Communication
An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis Communication An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis Received: 23 September 2015 ; Accepted: 12 November 2015 ; Published: 19 November 2015
Fatemeh Rajabi 1, *, Diego Alves 2 and Rafael Luque 3
Academic Editors: Nicola Cioffi, Antonio Monopoli and Massimo Innocenti Fatemeh Rajabi 1,*, Diego Alves 2 and Rafael Luque 3 1 Department of Science, Payame Noor University, P. O. Box: 19395-4697, Tehran 19569, Iran Received: 23 September 2015; Accepted: 12 November 2015; Published: 2 Laboratório de Síntese Orgânica Limpa—LASOL, Universidade Federal de Pelotas UFPEL, Pelotas, Academic Editors: Nicola Cioffi, Antonio Monopoli and Massimo Innocenti CEP 96010-900, Brazil;
[email protected] 1 Department of Science, Payame Noor University, P. O. Box: 19395-4697, Tehran 19569, Iran 3 Departamento de Quimica Organica, Universidad de Cordoba, Campus de Rabanales, 2 Laboratório de Síntese Orgânica Limpa—LASOL, Universidade Federal de Pelotas UFPEL, Edificio Marie Curie (C3), Ctra Nnal IV-A, Km 396, Cordoba E14014, Spain;
[email protected] Pelotas, CEP 96010-900, Brazil;
[email protected] * Correspondence:
[email protected]; Tel.: +34-957211050 (ext. 1050) 3 Departamento de Quimica Organica, Universidad de Cordoba, Campus de Rabanales, Edificio Marie Curie (C3), Ctra Nnal IV-A, Km 396, Cordoba E14014, Spain;
[email protected] Abstract: The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl * Correspondence:
[email protected]; Tel.: +34-957211050 (ext. 1050)
compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The Abstract: The syntheses of quinoxalines derived from 1,2-diamine and it 1,2-dicarbonyl compounds supported nanocatalyst exhibited excellent activity and stability and could be reused for at least under mild reaction conditions was carried out using a nanoparticle-supported cobalt ten times without any loss of activity. No cobalt contamination could be detected in the catalyst. products by The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial. least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial.
Keywords: quinoxaline; catalysis; nanoparticles; cobalt; green chemistry Keywords: quinoxaline; catalysis; nanoparticles; cobalt; green chemistry
1. Introduction 1. Introduction
Quinoxaline derivatives are attractive N-containing heterocycles and these scaffolds have derivatives areinattractive heterocycles these scaffolds have attracted Quinoxaline much attention, not only syntheticN-containing chemistry [1–3] but also and in the medicinal field [4–11]. attracted much attention, not only in synthetic chemistry [1–3] but also in the medicinal field [4–11]. These compounds exhibit diverse biological activities, such as antiviral [4,5], antibacterial [6], These compounds exhibit diverse biological activities, such as antiviral [4,5], antibacterial [6], anti-inflammatory [7], antitumoral [8,9] and anti-HIV properties [10,11]. Examples of quinoxalineanti-inflammatory [7], antitumoral [8,9] and anti-HIV properties[10,11]. Examples of quinoxalinecontaining pharmacological entities are shown in Figure 1. In addition, quinoxalines have been containing pharmacological entities are shown in Figure 1. In addition, quinoxalines have been applied applied as building blocks for the development macrocyclic molecular receptors [12,13], as building blocks for the development of macrocyclicofmolecular receptors [12,13], semiconducting semiconducting materials [14–20], dyes [21], cavitands [22] and luminescent materials [23]. materials [14–20], dyes [21], cavitands [22] and luminescent materials [23]. N
O N
N H
N
O Cl
N
NCG555879-01 S N NH N
N
varenicline
CH3 COOH
O
XK469 (NSC 697807)
O N
O
N
O
N H COOH
COOH N
Br N
O
quinacilin
H N
H N N
N
brimonidine
Figure 1. Biologically important quinoxalines.
Figure 1. Biologically important quinoxalines.
