Jaimin Shah | IISER Bhopal (original) (raw)
Papers by Jaimin Shah
Proceedings of the National Academy of Sciences, India Section A: Physical Sciences, 2014
Your article is protected by copyright and all rights are held exclusively by The National Academ... more Your article is protected by copyright and all rights are held exclusively by The National Academy of Sciences, India. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
ChemInform, 2012
ABSTRACT The heterocyclic systems are available in the presence of either KOtBu or AIBN.
Organic Letters, 2012
Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-be... more Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-benzamides in the presence of potassium tert-butoxide and a catalytic amount of 1,10-phenanthroline or AIBN. This new carbon-carbon bond forming reaction gives direct access to various biaryl lactams containing six- and seven-membered rings chemoselectively. Carbon-carbon coupling seems to proceed by the generation of a radical in the amide ring which leads to C-H arylation of aniline.
RSC Advances, 2014
Isothiazolone and isoselenazolone based colorimetric probes for the detection of thiols have been... more Isothiazolone and isoselenazolone based colorimetric probes for the detection of thiols have been reported. A regenerable probe for the detection of organothiols is developed from isoselenazolone. Both of these probes possess higher selectivity for aromatic thiols, cysteine and glutathione.
![Research paper thumbnail of An efficient copper mediated synthetic methodology for benzo[d]isothiazol-3(2H)-ones and related sulfur–nitrogen heterocycles](https://attachments.academia-assets.com/74947704/thumbnails/1.jpg)
](Tetrahedron Letters, 2012
Tetrahedron, 2011
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for t... more Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the seleniumenitrogen coupling reaction by employing 25e100 mol % of CuI/ 1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloroarylamides also underwent seleniumenitrogen coupling reaction to give biologically important seleniumenitrogen heterocycles. Also, copper-catalyzed seleniumenitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external SeeN coupling partner.
Synthesis, 2012
An efficient copper-catalyzed synthetic method for the preparation of 2-hydroxybenzamides is desc... more An efficient copper-catalyzed synthetic method for the preparation of 2-hydroxybenzamides is described for the first time from 2-chlorobenzamide substrates using copper iodide/1,10-phenanthroline and a base, potassium hydroxide, in neat water. By using this reaction, a series of 2-hydroxybenzamides with functional groups such as fluoro, chloro, iodo, methoxy, amide, and alcohol have been obtained in 33-96% yield. Other aromatic 2-chloroarylamides such as naphthalene, pyridine, and thiophene are found to be equally compatible to the reaction. It is proposed that the reaction proceed via formation of copper-amide complex, which may facilitate the hydroxylation in water. Overall, the first report on coppercatalyzed hydroxylation reaction in water and first catalytic route for the synthesis of 2-hydroxybenzamides is presented. Simple purification procedure and convenience of employing low-cost reagents in neat water make this method practical and economical for the synthesis of 2-hydroxybenzamides.
Organic Letters, 2010
General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C N... more General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C NMR, Mass spectra for selected Se-N heterocycles & substrates S32-S140 References S141-S142 General Experimental Details All NMR experiments were carried out on 400 or 500 MHz spectrometers in DMSO-d 6 or CDCl 3 and NMR chemical shifts are reported in ppm referenced to the solvent peaks of CDCl 3 (7.26 ppm for 1 H and 77.16 (± 0.06) ppm for 13 C, respectively) or DMSO-d 6 (2.50 ppm for 1 H and 39.50 ppm for 13 C, respectively). 