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An efficient synthesis of 1,8-dioxo-octahydroxanthenes using heterogeneous catalysts
Catalysis Communications 8 (2007) 535–538 www.elsevier.com/locate/catcom
An efficient synthesis of 1,8-dioxo-octahydroxanthenes using heterogeneous catalysts q Biswanath Das *, Ponnaboina Thirupathi, K. Ravinder Reddy, B. Ravikanth, Lingaiah Nagarapu Organic Chemistry Division-I, Indian Institute of Chemical Technology, NPL, IICT, Uppal Road, Hyderabad 500 007, India Received 22 December 2005; received in revised form 14 February 2006; accepted 23 February 2006 Available online 3 March 2006
Abstract 1,8-Dioxo-octahydroxanthenes have efficiently been synthesized from 5,5-dimethyl-1,3-cyclohexanedione and aromatic aldehydes using silica supported sodium hydrogen sulfate (NaHSO4 Æ SiO2) or silica chloride as a heterogeneous catalyst. The experimental procedure is very simple and the products are formed in high yields. Ó 2006 Elsevier B.V. All rights reserved. Keywords: 1,8-Dioxo-octahydroxanthene; 5,5-Dimethyl-1,3-cyclohexanedione; Silica chloride; NaHSO4 Æ SiO2; Heterogeneous catalyst
Heterogeneous catalysts have gained interesting attraction in recent years due to economic and environmental considerations. These catalysts are generally inexpensive and easily available. They can conveniently be handled and removed from the reaction mixture, thus making the experimental procedure simple and eco-friendly. Recently, we have utilized different heterogeneous catalysts successfully for various chemical transformations [1]. In continuation of the work [1] we have observed that 5,5dimethyl-1,3-cyclohexanedione (1) can easily undergo the condensation with aromatic aldehydes (2) in the presence of silica supported sodium hydrogen sulfate (NaHSO4 Æ SiO2) or silica chloride to form 1,8-dioxo-octahydroxanthene derivative (3) (Scheme 1). The mixture of 1 and 2 was refluxed in CH3 CN using either of these two catalysts [2]. Earlier, compound 3 was not synthesized using a heterogeneous catalyst [3].
q Part 76 in the series, ‘‘Studies on Novel Synthetic Methodologies’’. IICT Communication No. 060323. * Corresponding author. Tel./fax: +91 40 7160512. E-mail address: [email protected] (B. Das).
1566-7367/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2006.02.023
Several functionalized 1,8-dioxo-octahydroxanthenes were prepared from various aromatic aldehydes (Table 1) following the above method. The aromatic aldehydes containing both electron-donating and electron-withdrawing groups worked well. Cinnamaldehyde and 4-dimethyl aminobenzaldelyde also afforded the product in high yields. The structures of the prepared compounds were established from their spectral (1H NMR and MS) data. NaHSO4 Æ SiO2 and silica chloride work under heterogeneous conditions. The first catalyst could conveniently be prepared [4a] from the readily available ingredients, NaHSO4 and silica gel while the second catalyst from thionyl chloride and silica gel [4b]. The conversion required 6.5 h to get the products in maximum yields using NaHSO4 Æ SiO2 and 6.0 h using silica chloride. However, the yields of the products were almost similar with both of these two catalysts. When the conversion was carried out at room temperature, the dihydroxy compound 4 was formed within 5.0 h. No cyclization product 3 was obtained even if the reaction time was extended to 24.0 h. However, intermediate 4 was cyclized to 3 when it was refluxed in CH3CN for 3.0 h using one of these catalysts. Thus the present
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B. Das et al. / Catalysis Communications 8 (2007) 535–538
conversion is possibly forming the product 3 via the intermediate 4.
O + ArCHO
O
Ar
O
O 1
NaHSO4.SiO2 or silica chloride CH3CN 6.0-6.5h reflux
O
Ar
O
O 90-98% 3a-o
2a-o Scheme 1.
