CC BY ND NC 4.0 · SynOpen 2017; 01(01): 0143-0146
DOI: 10.1055/s-0036-1590959
letter
Copyright with the author

Ball-Milling Promoted Monobromination Reactions: One-pot Regioselective Synthesis of Aryl Bromides and α-Bromoketones by NBS and Recyclable MCM-41-SO3H at Room Temperature

N. Ghanbari, H. Ghafuri*, H. R. Esmaili Zand, M. Eslami
  • Catalysis and Organic Synthesis Research Laboratory, Department of Chemistry of Iran, University of Science and Technology, Tehran 16846-13114, Iran   Email: ghafuril@iust.ac.ir
Further Information

Publication History

Received: 09 August 2017

Accepted after revision: 23 October 2017

Publication Date:
16 November 2017 (online)

 

Abstract

An effective approach to monobromination reactions utilizing room temperature ball-milling is introduced for the synthesis of aryl bromides and bromoketones with N-bromosuccinimide (NBS) and MCM-41-SO3H. Advantages of this technique are short reaction times and high regioselectivity. In contrast to other techniques using microwaves, ultrasound, or ionic liquids, handling of sensitive materials is possible and furthermore, this method has advantages over other solvent-free techniques that require a higher reaction temperature for high yield of products.


#

Halogenated compounds have diverse applications in various fields such as pharmaceuticals and agrochemicals.[1] Aromatic halides are the key fragments of coupling reactions such as Heck, Suzuki, Sonogashira, and hetero coupling reactions.[2] [3] [4] [5]

For the synthesis of brominated aromatic compounds, Br2 is the traditional reagent, but results in the production of HBr and procedures often require careful control of temperature and amount of Br2. As a result, improved mild brominating agents have been developed,[6] [7] [8] [9] [10] [11] [12] [13] but a fundamental disadvantage for many of these methods is unwanted oxidation of sensitive functional groups.

To eliminate such problems, NBS has been used for brominating aromatic compounds[14] and several reaction conditions in organic solvents have been reported to activate the halogenating ability of NBS.[15] [16] [17]

There are some reports that describe halogenations in the presence acidic catalyst, such as trihaloisocyanuric acid for halogenation of β-dicarbonyl compounds,[18a] sodium hypochlorite­ for the halogenation of β-dicarbonyl compounds,[18b] and NBS in the presence of acidic catalyst.[16]

It became clear to us that combining an acidic catalyst and NBS leads to more efficient bromination reactions. In addition, using heterogeneous acidic nanocatalysts can be advantageous over homogeneous catalysts as a result of their high surface area, recyclability and simplified work-up.

A specific example of a silica material with ordered structure, narrow pore-size distribution (1.5–10 nm) and very high surface area (more than 1500 m2 g–1) that can be used as a heterogeneous nanocatalyst is MCM-41. Modification of its surface can result in a solid acid with high uniformity, modified by covalent anchoring of different organic moieties in a well-ordered mesoporous material. Thus, nanoparticulate MCM-41-SO3H with covalently bound sulfonic acid was selected for investigation as a heterogeneous acidic nanocatalyst.

It has been said that ‘the best solvent is no solvent’, but to obtain high yields under solvent-free conditions frequently involves high temperatures that are not suitable for materials that are temperature sensitive such as terminal alkynes.[19]

One solution can be found in ‘mechanochemistry’,[20] which involves induction of a chemical reaction by the direct absorption of mechanical energy.[1] In mechanochemistry, mechanical energy in the solid state is used for bond breaking (as compared to microwave and sonication in which thermal activation is used for bond breaking).[21] Intramolecular bonds can be mechanically broken and this is then followed by further chemical reactions.[19] [22] Mechanochemistry is now conducted using ball-mills under solvent-free conditions.[23–27] Ball-milling is an emerging field with applications in the synthesis of metal complexes, the formation of metal–organic frameworks, the synthesis of catalysts, and the assembly of co-crystals between pharmacologically active compounds.[28–32] Examples of ball-milling applications in organic synthesis include C–H bond-functionalization, C–N coupling, and the formation of pyrazoles and indoles.[33] [34]

In this study, ball-milling was examined for bromination reactions with NBS in the presence of MCM-41-SO3H as a co-catalyst.[35] It was found that using NBS without any co-catalyst led to extended reaction times (Table [1]), but reaction in the presence of MCM-41-SO3H under ball-milling conditions afforded the corresponding brominated products of aryl alcohols in 1–10 min and ketones in 4–20 min in 85–96% product yields. In this manuscript, we thus present the mechanochemical monobromination of activated aromatic and aliphatic substrates as a novel protocol (Scheme [1]).[34b] [34c] In conclusion, we have developed an efficient technique for monobromination reaction, and, in comparison to other solvent-free techniques that require high temperature, this method is highly effective.