1 H NMR for compound 7 and 1 H and 13 C for compound 8 was also recorded in CD 3 OD (1 H and 13 C chemical shift 3.30 and 48.0 ppm respectively). High resolution mass spectra (HRMS), electron spray mass spectra (ESMS), and low resolution mass spectra (LRMS) are reported for ions of 80 Se. Mass analysis is performed on quadruple-time of S-2 flight (Q-TOF) mass spectrometer equipped with an ESI source (+ve). Infrared (IR) spectra were recorded as a plate in KBr with a FTIR machine. Melting points are uncorrected. DMF with seal septa, selenium powder (60 mesh size), copper iodide, and 1,10-phenanthroline were used as received from Aldrich. Grinded anhydrous K 2 CO 3 powder was used which was grinded using mortar, dried in oven at 160 o C for 6 h and stored in a desiccator. Selenium-nitrogen coupling reactions were carried out under nitrogen atmosphere. Silica gel (60 mesh size) was used for column chromatography. TLC analysis of reaction mixtures was performed using silica gel plates. Substituted benzoyl chlorides were prepared from respective benzoic acids by refluxing with excess of thionyl chloride otherwise prepared according to reported procedure. Excess of thionyl chloride was removed under vacuo and resulted residue was used for amide preparation without further purification. Substrates: 2-iodo-N-phenylbenzamide, 1 2-bromo-Nphenylbenzamide, 2 2-chloro-N-phenylbenzamide 3 for 1, 2-iodo-N-benzylbenzamide, 1c 2-bromo-N-benzylbenzamide 4 for 2, 2-iodo-N-methylbenzamide 1c for 3, 2-iodo-N-cyclohexylbenzamide 5 for 4, 2-iodo-N-(1-phenylethyl)benzamide 1a for 5, 2-iodobenzamide 1c for 6, 2-iodo-N-(2hydroxyethyl)benzamide 6 for 7, 2-iodo-N-(3-hydroxypropyl)benzamide 7 for 8, 2-chloro-3-nitro-N-phenylbenzamide 8 for 10, 2-chloro-N-benzyl-4-nitrobenzamide 9 for 11, 2-chloro-N-benzyl-5nitrobenzamide 10 for 12, 2-bromo-N-(4-bromo-phenyl)benzamide 11 for 14, N,N'-(hexane-1,6diyl)bis(2-iodobenzamide) 12 for 16, ethyl 4-(2-iodobenzamido)benzoate 1a for 26, and 3-iodo-Nphenyl-2-naphthamide 13 for 27 were prepared according to literature procedures. Synthesis of Se-N heterocycles by Cu-catalyzed coupling reaction 2-Phenylbenzo[d][1,2]selenazol-3(2H)-one (1) from 2-Iodo-N-phenylbenzamide (Typical Procedure): Copper iodide (114 mg, 0.6 mmol) and 1,10-phenanthroline (108 mg, 0.6 mmol) were added into DMF (3 mL) in a single neck flask. Resulted brownish solution was stirred for 15 min and then 2-iodo-N-phenylbenzamide 1 (0.97 g, 3.0 mmol), selenium powder (0.29 g, 3.6 mmol), and potassium carbonate powder (0.65 g, 4.7 mmol) were added sequentially to same
Organic & Biomolecular Chemistry, 2014
Benzamide ring-substituted, quinine-derived ebselen analogue is synthesized which exists in selen... more Benzamide ring-substituted, quinine-derived ebselen analogue is synthesized which exists in selenol form upon addition of PhSH. It catalyses oxidation of PhSH with H2O2 faster (103-fold) than ebselen.
The Journal of Organic Chemistry, 2013
A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical di... more A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by (77)Se NMR spectroscopy by using diphenyl diselenide as the substrate. (77)Se NMR study suggests that electrophilic species ArE(+) is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
The Journal of Organic Chemistry, 2012
Isoselenazolones were synthesized by a copper-catalyzed Se-N bond forming reaction between 2-halo... more Isoselenazolones were synthesized by a copper-catalyzed Se-N bond forming reaction between 2-halobenzamides and selenium powder. The catalytic activity of the various isoselenazolones was studied in the bromolactonization of pent-4-enoic acid. Isoselenazolone 9 was studied as a catalyst in several reactions: the bromolactonization of a series of alkenoic acids with bromine or N-bromosuccinimide (NBS) in the presence of potassium carbonate as base, the bromoesterification of a series of alkenes using NBS and a variety of carboxylic acids, and the oxidation of secondary alcohols to ketones using bromine as an oxidizing reagent. Mechanistic details of the isoselenazolone-catalyzed bromination reaction were revealed by (77)Se NMR spectroscopic and ES-MS studies. The oxidative addition of bromine to the isoselenazolone gives the isoselenazolone(IV) dibromide, which could be responsible for the activation of bromine under the reaction conditions. Steric effects from an N-phenylethyl group on the amide of the isoselenazolone and electron-withdrawing fluoro substituents on the benzo fused-ring of the isoselenazolone appear to enhance the stability of the isoselenazolone as a catalyst for the bromination reaction.
