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Pandolfi F, Chiarotto I, Feroci M. Electrochemically modified Corey-Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene. Beilstein J Org Chem 2018; 14:891-899. [PMID: 29765470 PMCID: PMC5942384 DOI: 10.3762/bjoc.14.76] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/12/2018] [Indexed: 12/05/2022] Open
Abstract
The electrochemical reduction of 2-(2,2-dibromovinyl)naphthalene in a DMF solution (Pt cathode) yields selectively 2-ethynylnaphthalene or 2-(bromoethynyl)naphthalene in high yields, depending on the electrolysis conditions. In particular, by simply changing the working potential and the supporting electrolyte, the reaction can be directed towards the synthesis of the terminal alkyne (Et4NBF4) or the bromoalkyne (NaClO4). This study allowed to establish that 2-(bromoethynyl)naphthalene can be converted into 2-ethynylnaphthalene by cathodic reduction.
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Affiliation(s)
- Fabiana Pandolfi
- Deptartment of Fundamental and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, via Castro Laurenziano, 7, 00161, Rome, Italy
| | - Isabella Chiarotto
- Deptartment of Fundamental and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, via Castro Laurenziano, 7, 00161, Rome, Italy
| | - Marta Feroci
- Deptartment of Fundamental and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, via Castro Laurenziano, 7, 00161, Rome, Italy
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Morris JB. Nasal dosimetry of inspired naphthalene vapor in the male and female B6C3F1 mouse. Toxicology 2013; 309:66-72. [PMID: 23619605 DOI: 10.1016/j.tox.2013.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/28/2013] [Accepted: 04/12/2013] [Indexed: 11/29/2022]
Abstract
Naphthalene vapor is a nasal cytotoxicant in the rat and mouse but is a nasal carcinogen in only the rat. Inhalation dosimetry is a critical aspect of the inhalation toxicology of inspired vapors and may contribute to the species differences in the nasal response. To define the nasal dosimetry of naphthalene in the B6C3F1 male and female mouse, uptake of naphthalene vapor was measured in the surgically isolated upper respiratory tract (URT) at inspiratory flow rates of 25 or 50 ml/min. Uptake was measured at multiple concentrations (0.5, 3, 10, 30 ppm) in controls and mice treated with the cytochrome P450 inhibitor 5-phenyl-1-pentyne. In both sexes, URT uptake efficiency was strongly concentration dependent averaging 90% at 0.5 ppm compared to 50% at 30 ppm (25 ml/min flow rate), indicating saturable processes were involved. Both uptake efficiency and the concentration dependence of uptake were significantly diminished by 5-phenyl-1-pentyne indicating inspired naphthalene vapor is extensively metabolized in the mouse nose with saturation of metabolism occurring at the higher concentrations. A hybrid computational fluid dynamic physiologically based pharmacokinetic model was developed for nasal dosimetry. This model accurately predicted the observed URT uptake efficiencies. Overall, the high URT uptake efficiency of naphthalene in the mouse nose indicates the absence of a tumorigenic response is not attributable to low delivered dose rates in this species.
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Affiliation(s)
- John B Morris
- Toxicology Program, Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 N. Eagleville Road, Storrs, CT 06269, USA.
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Abstract
Previous studies have shown that the presence of one P450 enzyme can affect the function of another. The goal of the present study was to determine if P450 enzymes are capable of forming homomeric complexes that affect P450 function. To address this problem, the catalytic activities of several P450s were examined in reconstituted systems containing NADPH-POR (cytochrome P450 reductase) and a single P450. CYP2B4 (cytochrome P450 2B4)-, CYP2E1 (cytochrome P450 2E1)- and CYP1A2 (cytochrome P450 1A2)-mediated activities were measured as a function of POR concentration using reconstituted systems containing different concentrations of P450. Although CYP2B4-dependent activities could be explained by a simple Michaelis-Menten interaction between POR and CYP2B4, both CYP2E1 and CYP1A2 activities generally produced a sigmoidal response as a function of [POR]. Interestingly, the non-Michaelis behaviour of CYP1A2 could be converted into a simple mass-action response by increasing the ionic strength of the buffer. Next, physical interactions between CYP1A2 enzymes were demonstrated in reconstituted systems by chemical cross-linking and in cellular systems by BRET (bioluminescence resonance energy transfer). Cross-linking data were consistent with the kinetic responses in that both were similarly modulated by increasing the ionic strength of the surrounding solution. Taken together, these results show that CYP1A2 forms CYP1A2-CYP1A2 complexes that exhibit altered catalytic activity.
