Immobilized palladium metal containing ionic liquid catalyzed one step synthesis of isoindole-1,3-diones by carbonylative cyclization reaction

Journal of Molecular Catalysis A: Chemical 385 (2014) 91–97

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Immobilized palladium metal containing ionic liquid catalyzed one step synthesis of isoindole-1,3-diones by carbonylative cyclization reaction Mayur V. Khedkar a , Ajinkya R. Shinde a , Takehiko Sasaki b , Bhalchandra M. Bhanage a,∗ a

Department of Chemistry, Institute of Chemical Technology, N. Parekh Marg, Matunga (E), Mumbai 400 019, India Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8561, Japan b

a r t i c l e

i n f o

Article history: Received 26 December 2013 Received in revised form 20 January 2014 Accepted 22 January 2014 Available online 2 February 2014 Keywords: Carbonylation reaction Immobilization Heterogeneous catalysis Phosphine free Palladium.

a b s t r a c t Immobilized palladium metal containing ionic liquid (ImmPd-IL) catalyzed carbonylative cyclization reaction of 2-iodobenzoic acid and primary amine provided N-substituted isoindole-1,3-dione derivatives in good to excellent yield. The influence of various reaction parameters including the effect of base, solvent, temperature, time and CO pressure on carbonylative cyclization reaction using ImmPd-IL catalyst was investigated. Using optimized reaction parameters different aromatic, aliphatic and heterocyclic N-substituted isoindole-1,3-dione derivatives were synthesized from corresponding aryl amines. The developed protocol is heterogeneous, phosphine free and requires attainable reaction conditions like atmospheric CO pressure and lesser reaction time. The scope of the developed protocol was also extended for the synthesis of N-substituted isoindole-1,3-diones from methyl-2-iodobenoate and 1,2diiodo benzene. The ImmPd-IL catalyst was recyclable up to four consecutive cycles and recycled catalyst was characterized by XPS analysis. © 2014 Elsevier B.V. All rights reserved.

1. Introduction The carbon monoxide (CO) is an important building block to introduce carbonyl functionality into organic molecules. It is one of the excellent C1 source and has gained considerable attention due to its utilization for the synthesis of diverse type of carbonyl compounds including aldehydes, ketones, esters, amides and cyclic imides etc. [1–3]. Carbonylation methodology represents industrial core technologies to convert both bulk and fine chemicals to a diverse set of useful products of our day-to-day life. It has been noticed that compounds possessing cyclic imide ring system have wide spread pharmaceutical applications, as it represents the core structural unit of various natural products and designed pharmaceutical molecules [4,5]. N-substituted isoindole-1,3-diones derivatives shows medicinal applications in the treatment of cancer [6], acquired immune deficiency syndrome (AIDS) [7,8], leprosy [9] and other diseases [10,11]. They also find important role in agrochemical, pharmaceutical as well as dye

∗ Corresponding author. Tel.: +91 22 3361 1111x2222; fax: +91 22 2414 5614. E-mail addresses: [email protected], [email protected] (B.M. Bhanage). 1381-1169/$ – see front matter © 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.molcata.2014.01.018

and polymer industries [12]. Therefore N-substituted isoindole1,3-diones derivatives has become a centre of attraction to many of the synthetic chemists. The most common method for the synthesis of isoindole1,3-diones derivatives involves condensation of aryl amine with phthalic anhydride [13,14]. In 1979, Ban and co-workers for the first time developed palladium-catalysed carbonylative cyclization method for the synthesis of isoindole-1,3-diones [15]. Thereafter in 1991, Perry and Turner reported double carbonylative cyclization of o-dihaloarenes with arylamines using PdCl2 (PPh3 )2 as a catalyst [16]. This work was then extended by Alper and Cao by using phosphonium salt ionic liquid (PSIL) as a reaction media [17]. On similar lines, Worlikar and Larock synthesized N-substituted isoindole-1,3-diones by carbonylative cyclization of methyl-2-iodobenzoate using homogeneous palladium complex [18]. Kollar and co-workers reported the synthesis of 1,8-naphthalimides from 1,8-diiodonaphthalene, a primary amine and CO using a palladium phosphine catalytic system [19]. Buchwald and co-workers developed Xantphos based catalytic system for the aminocarbonylative cyclization reaction [20]. Rhodium(III)catalyzed oxidative carbonylation of benzamides was also reported by Du et al. [21]. Begouin and Queiroz reported CO free approach for the carbonylative synthesis of substituted isoindole-1,3-diones [22].