Organic Letters
General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C N... more General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C NMR, Mass spectra for selected Se-N heterocycles & substrates S32-S140 References S141-S142 General Experimental Details All NMR experiments were carried out on 400 or 500 MHz spectrometers in DMSO-d 6 or CDCl 3 and NMR chemical shifts are reported in ppm referenced to the solvent peaks of CDCl 3 (7.26 ppm for 1 H and 77.16 (± 0.06) ppm for 13 C, respectively) or DMSO-d 6 (2.50 ppm for 1 H and 39.50 ppm for 13 C, respectively). 1 H NMR for compound 7 and 1 H and 13 C for compound 8 was also recorded in CD 3 OD (1 H and 13 C chemical shift 3.30 and 48.0 ppm respectively). High resolution mass spectra (HRMS), electron spray mass spectra (ESMS), and low resolution mass spectra (LRMS) are reported for ions of 80 Se. Mass analysis is performed on quadruple-time of S-2 flight (Q-TOF) mass spectrometer equipped with an ESI source (+ve). Infrared (IR) spectra were recorded as a plate in KBr with a FTIR machine. Melting points are uncorrected. DMF with seal septa, selenium powder (60 mesh size), copper iodide, and 1,10-phenanthroline were used as received from Aldrich. Grinded anhydrous K 2 CO 3 powder was used which was grinded using mortar, dried in oven at 160 o C for 6 h and stored in a desiccator. Selenium-nitrogen coupling reactions were carried out under nitrogen atmosphere. Silica gel (60 mesh size) was used for column chromatography. TLC analysis of reaction mixtures was performed using silica gel plates. Substituted benzoyl chlorides were prepared from respective benzoic acids by refluxing with excess of thionyl chloride otherwise prepared according to reported procedure. Excess of thionyl chloride was removed under vacuo and resulted residue was used for amide preparation without further purification. Substrates: 2-iodo-N-phenylbenzamide, 1 2-bromo-Nphenylbenzamide, 2 2-chloro-N-phenylbenzamide 3 for 1, 2-iodo-N-benzylbenzamide, 1c 2-bromo-N-benzylbenzamide 4 for 2, 2-iodo-N-methylbenzamide 1c for 3, 2-iodo-N-cyclohexylbenzamide 5 for 4, 2-iodo-N-(1-phenylethyl)benzamide 1a for 5, 2-iodobenzamide 1c for 6, 2-iodo-N-(2hydroxyethyl)benzamide 6 for 7, 2-iodo-N-(3-hydroxypropyl)benzamide 7 for 8, 2-chloro-3-nitro-N-phenylbenzamide 8 for 10, 2-chloro-N-benzyl-4-nitrobenzamide 9 for 11, 2-chloro-N-benzyl-5nitrobenzamide 10 for 12, 2-bromo-N-(4-bromo-phenyl)benzamide 11 for 14, N,N'-(hexane-1,6diyl)bis(2-iodobenzamide) 12 for 16, ethyl 4-(2-iodobenzamido)benzoate 1a for 26, and 3-iodo-Nphenyl-2-naphthamide 13 for 27 were prepared according to literature procedures. Synthesis of Se-N heterocycles by Cu-catalyzed coupling reaction 2-Phenylbenzo[d][1,2]selenazol-3(2H)-one (1) from 2-Iodo-N-phenylbenzamide (Typical Procedure): Copper iodide (114 mg, 0.6 mmol) and 1,10-phenanthroline (108 mg, 0.6 mmol) were added into DMF (3 mL) in a single neck flask. Resulted brownish solution was stirred for 15 min and then 2-iodo-N-phenylbenzamide 1 (0.97 g, 3.0 mmol), selenium powder (0.29 g, 3.6 mmol), and potassium carbonate powder (0.65 g, 4.7 mmol) were added sequentially to same
Synlett, 2013
This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation... more This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research spotlight 2-Halobenzamides Compiled by Shah Jaimin Balkrishna Shah Jaimin Balkrishna was born in Vadodara, Gujarat, India in 1984. He received his B.Sc. degree in chemistry (2005) and his M.Sc. degree in organic chemistry (2007) from The Maharaja
Proceedings of the National Academy of Sciences, India Section A: Physical Sciences, 2014
Your article is protected by copyright and all rights are held exclusively by The National Academ... more Your article is protected by copyright and all rights are held exclusively by The National Academy of Sciences, India. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
ChemInform, 2012
ABSTRACT The heterocyclic systems are available in the presence of either KOtBu or AIBN.