O H HO
4
NaHSO4 Æ SiO2 and silica chloride. The simple experimental work-up, high yields and application of inexpensive catalysts are the advantages of the present procedure.
In conclusion, we have developed a convenient and efficient method for the synthesis of 1,8-dioxo-octahydroxanthenes utilizing two heterogeneous catalysts,
Table 1 Preparation of 1,8-dioxo-octahydroxanthenes using NaHSO4 Æ SiO2 and silica chlorideb Entry a
Substrate
Product
CHO
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
90 93
[3] [3]
i ii
6.5 6.0
94 92
[3] [3]
i ii
6.5 6.0
90 91
[3] [3]
i ii
6.5 6.0
90 92
[3] [3]
i ii
6.5 6.0
90 91
[3] [3]
O
O b
Cl
CHO
O
O
Cl
O c
CHO
Cl O
O
Cl
O d
CHO Cl O
Cl O
O e
Cl
CHO Cl
Cl O
O Cl O
B. Das et al. / Catalysis Communications 8 (2007) 535–538
537
Table 1 (continued) Entry f
Substrate
Product
CHO
CH 3
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
95 93
[3] [3]
i ii
6.5 6.0
92 92
[3] [3]
i ii
6.5 6.0
94 92
[3] [3]
i ii
6.5 6.0
93 90
[3] [3]
i ii
6.5 6.0
95 94
[3] [3]
i ii
6.5 6.0
98 95
[3] [3]
i ii
6.5 6.0
95 95
[3] [3]
O
CH 3 O g
CHO NO2 O
NO2 O
O h
CHO
NO2 O
O
NO2 O i
NO2
CHO
O
O
NO2 O CHO
j
H3C
N
CH3
O H3C
N
O
CH3 O
k
CHO
OH
O
O
OH O l
OCH3
CHO
O
O
OCH3 O (continued on next page)
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B. Das et al. / Catalysis Communications 8 (2007) 535–538
Table 1 (continued) Entry
Substrate
m
Product
CHO
OH OCH3 OCH3
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
93 95
[3] [3]
i ii
6.5 6.0
90 92
[3] [3]
i ii
6.5 6.0
93 92
[3] [3]
O
OH O n
O CH2 O
CHO
O
O
O
O CH2
O o
H
C
C
H
H O
C
C H O
CHO
O a b
Catalyst (i) NaHSO4 Æ SiO2; (ii) silica chloride. The structures of the products were settled from their physical and spectral (IR, 1H NMR and MS) data.
Acknowledgements The authors thank CSIR and UGC, New Delhi for financial assistance. References [1] (a) K.V.N.S. Srinivas, B. Das, J. Org. Chem. 68 (2003) 1165; (b) C. Ramesh, N. Ravindranath, B. Das, J. Org. Chem. 68 (2003) 7101; (c) B. Das, G. Mahender, V.S. Kumar, N. Chowdhury, Tetrahedron Lett. 45 (2004) 6709; (d) B. Das, J. Banerjee, N. Ravindranath, Tetrahedron 60 (2004) 8357; (e) B. Das, V.S. Reddy, M.R. Reddy, Tetrahedron Lett. 45 (2004) 17. [2] Experimental procedure: To a solution of an aromatic aldehyde (1 mmol) and 5,5-dimethyl-1,3-cyclohexanedione (2 mmol) in CH3CN (10 ml), NaHSO4 Æ SiO2 or silica chloride (100 mg) was added. The mixture was refluxed for 6.5 h (with first catalyst) or 6.0 h (with second catalyst). The progress of the reaction was monitored by thin layer chromatography. After completion of the reaction, the mixture was filtered, the filtrate was concentrated and the residue was purified by