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Scheme 1. ImmPd-IL catalyzed carbonylative cyclization reaction.

The literature reports reveals that, carbonylative cyclization of diiodoaryls, o-halo benzoates and o-halo benzoic acid derivatives have been explored for the synthesis of isoindole-1,3-diones using variety of homogeneous Pd complexes and various air and moisture sensitive N/P-containing ligands. In the homogeneous catalytic processes recovery and reuse of the palladium catalyst is a challenging task. Moreover, the used phosphine ligands are expensive, toxic and air/moisture sensitive. In addition, requirement of high temperature, more reaction time and high CO pressure implies concerns regarding safety related issues. The uses of immobilized palladium complexes, which are be easily recovered by simple filtration procedure, are expected to solve this issue [23]. An ionic liquid containing palladium metal ion are immobilized on solid support and used as catalytic precursors, thus facilitates the reuse of catalysts [24–26]. These immobilized palladium metal containing ionic liquid [ImmPd-IL] catalysts are finding a promising use in various organic transformations [27]. In continuation of our ongoing research on the development of efficient, heterogeneous and phosphine-free protocols for carbonylative cyclization reactions [28,24], herein we report ImmPd-IL as a common catalyst for carbonylative cyclization reaction of 2-iodobenzoic acid, methyl-2-iodobenzoate and 1,2diiodobenzene with range aryl amines (Scheme 1). 2. Experimental 2.1. Materials and method N-methylimidazole (99 + %) and 3-trimethoxysilylpropyl chloride (97 + %) were purchased from Aldrich. PdCl2 was purchased from WAKO. Anhydrous redistilled 1-methylimidazole (99 + %) was purchased from Aldrich. All the dehydrated solvents were obtained from WAKO. Aerosil 300 (300 m2 /g) was obtained from Japan Aerosil Co. and calcined at 573 K for 1.5 h in air and 30 min in vacuum before use as support. The procedure for catalyst preparation was based on our previous publication [21,22] with some modifications. Prepared catalyst was characterized by using IR, elemental analysis, and loading of the catalyst was calculated by XRF measurements (SEA-2010, Seiko Electronic Industrial Co.). The XPS of ImmPd-IL was measured using a PHI5000 Versa Probe with a monochromatic focused (100 ␮m × 100 ␮m) Al K␣ X-ray radiation (15 kV, 30 mA) and dual beam neutralization using a combination of Argon ion gun and electron irradiation. The products are well known in the literature and compared with authentic samples. Progress of the reaction was monitored by gas chromatography (GC). The product was purified by column chromatography on silica gel (60–120 mesh). Gas chromatography analysis was carried out on Perkin Elmer Clarus 400 GC equipped flame ionization detector with a capillary column (Elite-1, 30 m × 0.32 mm × 0.25 ␮m). GC-MS-QP 2010 instrument (Rtx-17, 30 m × 25 mm ID, film thickness 0.25 ␮m df) (column flow 2 mL min−1 , 80–240 ◦ C at 10◦ /min rise.). The 1 H NMR spectra recorded on Varian-300 MHz FT-NMR spectrometer in CDCl3 using TMS as internal standard. The 13 C NMR spectra was recorded with JEOL FT-NMR, Model-AL300 (75 MHz) spectrometer in CDCl3 . Chemical shifts are reported in parts per million (ı) relative to tetramethylsilane as internal standard. J (coupling constant)

Scheme 2. Preparation of palladium metal-ion-containing immobilized ionic liquid.

values were reported in Hz. Splitting patterns of proton are described as s (singlet), d (doublet), t (triplet), and m (multiplet).