Organic Letters, 2012
Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-be... more Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-benzamides in the presence of potassium tert-butoxide and a catalytic amount of 1,10-phenanthroline or AIBN. This new carbon-carbon bond forming reaction gives direct access to various biaryl lactams containing six- and seven-membered rings chemoselectively. Carbon-carbon coupling seems to proceed by the generation of a radical in the amide ring which leads to C-H arylation of aniline.
RSC Advances, 2014
Isothiazolone and isoselenazolone based colorimetric probes for the detection of thiols have been... more Isothiazolone and isoselenazolone based colorimetric probes for the detection of thiols have been reported. A regenerable probe for the detection of organothiols is developed from isoselenazolone. Both of these probes possess higher selectivity for aromatic thiols, cysteine and glutathione.
Tetrahedron Letters, 2012
Tetrahedron, 2011
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for t... more Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the seleniumenitrogen coupling reaction by employing 25e100 mol % of CuI/ 1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloroarylamides also underwent seleniumenitrogen coupling reaction to give biologically important seleniumenitrogen heterocycles. Also, copper-catalyzed seleniumenitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external SeeN coupling partner.
Synthesis, 2012
An efficient copper-catalyzed synthetic method for the preparation of 2-hydroxybenzamides is desc... more An efficient copper-catalyzed synthetic method for the preparation of 2-hydroxybenzamides is described for the first time from 2-chlorobenzamide substrates using copper iodide/1,10-phenanthroline and a base, potassium hydroxide, in neat water. By using this reaction, a series of 2-hydroxybenzamides with functional groups such as fluoro, chloro, iodo, methoxy, amide, and alcohol have been obtained in 33-96% yield. Other aromatic 2-chloroarylamides such as naphthalene, pyridine, and thiophene are found to be equally compatible to the reaction. It is proposed that the reaction proceed via formation of copper-amide complex, which may facilitate the hydroxylation in water. Overall, the first report on coppercatalyzed hydroxylation reaction in water and first catalytic route for the synthesis of 2-hydroxybenzamides is presented. Simple purification procedure and convenience of employing low-cost reagents in neat water make this method practical and economical for the synthesis of 2-hydroxybenzamides.
Organic Letters, 2010
General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C N... more General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C NMR, Mass spectra for selected Se-N heterocycles & substrates S32-S140 References S141-S142 General Experimental Details All NMR experiments were carried out on 400 or 500 MHz spectrometers in DMSO-d 6 or CDCl 3 and NMR chemical shifts are reported in ppm referenced to the solvent peaks of CDCl 3 (7.26 ppm for 1 H and 77.16 (± 0.06) ppm for 13 C, respectively) or DMSO-d 6 (2.50 ppm for 1 H and 39.50 ppm for 13 C, respectively). 1 H NMR for compound 7 and 1 H and 13 C for compound 8 was also recorded in CD 3 OD (1 H and 13 C chemical shift 3.30 and 48.0 ppm respectively). High resolution mass spectra (HRMS), electron spray mass spectra (ESMS), and low resolution mass spectra (LRMS) are reported for ions of 80 Se. Mass analysis is performed on quadruple-time of S-2 flight (Q-TOF) mass spectrometer equipped with an ESI source (+ve). Infrared (IR) spectra were recorded as a plate in KBr with a FTIR machine. Melting points are uncorrected. DMF with seal septa, selenium powder (60 mesh size), copper iodide, and 1,10-phenanthroline were used as received from Aldrich. Grinded anhydrous K 2 CO 3 powder was used which was grinded using mortar, dried