column chromatography over silica gel using EtOAc: hexane (2:3) as eluent to obtain pure 1,8-dioxo-octahydroxanthene derivative. All the products are known compounds (references in Table 1) and were characterized from their spectroscopic (1H NMR and MS) properties. The spectral data of some representative compounds are given below. Compound (3f); 3,3,6,6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxooctahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.12 (2H, d, J = 8.0 Hz), 6.96 (2H, d, J = 8.0 Hz), 4.62 (1H, s), 2.42 (3H, s), 2.24 (4H, s), 2.18 (4H, dd, J = 2.4, 1.6 Hz), 1.13 (6H, s), 1.00 (6H, s). EIMS: m/z 364 (M+), 349, 273, 217. Compound (3m); 3,3,6,6-Tetramethyl-9-(4hydroxy-3-methoxyphenyl)-1,8-dioxo-octahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.02 (1H, d, J = 2.0 Hz), 6.73 (1H, d, J = 8.0 Hz), 6.48 (1H, dd, J = 8.0, 2.0 Hz), 4.61 (1H, s), 3.96 (3H, s), 2.45 (4H, s), 2.24 (4H, d, J = 3.5 Hz), 1.17 (6H, s), 1.05 (6H, s). EIMS: m/z 396 (M+), 371, 285, 229. Compound (3o); 3,3,6,6,-Tetramethyl-9-(2phenyl-ethylene)-1,8-dioxo-octahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.28–7.02 (5H, m), 6.27–6.21 (2H, m), 4.35 (1H, d, J = 7.0 Hz), 2.42 (4H, s), 2.27 (4H, s) 1.11 (12H, s). EIMS: m/z 376 (M+), 358, 291, 282, 225. [3] T.-S. Jin, J.-S. Zhang, J.-C. Wiao, A.-Q. Wang, T.-S. Li, Synlett 866 (2004), and references cited therein. [4] (a) G.W. Breton, J. Org. Chem. 62 (1997) 8952; (b) H. Firouzabadi, N. Iranpoor, H. Hazarkhani, Tetrahedron Lett. 43 (2002) 7139.
An efficient synthesis of 1,8-dioxo-octahydroxanthenes using heterogeneous catalysts q Biswanath Das *, Ponnaboina Thirupathi, K. Ravinder Reddy, B. Ravikanth, Lingaiah Nagarapu Organic Chemistry Division-I, Indian Institute of Chemical Technology, NPL, IICT, Uppal Road, Hyderabad 500 007, India Received 22 December 2005; received in revised form 14 February 2006; accepted 23 February 2006 Available online 3 March 2006
Abstract 1,8-Dioxo-octahydroxanthenes have efficiently been synthesized from 5,5-dimethyl-1,3-cyclohexanedione and aromatic aldehydes using silica supported sodium hydrogen sulfate (NaHSO4 Æ SiO2) or silica chloride as a heterogeneous catalyst. The experimental procedure is very simple and the products are formed in high yields. Ó 2006 Elsevier B.V. All rights reserved. Keywords: 1,8-Dioxo-octahydroxanthene; 5,5-Dimethyl-1,3-cyclohexanedione; Silica chloride; NaHSO4 Æ SiO2; Heterogeneous catalyst
Heterogeneous catalysts have gained interesting attraction in recent years due to economic and environmental considerations. These catalysts are generally inexpensive and easily available. They can conveniently be handled and removed from the reaction mixture, thus making the experimental procedure simple and eco-friendly. Recently, we have utilized different heterogeneous catalysts successfully for various chemical transformations [1]. In continuation of the work [1] we have observed that 5,5dimethyl-1,3-cyclohexanedione (1) can easily undergo the condensation with aromatic aldehydes (2) in the presence of silica supported sodium hydrogen sulfate (NaHSO4 Æ SiO2) or silica chloride to form 1,8-dioxo-octahydroxanthene derivative (3) (Scheme 1). The mixture of 1 and 2 was refluxed in CH3 CN using either of these two catalysts [2]. Earlier, compound 3 was not synthesized using a heterogeneous catalyst [3].
q Part 76 in the series, ‘‘Studies on Novel Synthetic Methodologies’’. IICT Communication No. 060323. * Corresponding author. Tel./fax: +91 40 7160512. E-mail address: [email protected] (B. Das).