2.2. Preparation of ImmPd-IL Immobilized metal ion-containing ionic liquid catalyst was prepared as shown in Scheme 2. 1-Methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride was synthesized by mixing Nmethylimidazole (0.690 mol) and 3-trimethoxysilylpropyl chloride (0.690 mol) in a dry 300 mL flask under a nitrogen atmosphere and refluxed for 48 h. After cooling to room temperature, the resultant liquid was washed by dehydrated ethyl acetate five times and dried at room temperature under reduced pressure for 48 h. The obtained compound was stored at 253 K under dry nitrogen. Silica (Aerosil 300, surface area 300 m2 /g, calcined at 573 K for 1.5 h in air) and 1methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride (weight ratio 1:1) was dispersed in dehydrated toluene and the mixture was refluxed for 48 h under nitrogen. After the reflux, toluene was removed by filtration using glass filter and the excess ionic liquid was removed by washing with dichloromethane several times. The resultant solid is denoted as Imm-IL. In the next step, Imm-IL was added to an acetonitrile solution of PdCl2 and refluxed for 24 h. Acetonitrile and excess of metal chloride were removed by washing acetone using glass filter several times. The metal loading of ImmPd-IL was 3.4 wt% as determined by XRF measurements (SEA-2010, Seiko Electronic Industrial Co.).

2.3. General procedure for carbonylative cyclization of 2-iodobenzoic acid for the synthesis of N-substituted isoindole-1,3-diones using ImmPd-IL as a catalyst To a 100 mL stainless steel autoclave, 2-iodobenzoic acid (1 mmol), aryl amine (2 mmol), ImmPd-IL (2 mol%), toluene (10 mL) and Et3 N (2.5 mmol) were added. The autoclave was closed, purged three times with nitrogen followed with carbon monoxide and then pressurized with 1 atm of CO and heated at 100 ◦ C for 4 h. After completion of reaction the reactor was cooled to room temperature, the remaining CO gas was carefully vented, and the reactor was opened. The reactor vessel was thoroughly washed with ethyl acetate (10–15 mL) to remove any traces of product and catalyst if present. The catalyst was filtered and the reaction mixture was evaporated under vacuum. The residue obtained was purified by column chromatography (silica gel, 60–120 mesh; petroleum ether/ethyl acetate, 95:05) to afford the desired product. The products were confirmed by GC, GC-MS, 1 H NMR and 13 C NMR spectroscopic techniques. The purity of compounds was determined by GC-MS analysis.

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2.4. General experimental procedure for recycling of ImmPd-IL After completion of the reaction, the reaction mixture was cooled to room temperature, and the catalyst was collected by filtration. The filtered catalyst was washed with distilled water (3 mL × 5 mL) and methanol (3 mL × 5 mL) to remove all traces of product or reactant present. The filtered catalyst was then dried under reduced pressure. The dried catalyst was then used for the further reaction. 2.5. General procedure carbonylative cyclization of methyl-2-iodobenoate/1,2-diiodo benzene for the synthesis of N-substituted isoindole-1,3-diones using ImmPd-IL as a catalyst In a 100 mL stainless steel autoclave, methyl-2-iodobenoate/ 1,2-diiodobenzene (1 mmol), aryl amine (2 mmol), ImmPd-IL (2 mol%), toluene (10 mL) and Et3 N (2.5 mmol) were added. The autoclave was closed, purged three times with nitrogen followed with carbon monoxide, and then pressurized with 1 atm of CO and heated at 100 ◦ C for 6 h. After completion of reaction the reactor was cooled to room temperature, the remaining CO gas was carefully vented, and the reactor was opened. The reactor vessel was thoroughly washed with ethyl acetate (10–15 mL) to remove any traces of product and catalyst if present. The catalyst was filtered and the reaction mixture was evaporated under vacuum. The residue obtained was purified by column chromatography (silica gel, 60–120 mesh; petroleum ether/ethyl acetate, 95:05) to afford the desired product. The products were confirmed by GC, GC-MS, 1 H NMR and 13 C NMR spectroscopic techniques. The purity of compounds was determined by GC-MS analysis.