Generally, quinoxalines can be prepared via a double condensation of 1,2-phenylenediamines
Generally, quinoxalines can be prepared viahave a double condensation 1,2-phenylenediamines with 1,2-diketones [24–28]. A number of reagents been shown to catalyzeof these reactions such as alumina [29], citric A acid [30], magnetic Fe3O4have nanoparticles in H2to O [31], silica-bonded sulfonic such with acidic 1,2-diketones [24–28]. number of reagents been shown catalyze these reactions as acidic alumina [29], citric acid [30], magnetic Fe3 O4 nanoparticles in H2 O [31], silica-bonded Molecules 2015, 20, page–page; doi:10.3390/molecules201119731
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sulfonic acid [32], among others [33,34]. Other protocols to synthesize quinoxalines mainly involve oxidative of vicinal diols or α-hydroxy ketones mainly with 1,2-diamines [35–42], acid [32],the among others trapping [33,34]. Other protocols to synthesize quinoxalines involve the oxidative 1,4-addition of 1,2-diamines to diazenylbutenes [43], coupling of epoxides ene-1,2-diamines [44,45], trapping of vicinal diols or α-hydroxy ketones with 1,2-diamines [35–42],with 1,4-addition of 1,2-diamines 2-nitroanilines with phenethylamines alkynes or ene-1,2-diamines ketones with 1,2-diamines via a key oxidation to diazenylbutenes [43], coupling of [46], epoxides with [44,45], 2-nitroanilines with process [47–51]. Therefore, the development of efficient methods for accessing quinoxalines phenethylamines [46], alkynes or ketones with 1,2-diamines via a key oxidation process [47–51]. derivatives continues to be an areamethods of research. Therefore, the development ofactive efficient for accessing quinoxalines derivatives continues to Nanoparticle-supported catalysts can offer important advantages as compared to homogeneous be an active area of research. transition metal systems andcatalysts colloidal These includeasacompared good reusability coupled Nanoparticle-supported cannanoparticles. offer important advantages to homogeneous with highmetal activities and and specificities different chemistries based on their excelling properties transition systems colloidal in nanoparticles. These include a good reusability coupled with (high surface areas, degenerated density of energy states and plasmon) [52–54]. In this regard, high activities and specificities in different chemistries based on their excelling properties (high surface Co/supported catalysts were previously to be highly and versatile for acid and redox areas, degenerated density of energy statesreported and plasmon) [52–54].active In this regard, Co/supported catalysts catalyzed processes [54,55]. were previously reported to be highly active and versatile for acid and redox catalyzed processes [54,55]. To To the the best best of our knowledge, there is no protocol describing the preparation of quinoxaline derivatives using aa nanoparticle-supported In view view of the explained above, we nanoparticle-supported cobalt cobalt catalyst. catalyst. In decided to examine the synthesis of substituted quinoxalines by 1,2-diketones with examine the synthesis of substituted quinoxalines by reaction reaction ofof1,2-diketones 1,2-phenylenediamines using a nanoparticle-supported nanoparticle-supported cobalt cobalt catalyst catalyst (Scheme (Scheme 1). 1).
Scheme 1. 1.General Scheme General scheme scheme of of the the reactions. reactions.
