scholarly journals ALDOL CONDENSATION OF N-ALKYLATED-3-ARYL-4,6-DIMETHOXY-7-FORMYLINDOLES AS A GOOD METHOD FOR THE SYNTHESIS OF 1-ARYL-6,8-DIMETHOXYPYRROLO[3,2,1-hi]INDOLE-4-CARBOXYLATES

2010 ◽  
Vol 6 (3) ◽  
pp. 297-303
Author(s):  
Jumina Jumina
Keyword(s):  
Spectroscopic Data ◽  
Aldol Condensation ◽  
Sodium Hydride ◽  
Good Method ◽  
X Ray ◽  
X Ray Crystallography ◽  
Structural Assignment ◽  
Vilsmeier Formylation

Alkylation of 3-aryl-4,6-dimethoxyindole 3a and 3b with methyl and ethyl a-bromoacetates afforded good yields of indol-1-ylacetates 4. Treatment of these indoles 4 with the Vilsmeier formylation reagent gave formylindoles 5 in 54-81 % yield. These formylindole 5 underwent intramolecular aldol condensation when treated with sodium hydride in tetrahydrofuran to give pyrroloindole-4-carboxylates 6 in 30-60 % yield. Structural assignment based on spectroscopic data confirmed the structure of the synthesized pyrroloindoles. In the case of pyrroloindole 6c, the structure of this molecule was also proven by X-ray crystallography data.    Keywords: indole, pyrroloindole, aldol condensation, alkylation, and formylation

scholarly journals Phenylhydrazone and Quinazoline Derivatives from the Cold-Seep-Derived Fungus Penicillium oxalicum

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 9
Author(s):  
Ya-Ping Liu ◽  
Sheng-Tao Fang ◽  
Zhen-Zhen Shi ◽  
Bin-Gui Wang ◽  
Xiao-Nian Li ◽  
...  
Keyword(s):  
Deep Sea ◽  
Spectroscopic Data ◽  
2D Nmr ◽  
Penicillium Oxalicum ◽  
Marine Phytoplankton ◽  
Cold Seep ◽  
Phytoplankton Species ◽  
X Ray ◽  
X Ray Crystallography ◽  
Quinazoline Derivatives

Three new phenylhydrazones, penoxahydrazones A–C (compounds 1–3), and two new quinazolines, penoxazolones A (compound 4) and B (compound 5), with unique linkages were isolated from the fungus Penicillium oxalicum obtained from the deep sea cold seep. Their structures and relative configurations were assigned by analysis of 1D/2D NMR and mass spectroscopic data, and the absolute configurations of 1, 4, and 5 were established on the basis of X-ray crystallography or ECD calculations. Compound 1 represents the first natural phenylhydrazone-bearing steroid, while compounds 2 and 3 are rarely occurring phenylhydrazone tautomers. Compounds 4 and 5 are enantiomers that feature quinazoline and cinnamic acid units. Some isolates exhibited inhibition of several marine phytoplankton species and marine-derived bacteria.

Crotaleschenine, an Alkaloid of Crotalaria leschenaultii

1988 ◽  
Vol 41 (4) ◽  
pp. 429 ◽  
Author(s):  
LW Smith ◽  
JA Edgar ◽  
RI Willing ◽  
RW Gable ◽  
MF Mackay ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
X Ray ◽  
X Ray Crystallography

An alkaloid of Crotalaria leschenaultii DC., previously reported as crispatine and now named crotaleschenine, has been re-investigated and shown to be (7β,8α-H,12α,13α,14α)-12β-hydroxy-1,2-didehydrocrotalane-11,15-dione.1 Spectroscopic data are presented and the stereochemistry determined by X-ray crystallography. The esterifying acid of crotaleschenine is identical with that of retusine , which is thereby determined as (1a,7β,8α-H,12α,13α,14α)-12β- hydroxycrotalane-11,15-dione.

scholarly journals Five-membered ring annelation in [2.2]paracyclophanes by aldol condensation

2014 ◽  
Vol 10 ◽  
pp. 2021-2026 ◽  
Author(s):  
Henning Hopf ◽  
Swaminathan Vijay Narayanan ◽  
Peter G Jones
Keyword(s):  
Structural Analysis ◽  
Spectroscopic Data ◽  
Acid Treatment ◽  
Aldol Condensation ◽  
Membered Ring ◽  
X Ray

Under basic conditions 4,5,12,13-tetraacetyl[2.2]paracyclophane (9) cyclizes by a double aldol condensation to provide the two aldols 12 and 15 in a 3:7 ratio. The structures of these compounds were obtained from X-ray structural analysis, spectroscopic data, and mechanistic considerations. On acid treatment 12 is dehydrated to a mixture of the condensed five-membered [2.2]paracyclophane derivatives 18–20, whereas 15 yields a mixture of the isomeric cyclopentadienones 21–23. The structures of these elimination products are also deduced from X-ray and spectroscopic data. The sequence presented here constitutes the simplest route so far to cyclophanes carrying an annelated five-membered ring.