Scheme 3. ImmPd-IL iodobenzoate.

catalyzed

carbonylative

cyclization

of

methyl-2-

2.6.7. 2-Methylisoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.84 (2H, dd, J = 5.4, 3.3 Hz), 7.71 3 (2H, dd, J = 5.4, 3.3 Hz), 3.18 (3H, s); 13 C NMR (75 MHz, CDCl3 ): ı 168.48, 133.89, 132.26, 123.17, 23.95. 2.6.8. 2-(3-Chlorophenyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.96 (2H, dd, J = 5.4, 3.3 Hz), 7.80 3 (2H, dd, J = 5.4, 3.3 Hz), 7.47–7.50 (1H, m), 7.39–7.41 (2H, m), 7.36–7.37 (1H, m); 13 C NMR (75 MHz, CDCl3 ): ı 166.87, 134.67, 134.01, 132.87, 131.59, 130.08, 128.24, 126.71, 124.63, 123.95. 2.6.9. 2-(2-Fluorophenyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.97 (2H, dd, J = 5.4, 2.7 Hz), 7.80 3 (2H, dd, J = 5.4, 2.7 Hz), 7.26–7.44 (4H, m); 13 C NMR (75 MHz, CDCl3 ): ı 166.57, 159.61, 132.0, 130.85, 130.74, 129.93, 124.72, 124.68, 123.98, 116.95. 2.6.10. 2-((5-Methylfuran-2-yl)methyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı = 7.86 (dd, 2H, J = 5.5, 3.0 Hz,), 7.71 3 (dd, 2H, J = 5.5, 3.0 Hz,), 6.23 (d, 1H, J = 3 Hz), 5.87 (d, 1H, J = 2.1 Hz), 4.79 (s, 2H), 2.24 (s, 3H); 13 C NMR (75 MHz, CDCl3 ): ı = 167.5, 152, 147, 133.9, 132, 123, 109, 106, 34, 13.4.

2.6. Spectral data of the products 2.6.1. 2-(Cyclohexylmethyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.84 (2H, dd, J = 5.4, 3.3 Hz), 7.71 3 (2H, dd, J = 5.4, 3.3 Hz), 3.52 (2H, d, J = 6.9 Hz), 1.66–1.75 (1H, m), 1.06–1.15 (10H, m); 13 C NMR (75 MHz, CDCl3 ): ı 168.76, 133.89, 132.09, 123.21, 44.16, 37.02, 30.78, 26.28, 25.7. 2.6.2. 2-(4-(tert-butyl)benzyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.83 (2H, dd, J = 5.4, 3.3 Hz), 7.69 3 (2H, dd, J = 5.4, 3.3 Hz), 7.31–7.39 (4H, m), 4.81 (2H, s), 1.27 (9H, s); 13 C NMR (75 MHz, CDCl ): ı 168.14, 150.80, 133.98, 133.46, 132.22, 3 128.49, 125.64, 123.35, 41.29, 34.56, 31.34. 2.6.3. 2-(2-Methoxyethyl)isoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı 7.82 (2H, dd, J = 5.4, 3.3 Hz), 7.68 3 (2H, dd, J = 5.4, 3.3 Hz), 3.61 (2H, t, J = 5.4 Hz), 3.88 (2H, t, J = 5.4 Hz), 3.32 (3H, s); 13 C NMR (75 MHz, CDCl3 ): ı 168.35, 133.96, 132.15, 123.30, 69.45, 58.67, 37.35. 2.6.4. 2-Cyclopropylisoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı = 7.88 (dd, 2H, J = 5.4, 3.3 Hz), 7.85 3 (dd, 2H, J = 5.4, 3.3 Hz), 2.32 (m, 1H), 0.90 (m, 4H); 13 C NMR (75 MHz): ı = 168, 134, 131, 123, 20, 5. 2.6.5. 2-Cyclopentylisoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı = 7.88 (dd, 2H, J = 5.2, 3 Hz), 7.85 3 (dd, 2H, J = 5.2, 3 Hz), 3.61 (m, 1H), 1.93 (m, 4H), 1.56 (m, 4H); 13 C NMR (75 MHz): ı = 168, 133, 132, 122, 51, 29, 25. 2.6.6. 2-Neopentylisoindoline-1,3-dione 1 H NMR (300 MHz, CDCl ): ı = 7.88 (dd, 2H, J = 5.4, 3.3 Hz), 7.85 3 (dd, 2H, J = 5.4, 3.3 Hz), 3.55 (S, 2H), 0.94 (S, 9H); 13 C NMR (75 MHz): ı = 169, 133, 132, 123, 49, 33, 28.