in oven at 160 o C for 6 h and stored in a desiccator. Selenium-nitrogen coupling reactions were carried out under nitrogen atmosphere. Silica gel (60 mesh size) was used for column chromatography. TLC analysis of reaction mixtures was performed using silica gel plates. Substituted benzoyl chlorides were prepared from respective benzoic acids by refluxing with excess of thionyl chloride otherwise prepared according to reported procedure. Excess of thionyl chloride was removed under vacuo and resulted residue was used for amide preparation without further purification. Substrates: 2-iodo-N-phenylbenzamide, 1 2-bromo-Nphenylbenzamide, 2 2-chloro-N-phenylbenzamide 3 for 1, 2-iodo-N-benzylbenzamide, 1c 2-bromo-N-benzylbenzamide 4 for 2, 2-iodo-N-methylbenzamide 1c for 3, 2-iodo-N-cyclohexylbenzamide 5 for 4, 2-iodo-N-(1-phenylethyl)benzamide 1a for 5, 2-iodobenzamide 1c for 6, 2-iodo-N-(2hydroxyethyl)benzamide 6 for 7, 2-iodo-N-(3-hydroxypropyl)benzamide 7 for 8, 2-chloro-3-nitro-N-phenylbenzamide 8 for 10, 2-chloro-N-benzyl-4-nitrobenzamide 9 for 11, 2-chloro-N-benzyl-5nitrobenzamide 10 for 12, 2-bromo-N-(4-bromo-phenyl)benzamide 11 for 14, N,N'-(hexane-1,6diyl)bis(2-iodobenzamide) 12 for 16, ethyl 4-(2-iodobenzamido)benzoate 1a for 26, and 3-iodo-Nphenyl-2-naphthamide 13 for 27 were prepared according to literature procedures. Synthesis of Se-N heterocycles by Cu-catalyzed coupling reaction 2-Phenylbenzo[d][1,2]selenazol-3(2H)-one (1) from 2-Iodo-N-phenylbenzamide (Typical Procedure): Copper iodide (114 mg, 0.6 mmol) and 1,10-phenanthroline (108 mg, 0.6 mmol) were added into DMF (3 mL) in a single neck flask. Resulted brownish solution was stirred for 15 min and then 2-iodo-N-phenylbenzamide 1 (0.97 g, 3.0 mmol), selenium powder (0.29 g, 3.6 mmol), and potassium carbonate powder (0.65 g, 4.7 mmol) were added sequentially to same
Organic & Biomolecular Chemistry, 2014
Benzamide ring-substituted, quinine-derived ebselen analogue is synthesized which exists in selen... more Benzamide ring-substituted, quinine-derived ebselen analogue is synthesized which exists in selenol form upon addition of PhSH. It catalyses oxidation of PhSH with H2O2 faster (103-fold) than ebselen.
The Journal of Organic Chemistry, 2013
A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical di... more A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by (77)Se NMR spectroscopy by using diphenyl diselenide as the substrate. (77)Se NMR study suggests that electrophilic species ArE(+) is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
The Journal of Organic Chemistry, 2012
Isoselenazolones were synthesized by a copper-catalyzed Se-N bond forming reaction between 2-halo... more Isoselenazolones were synthesized by a copper-catalyzed Se-N bond forming reaction between 2-halobenzamides and selenium powder. The catalytic activity of the various isoselenazolones was studied in the bromolactonization of pent-4-enoic acid. Isoselenazolone 9 was studied as a catalyst in several reactions: the bromolactonization of a series of alkenoic acids with bromine or N-bromosuccinimide (NBS) in the presence of potassium carbonate as base, the bromoesterification of a series of alkenes using NBS and a variety of carboxylic acids, and the oxidation of secondary alcohols to ketones using bromine as an oxidizing reagent. Mechanistic details of the isoselenazolone-catalyzed bromination reaction were revealed by (77)Se NMR spectroscopic and ES-MS studies. The oxidative addition of bromine to the isoselenazolone gives the isoselenazolone(IV) dibromide, which could be responsible for the activation of bromine under the reaction conditions. Steric effects from an N-phenylethyl group on the amide of the isoselenazolone and electron-withdrawing fluoro substituents on the benzo fused-ring of the isoselenazolone appear to enhance the stability of the isoselenazolone as a catalyst for the bromination reaction.
