Condensation of cis-9-methyl-2-decalone with cyclic β-amino esters: synthesis and X-ray crystallography of perhydroazacyclopentaanthracenes and perhydroazabenzanthracenes

1976 ◽  
Vol 54 (10) ◽  
pp. 1512-1520 ◽  
Author(s):  
Ronald B. Kelly ◽  
Barry A. Beckett ◽  
Ijaz Mumtaz ◽  
Eric Stanley ◽  
Peter S. White
Keyword(s):  
Carbon Atom ◽  
Crystallographic Analysis ◽  
Amino Ketone ◽  
Structural Isomers ◽  
X Ray ◽  
X Ray Crystallography ◽  
Amino Esters ◽  
Condensation Products ◽  
Vinylogous Amides ◽  
Pure Isomer

Condensation of cis-9-methyl-2-decalone, 9, with ethyl 2-pyrrolidineacetate, 10, afforded a mixture of two isomeric vinylogous amides, 11. Oxidation of either one pure isomer, 11a, or the mixture 11 to the same pyridone, 12, revealed that the two condensation products were stereoisomeric at a single carbon atom and not structural isomers. Reduction of 11a afforded the amino ketone 13. The structures assigned to 11, 12, and 13 are based on X-ray crystallographic analysis of 13.Similarly, condensation of 9 with ethyl 2-piperidineacetate, 14, afforded the isomers 15a and 15b both of which were oxidized to the same pyridone, 16. Reduction of 15a afforded 17. The structures assigned to 15, 16, and 17 are based on X-ray crystallographic analysis of 17.

Synthesis of cyclohexapyrrolizidines: C-methylation of vinylogous amides

1978 ◽  
Vol 56 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Ronald B. Kelly ◽  
Sandra J. Alward
Keyword(s):  
Convenient Method ◽  
X Ray ◽  
X Ray Crystallography ◽  
Vinylogous Amides ◽  
High Yields

A synthesis of the cyclohexapyrrolizidines 32 and 33 is described; the structure of the latter was determined by X-ray crystallography. It is anticipated that this synthesis will serve as a model for the construction of a similar pyrrolizidine system during a projected synthesis of thelepogine 2.A convenient method for the C-methylation of cyclic vinylogous amides is also described. This procedure, which is similar to published procedures, affords high yields of methylated product and is regiospecific.

scholarly journals Synthesis, Characterization, and Bioactivity of Schiff Bases and TheirCd2+,Zn2+,Cu2+, andNi2+Complexes Derived from Chloroacetophenone Isomers with S-Benzyldithiocarbazate and the X-Ray Crystal Structure of S-Benzyl-β-N-(4-chlorophenyl)methylenedithiocarbazate

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Mohammed Khaled bin Break ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Teng-Jin Khoo
Keyword(s):  
Crystal Structure ◽  
Phenyl Ring ◽  
Crystallographic Analysis ◽  
Gram Negative Bacteria ◽  
Schiff Base Ligands ◽  
Gram Negative ◽  
X Ray ◽  
X Ray Crystallography ◽  
Gram Positive Bacteria ◽  
Antimicrobial Assay

Two bidentate Schiff base ligands having nitrogen sulphur donor sequence were derived from the condensation of S-benzyldithiocarbazate (SBDTC) with 2-chloroacetophenone and 4-chloroacetophenone to give S-benzyl-β-N-(2-chlorophenyl)methylenedithiocarbazate (NS2) and S-benzyl-β-N-(4-chlorophenyl)methylenedithiocarbazate (NS4) isomers. Each of the ligands was then chelated with Cd2+, Zn2+, Cu2+, and Ni2+. The compounds were characterized via IR spectroscopy and melting point while the structure of NS4 was revealed via X-ray crystallography. Finally, the compounds were screened for antimicrobial activity to investigate the effect that is brought by the introduction of the chlorine atom to the benzene ring. X-ray crystallographic analysis showed that the structure of NS4 is planar with a phenyl ring that is nearly perpendicular to the rest of the molecules. The qualitative antimicrobial assay results showed that NS4 and its complexes lacked antifungal activity while Gram-positive bacteria were generally inhibited more strongly than Gram-negative bacteria. Furthermore, NS4 metal complexes were inhibited more strongly than the ligand while the opposite was seen with NS2 ligand and its complexes due to the partial solubility in dimethyl sulfoxide (DMSO). It was concluded that generally NS2 derivatives have higher bioactivity than that of NS4 derivatives and that the Cd complexes of both ligands have pronounced activity specifically onK. rhizophila.