scholarly journals Bromobenzoylation of Methyl α-D-Mannopyranoside: Synthesis and Spectral Characterization

2021 ◽  
pp. 171-183
Author(s):  
Farhana Yasmin ◽  
Md. R. Amin ◽  
Anowar Hosen ◽  
M.A. Kawsar Sarkar
Keyword(s):  
Spectroscopic Data ◽  
Direct Method ◽  
Good Method ◽  
Substitution Product ◽  
X Ray ◽  
Chemical Structures ◽  
Therapeutic Drugs ◽  
Health And Disease ◽  
Derivatives Of ◽  
Acyl Derivatives

The widening importance of carbohydrate derivatives as unrivaled potential antimicrobial and therapeutic drugs has attracted attentionto the synthesis of mannopyranoside derivatives. In the present study, regioselective 3-bromobenzoylation of methyl α-D-mannopyranoside (1) was carried out using the direct method and gave the corresponding 6-O-(3-bromobenzoyl) derivative (2) in excellent yield. A number of 2,3,4-tri-O-acyl derivatives (3–10) of this 6-substitution product using a wide variety of acylating agents were also prepared in order to obtain newer derivatives of synthetic and biological importance. The chemical structures of the newly synthesized compounds were ascertained by analyzing their physicochemical, elemental, and spectroscopic data. Additionally, the X-ray powder diffraction (XRD) of these acylated products was studiedfor quantitatively identifying crystalline compounds.Therefore, due to the importance of carbohydrates, it might be useful to develop a good method for the synthesis of carbohydrate-based drugs of the current global situation for health and disease

Mononuclear and Binuclear Complexes of Platinum(0) Containing (Alkynyl)phenylsilanes

1999 ◽  
Vol 52 (1) ◽  
pp. 51 ◽  
Author(s):  
Martin A. Bennett ◽  
Christopher J. Cobley ◽  
David C. R. Hockless ◽  
Thomas Klettke
Keyword(s):  
Spectroscopic Data ◽  
Chair Conformation ◽  
Membered Ring ◽  
Binuclear Complexes ◽  
Nickel Compound ◽  
X Ray ◽  
X Ray Crystallography

Reaction of bis(cycloocta-1,5-diene)platinum(0) with the (alkynyl)phenylsilanes Ph3SiC2But, Ph2Si(C2But)2 and PhSi(C2But)3 gives, respectively, [Pt (Ph3SiC2But)2] (1b), [Pt {Ph2Si(C2But)}]2 (2b), and [Pt {PhSi(C2But)3}]2 (4b), which contain zerovalent platinum atoms coordinated by two alkyne units. Spectroscopic data indicate that (2b) and (4b) contain two PtC4 and two SiC4 tetrahedra joined at the corners. X-Ray crystallography shows that complex (4b) is isostructural and isomorphous with the known nickel analogue, two of the alkyne units being uncoordinated; the central eight-membered ring comprising two silicon, four alkyne carbon and two platinum atoms has an approximate chair conformation. In contrast, the monomer (1b) is isostructural but not isomorphous with the analogous nickel compound (1a); in the crystal there is evidence for a weak intramolecular phenyl-phenyl interaction.

scholarly journals Sesquiterpene Lactones from Inula oculus-christi

2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Mahmoud Mosaddegh ◽  
Maryam Hamzeloo Moghadam ◽  
Saeedeh Ghafari ◽  
Farzaneh Naghibi ◽  
Seyed Nasser Ostad ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Sesquiterpene Lactones ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

Inula oculus-christi L. (Compositae) extract was chromatographed and three sesquiterpene lactones ergolide, gaillardin and pulchellin C were isolated. The structures of these compounds were determined by analysis of their spectroscopic data, and their crystal structures were defined using X-ray crystallography; the isolation of ergolide and pulchellin C is reported for the first time from this species. These three compounds were evaluated for their in vitro cytotoxic activity against MDBK, MCF7 and WEHI164 cells; ergolide and gaillardin exhibited lower and significantly different IC50 values compared with pulchellin C ( p<0.001).

scholarly journals Übergangsmetall-Carben-Komplexe, CXXXIV [1]. Synthese neuer Mono- und Biscarben-Komplexe der VI. Nebengruppe; Röntgenstruktur des ersten Bis[amino(alkoxy)carben]-Komplexes / Transition Metal Carbene Complexes, CXXXIV [1]. Synthesis of New Mono- and Bis-Carbene Complexes of Group VIb Elements; Structure of the First Bis[amino(alkoxy)carbene]-Complex

1984 ◽  
Vol 39 (5) ◽  
pp. 668-674 ◽  
Author(s):  
Ernst Otto Fischer ◽  
Rudolf Reitmeier ◽  
Klaus Ackermann
Keyword(s):  
Molecular Structure ◽  
Transition Metal ◽  
Spectroscopic Data ◽  
The Novel ◽  
Nucleophilic Agent ◽  
Reaction Conditions ◽  
Carbene Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Compounds