2. Results 2. Resultsand andDiscussion Discussion Initially, we chose 1,2-diphenylethanedione 1,2-diphenylethanedione (1a)and (1a)and 1,2-diamino-4-nitrobenzene 1,2-diamino-4-nitrobenzene (2a) (2a) as as model model Initially, we chose substrates to to establish establish the the best best conditions conditions for for this this reaction and some some experiments experiments were were performed performed to to substrates reaction and synthesize the corresponding quinoxaline 3a (Table 1). We started our studies reacting 1,2-diketone synthesize the corresponding quinoxaline 3a (Table 1). We started our studies reacting 1,2-diketone 1a 1a (1.0 mmol) with 1,2-phenylenediamine (1.0 mmol) 100˝ C °Cfor for22h, h,without withoutcatalyst catalyst and and solvent. solvent. (1.0 mmol) with 1,2-phenylenediamine 2a2a (1.0 mmol) atat100 Under these conditions, product 3a was not obtained (Table 1, entry 1). Good results were obtained Under these conditions, product 3a was not obtained (Table 1, entry 1). Good results were obtained however when when the the reactions reactions of of substrates substrates 1a 1a and and 2a 2a were were carried carried out out using using H H2O O as as solvent solvent in in the the however 2 presence of of Co Co NPs NPs (2 (2 mol mol %) %) as as catalyst. catalyst. Reactions Reactions performed performed at at 100 100 ˝°C and 50 50 ˝°C the desired desired presence C and C gave gave the product in 87% and 57% yield, respectively (Table 1, entries 2 and 3). A similar result was obtained product in 87% and 57% yield, respectively (Table 1, entries 2 and 3). A similar result was obtained when the the reaction reaction was was conducted conducted at at 100 100 ˝°C, 1, when C, however however using using 11 mol% mol% of of Co Co NPs NPs (86% (86% yield) yield) (Table (Table 1, entry 4). 4). Good EtOH as as solvent solvent entry Good results results were were also also found found when when the the reactions reactions were were performed performed using using EtOH (Table 1, entry 5–9). Excellent yields of product 3a were achieved in reactions carried out in EtOH at (Table 1, entry 5–9). Excellent yields of product 3a were achieved in reactions carried out in EtOH at 78 ˝°C catalyst (Table (Table 1, 1, entries entries 7–8). 7–8). When to 78 C using using 11 mol% mol% of of catalyst When the the amount amount of of catalyst catalyst was was reduced reduced to 0.5 mol %, a decrease in the yield of product 3a was observed (Table 1, entry 9). Finally, the reaction 0.5 mol %, a decrease in the yield of product 3a was observed (Table 1, entry 9). Finally, the reaction performed using 1 mol % of Co NPs at 100 °C and in absence of EtOH yielded the quinoxaline 3a in performed using 1 mol % of Co NPs at 100 ˝ C and in absence of EtOH yielded the quinoxaline 3a in 72% yield yield (Table (Table 1, 1, entry entry 10). 10). 72% Analyzing the results shown in Table 1, we established the best reaction conditions reacting Analyzing the results shown in Table 1, we established the best reaction conditions reacting 1,2-diphenylethanedione (1a, 1.0 mmol, 0.033 g) with 1,2-diamino-4-nitrobenzene (2a, 1.0 mmol) 1,2-diphenylethanedione (1a, 1.0 mmol, 0.033 g) with 1,2-diamino-4-nitrobenzene (2a, 1.0 mmol) using supported CoNPs (1 mol %) as catalyst and EtOH (5 mL) as solvent. After that, the mixture was using supported CoNPs (1 mol %) as catalyst and EtOH (5 mL) as solvent. After that, the mixture stirred at reflux for 90 min in open atmosphere, affording 6-nitro-2,3-diphenylquinoxaline(3a) in 92% was stirred at reflux for 90 min in open atmosphere, affording 6-nitro-2,3-diphenylquinoxaline(3a) in yield after crystallization. 92% yield after crystallization.
20710
2
Molecules 2015, page–page Molecules 2015, page–page Molecules 2015, 20, page–page Molecules 2015, 20,20, page–page Molecules 2015, 20,20, page–page a. a Molecules 2015, 20, 20709–20718 Table a. condition a. a. Table Optimization reaction condition Table 1. Optimization of reaction Table 1. Optimization of reaction condition . 1. 1. Optimization ofof reaction Table 1. Optimization of condition reaction condition
Molecules 2015, 20, page–page
OOO
OO
Table 1. Optimization of reaction condition a .