1566-7367/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2006.02.023
Several functionalized 1,8-dioxo-octahydroxanthenes were prepared from various aromatic aldehydes (Table 1) following the above method. The aromatic aldehydes containing both electron-donating and electron-withdrawing groups worked well. Cinnamaldehyde and 4-dimethyl aminobenzaldelyde also afforded the product in high yields. The structures of the prepared compounds were established from their spectral (1H NMR and MS) data. NaHSO4 Æ SiO2 and silica chloride work under heterogeneous conditions. The first catalyst could conveniently be prepared [4a] from the readily available ingredients, NaHSO4 and silica gel while the second catalyst from thionyl chloride and silica gel [4b]. The conversion required 6.5 h to get the products in maximum yields using NaHSO4 Æ SiO2 and 6.0 h using silica chloride. However, the yields of the products were almost similar with both of these two catalysts. When the conversion was carried out at room temperature, the dihydroxy compound 4 was formed within 5.0 h. No cyclization product 3 was obtained even if the reaction time was extended to 24.0 h. However, intermediate 4 was cyclized to 3 when it was refluxed in CH3CN for 3.0 h using one of these catalysts. Thus the present
536
B. Das et al. / Catalysis Communications 8 (2007) 535–538
conversion is possibly forming the product 3 via the intermediate 4.
O + ArCHO
O
Ar
O
O 1
NaHSO4.SiO2 or silica chloride CH3CN 6.0-6.5h reflux
O
Ar
O
O 90-98% 3a-o
2a-o Scheme 1.
O H HO
4
NaHSO4 Æ SiO2 and silica chloride. The simple experimental work-up, high yields and application of inexpensive catalysts are the advantages of the present procedure.
In conclusion, we have developed a convenient and efficient method for the synthesis of 1,8-dioxo-octahydroxanthenes utilizing two heterogeneous catalysts,
Table 1 Preparation of 1,8-dioxo-octahydroxanthenes using NaHSO4 Æ SiO2 and silica chlorideb Entry a
Substrate
Product
CHO
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
90 93
[3] [3]
i ii
6.5 6.0
94 92
[3] [3]
i ii
6.5 6.0
90 91
[3] [3]
i ii
6.5 6.0
90 92
[3] [3]
i ii
6.5 6.0
90 91
[3] [3]
O
O b
Cl
CHO
O
O
Cl
O c
CHO
Cl O
O
Cl
O d
CHO Cl O
Cl O
O e
Cl
CHO Cl
Cl O
O Cl O
B. Das et al. / Catalysis Communications 8 (2007) 535–538
537
Table 1 (continued) Entry f
Substrate
Product
CHO
CH 3
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
95 93
[3] [3]
i ii
6.5 6.0
92 92
[3] [3]
i ii
6.5 6.0
94 92
[3] [3]
i ii
6.5 6.0
93 90
[3] [3]
i ii
6.5 6.0
95 94
[3] [3]
i ii
6.5 6.0
98 95
[3] [3]
i ii
6.5 6.0
95 95
[3] [3]
O
CH 3 O g
CHO NO2 O
NO2 O
O h
CHO
NO2 O
O
NO2 O i
NO2
CHO
O
O
NO2 O CHO
j
H3C
N
CH3
O H3C
N
O
CH3 O
k
CHO
OH
O
O
OH O l
OCH3
CHO
O
O
OCH3 O (continued on next page)
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B. Das et al. / Catalysis Communications 8 (2007) 535–538
Table 1 (continued) Entry
Substrate
m
Product
CHO
OH OCH3 OCH3
O
Catalysta
Time (h)
Isolated yield (%)
Reference
i ii
6.5 6.0
93 95
[3] [3]
i ii
6.5 6.0
90 92
[3] [3]
i ii
6.5 6.0
93 92
[3] [3]
O
OH O n
O CH2 O
CHO
O
O
O
O CH2
O o
H
C
C
H
H O
C
C H O
CHO
O a b
Catalyst (i) NaHSO4 Æ SiO2; (ii) silica chloride. The structures of the products were settled from their physical and spectral (IR, 1H NMR and MS) data.