The hexacarbonyl compounds of chromium, molybdenum and tungsten react with the highly nucleophilic agent Li NiPr2 and in a subsequent alkylation with (Et3O)BF4 to give the carbene complexes (CO)5M[C(N′Pr2)OEt] (1, 3, 4). In case of W(CO)6 and Mo(CO)6 the novel biscarbene complexes cis(CO)4M[C(NiPr2)OEt]2 (2, 5) are additionally obtained. Reaction conditions, properties and spectroscopic data of the new compounds are reported. The molecular structure of cis(CO)4W[C(NiPr2)OEt]2 (4) was determined by X-ray crystallography

Analysis of structural MtrC models based on homology with the crystal structure of MtrF

2012 ◽  
Vol 40 (6) ◽  
pp. 1181-1185 ◽  
Author(s):  
Marcus J. Edwards ◽  
James K. Fredrickson ◽  
John M. Zachara ◽  
David J. Richardson ◽  
Thomas A. Clarke
Keyword(s):  
Crystal Structure ◽  
Outer Membrane ◽  
Domain Structure ◽  
Spectroscopic Data ◽  
Sequence Similarity ◽  
Shewanella Oneidensis ◽  
Significant Sequence Similarity ◽  
X Ray ◽  
X Ray Crystallography ◽  
Homology Models

The outer-membrane decahaem cytochrome MtrC is part of the transmembrane MtrCAB complex required for mineral respiration by Shewanella oneidensis. MtrC has significant sequence similarity to the paralogous decahaem cytochrome MtrF, which has been structurally solved through X-ray crystallography. This now allows for homology-based models of MtrC to be generated. The structure of these MtrC homology models contain ten bis-histidine-co-ordinated c-type haems arranged in a staggered cross through a four-domain structure. This model is consistent with current spectroscopic data and shows that the areas around haem 5 and haem 10, at the termini of an octahaem chain, are likely to have functions similar to those of the corresponding haems in MtrF. The electrostatic surfaces around haem 7, close to the β-barrels, are different in MtrF and MtrC, indicating that these haems may have different potentials and interact with substrates differently.

Direct Synthesis of 6H-Chromeno[3,4-b]quinolin-6-ol Derivatives from Substituted 3-Nitro-2H-chromenes and 2-Nitrobenzaldehydes Mediated by Fe/AcOH System

Synthesis ◽  
2017 ◽  
Vol 50 (06) ◽  
pp. 1350-1358 ◽  
Author(s):  
Cunde Wang ◽  
Xushun Qing ◽  
Ting Wang ◽  
Chenlu Dai ◽  
Zhenjie Su
Keyword(s):  
Acetic Acid ◽  
Nucleophilic Addition ◽  
Aldol Condensation ◽  
Direct Synthesis ◽  
Reductive Cyclization ◽  
Quinoline Derivatives ◽  
Acid System ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sequential Reduction

An efficient iron/acetic acid system-mediated reductive cyclization reaction of substituted 2-aryl-3-nitro-2H-chromenes with substituted 2-nitrobenzaldehydes for the synthesis of 6-aryl-6H-chromeno[3,4-b]quinolines was developed. This reaction involves the sequential reduction, hydrolysis, aldol condensation, intramolecular addition, and the nucleophilic addition of substituted 2-aryl-3-nitro-2H-chromenes with substituted 2-nitrobenzaldehydes to give the corresponding 6H-chromeno[3,4-b]quinolines. This transformation provides a straightforward synthetic protocol for constructing substituted 6H-chromeno[3,4-b]quinoline derivatives. The structures of three typical products were confirmed by X-ray crystallography.

Nano ZrO2: an efficient, recyclable, and inexpensive catalyst for diastereoselective three-component Mannich reactions

2014 ◽  
Vol 92 (7) ◽  
pp. 659-664 ◽  
Author(s):  
M. Saeed Abaee ◽  
Elahe Akbarzadeh ◽  
Abbas Shockravi ◽  
Mohammad M. Mojtahedi ◽  
Hamid Reza Khavasi
Keyword(s):  
Spectroscopic Data ◽  
Room Temperature ◽  
Aromatic Aldehydes ◽  
Significant Loss ◽  
Mannich Reactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Aniline Derivatives ◽  
High Yields ◽  
Acyclic Ketones

A facile procedure is developed for the three-component Mannich reactions of several heterocyclic, homocyclic, and acyclic ketones by using catalytic quantities of nano ZrO2. As a result, the starting ketones undergo rapid reactions with a variety of aromatic aldehydes and aniline derivatives at room temperature to produce stereoselectively high yields of the corresponding anti β-amino ketones. Interestingly, the catalyst could be recycled for several runs in a row without significant loss of its activity. The structure of the products was assigned based on their spectroscopic data and the anti stereoselectivity was confirmed by X-ray crystallography.

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