O NH N2NNNN N N NH 2N O NH OO NH Table Optimization of condition a.OO O2O N1.2N 2N O2O 2N 2N 2 2N 2N 2 2 2 NH 2reaction Co NPs NPs Co NPs Co NPs CoCo NPs Molecules 2015, 20, page–page +++ + + solvent solvent solvent solvent solvent O N O NH NN NH2 O O OO NH NH 2 2 NH 2NH NN N a.O2N O time time 2N 1. Optimization 2 Table of2reaction condition time time time Co NPs 2a2a 2a2a 1a1a1a 1a1a + 2a temperature temperature temperature temperature temperature solvent 3a N 3a3a 3a3a O O NH2 time b b3a (%) NYield O N b 3a O N NH 2a Entry Catalyst (mol Solvent Temperature (°C) Time (h) Yield (%) 2 Entry Catalyst %) Solvent Temperature (°C) Time (h) Yield 1a EntryEntry Catalyst (mol %)(mol (°C) (°C) Time (h) Yield 3a (%) 2Solvent 2Temperature Entry Catalyst (mol %)%) Solvent Temperature (°C) Time (h) 3a3a (%) Catalyst (mol %) Solvent Temperature Time (h) Yield (%) b b Co NPs temperature 3a 100 100 100 100 111 --100 222 --1 1 - - + --- 2 2 - solvent b ˝ C) Time b N Yield Entry Catalyst (mol %) H2Solvent Temperature (°C) (h) Yield 3a 3a (%) O NH Entry Catalyst (mol %) Solvent Temperature ( Time (h) (%) 2 2 2 O 100 2 87 2 2 H 2 O 100 2 2 2 2 2 H2OH2O H2O 100100 2 2 87 87 8787 2 2 2 time 100 2a 1a 1 100 2 2O temperature 13 3 100 - 5757 5757 H 2O- H2H 50 5050 333 2 2 2 - 22 2 HH 2O 5050 2 22 2 3a2 2 87 57 O2O 2 H2O 100 2 2 2 H O 100 2 87 2 4 1 H 2 O 100 2 4 1 H 2 O 100 2 4 1 H 2 O 100 2 b 4 1Catalyst21(mol %) H2OSolvent 10050 (°C) 868686 43 100 2 57 8686 Entry Time Yield 3a (%) H2OH2O Temperature 22 (h) 3 2 H2 O 50 2 57 EtOH EtOH EtOH 78 7878 555 2 2 2 1-2 2 EtOH 7878 5 415 EtOH 2 2 86 - 939393 9393 H-2O 100 22 2 2 4 1 H2 O 100 2 86 26 22 2 H2O 100 87 606060 6060 5 EtOH 78 2 93 2 EtOH 50 2 EtOH 50 2 2 EtOH 50 2 666 2 EtOH 50 2 6 EtOH 50 2 5 2 EtOH 78 2 93 H2O 57 60 EtOH 5078 22 22 2 EtOH EtOH EtOH 777 1 1 1 221 1 EtOH 7878 939393 9393 EtOH 2 2 60 67 637 EtOH 50 7878 4 1 H2O 100 86 93 7 EtOH 78 2 93 7 1 EtOH 78 2 EtOH 1.5 EtOH EtOHEtOH 1.5 1.51.5 929292 9292 888 111 EtOH 787878 7878 1.5 8 8 1 1 7878 2 1.5 93 12 EtOH 1.5 92 92 8 859 EtOHEtOH 0.5 EtOH 7878 1.5 0.5 78 0.5 10.5 EtOH 1.5 1.51.5 60 999 0.5 EtOH 78 1.5 808080 8080 9 96 0.5 EtOH 78 2 50 2 EtOH 78 1.5 80 80 9 0.5 EtOH 78 1.5 10 1 100 2 10 1 100 2 - -- 100 10 10 10 1 1 111 - EtOH 100100 727272 7272 1010 2 93 7 78 22 2 2 72 72 100 100 aaReactions a8 Reactions are performed using, 1,2-diphenylethanedione (1.0 mmol) and 1,2-diamino-4-nitrobenzene 1using, EtOH 78 1.5 92 Reactions performed using, 1,2-diphenylethanedione 1a (1.0 mmol) and 1,2-diamino-4-nitrobenzene areare performed using, 1,2-diphenylethanedione 1a (1.0 mmol) and 1,2-diamino-4-nitrobenzene Reactions are performed using, 1,2-diphenylethanedione 1a (1.0 and 1,2-diamino-4-nitrobenzene Reactions are performed 1,2-diphenylethanedione 1a1a (1.0 mmol) and 1,2-diamino-4-nitrobenzene Reactions are performed 1,2-diphenylethanedione 1ammol) (1.0 mmol) and 1,2-diamino-4-nitrobenzene a Reactions are performed using,using, 1,2-diphenylethanedione 1a (1.0 mmol) and 1,2-diamino-4-nitrobenzene 2a b Yields b Yields b are bEtOH 9 0.5 78 1.5 80 crystallization. b b 2a (1.0 mmol) in open atmosphere. given for isolated product 3a after crystallization. b 2a (1.0 mmol) in open atmosphere. are given for isolated product 3a after crystallization. 2a (1.0 mmol) in open atmosphere. Yields are given for isolated product 3a after 2a (1.0 mmol) in open atmosphere. Yields are given for isolated product 3a after crystallization. 2a (1.0(1.0 mmol) inin open Yields given for isolated 3a after crystallization. 2a (1.0 mmol) in open atmosphere. Yields given forproduct isolated product 3a after crystallization. mmol) open atmosphere. atmosphere. Yields areare given forare isolated product 3a after crystallization.