3. Results and discussion Considering the objective of the development of efficient, phosphine free, heterogeneous and recyclable protocol, ImmPd-IL was developed as a common catalyst for carbonylative cyclization for the synthesis of various aromatic, aliphatic and heterocyclic Nsubstituted isoindole-1,3-diones. 3.1. Immobilized Pd-IL catalyzed carbonylative cyclization of 2-iodobenzoic acid While, setting up the protocol we observed that the nature of solvent, base, temperature, CO pressure and reaction time needs to be optimized for enhancing the yield of the desired products. Hence, we optimized the reaction parameters using 2-iodobenzoic acid with aniline as a model system in the presence of ImmPd-IL as a catalyst (Scheme 3). While studying the effect of solvent we observed that, nature of solvent plays a very crucial role in the reaction outcome. Hence various solvents like ACN, THF, DMF, DMSO and Toluene were screened (Table 1, entries 1–5). It was observed that on decreasing the polarity of the solvent, the yield of desired product goes on increasing. This observation can be attributed to the nature of catalyst employed for the protocol. As the ImmPd-IL catalyst is somewhat ionic in nature, results in decrease in yield of the desired product in polar solvents due to the interaction of catalyst with the solvent, thus decreases the catalyst activity possibly due to leaching of chloropalladate anion. Hence non-polar solvents like toluene provided promising result with the 95% yield of the desired product (Table 1, entry 5). Considering role of base in the reaction, various organic and inorganic bases were screened with the aim of obtaining higher yield of expected product. The hindered amine such as DABCO,

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Table 1 Optimization of the ImmPd-IL catalyzed carbonylative cyclization reaction of 2iodobenzoic acid with aniline.a Entry

Solvent

Base

Effect of solvent ACN Et3N 1 2 THF Et3N DMF Et3N 3 DMSO Et3N 4 Toluene Et3N 5 Effect of base Toluene DABCO 6 Toluene DBU 7 Toluene K2CO3 8 Effect of temperature Toluene Et3N 9 Toluene Et3N 10 Effect of time and CO pressure Toluene Et3N 11 Toluene Et3N 12 Effect of catalyst loading 13c Toluene Et3N Toluene Et3N 14d

Time (h)

Temp. (◦ C)

CO (atm)

Yield (%)b

4 4 4 4 4

100 100 100 100 100

1 1 1 1 1

10 35 55 64 95

4 4 4

100 100 100

1 1 1

70 75 35

4 4

120 140

1 1

90 65

4 2

100 100

3.4 1

94 86

4 4

100 100

1 1

90 96

Table 2 ImmPd-IL catalyzed carbonylative cyclization reaction of 2-iodobenzoic acid with different aromatic, aliphatic and heteroaromatic amines.a Entry 2-Iodobenzoic Amine acid

