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Abbasi Tarighat M. Orthogonal projection approach and continuous wavelet transform-feed forward neural networks for simultaneous spectrophotometric determination of some heavy metals in diet samples. Food Chem 2016; 192:548-56. [DOI: 10.1016/j.foodchem.2015.07.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 06/01/2015] [Accepted: 07/07/2015] [Indexed: 10/23/2022]
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De Rosa M, Arnold D, Hartline D, Truong L, Verner R, Wang T, Westin C. Effect of Bronsted Acids and Bases, and Lewis Acid (Sn(2+)) on the Regiochemistry of the Reaction of Amines with Trifluoromethyl-β-diketones: Reaction of 3-Aminopyrrole to Selectively Produce Regioisomeric 1H-Pyrrolo[3,2-b]pyridines. J Org Chem 2015; 80:12288-99. [PMID: 26575797 DOI: 10.1021/acs.joc.5b02192] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of 3-aminopyrrole (as its salt) with trifluoromethyl-β-diketones gave γ-1H-pyrrolo[3,2-b]pyridines via reaction at the less reactive carbonyl group. The trifluoromethyl group increased the electrophilicity of the adjacent carbonyl group and decreased the basicity of the hydroxyl group of the CF3 amino alcohol formed. This amino alcohol was formed faster, but its subsequent dehydration to the β-enaminone was slow resulting in the preferential formation of the γ-regioisomer. Reaction of 4,4,4-trifluoro-1-phenyl-1,3-butadione with 3-aminopyrrole was carried out using a series of 6 amine buffers. Yields of the α-1H-pyrrolo[3,2-b]pyridine increased as the pKa of the amine buffer decreased. Surprisingly the yield went down at higher pKas. There was a change in mechanism as the reaction mixture became more basic. With strong amines trifluoromethyl-β-diketones were present mainly or completely as the enolate. Under reductive conditions (3-nitropyrrole/Sn/AcOH/trifluoromethyl-β-diketone) the α-1H-pyrrolo[3,2-b]pyridine was the major product as a result of Lewis acid catalysis by Sn(2+). Similar α-regiochemistry was observed when the reaction of the 3-aminopyrrole salt with trifluoromethyl-β-diketones was carried out in the presence of base and tin(II) acetate.
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Affiliation(s)
- Michael De Rosa
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - David Arnold
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Douglas Hartline
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Linda Truong
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Roman Verner
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Tianwei Wang
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Christian Westin
- Department of Chemistry, Penn State Brandywine , 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
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Mohammadi K, Azad SS, Amoozegar A. New tetradentate Schiff bases of 2-amino-3,5-dibromobenzaldehyde with aliphatic diamines and their metal complexes: synthesis, characterization and thermal stability. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 146:221-227. [PMID: 25813179 DOI: 10.1016/j.saa.2015.02.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 02/10/2015] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
The tetradentate Schiff base ligands (L(1)-L(4)), were synthesized by reaction between 2-amino-3,5-dibromobenzaldehyde and aliphatic diamines. Then, nickel and oxovanadium(IV) complexes of these ligands were synthesized and characterized by (1)H NMR, Mass, IR, UV-Vis spectroscopy and thermogravimetry. The kinetic parameters of oxovanadium(IV) complexes were calculated from thermal studies. According to the results of thermogravimetric data, the thermal stability of oxovanadium(IV) complexes is as follow: [Formula: see text].
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Affiliation(s)
- Khosro Mohammadi
- Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran.
| | - Seyyedeh Sedigheh Azad
- Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran
| | - Ameneh Amoozegar
- Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran
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Tarighat MA, Mohammadi K. Simultaneous spectrophotometric determination of Cu2+, Hg2+, and Cd2+ ions using 2-(3-hydroxy-1-methylbut-2-enylideneamino)pyridine-3-ol. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:197. [PMID: 25792026 DOI: 10.1007/s10661-015-4411-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/04/2015] [Indexed: 06/04/2023]
Abstract
New complexes of Cu2+, Hg2+, and Cd2+ with a recently synthesized Schiff base derived from 2-(3-hydroxy-1-methylbut-2-enylideneamino)pyridine-3-ol were applied for their simultaneous determination with artificial neural networks. A new analytical method using principal component-feed forward neural networks (PC-FFNNs) and principal component-radial basis function networks (PC-RBFNs) was used. Spectral data was reduced using principal component analysis and subjected to ANNs. The data obtained from synthetic mixtures of metal ions were processed by PC-FFNNs and PC-RBFNs. Performances of the proposed methods were tested with regard to relative standard error of prediction. Limit of detections and limit of quantifications were determined. The results obtained by PC-FFNNs and PC-RBFNs were compared to each other. Under the working conditions, the proposed methods were successfully applied to simultaneous determination of Hg2+, Cu2+, and Cd2+ in different water and soil samples. Concentrations of metal ions in the samples were also determined by flame atomic absorption spectrometry (FAAS) and standard addition method. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by FAAS and standard addition method.
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Affiliation(s)
- Maryam Abbasi Tarighat
- Department of Chemistry, Faculty of Sciences, Persian Gulf University, Bushehr, 75169, Iran,
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