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Cheng D, Harris D, Reed JR, Backes WL. Inhibition of CYP2B4 by 2-ethynylnaphthalene: evidence for the co-binding of substrate and inhibitor within the active site. Arch Biochem Biophys 2007; 468:174-82. [PMID: 17967439 PMCID: PMC2121586 DOI: 10.1016/j.abb.2007.07.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2007] [Revised: 07/21/2007] [Accepted: 07/25/2007] [Indexed: 10/22/2022]
Abstract
2-ethynylnaphthalene (2EN) is an effective mechanism-based inhibitor of CYP2B4. There are two inhibitory components: (1) irreversible inactivation of CYP2B4 (a typical time-dependent inactivation), and (2) a reversible component. The reversible component was unusual in that the degree of inhibition was not simply a characteristic of the enzyme-inhibitor interaction, but dependent on the size of the substrate molecule used to monitor residual activity. The effect of 2EN on the metabolism of seven CYP2B4 substrates showed that it was not an effective reversible inhibitor of substrates containing a single aromatic ring; substrates with two fused rings were competitively inhibited by 2EN; and larger substrates were non-competitively inhibited. Energy-based docking studies demonstrated that, with increasing substrate size, the energy of 2EN and substrate co-binding in the active site became unfavorable precisely at the point where 2EN became a competitive inhibitor. Hierarchical docking revealed potential allosteric inhibition sites separate from the substrate binding site.
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Affiliation(s)
- Dongmei Cheng
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
| | - Danni Harris
- Molecular Research Institute, Mountain View, CA 94043
| | - James R. Reed
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
| | - Wayne L. Backes
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
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Wright AT, Cravatt BF. Chemical proteomic probes for profiling cytochrome p450 activities and drug interactions in vivo. ACTA ACUST UNITED AC 2007; 14:1043-51. [PMID: 17884636 PMCID: PMC2044501 DOI: 10.1016/j.chembiol.2007.08.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 08/13/2007] [Accepted: 08/13/2007] [Indexed: 10/22/2022]
Abstract
The cytochrome P450 (P450) superfamily metabolizes many endogenous signaling molecules and drugs. P450 enzymes are regulated by posttranslational mechanisms in vivo, which hinders their functional characterization by conventional genomic or proteomic methods. Here we describe a chemical proteomic strategy to profile P450 activities directly in living systems. Derivatization of a mechanism-based inhibitor with a "clickable" handle provided an activity-based probe that labels multiple P450s both in proteomic extracts and in vivo. This probe was used to record alterations in liver P450 activities triggered by chemical agents, including inducers of P450 expression and direct P450 inhibitors. The chemical proteomic strategy described herein thus offers a versatile method to monitor P450 activities and small-molecule interactions in any biological system and, through doing so, should facilitate the functional characterization of this large and diverse enzyme class.
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Affiliation(s)
- Aaron T Wright
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Cheng D, Reed JR, Harris D, Backes WL. Inhibition of CYP2B4 by the mechanism-based inhibitor 2-ethynylnaphthalene: inhibitory potential of 2EN is dependent on the size of the substrate. Arch Biochem Biophys 2007; 462:28-37. [PMID: 17470357 PMCID: PMC2041879 DOI: 10.1016/j.abb.2007.03.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Revised: 03/22/2007] [Accepted: 03/23/2007] [Indexed: 11/27/2022]
Abstract
2-Ethynylnaphthalene (2EN) is a mechanism-based inhibitor of CYP2B4 with two components to the inhibition, (1) enzyme inactivation, which requires covalent binding of the 2EN metabolite, and (2) reversible inhibition by 2EN itself. Both inhibitory components were examined using several different CYP2B4 substrates. Preincubation of CYP2B4 with 2EN led to a time-dependent inactivation of each of the CYP2B4-dependent activities examined; however, the ability of 2EN to reversibly inhibit CYP2B4 depended on the substrate employed, which is inconsistent with classical inhibition patterns. The degree 2EN's reversible inhibition was shown not to correlate with the substrate affinity for the active site, but with parameters related to the molecular size of the substrate. The results are consistent with 2EN and the smaller substrates simultaneously fitting in the CYP2B4 active site, leading to very little inhibition. Larger substrates exhibited greater degrees of inhibition because of their inability to co-bind with inhibitor in the active site.