Zoom Image
Scheme 1 Monobromination of aryl and aliphatic compounds

Bromination was examined using ball-milling (a Retsch Mixer Mill MM 400) with NBS with and without MCM-41-SO3H and the results showed that the time required without MCM-41-SO3H co-catalyst was twice as long as reaction with the presence of the MCM-41-SO3H (Table [1]). In the presence of NBS and MCM-41-SO3H in ethanol, the desired products were obtained in 1 h, whereas in the presence of other co-catalysts, much longer times were required (Table [2], entries 3 and 5).

Table 1 Bromination Reaction with and without Co-catalysta

Substrate

NBS

NBS and MCM-41-SO3H

Naphthalen-2-ol

10 min, 75%

5 min, 95%

Acetophenone

30 min, 70%

15 min, 87%

a Ball-milling at room temperature.

To optimize the amount of catalyst, 0.01 g catalyst for each mmol of substrate was initially used, but starting material remained. When the amount of catalyst was increased to 0.02 g the yields of reaction were optimal. When the amount of catalyst was increased to 0.03 and 0.04 g, dibrominated products were produced. Various solvent systems were investigated, but the best yields were gained when ball-milling alone was used.

The vibrational frequency of the ball-milling device was 3–30 Hz, and the grinding jars were stainless steel with a volume of 10 mL. The size of the milling balls was 10 mm. Initial studies used a rotational frequency of 20 Hz at room temperature for a total of 11 minutes for bromination of 2-chlorophenol. Increasing the rotational frequency from 20 to 30 Hz led to increased product yield, along with a 10 minute decrease in the reaction time. The highest yield of 96% of 4-bromo-2-chlorophenol was obtained at a rotational frequency of 30 Hz within 1 minute (Table 3, entry 4).

Table 2 Comparison with Other Catalytic Systemsa

Entry

Catalyst

Time

Solvent

Temp. (°C)

Yield (%)

Ref.

1

NH4Br-oxone

7 h

MeOH

r.t.

81

[36]

2

H2O2-HBr

3 h

H2O

r.t.

60

[37]

3

NBS-pTSA

30 min

CH3CN

80

46

[38]

4

HBr

10 h

DMSO

40

69

[39]

5

p-TsOH·H2O-NBS

9 h

CH3Cl

r.t.

92

[40]

6

MCM41-SO3H

15 min

solvent free

r.t.

87

a Bromination reaction of acetophenone.

A range of bromination reactions was investigated using this protocol and the results are shown in Table 3 and Table 4. All the substrates treated with 0.01 g of NBS and 0.02 g of MCM-41-SO3H for each mmole of substrate at room temperature afforded the corresponding brominated products in high yield with high regioselectivity. Worthy of note, the reaction of NBS and benzaldehyde in the presence of 0.02 g MCM-41-SO3H did not give the expected direction of substitution and 4-bromo benzaldehyde was obtained instead.[48] [49] [50]

Table 3 Bromination of Aromatic Compoundsa

Entry

Substrates

Products

Time (min)

Yield (%)

Mp lit/found

1

phenol

4-bromophenol

1

96

65–66[41]/63–65

2

2,4-dichlorophenol

2-bromo-2,4-dichlorophenol

1

94

68[42]/68

3

benzaldehyde

4-bromobenzaldehyde

1

96

liquid

4

2-chlorophenol

4-bromo-2-chlorophenol

1

96

49–50[41]/50–53

5

2-nitrophenol

4-bromo-2-nitrophenol

2

92

91–93[41]/91–93

6

2-hydroxybenzaldehyde

4-bromo-2-hydroxybenzaldehyde

2

94

102–104[43]/103–104

7

resorcinol

2-bromo-1,3-diol

4

95

99–101[43]/98–101

8

naphthalen-1-ol

4-bromo-1-naphthol

4

93

44–46[44]/130–133

9

naphthalen-2-ol

1-bromo-2-naphthol

5

95

83–84[43]/81–83

10

2-bromo-4-chlorophenol

2,6-dibromo-4-chlorophenol

5

95

92[41]/32–33

11

2,5-dimethylphenol

4-bromo-2,5-dimethylphenol

10

94

86–88[41]/88–90

a All reactions were carried out in a ball-mill at r.t.