scholarly journals Mutation of High-Affinity Methionine Permease Contributes to Selenomethionyl Protein Production in Saccharomyces cerevisiae

2010 ◽  
Vol 76 (19) ◽  
pp. 6351-6359 ◽  
Author(s):  
Toshihiko Kitajima ◽  
Yasunori Chiba ◽  
Yoshifumi Jigami
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Methylotrophic Yeast ◽  
Culture Conditions ◽  
Crystallographic Analysis ◽  
Gene Encoding ◽  
X Ray ◽  
X Ray Crystallography ◽  
High Affinity ◽  
Standard Culture ◽  
Resistant Mutants

ABSTRACT The production of selenomethionine (SeMet) derivatives of recombinant proteins allows phase determination by single-wavelength or multiwavelength anomalous dispersion phasing in X-ray crystallography, and this popular approach has permitted the crystal structures of numerous proteins to be determined. Although yeast is an ideal host for the production of large amounts of eukaryotic proteins that require posttranslational modification, the toxic effects of SeMet often interfere with the preparation of protein derivatives containing this compound. We previously isolated a mutant strain (SMR-94) of the methylotrophic yeast Pichia pastoris that is resistant to both SeMet and selenate and demonstrated its applicability for the production of proteins suitable for X-ray crystallographic analysis. However, the molecular basis for resistance to SeMet by the SMR-94 strain remains unclear. Here, we report the characterization of SeMet-resistant mutants of Saccharomyces cerevisiae and the identification of a mutant allele of the MUP1 gene encoding high-affinity methionine permease, which confers SeMet resistance. Although the total methionine uptake by the mup1 mutant (the SRY5-7 strain) decreased to 47% of the wild-type level, it was able to incorporate SeMet into the overexpressed epidermal growth factor peptide with 73% occupancy, indicating the importance of the moderate uptake of SeMet by amino acid permeases other than Mup1p for the alleviation of SeMet toxicity. In addition, under standard culture conditions, the mup1 mutant showed higher productivity of the SeMet derivative relative to other SeMet-resistant mutants. Based on these results, we conclude that the mup1 mutant would be useful for the preparation of selenomethionyl proteins for X-ray crystallography.

The Absolute Configurations of Haliclonacyclamines A and B Determined by X-Ray Crystallographic Analysis

2009 ◽  
Vol 62 (7) ◽  
pp. 667 ◽  
Author(s):  
I. Wayan Mudianta ◽  
Mary J. Garson ◽  
Paul V. Bernhardt
Keyword(s):  
Biosynthetic Pathway ◽  
Crystallographic Analysis ◽  
Marine Alkaloids ◽  
Enantiomerically Pure ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute ◽  
Insight Into

X-Ray crystallography establishes that the marine alkaloids (–)-haliclonacyclamine A 1 and (+)-haliclonacyclamine B 2 each have the configuration C2 (R), C3 (R), C7 (R), and C9 (R). The alkaloids appear to be enantiomerically pure; this provides an insight into the stereochemical consequences of the biosynthetic pathway leading to these bioactive 3-alkylpiperidine alkaloids.

What can Crystallographic Analysis tell us About Fibrinogen?