Acknowledgements The authors thank CSIR and UGC, New Delhi for financial assistance. References [1] (a) K.V.N.S. Srinivas, B. Das, J. Org. Chem. 68 (2003) 1165; (b) C. Ramesh, N. Ravindranath, B. Das, J. Org. Chem. 68 (2003) 7101; (c) B. Das, G. Mahender, V.S. Kumar, N. Chowdhury, Tetrahedron Lett. 45 (2004) 6709; (d) B. Das, J. Banerjee, N. Ravindranath, Tetrahedron 60 (2004) 8357; (e) B. Das, V.S. Reddy, M.R. Reddy, Tetrahedron Lett. 45 (2004) 17. [2] Experimental procedure: To a solution of an aromatic aldehyde (1 mmol) and 5,5-dimethyl-1,3-cyclohexanedione (2 mmol) in CH3CN (10 ml), NaHSO4 Æ SiO2 or silica chloride (100 mg) was added. The mixture was refluxed for 6.5 h (with first catalyst) or 6.0 h (with second catalyst). The progress of the reaction was monitored by thin layer chromatography. After completion of the reaction, the mixture was filtered, the filtrate was concentrated and the residue was purified by
column chromatography over silica gel using EtOAc: hexane (2:3) as eluent to obtain pure 1,8-dioxo-octahydroxanthene derivative. All the products are known compounds (references in Table 1) and were characterized from their spectroscopic (1H NMR and MS) properties. The spectral data of some representative compounds are given below. Compound (3f); 3,3,6,6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxooctahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.12 (2H, d, J = 8.0 Hz), 6.96 (2H, d, J = 8.0 Hz), 4.62 (1H, s), 2.42 (3H, s), 2.24 (4H, s), 2.18 (4H, dd, J = 2.4, 1.6 Hz), 1.13 (6H, s), 1.00 (6H, s). EIMS: m/z 364 (M+), 349, 273, 217. Compound (3m); 3,3,6,6-Tetramethyl-9-(4hydroxy-3-methoxyphenyl)-1,8-dioxo-octahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.02 (1H, d, J = 2.0 Hz), 6.73 (1H, d, J = 8.0 Hz), 6.48 (1H, dd, J = 8.0, 2.0 Hz), 4.61 (1H, s), 3.96 (3H, s), 2.45 (4H, s), 2.24 (4H, d, J = 3.5 Hz), 1.17 (6H, s), 1.05 (6H, s). EIMS: m/z 396 (M+), 371, 285, 229. Compound (3o); 3,3,6,6,-Tetramethyl-9-(2phenyl-ethylene)-1,8-dioxo-octahydroxanthene: 1H NMR (200 MHz, CDC13): d 7.28–7.02 (5H, m), 6.27–6.21 (2H, m), 4.35 (1H, d, J = 7.0 Hz), 2.42 (4H, s), 2.27 (4H, s) 1.11 (12H, s). EIMS: m/z 376 (M+), 358, 291, 282, 225. [3] T.-S. Jin, J.-S. Zhang, J.-C. Wiao, A.-Q. Wang, T.-S. Li, Synlett 866 (2004), and references cited therein. [4] (a) G.W. Breton, J. Org. Chem. 62 (1997) 8952; (b) H. Firouzabadi, N. Iranpoor, H. Hazarkhani, Tetrahedron Lett. 43 (2002) 7139.