Table 4 α-Bromination of Carbonyl Compoundsa

Entry

Substrates

Products

Time (min)

Yield (%)

Mp lit/found

1

methyl-3 oxobutanoate

methyl-2-bromo-3 oxobutanoate

4

93

liquid

2

ethyl-3 oxobutanoate

ethyl-2-bromo-3 oxobutanoate

5

94

liquid

3

cyclohexane-1,3-dione

2-bromo-cyclohexane-1,3-dione

8

90

159–161[45]/157–160

4

5,5-dimethylcyclohexane-1,3-dione

2-bromo-5,5-dimethylcyclohexane-1,3-dione

10

89

158–160[45]/160–162

5

acetophenone

2-bromoacetophenone

15

87

49–51[46]/48–50

6

4-nitro-acetophenone

2-bromo-1-(4-nitrophenyl)ethanone

15

88

95–98[36]/100–101

7

4-methyl-acetophenone

2-bromo-1-(4-methoxyphenyl)ethanone

20

85

69–70[47]/70–72

a All reactions were carried out in a ball-mill at r.t.


#

Acknowledgment

The authors gratefully acknowledge support from the Research Council of the Iran University of Science and Technology.

Supporting Information

  • References

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  • 2 Kaupp G. Top. Curr. Chem. 2005; 254: 95
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  • 37 Podgoršek A. Stavber S. Zupan M. Iskra J. Green Chem. 2007; 9: 1212
  • 38 Guan XY. Al-Misba Z. Huang KW. Arabian J. Chem. 2015; 8: 892
  • 39 Cao Z. Shi D. Qu Y. Tao C. Liu W. Yao G. Molecules 2013; 18: 15717
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  • 41 Adibi H. Hajipour AR. Hashemi M. Tetrahedron Lett. 2007; 48: 1255
  • 42 Li X. Wang Y. Ding C. Zhang G. Liangc X. Synlett 2011; 2265
  • 43 Moghaddam FM. Zargarani D. Synth. Commun. 2009; 39: 4212
  • 44 Sharma SK. Agarwal DD. J. Agric. Life Sci. 2014; 16: 65
  • 45 Pathak S. Kundu A. Pramanik A. RSC Adv. 2014; 4: 10180
  • 46 Pravst I. Zupana M. Stavber S. Tetrahedron Lett. 2006; 47: 4707
  • 47 Meshram HM. Reddy PN. Vishnu P. Sadashiv K. Yadav JS. Tetrahedron Lett. 2006; 47: 991
  • 48 Preparation of MCM-41-SO3H: Diethylamine (2.7 g) was added to deionized water (42 mL) at room temperature. The mixture was stirred for 10 min, then cetyltrimethylammonium bromide (1.47 g) was added and the mixture was stirred for 30 min until a clear solution was obtained. To this mixture, tetraethoxysilane (2.1 g) was added dropwise and the pH of the reaction mixture was maintained at 8.5 by adding hydrochloric acid solution (1 M). After 2 h, the solid product was filtered, washed with deionized water, dried at 45 °C for 12 h, and then calcined at 550 °C for 5 h
  • 49 Preparation of MCM-41-SO3H: Dichloromethane (5 mL) containing MCM-41 (1.0 g) was added to a flask equipped with a pressure equilibrating dropping funnel charged with chlorosulfonic acid (2 mL) and equipped with a gas inlet tube. The chlorosulfonic acid was added dropwise over 30 min at room temperature and HCl gas generated was swept from the reaction vessel. The mixture was then stirred for 30 min and the solvent was evaporated to obtain MCM-41-SO3H
  • 50 General bromination experimental procedure: Substrate (1 mmol), NBS (0.1 g) and MCM-41-SO3H (0.2 g) were added to a ball-mill jar. Reaction was conducted at a rotational frequency of 30 Hz at room temperature and the reaction was followed by TLC. After completion, the mixture was separated and MCM-41-SO3H was recovered. The recovered MCM-41-SO3H was reused five more times without any decrease in its catalytic ability