a a a
10 1 100 2 72 a Reactions In order toareextend the using, scope 1,2-diphenylethanedione of the reaction, the best conditions were employed in reactions of performed 1a (1.0 mmol) and 1,2-diamino-4-nitrobenzene to extend the scope of the reaction, the best conditions were employed ofof of of to extend the scope of reaction, the best conditions were employed reactions Inorder order toorder extend the scope of the the best conditions were employed inreactions reactions InInorder toIn extend scope of the reaction, the best conditions were employed ininreactions of In order tothe extend the scope ofreaction, thethe reaction, the best conditions were employed in in reactions b other In 1,2-diamino-4-nitrobenzene order to extend the reaction, theforbest conditions employed in reactions of (2a)of with 1,2-diketones 1b–e with different of substitution 2a (1.0 mmol) in the openscope atmosphere. Yields are given isolated product 3a were afterpatterns crystallization. 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different patterns of substitution 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different patterns of substitution 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different patterns of substitution 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different patterns of substitution 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different patterns of substitution and the results are summarized in Table 2. As it can be seen on Table 2 (Entries 1–5),patterns our methodology 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e with different of substitution and the results are summarized Table 2. As it can be seen on Table 2were (Entries methodology and the results are summarized in Table 2. As itbest can be seen 21–5), (Entries 1–5), our methodology and the are in Table 2. As it can be seen on Table 2Table (Entries 1–5), our methodology and the results are summarized inin Table 2. As it can be on Table 2 on (Entries 1–5), our methodology and theIn results are summarized in Table itseen can be seen on Table 2 (Entries 1–5), our order torange extend the scope of the the conditions employed inour reactions ofmethodology isresults suitable to asummarized of substituted 1,2-diketones containing electron-withdrawing groups, affording and the results are summarized in Table 2. reaction, As2. it As can be seen on Table 2 (Entries 1–5), our methodology to substituted 1,2-diketones containing electron-withdrawing affording is suitable to aof range substituted 1,2-diketones containing electron-withdrawing groups, affording 1,2-diamino-4-nitrobenzene (2a) with other 1,2-diketones 1b–e withthe different patterns ofgroups, substitution excellent yields to desired products in all examples. In addition, possibility of groups, performing the issuitable suitable arange range substituted 1,2-diketones containing electron-withdrawing groups, affording isis suitable to atoarange of substituted 1,2-diketones containing electron-withdrawing affording is suitable to a of range of of substituted 1,2-diketones containing electron-withdrawing groups, affording is suitable to a range of substituted 1,2-diketones containing electron-withdrawing groups, affording and theto results are summarized in Table As itall can beIn seen onIn Table 2the (Entries 1–5), our methodology reaction of 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated (Table entries 6–10). excellent yields todesired desired products in examples. possibility the excellent yields to desired products in examples. In addition, the possibility of performing excellent yields to desired products inallexamples. all2. examples. Inaddition, addition, the possibility ofperforming performing the thethe excellent yields products in all In addition, the possibility of2,of performing the excellent yields to desired products in all examples. addition, the possibility of performing excellent yields desired