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Affiliation(s)
- Dongmei Cheng
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
| | - James R. Reed
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
| | - Danni Harris
- Molecular Research Institute, Mountain View, CA 94043
| | - Wayne L. Backes
- Department of Pharmacology and Experimental Therapeutics, and The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA
- Corresponding author: Wayne L. Backes, Ph.D., Department of Pharmacology & The Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 533 Bolivar St., New Orleans, LA 70112, Tel. 504-568-6557, FAX 504-568-6888, E-mail:
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Chan WK, Ho CM, Wong MK, Che CM. Oxidative Amide Synthesis and N-Terminal α-Amino Group Ligation of Peptides in Aqueous Medium. J Am Chem Soc 2006; 128:14796-7. [PMID: 17105276 DOI: 10.1021/ja064479s] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new method for oxidative synthesis of amides from alkynes and amines in high yields (up to 96%) using [Mn(2,6-Cl2TPP)Cl] 1 as a catalyst and Oxone/H2O2 as an oxidant in aqueous medium has been developed. This method could be used for N-terminal alpha-amino group ligation of unprotected peptides with aryl, aliphatic, and internal alkynes under mild conditions.
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Affiliation(s)
- Wing-Kei Chan
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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Kitamura S, Kohno Y, Okamoto Y, Takeshita M, Ohta S. Reductive metabolism of an alpha,beta-ketoalkyne, 4-phenyl-3-butyn-2-one, by rat liver preparations. Drug Metab Dispos 2002; 30:414-20. [PMID: 11901095 DOI: 10.1124/dmd.30.4.414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The reduction of the triple bond and carbonyl group of an alpha,beta-ketoalkyne, 4-phenyl-3-butyn-2-one (PBYO), by rat liver microsomes and cytosol was investigated. The triple-bond-reduced product trans-4-phenyl-3-buten-2-one (PBO) and the carbonyl-reduced product 4-phenyl-3-butyn-2-ol (PBYOL) were formed when PBYO was incubated with rat liver microsomes in the presence of NADPH. The triple bond of 1-phenyl-1-butyne, deprenyl, ethynylestradiol, ethinamate, and PBYOL, in which the triple bond is not adjacent to a carbonyl group, were not reduced by liver microsomes even in the presence of NADPH. PBO was further reduced to 4-phenyl-2-butanone (PBA) by liver cytosol with NADPH. PBYOL was also formed from PBYO by liver cytosol in the presence of NADPH or NADH. The microsomal triple-bond reductase activity was inhibited by disulfiram, 7-dehydrocholesterol, and 18 beta-glycyrrhetinic acid but not beta-diethylaminoethyldiphenylpropylacetate or carbon monoxide. The triple-bond reductase activity in liver microsomes was not enhanced by several inducers of the rat cytochrome P450 system. These results suggested that the triple-bond reduction is caused by a new type of reductase, not cytochrome P450. The microsomal and cytosolic carbonyl reductase activities were not inhibited by quercitrin, indomethacin, or phenobarbital. Only S-PBYOL was formed from PBYO by liver cytosol. In contrast, liver microsomes produced R-PBYOL together with the S-enantiomer to some extent. Ethoxyresorufin-O-dealkylase activity in rat liver microsomes was markedly inhibited by PBYO and PBO, partly by PBYOL, but not by PBA.
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Affiliation(s)
- Shigeyuki Kitamura
- Institute of Pharmaceutical Science, Hiroshima University School of Medicine, Minami-ku, Hiroshima, Japan
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