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Journal ArticleDOI

4,5,6,7,8,9-Hexahydro-2H-cyclo-octa[c]pyrazol-1-ium-3-olate.

31 Oct 2010-Acta Crystallographica Section E-structure Reports Online (International Union of Crystallography)-Vol. 66, Iss: 11
TL;DR: The title compound, C9H14N2O, exists in the zwitterionic form in the crystal, where the cyclooctane ring adopts a twisted boat-chair conformation.
Abstract: The title compound, C9H14N2O, exists in the zwitterionic form in the crystal. The cyclo­octane ring adopts a twisted boat-chair conformation. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into sheets lying parallel to the bc plane. The structure is also stabilized by π–π inter­actions, with a centroid-to-centroid distance of 3.5684 (8) A.
Citations
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Journal ArticleDOI
19 Jul 2013
TL;DR: A simple method to synthesize β-keto esters from ketones and ethyl chloroformate by changing the base and reagent is developed that can be useful for the synthesis of pharmaceutically important pyrazolones also.
Abstract: Background Pyrazolones are traditionally synthesized by the reaction of β-keto esters with hydrazine and its derivatives. There are methods to synthesize β-keto esters from esters and aldehydes, but these methods have main limitation in varying the substituents. Often, there are a number of methods such as acylation of enolates in which a chelating effect has been employed to lock the enolate anion using lithium and magnesium salts; however, these methods suffer from inconsistent yields in the case of aliphatic acylation. There are methods to synthesize β-keto esters from ketones like caboxylation of ketone enolates using carbon dioxide and carbon monoxide sources in the presence of palladium or transition metal catalysts. Currently, the most general and simple method to synthesize β-keto ester is the reaction of dimethyl or ethyl carbonate with ketone in the presence of strong bases which also requires long reaction time, use of excessive amount of reagent and inconsistent yield. These factors lead us to develop a simple method to synthesize β-keto esters by changing the base and reagent.

18 citations

Journal ArticleDOI
TL;DR: In this article, the crystal structure of 4-(4-fluorophenyl)-2-(1H-indol-3-yl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine-3 carbonitrile (Ia) and 2-( 1H-INDOL-3yl)-4-(thiophen-2-yl]-5, 6, 7, 8, 9, 10, 10-hexahexa hexahexacrylate (Ib) were eluc

7 citations

31 Jul 2016
TL;DR: In this article, two new inhibitors, 2-amino-4-(4-cholorophenyl)-5,6,7,8,9,10,hexahydrobenzo[8] annulene-1,3,3(4H)-tricarbonitrile(Ia) and 2amino 4-(4)-bromophenyl]-5, 6, 7, 8, 9, 10,10-hexahedrobenzos [8]annulene]-1, 3, 3-4H-tric
Abstract: Tuberculosis is a disease caused by Mycobacterium tuberculosis. The bacterial cell wall has a characteristic low permeability, which essentially makes antibiotics ineffective. The cell wall material must be regulated so that its deposition does not compromise its structure. In this study, two new inhibitors, 2-amino-4-(4-cholorophenyl)-5,6,7,8,9,10-hexahydrobenzo[8] annulene-1,3,3(4H)-tricarbonitrile(Ia) and 2-amino-4-(4-bromophenyl)-5,6,7,8,9,10-hexahydrobenzo[8]annulene-1,3,3(4H)-tricarbonitrile(Ib) were synthesized. The crystal structures of the above compounds were determined by single crystal X-ray diffraction. The compounds C 21 H 19 Cl N 3 (Ia) and C 21 H 19 Br N 3 (Ib) were crystallized in the monoclinic and triclinic system. In both compounds, the cyclohexane ring was found to adopt a boat conformation. The cyclooctane ring of both compounds adopted a twisted chair-chair conformation. In silico analyses revealed that both compounds showed good anti-mycobacterial activities against the enoyl-acyl carrier enzyme and the N-acetyl-gamma protein, both of which are critical for bacterial survival. Synthesis, structure determination, conformation, intra, inter-molecular interactions and docking studies of both compounds are presented herein.

2 citations


Cites background from "4,5,6,7,8,9-Hexahydro-2H-cyclo-octa..."

  • ...The cyclooctane ring adopts a twisted chair-chair conformation in compounds (Ia) and (Ib) as found in related structures (Fun et al. 2010, Suresh et al. 2007)....