1979 ◽  
Author(s):  
Carolyn Cohen ◽  
John W. Weisel
Keyword(s):  
Electron Microscopy ◽  
Protein Molecule ◽  
Crystallographic Analysis ◽  
X Ray Diffraction ◽  
Technical Problems ◽  
Crystal Forms ◽  
X Ray ◽  
X Ray Crystallography ◽  
Large Size ◽  
Hydrated Protein

A major project in our laboratory has been the determination of the molecular structure of fibrinogen and its Interactions to form fibrin. We have approached this problem by attempting to obtain ordered forms of fibrinogen and, In fact, to crystallize the molecule. X-ray crystallography is the only objective method that can yield the detailed structure of the native hydrated protein molecule. In order to obtain crystals of fibrinogen, we found that limited proteolytic digestion is required. We have now produced three macroscopic crystal forms and a variety of microcrystals using several different enzymes and fibrinogens from different species. These modified molecules are largely intact and retain their biological function to form clots with thrombin similar in appearance to native fibrin by electron microscopy. The degree of order in all these aggregates is, moreover, far superior to that of fibrin. Some of the microcrystalline forms have been shown to be closely related to fibrin. Since the fibrinogen molecule is several times larger than any protein yet solved by X-ray methods, the technical problems in the crystallographic analysis are formidable. Because of the large size of the molecule, however, electron microscopy provides Information essential for the solution. We have completed a preliminary X-ray characterization of the ctystals and, using coordinated X-ray diffraction and electron microscopy, deduced plausible packing models. The results from this first stage in the X-ray analysis of fibrinogen give insight also into the packing of the molecules to form fibrin. Supported by USPHS grant #AM17346.

Synthesis and X-ray structure of 1,2,2,2-tetrakis(3-methoxyphenyl)ethanone

2000 ◽  
Vol 78 (12) ◽  
pp. 1647-1650
Author(s):  
LeRoy H Klemm ◽  
Timothy JR Weakley
Keyword(s):  
Carbon Atom ◽  
Chemical Bonding ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Reductive Dimerization ◽  
X Ray Crystallography ◽  
H Nmr

Photochemical reductive dimerization of 3,3'-dimethoxybenzophenone (1b) gave the symmetrical benzopinacol 1,1,2,2-tetrakis(3-methoxyphenyl)ethane-1,2-diol (2b), which was rearranged to the benzopinacolone 1,2,2,2-tetrakis(3-methoxyphenyl)ethanone (3b) by means of I2 in boiling glacial HOAc. The structure of 3b was indicated by 1H NMR and determined definitively by X-ray crystallography. The crystals are monoclinic, space group P21/c, a = 12.250(2), b = 9.6997(12), c = 20.866(2) Å, β = 95.319(11)°, Z = 4, R = 0.053 for 4523 independent reflections. The structure establishes that the migrating 3-methoxyphenyl group retains bonding through its number 1' carbon atom to the parent C2-unit during the rearrangement process.Key words: X-ray structure, pinacol-pinacolone rearrangement, chemical bonding.

Dicyanomethylene Compounds as Cyanation Reagents

2002 ◽  
Vol 57 (4) ◽  
pp. 460-470 ◽  
Author(s):  
Dietrich Döpp ◽  
Sabine Jüschke ◽  
Gerald Henkel
Keyword(s):  
Carbon Atom ◽  
Single Crystal ◽  
Benzene Solution ◽  
Acetonitrile Solution ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydride Abstraction

Ethenetetracarbonitrile (2, in benzene solution) and 1,3-dioxoindan-2-ylidene propanedinitrile (4, in ethanol or acetonitrile solution) act on N-aryl-2,3-dihydro-1H-benz[d,e]isoquinolines 6a-d and N-aryl-6,7-dihydro-5H-dibenz[c,e]azepines 11a-d via hydride abstraction followed by addition of cyanide to the iminium carbon atom forming the corresponding 1- and 5-carbonitriles 9a-d and 13a-d, respectively, in moderate to medium yields.Additionally , the known 1,3-dihydroxy-2H-inden-2-ylidenepropanedinitrile 15 and a novel dispirocyclopropane (17) are formed from 4 in the reaction with 6 in acetonitrile and ethanol, respectively. The structures of 17 and 6-(4-methylphenyl)-6,7-dihydro-5H-dibenz[c,e]azepine-5-carbonitrile have been unambiguously confirmed by single-crystal X-ray crystallography.

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