OH

1

I

DBU and triethylamine were found to be compatible base (Table 1, entries 5–7), while inorganic base (K2 CO3 ) provided 35% yield of the desired product (Table 1, entry 8). Thus, further reactions were carried out using Et3 N as a base (Table 1, entries 5–8). In order to examine the effect of temperature, reaction was carried out at different temperatures ranging from 100 to 140 ◦ C. At 100 ◦ C reaction temperature, 95% yield of 2-phenylisoindole1,3-dione was obtained whereas, on increasing the reaction temperature up to 140 ◦ C there was a drastic decrease in the amount of product, which may be attributed to the dehalognation at earlier stage of the reaction (Table 1, entries 9–10). Next, we studied the effect of CO pressure, while increasing the CO pressure equivalent yield of the expected product was observed hence further reactions were carried out at 1 atm CO pressure (Table 1, entry 11). When the reaction time was decreased, a lower yield of the desired product was observed (Table 1, entry 12). The effect of catalyst loading on the reaction outcome was also studied (Table 1, entries 5 and 13–14), Hence, the optimized reaction conditions were the following; base, Et3 N; ImmPd-IL, 2 mol%; temperature, 100 ◦ C; solvent, toluene; time, 4 h and 1 atm CO pressure. With these optimized reaction conditions scope of the protocol was extended for the synthesis of various N-substituted isoindole-1,3-diones by carbonylative cyclization of 2-iodobenzoic acid with different aromatic, aliphatic and heteroaromatic aryl amines (Table 2, entries 1–11). Model reaction of 2-iodobenzoic acid with aniline under optimized reaction condition provided 90% isolated yield of 2-phenyl isoindole-1,3-dione (Table 2, entry 1). Reaction of different ortho, para and meta substituted aniline derivatives including o-toluidine, p-toluidine and m-chloroaniline provided good to excellent yield of corresponding N-substituted isoindole-1,3-dione derivative (Table 2, entries 2–4). It is noteworthy to mention that, the aliphatic amines were quite eligible for the carbonylative cyclization reaction. Aliphatic amines including methanamine, 2-methoxyethanamine and 2,2-dimethylpropan-1-amine furnished excellent yield of the corresponding product (Table 2, entries 5–7). Strained cyclopropyl amine provided 80% yield of 2-cyclopropylisoindoline-1,3-dione (Table 2, entry 8). Encouraged by these results, various heteroaromatic amines including 3-amine pyridine, 2-amine thiazol and (5-methylfuran-2-yl)methanamine were screened. To our delight

90

O

OH I

N

94

O

O

O OH I

a

N

NH2 O

O 2

Yield (%)b

O

O

3

Reaction conditions: 2-iodobenzoic acid (1 mmol), aniline (2 mmol), ImmPd-IL (2 mol%), base (2.5 mmol), solvent (10 mL). b GC yield. c ImmPd-IL (1.5 mol%). d ImmPd-IL (2.5 mol%).

Product

N

90

O

O 4

OH

91

OH CH –NH 3 2

95

I O 5

I

O

O OH

6

I

O

90

O O

O OH

7

N

I

N

89

O

O OH

8

80

I

O

O OH

9

I

N

N

81

O

O 10

OH

79

OH

82

I O 11

I a Reaction conditions: 2-iodobenzoic acid (1 mmol), amine (2 mmol), Et3 N (2.5 mmol), toluene (10 mL), ImmPd-IL (2 mol%), time (4 h), CO pressure (1 atm), temp. (100 ◦ C). b Isolated yield.

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95

Table 3 ImmPd-IL catalyzed carbonylative with iodobenzoate/1,2-dihaloarenes heteroaromatic amines.a Entry Iododerivative Scheme 4. ImmPd-IL iodobenzoate.

catalyzed

carbonylative

cyclization

of

cyclization reaction different aromatic,

Amine

Product

of methyl-2aliphatic and

Yield (%)b

methyl-2-

O

O O

1

N

NH2

I

88

O

O Scheme 5. ImmPd-IL catalyzed carbonylative cyclization of 1,2-diiodo benzene.

In order to extend the scope of the developed protocol, methyl2-iodobenzoate and 1,2-diiodo benzene were screened, which provided the corresponding N-substituted isoindole-1,3-diones in good to excellent yield (Schemes 4 and 5). Carbonylative cyclization of methyl-2-iodobenzoate was earlier reported by Larock et al. using Pd(OAc)2 [18], and Cheng et al. by using Ni(Br2 )dppe as a catalyst [29] both of these protocols required phosphine ligand and longer reaction time up to 24–36 h, furthermore the protocols are homogeneous. Therefore, in order to show wide applicability of our developed protocol, we expanded our view to synthesis of N-substituted isoindole-1,3-diones by carbonylative cyclization of methyl-2-iodobenzoate with primary amines using ImmPd-IL as a catalyst (Scheme 4). Methyl-2-iodobenzoate reacts efficiently with aniline and 2fluroaniline, providing 88% and 75% yield of expected product respectively (Table 3, entries 1–2). Whereas, aliphatic amines like cyclopropyl amine and (4-(tert-butyl)phenyl)methanamine provided 78–80% yield of expected product (Table 3, entries 3–4). The developed catalyst was also extended for the carbonylative cyclization of 1,2-diiodo benzene with aryl amines (Scheme 5). Different aromatic, aliphatic and heteroaromatic aryl amines were screened wherein the entire cases moderate to good yield of corresponding products were obtained (Table 3 entries 5–8).