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Journal ArticleDOI
TL;DR: The present work is an example of how the simple replacement of a substituent in the main molecular scaffold may transform the structure type, paving the way for a variety of supramolecular motifs and consequently altering the complexity of the intermolecular interaction patterns.
Abstract: The structures of three new pyridine derivatives, 2-meth­oxy-4-(4-meth­oxy­phenyl)-5,6,7,8,9,10-hexa­hydro­cyclo­octa­[b]pyridine-3-carbo­nitrile, C20H22N2O2, (I), 2-eth­oxy-4-(3-nitrophenyl)-5,6,7,8,9,10-hexa­hydro­cyclo­octa­[b]pyridine-3-carbonitrile, C20H21N3O3, (II), and 2-eth­oxy-4-(4-meth­oxy­phenyl)-5,6,7,8,9,10-hexa­hydro­cyclo­octa­[b]pyridine-3-carbo­nitrile, C21H24N2O2, (III), differ in the nature of the substituents either at the 2-position of the central pyridine ring or on the pendent aryl ring. This simple change in the structure substantially alters the inter­molecular inter­action patterns. The substituted phenyl group adopts a synclinal geometry with respect to the plane of the pyridine ring in all three compounds. In (I), a C—H⋯N inter­action results in a one-dimensional chain parallel to the b axis. In (II), there are two C—H⋯N(nitrile) inter­actions from different symmetry-related mol­ecules, resulting in a two-dimensional network parallel to the bc plane. There is also a weak C—H⋯O inter­action from the eth­oxy group to an adjacent nitro O atom. The present work is an example of how the simple replacement of a substituent in the main mol­ecular scaffold may transform the structure type, paving the way for a variety of supra­molecular motifs and consequently altering the complexity of the inter­molecular inter­action patterns.
References
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Journal ArticleDOI
TL;DR: This paper could serve as a general literature citation when one or more of the open-source SH ELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.
Abstract: An account is given of the development of the SHELX system of computer programs from SHELX-76 to the present day. In addition to identifying useful innovations that have come into general use through their implementation in SHELX, a critical analysis is presented of the less-successful features, missed opportunities and desirable improvements for future releases of the software. An attempt is made to understand how a program originally designed for photographic intensity data, punched cards and computers over 10000 times slower than an average modern personal computer has managed to survive for so long. SHELXL is the most widely used program for small-molecule refinement and SHELXS and SHELXD are often employed for structure solution despite the availability of objectively superior programs. SHELXL also finds a niche for the refinement of macromolecules against high-resolution or twinned data; SHELXPRO acts as an interface for macromolecular applications. SHELXC, SHELXD and SHELXE are proving useful for the experimental phasing of macromolecules, especially because they are fast and robust and so are often employed in pipelines for high-throughput phasing. This paper could serve as a general literature citation when one or more of the open-source SHELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.

81,116 citations


"4,5,6,7,8,9-Hexahydro-2H-cyclo-octa..." refers methods in this paper

  • ...Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009)....

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  • ...Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL…...

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Journal ArticleDOI
TL;DR: In this paper, a continuous nitrogen-flow cooling device for X-ray diffraction studies is described, which works in the range 77.4 to 323.0 k with a precision of ± 0.1 k and a liquid-nitrogen constant consumption rate of 0.5 k−1 over the whole temperature range.
Abstract: A continuous nitrogen-flow cooling device, generally applicable to X-ray diffraction studies, is described. The device works in the range 77.4 to 323.0 K with a precision of ±0.1 K and a liquid-nitrogen constant consumption rate of 0.5 l h−1 over the whole temperature range. The supply vessel is unpressurized, so that refilling can be done without any observable influence on the cooling of the sample.

1,946 citations


"4,5,6,7,8,9-Hexahydro-2H-cyclo-octa..." refers methods in this paper

  • ...The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. Geometry....

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  • ...For the stability of the temperature controller used for data collection, see: Cosier & Glazer (1986)....

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Journal ArticleDOI
TL;DR: Interestingly all the synthesized compounds exhibited good antibacterial and antifungal activity (except 2a-c, 6a, 8, 9a).

134 citations


"4,5,6,7,8,9-Hexahydro-2H-cyclo-octa..." refers background in this paper

  • ...Related literature For pyrazole derivatives and their microbial activities, see: Ragavan et al. (2009, 2010)....

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  • ...As part of our on-going research aiming on the synthesis of new antimicrobial compounds, we have reported the synthesis of novel pyrazole derivatives and their microbial activities (Ragavan et al., 2009, 2010)....

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Journal ArticleDOI
TL;DR: alpha-Oxy/thio substituted-beta-keto esters were synthesized through an efficient cross-Claisen condensation of aryl oxy/thIO acetic acid ethyl esters with acid chlorides and screened for their antibacterial, antifungal activities.

81 citations


"4,5,6,7,8,9-Hexahydro-2H-cyclo-octa..." refers background in this paper

  • ...Related literature For pyrazole derivatives and their microbial activities, see: Ragavan et al. (2009, 2010)....

    [...]

  • ...As part of our on-going research aiming on the synthesis of new antimicrobial compounds, we have reported the synthesis of novel pyrazole derivatives and their microbial activities (Ragavan et al., 2009, 2010)....

    [...]