Organic Letters
General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C N... more General experimental details S1-S25 Crystallographic data for compound 28 S26-S31 1 H NMR, 13 C NMR, Mass spectra for selected Se-N heterocycles & substrates S32-S140 References S141-S142 General Experimental Details All NMR experiments were carried out on 400 or 500 MHz spectrometers in DMSO-d 6 or CDCl 3 and NMR chemical shifts are reported in ppm referenced to the solvent peaks of CDCl 3 (7.26 ppm for 1 H and 77.16 (± 0.06) ppm for 13 C, respectively) or DMSO-d 6 (2.50 ppm for 1 H and 39.50 ppm for 13 C, respectively). 1 H NMR for compound 7 and 1 H and 13 C for compound 8 was also recorded in CD 3 OD (1 H and 13 C chemical shift 3.30 and 48.0 ppm respectively). High resolution mass spectra (HRMS), electron spray mass spectra (ESMS), and low resolution mass spectra (LRMS) are reported for ions of 80 Se. Mass analysis is performed on quadruple-time of S-2 flight (Q-TOF) mass spectrometer equipped with an ESI source (+ve). Infrared (IR) spectra were recorded as a plate in KBr with a FTIR machine. Melting points are uncorrected. DMF with seal septa, selenium powder (60 mesh size), copper iodide, and 1,10-phenanthroline were used as received from Aldrich. Grinded anhydrous K 2 CO 3 powder was used which was grinded using mortar, dried in oven at 160 o C for 6 h and stored in a desiccator. Selenium-nitrogen coupling reactions were carried out under nitrogen atmosphere. Silica gel (60 mesh size) was used for column chromatography. TLC analysis of reaction mixtures was performed using silica gel plates. Substituted benzoyl chlorides were prepared from respective benzoic acids by refluxing with excess of thionyl chloride otherwise prepared according to reported procedure. Excess of thionyl chloride was removed under vacuo and resulted residue was used for amide preparation without further purification. Substrates: 2-iodo-N-phenylbenzamide, 1 2-bromo-Nphenylbenzamide, 2 2-chloro-N-phenylbenzamide 3 for 1, 2-iodo-N-benzylbenzamide, 1c 2-bromo-N-benzylbenzamide 4 for 2, 2-iodo-N-methylbenzamide 1c for 3, 2-iodo-N-cyclohexylbenzamide 5 for 4, 2-iodo-N-(1-phenylethyl)benzamide 1a for 5, 2-iodobenzamide 1c for 6, 2-iodo-N-(2hydroxyethyl)benzamide 6 for 7, 2-iodo-N-(3-hydroxypropyl)benzamide 7 for 8, 2-chloro-3-nitro-N-phenylbenzamide 8 for 10, 2-chloro-N-benzyl-4-nitrobenzamide 9 for 11, 2-chloro-N-benzyl-5nitrobenzamide 10 for 12, 2-bromo-N-(4-bromo-phenyl)benzamide 11 for 14, N,N'-(hexane-1,6diyl)bis(2-iodobenzamide) 12 for 16, ethyl 4-(2-iodobenzamido)benzoate 1a for 26, and 3-iodo-Nphenyl-2-naphthamide 13 for 27 were prepared according to literature procedures. Synthesis of Se-N heterocycles by Cu-catalyzed coupling reaction 2-Phenylbenzo[d][1,2]selenazol-3(2H)-one (1) from 2-Iodo-N-phenylbenzamide (Typical Procedure): Copper iodide (114 mg, 0.6 mmol) and 1,10-phenanthroline (108 mg, 0.6 mmol) were added into DMF (3 mL) in a single neck flask. Resulted brownish solution was stirred for 15 min and then 2-iodo-N-phenylbenzamide 1 (0.97 g, 3.0 mmol), selenium powder (0.29 g, 3.6 mmol), and potassium carbonate powder (0.65 g, 4.7 mmol) were added sequentially to same
Synlett, 2013
This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation... more This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research spotlight 2-Halobenzamides Compiled by Shah Jaimin Balkrishna Shah Jaimin Balkrishna was born in Vadodara, Gujarat, India in 1984. He received his B.Sc. degree in chemistry (2005) and his M.Sc. degree in organic chemistry (2007) from The Maharaja