetonoxime, oxybis(diphenylborane), and formaldehyde or trichloroacetaldehyde, respectively, possess different boron chelate structures. With formaldehyde a COBON chelate ring is obtained and with trichloroacetaldehyde a BOCON chelate ring is formed. Keywords: boron chelates, boron compounds, organboron compounds, crystal structures.

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Purification, crystallization and X-ray crystallographic analysis of ATPase domain in transcription regulator DmpR

2019 ◽  
Vol 7 (2) ◽  
pp. 52-55
Author(s):  
Su-Jin Lee ◽  
In-Young Baek ◽  
Yan An ◽  
Woo-Chan Ahn ◽  
Kwang-Hyun Park ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Atpase Domain ◽  
X Ray ◽  
Transcription Regulator

Purification, crystallization and X-ray crystallographic analysis of methylglyoxal reductase Gre2 from Candida albicans

2019 ◽  
Vol 7 (2) ◽  
pp. 42-46 ◽  
Author(s):  
Giang Thu Nguyen ◽  
Shinae Kim ◽  
Hang-Suk Chun ◽  
Woo-Keun Kim ◽  
Jeong Ho Chang
Keyword(s):  
Candida Albicans ◽  
Crystallographic Analysis ◽  
X Ray

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

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