products in all examples. In addition, the possibility of performing is 1,2-diketones toto a range of asubstituted 1,2-diketones containing electron-withdrawing groups, affording Using these substrates, range of substituted quinoxalines was obtained in excellent yields2, using the 2, reaction 1a–e with o-phenylenediamine(2b) was also investigated (Table 6–10). reaction 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated (Table entries 6–10). reaction ofsuitable 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated (Table 2,entries entries 6–10). reaction ofof 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated (Table 2,(Table entries reaction of of 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated 2,6–10). entries 6–10). the reaction of yields 1,2-diketones 1a–e with o-phenylenediamine (2b) was alsoofinvestigated (Table 2, excellent to desired products inunder all examples. In reaction addition,conditions. the possibility performing the nanoparticle-supported cobalt catalyst optimized Using these substrates, quinoxalines was obtained in yields using the Using these substrates, aofsubstituted range substituted quinoxalines was excellent yields using Using these substrates, arange range substituted quinoxalines was obtained inexcellent excellent yields using the Using these substrates, a arange of substituted quinoxalines was obtained inobtained excellent yields using the Using these substrates, a of range of aof substituted quinoxalines was obtained in in excellent yields using thethe of 1,2-diketones 1a–e with o-phenylenediamine(2b) was also investigated (Table 2, entries 6–10). entries reaction 6–10). Using these substrates, range of substituted quinoxalines was obtained in excellent nanoparticle-supported cobalt catalyst under optimized reaction conditions. nanoparticle-supported cobalt catalyst under optimized reaction conditions. a nanoparticle-supported cobalt catalyst under optimized reaction conditions. nanoparticle-supported cobalt catalyst under optimized reaction conditions. nanoparticle-supported cobalt under reaction Tablea2.range Generality of the reaction ofoptimized 1,2-diketones with 1,2-diamines . yields using the Using the thesenanoparticle-supported substrates, of catalyst substituted was obtained inconditions. excellent yields using cobaltquinoxalines catalyst under optimized reaction conditions. nanoparticle-supported cobalt catalyst under optimized reaction conditions. a. a. a. a. a. Table Generality of the reaction of 1,2-diketones with 1,2-diamines Table 2. of Generality of reaction 1,2-diketones with 1,2-diamines Table 2. Generality of the reaction of 1,2-diketones with 1,2-diamines Table 2. 2. Generality the reaction of 1,2-diketones with 1,2-diamines 2. Generality thethe reaction of of 1,2-diketones with 1,2-diamines a. TableTable 2. Generality of theof reaction of 1,2-diketones with 1,2-diamines a
Table 2. Generality of the reaction of 1,2-diketones with 1,2-diamines .
Entry
1,2-Diketone 1
1,2-Diamines 2
Product 3
Yield (%)b
M.P. (°C)
1 Entry
1,2-Diketone 1 1a
1,2-Diamines 2
Product 3
92(%)bb Yield
188–190 M.P. (°C) ˝
1,2-Diketone 1 1,2-Diamines 1,2-Diamines 3 3 3Product (b(°C) C) (%) b b M.P. bYield b (°C) Entry 1,2-Diketone 22 (%) M.P. Entry 1,2-Diketone 1,2-Diamines 2Product 3Yield (%) M.P. (°C) EntryEntry 1,2-Diketone Product 3 Yield Yield (%) M.P. (°C) Entry 1,2-Diketone 1 1 1 1,2-Diamines Product (%) M.P. Entry 1,2-Diketone 1 11,2-Diamines 1,2-Diamines 2Product Product 3 Yield Yield (%) M.P. (°C) 2a 2 2 3a
92
1
111
11 1 2
1a
1a1a1a
1a1a
2a 2a
2a2a
1b
92 929292
3a
3a 3a3a3a 3b
1b
22 2
1b1b1b
1b1b 1b
2a 2a2a2a
2a2a 3
3
333 20711
3 3
188–190 92188–190 188–190 188–190 92188–190 188–190
92
195–197
92
195–197
92 929292
3b
3b 3b3b3b
188–190
3a3a
2a
2
222
2a 2a 2a
3b3b
195–197 92195–197 195–197 195–197 92195–197 195–197
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Entry
1,2-Diketone 1