75

I

in all the cases good to excellent yield of corresponding Nheterocyclic isoindole-1,3-dione was observed (Table 2, entries 9–11). 3.2. Immobilized Pd-IL catalyzed carbonylative cyclization of methyl-2-iodobenzoate and 1,2-diiodo benzene

O

2

O

O O

3

N

NH 2

I

80

O

O O

4

78

I O 5

NH2

N

89

O

O 6

N

NH 2

86

O O

NH2 7

N

96

O 3.3. Recycle study In order to prove that the developed protocol is more economical, we studied recyclability of the ImmPd-IL catalyst (Fig. 1). It was found that the ImmPd-IL catalyst showed excellent recyclability up to four consecutive cycles. Slight decline in the yield up to forth recycle run was due handling loss of the catalyst after each recycle run. To prove that our catalyst does not leaches out from the support, we carried out hot filtration test [30], which does not indicate any leaching of the metal in the solution. 3.4. XPS analysis of the catalyst XPS spectra were measured for the fresh ImmPd-IL, the 1st recycle and the 4th recycle catalysts to monitor valence states of catalysts. The wide scan and Pd 3d, Cl 2p, and I 3d regions are shown in Fig. 2. As for Pd 3d region, two peaks appear at 337 and 342.4 eV for the fresh ImmPd-IL, corresponding to 3d5/2 and 3d3/2 for Pd2+

8

85

a Reaction conditions: iododerivative (methyl-2-iodobenzoate/1,2-diiodo benzene) (1 mmol), amine (2 mmol), Et3 N (2.5 mmol), toluene (10 mL), ImmPd-IL (2 mol%), time (6 h), CO pressure (1 atm.), temp. (100 ◦ C). b Isolated yield.

species, respectively. For the 1st recycle and the 4th recycle catalysts, both peaks tend to shift to lower binding energies, suggesting that catalysts are slightly reduced during catalytic reactions. For Cl 2p region unresolved Cl 2p3/2 and Cl 2p1/2 peaks resulted in a broad peak at 298 eV for the fresh ImmPd-IL. For the 1st recycle and the 4th recycle catalysts, Cl 2p peaks almost vanished. Instead, in the I 3d region, two intensive peaks appear at 617.7 eV (I 3d5/2) and

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629.2 eV (I 3d3/2) for the reused catalysts, indicating that exchange between chlorine atoms and iodine atoms happens in the present catalytic reactions. 4. Conclusion

Fig. 1. Recyclability study of the ImmPd-IL catalyst.

In conclusion efficient heterogeneous and phosphine free protocol for the carbonylative cyclization reaction of 2-iodobenzoic acid have been developed. The developed protocol found to be promising due to several aspects like requirement of less reaction time 4 h and use of atmospheric CO pressure along with wide functional group tolerance affording moderate to the excellent yield of range of N-substituted isoindole-1,3-diones. The developed catalytic system was also extended for the carbonylative cyclization of methyl-2-iodobenzoate and 1,2-diiodo benzene. Furthermore, the catalytic system was also recycled upto four consecutive cycles without any significant loss in catalytic activity and the recycled catalyst was characterized by XPS analysis.

Fig. 2. XPS analysis of the ImmPd-ILcatalyst (a, wide Scan; b, Pd3d; c, Cl2p; d, I3d).

M.V. Khedkar et al. / Journal of Molecular Catalysis A: Chemical 385 (2014) 91–97

Acknowledgements The author (M.V. Khedkar) is greatly thankful to UGC (University Grant Commission, India) for providing Junior Research Fellowship. XPS measurements were conducted in Research Hub for Advanced Nano Characterization, the University of Tokyo, supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work is supported by JSPS and DST under the Japan-India Science Cooperative Program (Project No. DST/INT/JSPS/P-152/2013). Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.molcata. 2014.01.018. References [1] H.M. Colquhoun, D.J. Thompson, M.V. Twigg, Carbonylation, Direct Synthesis of Carbonyl Compounds, Plenum Press, New York, 1991. [2] R. Skoda-Foldes, L. Kollar, Curr. Org. Chem. 6 (2002) 1097–1119. [3] S.T. Gadge, B.M. Bhanage, RSC Adv. (2013), http://dx.doi.org/ 10.1039/C3RA46273K (in press). [4] R.A. Abramovitch, I. Shinkai, B.J. Mavunkel, K.M. More, S. O’Connor, G.H. Ooi, W.T. Pennington, P.C. Srinivasan, J.R. Stowers, Tetrahedron 52 (1996) 3339–3354. [5] J.L. Wood, B.M. Stoltz, S.N. Goodman, J. Am. Chem. Soc. 118 (1996) 10656–10657.