  • References

  • 1 Stolle A. Szuppa T. Leonhard SE. S. Ondruschka B. Chem. Soc. Rev. 2011; 40: 2317
  • 2 Kaupp G. Top. Curr. Chem. 2005; 254: 95
  • 3 Kaupp G. Prediction of Reactivity in Solid-State Chemistry . In Making Crystals by Design . Braga D. Grepioni F. Wiley-VCH; Weinheim; 2007: 87-148
  • 4 Kaupp G. CrystEngComm 2006; 794
  • 5 Tullberg E. Schacher F. Peters D. Frejd T. Synthesis 2006; 1183
  • 6 Watano S. Okamoto T. Tsuhari M. Koizumi I. Osako Y. Chem. Pharm. Bull. 2002; 50: 341
  • 7 Trost BM. Fleming I. Comprehensive Organic Synthesis, Vol. 9, Cumulative Index . Pergamon; Oxford; 1991
  • 10 Kad GL. Bhandari M. Kau J. Rathee R. Singh J. Green Chem. 2001; 3: 275
  • 11 Sharghi H. Sarvari MH. J. Chem. Res., Synop. 2000; 24
  • 12 Fazaeli R. Tangestaninejad S. Aliyan H. Catal. Commun. 2006; 7: 205
  • 13 Damljanovic I. Vukicevic M. Vukicevic RD. Wiener Mh. 2006; 137: 301
  • 14 Shriner RL. Hermann CK. F. Morrill TC. Curtin DY. Fuson RC. The Systematic Identification of Organic Compounds, 8th ed. . Wiley; NewYork; 2003: 656
  • 15 Das B. Venkateswarlu K. Krishnaiah M. Holla H. Tetrahedron Lett. 2006; 47: 8693
  • 16 Das B. Venkateswarlu K. Mahender G. Mahender I. Tetrahedron Lett. 2005; 46: 3041
  • 17 Ghafuri H. Hashemi MM. J. Sulfur Chem. 2009; 30: 578
    • 18a Mendonça GF. Sindra HC. de Almeida LS. Esteves PM. de Mattos MC. S. Tetrahedron Lett. 2009; 50: 473
    • 18b Meketa ML. Mahajan YR. Weinreb SM. Tetrahedron Lett. 2005; 46: 4749
  • 19 Kaupp G. CrystEngComm 2009; 388
  • 20 Noman A. Rahman M. Bishop R. Tan R. Shan N. Green Chem. 2005; 7: 207
  • 21 Pravst I. Zupan M. Stavber S. Green Chem. 2006; 8: 1001
  • 22 James SL. Adams CJ. Bolm C. Braga D. Collier P. Friščić T. Grepioni F. Harris KD. M. Hyett G. Jones W. Krebs A. Mack J. Maini L. Orpen AG. Parkin IP. Shearouse WC. Steed JW. Waddell DC. Chem. Soc. Rev. 2012; 41: 413
  • 23 Do JL. Friščić T. ACS Cent. Sci. 2017; 3: 13
  • 24 Jiménez-González C. Constable DJ. C. Ponder CS. Chem. Soc. Rev. 2012; 41: 1485
  • 25 Czaja A. Leung E. Trukhan N. Müller U. Industrial MOF synthesis . In Metal-Organic Frameworks: Applications from Catalysis to Gas Storage . Farrusseng D. Wiley-VCH Verlag GmbH; Weinheim; 2011
  • 26 Mokhtari J. Naimi-Jamal MR. Hamzeali H. Dekamin MG. Kaupp G. ChemSusChem 2009; 2: 248
  • 27 Kaupp G. J. Phys. Org. Chem. 2008; 21: 630
  • 28 Garay AL. Pichon A. James SL. Chem. Soc. Rev. 2007; 36: 846
    • 29a Pichon A. James SL. CrystEngComm 2008; 1839
    • 29b Yuan W. Friščić T. Apperley D. James SL. Angew. Chem. Int. Ed. 2010; 49: 3916
  • 30 Kubias B. Fait MJ. G. Schlögl R. In Handbook of Heterogeneous Catalysis . Ertl G. Knözinger H. Schüth F. Weitkamp J. Wiley-VCH; Weinheim; 2008. 2nd ed 571-583
  • 31 Friščić T. J. Mater. Chem. 2010; 20: 7599
  • 32 Friščić T. Jones W. Cryst. Growth Des. 2009; 9: 1621
  • 33 Juribasić M. Užarević K. Gracin D. Ćurić M. Chem. Commun. 2014; 10287