Table 2. Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. Table 2.Cont. 1,2-Diamines 2 Product 3
Yield (%) b
M.P. (˝ C)
bb (°C) bb b (%) Entry 1,2-Diketone 111,2-Diamines 1,2-Diamines Product Yield M.P. (°C) Entry 1,2-Diketone 1,2-Diamines Product Yield (%) M.P. b Entry 1,2-Diketone 1,2-Diamines Product Yield (%) M.P. (°C) bM.P. b Entry 1,2-Diketone Product Yield (%) M.P. (°C) bbb(°C) Entry 1,2-Diketone 111111 11 111,2-Diamines 222222 22 22222 Product 333Product (%) M.P. Entry 1,2-Diketone 1,2-Diamines Product Yield (%) (°C) Entry 1,2-Diketone 1,2-Diamines Product Yield M.P. (°C) bb b(%) Entry 1,2-Diketone Product 333 33 333333 Yield (%) M.P. (°C) bM.P. Entry 1,2-Diketone 1,2-Diamines Yield (%) M.P. (°C) Entry 1,2-Diketone 111,2-Diamines 1,2-Diamines Product Yield (%) M.P. (°C) Entry 1,2-Diketone 1,2-Diamines Product Yield (%) M.P. (°C) b (°C) Entry 1,2-Diketone 11 1,2-Diamines 1,2-Diamines Product 33Yield Yield (%) M.P. (°C) b Entry 1,2-Diketone 1,2-Diamines Product Yield (%) M.P. (°C) Entry 1,2-Diketone Product Yield (%) (°C) Entry 1,2-Diketone 1,2-Diamines Yield (%) M.P. Entry 1,2-Diketone 1,2-Diamines 222Product Product Yield (%) M.P. (°C)
333333 33 3 3333333 3
4444 4 4 444 44 4 44444
5555 5 5 555 55 5 55555
666666 66 6 66666 666
777777 77 7 7777777 7
8888 8 8 888 88 8 88888
9999 9 999 99 9 9 99999
10 1010 10 10 10 10 10 10 10 10 10 10 1010 10 10
11 1111 11 11 11 11 11 11 11 11 11 11 1111 11 11
12 1212 12 12 12 12 12 12 12 12 12 12 1212 12 12
1c 1c1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c
1d 1d1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d
1e 1e1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e
1a 1a1a 1a 1a 1a 1a 1a 1a 1a 1a 1a 1a 1a 1a 1a
1b 1b1b 1b 1b 1b 1b 1b 1b 1b 1b 1b 1b 1b 1b 1b 1b
1c 1c1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c 1c
1d 1d1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d 1d
1e 1e1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e 1e
92 173–175 92 173–175 9292 92 173–175 92 173–175 92 173–175 92 173–175 173–175 92 173–175 92173–175 173–175 92 173–175 92 173–175 92 173–175 173–175 92 92 173–175 92 173–175 92 173–175
2a 2a2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 3c 3c3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 2a 2a2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a
90 175–177 90 175–177 9090 90 175–177 90 175–177 90 175–177 90 175–177 175–177 175–177 90 175–177 90175–177 175–177 90 175–177 90 175–177 90 175–177 175–177 90 90 175–177 90 175–177 90 3d 3d3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d
2a 2a2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a
88 143–145 8888 88 143–145 88 143–145 88 143–145 88 143–145 88 143–145 143–145 143–145 88 143–145 88143–145 143–145 88 143–145 88 143–145 88 143–145 143–145 88 88 143–145 88 143–145 88 3e 3e3e 3e 3e 3e 3e 3e 3e 3e 3e 3e 3e 3e 3e 3e
2b2b 2b 2b 2b 2b 2b 2b
2b 2b 2b 2b 2b 2b 2b 2b
2b2b 2b 2b 2b 2b 2b 2b
2b 2b 2b 2b 2b 2b 2b 2b
92 127–129 9292 92 127–129 92 127–129 92 127–129 92 127–129 92 127–129 127–129 92 127–129 92127–129 127–129 92 127–129 92 127–129 92 127–129 127–129 92 92 127–129 92 127–129 92 127–129 3f 3f3f 3f 3f 3f 3f 3f 3f 3f 3f 3f 3f 3f 3f 3f 96 127–129 9696 96 127–129 96 127–129 96 127–129 96 127–129 96 127–129 127–129 96 127–129 96127–129 127–129 96 127–129 96 127–129 96 127–129 127–129 96 96 127–129 96 127–129 96 127–129 3g 3g3g 3g 3g 3g 3g 3g 3g 3g 3g 3g 3g 3g 3g 3g
2b 2b2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b
94 133–135 9494 94 133–135 94 133–135 94 133–135 94 133–135 133–135 133–135 94 133–135 94 133–135 94133–135 133–135 94 133–135 94 133–135 94 133–135 133–135 94 94 133–135 94 133–135 94 3h 3h3h 3h 3h 3h 3h 3h 3h 3h 3h 3h 3h 3h 3h 3h
2b 2b2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b
94 190–192 9494 94 190–192 94 190–192 94 190–192 94 190–192 190–192 190–192 94 190–192 94 190–192 94190–192 190–192 94 190–192 94 190–192 94 190–192 190–192 94 94 190–192 94 190–192 94 3i 3i3i 3i 3i 3i 3i 3i 3i 3i 3i 3i 3i 3i 3i 3i