97

[6] I.H. Hall, J.M. Chapman, O.T. Wong, Anti-Cancer Drugs 5 (1994) 75–82. [7] S. Makonkawkeyoon, R.N.R. Limson-Pobre, A.L. Moreira, V. Schauf, G. Kaplan, Proc. Natl. Acad. Sci. U. S. A. 90 (1993) 5974–5978. [8] W.D. Figg, S. Raje, K.S. Bauer, A. Tompkins, D. Venzon, R. Bergan, A. Chen, M. Hamilton, J. Pluda, E. Reed, J. Pharm. Sci. 88 (1999) 121–125. [9] E. Atra, E.I. Sato, Clin. Exp. Rheumatol. 11 (1993) 487–493. [10] S. Ochonisky, J. Verroust, S. Bastuji-Garin, R. Gherardi, J. Revuz, Arch. Dermatol. 130 (1994) 66–69. [11] H. Miyachi, A. Azuma, A. Ogasawara, E. Uchimura, N. Watanabe, Y. Kobayashi, F. Kato, M. Kato, Y. Hashimoto, J. Med. Chem. 40 (1997) 2858–2865. [12] G. Chen, X. Zhang, S. Zhang, T. Chen, Y. Wu, J. Appl. Polym. Sci. 106 (2007) 2808–2816. [13] X. Li, J. Zhan, Y. Li, Macromolecules 37 (2004) 7584–7594. [14] D. Hellwinkel, R. Lenz, F. Laemmerzahl, Tetrahedron 39 (1983) 2073–2084. [15] M. Mori, K. Chiba, N. Ohta, Y. Ban, Heterocycles 13 (1979) 329–332. [16] R.J. Perry, S.R. Turner, J. Org. Chem. 56 (1991) 6573–6576. [17] H. Cao, H. Alper, Org. Lett. 12 (2010) 4126–4129. [18] S.A. Worlikar, R.C. Larock, J. Org. Chem. 73 (2008) 7175–7180. [19] A. Takacs, P. Acs, L. Kollar, Tetrahedron 64 (2008) 983–987. [20] J.R. Martinelli, D.A. Watson, D.M. Freckmann, T.E. Barder, S.L. Buchwald, J. Org. Chem. 73 (2008) 7102–7107. [21] Y. Du, T.K. Hyster, T. Rovis, Chem. Commun. 47 (2011) 12074–12076. [22] A. Begouin, P. Queiroz, Eur. J. Org. Chem. 17 (2009) 2820–2827. [23] M.V. Khedkar, S.R. Khan, K.P. Dhake, B.M. Bhanage, Synthesis 44 (2012) 2623–2629. [24] M.V. Khedkar, T. Sasaki, B.M. Bhanage, RSC Adv. 3 (2013) 7791–7797. [25] T. Sasaki, C. Zhong, M. Tada, Y. Iwasawa, Chem. Commun. 19 (2005) 2506–2508. [26] T. Sasaki, M. Tada, C. Zhong, T. Kume, Y. Iwasawa, J. Mol. Catal. A: Chem. 279 (2008) 200–209. [27] M.V. Khedkar, T. Sasaki, B.M. Bhanage, ACS Catal. 3 (2013) 287–293. [28] M.V. Khedkar, B.M. Bhanage, Front. Chem. Sci. Eng. 7 (2013) 226–230. [29] J. Hsieh, C. Cheng, Chem. Commun. 36 (2005) 4554–4556. [30] H.B. Lempers, R.A. Sheldon, J. Catal. 175 (1998) 62–69.