    • 34a Tan D. Mottillo C. Katsenis AD. Štrukil V. Friščić T. Angew. Chem. Int. Ed. 2014; 53: 9321
    • 34b Zille M. Stolle A. Wild A. Schubert US. RSC Adv. 2014; 4: 13126
    • 34c Paveglio GC. Longhi K. Moreira DN. München TS. Tier AZ. Gindri IM. Bender CR. Frizzo CP. Zanatta N. Bonacorso HG. Martins MA. P. ACS Sustainable Chem. Eng. 2014; 2: 1895
    • 34d Ghafuri H. Khodashenas S. Naimi-Jamal MR. J. Iran. Chem. Soc. 2015; 12: 599
    • 35a Rostamizadeh Sh. Amani AM. Mahdavinia GH. Amiri G. Sepehrian H. Ultrason. Sonochem. 2010; 17: 306
    • 35b Dekamin MG. Mokhtari Z. Tetrahedron 2012; 68: 922
  • 36 Macharla AK. Nappunni RC. Marri MR. Peraka S. Nama N. Tetrahedron Lett. 2012; 53: 191
  • 37 Podgoršek A. Stavber S. Zupan M. Iskra J. Green Chem. 2007; 9: 1212
  • 38 Guan XY. Al-Misba Z. Huang KW. Arabian J. Chem. 2015; 8: 892
  • 39 Cao Z. Shi D. Qu Y. Tao C. Liu W. Yao G. Molecules 2013; 18: 15717
  • 40 Izumisaw Y. Togo H. Green Sustainable Chem. 2011; 1: 54
  • 41 Adibi H. Hajipour AR. Hashemi M. Tetrahedron Lett. 2007; 48: 1255
  • 42 Li X. Wang Y. Ding C. Zhang G. Liangc X. Synlett 2011; 2265
  • 43 Moghaddam FM. Zargarani D. Synth. Commun. 2009; 39: 4212
  • 44 Sharma SK. Agarwal DD. J. Agric. Life Sci. 2014; 16: 65
  • 45 Pathak S. Kundu A. Pramanik A. RSC Adv. 2014; 4: 10180
  • 46 Pravst I. Zupana M. Stavber S. Tetrahedron Lett. 2006; 47: 4707
  • 47 Meshram HM. Reddy PN. Vishnu P. Sadashiv K. Yadav JS. Tetrahedron Lett. 2006; 47: 991
  • 48 Preparation of MCM-41-SO3H: Diethylamine (2.7 g) was added to deionized water (42 mL) at room temperature. The mixture was stirred for 10 min, then cetyltrimethylammonium bromide (1.47 g) was added and the mixture was stirred for 30 min until a clear solution was obtained. To this mixture, tetraethoxysilane (2.1 g) was added dropwise and the pH of the reaction mixture was maintained at 8.5 by adding hydrochloric acid solution (1 M). After 2 h, the solid product was filtered, washed with deionized water, dried at 45 °C for 12 h, and then calcined at 550 °C for 5 h
  • 49 Preparation of MCM-41-SO3H: Dichloromethane (5 mL) containing MCM-41 (1.0 g) was added to a flask equipped with a pressure equilibrating dropping funnel charged with chlorosulfonic acid (2 mL) and equipped with a gas inlet tube. The chlorosulfonic acid was added dropwise over 30 min at room temperature and HCl gas generated was swept from the reaction vessel. The mixture was then stirred for 30 min and the solvent was evaporated to obtain MCM-41-SO3H
  • 50 General bromination experimental procedure: Substrate (1 mmol), NBS (0.1 g) and MCM-41-SO3H (0.2 g) were added to a ball-mill jar. Reaction was conducted at a rotational frequency of 30 Hz at room temperature and the reaction was followed by TLC. After completion, the mixture was separated and MCM-41-SO3H was recovered. The recovered MCM-41-SO3H was reused five more times without any decrease in its catalytic ability

Zoom Image
Scheme 1 Monobromination of aryl and aliphatic compounds