2b 2b2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b NH NHNH 2 NH 2 NH NH NH 2 NH NH 22 NH 222 2 NH NH NH NH 22222 2 NH2 NH NH 2 NH NHNH 22 2 NH NH NH NH 2 NH 2 NH NH 222 2 NH NH NH NH 22222 2 NH2 NH NH 2
2c 2c2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c 2c
94 134–135 9494 94 134–135 94 134–135 94 134–135 94 134–135 134–135 134–135 94 134–135 94134–135 134–135 94 134–135 94 134–135 94 134–135 94 134–135 134–135 94 94 134–135 94 134–135 94 3j 3j3j 3j 3j 3j 3j 3j 3j 3j 3j 3j 3j 3j 3j 3j 3j N N NNN N N N N NNN N N
N N N N
3k3k 3k 3k 3k 3k 3k 3k 3k N N NNN N N N N N N NN N N N N N
NN N NN NN N NN N NN NN N
3k 3k 3k 3k 3k 3k 3k F 3k F FFF F
F F F NN N NN NN N N N NN NN NNF F FFF F F F F
98 116–117 9898 98 116–117 98 116–117 98 116–117 98 116–117 116–117 98 116–117 98116–117 116–117 98 116–117 98 116–117 98 116–117 98 116–117 116–117 98 98 116–117 98 116–117 98 116–117 F FF FFFFF
95
F FF FFFFF
95 163–165 95 163–165 163–165
95 163–165 9595 95 163–165 95 163–165 163–165 163–165 95 163–165 95163–165 163–165 95 163–165 95 163–165 95 163–165 163–165 95 95 163–165 95 163–165 95 163–165 95
3l 3l3l 3l 3l 3l 3l 3l 3l 3l 3l 3l 3l 3l 3l 3l 3l Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol),
a aaa a a a aa
a aa aaaa a
Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions wereperformed performed using 1,2-diketones 1a–e (1.0mmol), mmol), 1,2-diamines 2a–b (1.0mmol), mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were using 1,2-diketones 1a–e (1.0 1,2-diamines 2a–b (1.0 Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), a Reactions Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), Reactions were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), bbare were performed using 1,2-diketones 1a–e (1.0 mmol), 1,2-diamines 2a–b (1.0 mmol), supported bb Yields supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields b b b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are b b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. are b b b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are b b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are b supported CoNPs (1 mol %, 0.033 g) and EtOH (5 mL) at reflux in open flask for 90 min. Yields are b b supported CoNPs (1(1 mol %, 0.033 g) mL) atat in flask for 90 min. Yields supported CoNPs (1 mol %, 0.033 g) and EtOH (5in mL) at reflux in90 open flask formin. 90 min. Yields are are supported CoNPs mol %, 0.033 g)and and EtOH (5reflux mL) reflux inopen open flask for 90 min. Yields are supported CoNPs (1 mol %, 0.033 g) and EtOH (5EtOH mL) at(5 inreflux open flask for 90 Yields CoNPs (1 mol %,isolated 0.033 g) and EtOH (5 mL) at reflux open flask for min. Yields are given forare isolated given for products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. given for isolated products after crystallization. products after crystallization. for products after crystallization. given for isolated products crystallization. given forisolated isolated products after crystallization. given forgiven isolated products afterafter crystallization.
4444 44 4444444 4 4420712
Molecules 2015, 20, 20709–20718
Reused runs were carried out under similarly optimized conditions using 5 mmol 1,2-diphenylethanedione (1a), 5 mmol of 1,2-diamino-4-nitrobenzene (2a) and supported cobalt catalyst (0.05 mmol, 0.165 g) at 78 ˝ C in 10 mL of ethanol. The catalyst showed excellent recoverability and reusability over ten successive runs under the same conditions as the first run. It is quite remarkable that all materials discussed in this study exhibited outstanding structural stability by TGA (results not shown). The cobalt catalyst was found to be highly stable and reusable under the investigated conditions (up to 12 runs) without any significant loss of its catalytic activity (Table 3). Indeed, ICP analysis of both reaction filtrate and catalyst showed no detectable Co leaching (
