Supporting Information File 1

Supporting Information File 1

for

A highly efficient green synthesis of 1, 8-dioxo-octahydroxanthenes

A. Ilangovan,a,* S. Malayappasamy,a S. Muralidharana and S. Maruthamuthub

aSchool of Chemistry, Bharathidasan University, Tiruchirappalli – 620024, India

b Corrosion Protection Division, Central Electro Chemical Research Institute, Karaikudi-630 006, India

*Corresponding author. Tel.: +91 9865436093; Fax: 04312407045 E-mail Address:

Experimental procedures and characterization data

Content

General experimental conditions / Page
General procedure A: Preparation of 2,2'-(arylmethylene)bis(3-
hydroxy-5,5- dimethyl-2-cyclohexene-1-one) / S2
General procedure B: Preparation of 3,3,6,6-Tetramethyl-9-aryl-
3,4,5,6,7,9-hexahydro-2H-xanthene-1,8-dione / S9

GENERAL EXPERIMENTAL CONDITIONS

All the commercial reagents and solvents were used without further purification unless otherwise stated. Melting points were recorded on GUNA478 melting point apparatus and are uncorrected. All yields reported are based on isolated compounds. TLC separations were carried out on silica gel plates with UV indicator from Aldrich; visualization was by UV fluorescence or by staining with iodine vapor. NMR spectra were recorded on FT-NMR Bruker 400MHz spectrometer as CDCl3 / DMSO solutions with TMS as internal reference.

For compounds already known in the literature Melting Point and 1H NMR values are given and compared with the spectral data already known and suitable references are also mentioned.

General Procedure A:

1. General Procedure for the Preparation of (3)

To asolution of an aldehyde (1mole) and 5,5-dimethyl-1,3-cyclohexanedione (2mole) SmCl3 was added and stirred at ambient temperature till the reaction was complete. The progress of the reaction was monitored by TLC (Silica gel, 9:1 Hexane:EtOAc).After completion of the reaction), filtered and driedto the product.The spectral data of 2,2’-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)derivatives 3a-3oare given below.

1.1. 2,2'-(phenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) (3a):

The reaction was carried out according to the general experimental procedure using benzaldehyde (100 mg, 0.0009 mole),5,5-dimethyl-1,3-cyclohexanedione (241 mg,0.0018mole) and SmCl3(24.2 mg, 10mol%)in water (1 mL) Conditions: room temperature, 20 minutes. The title compound 3awas obtained (341 mg, 97%) as asolid. The spectral data for the compound 3a was in agreement with the values already reported in the literature [1]. Mp: 186-188 0C.1H NMR (400 MHz, CDCl3):  1.10 (s, 6H, 2 x CH3), 1.23 (s, 6H, 2 x CH3), 2.17–2.48 (m, 8H,4 x CH2),5.54 (s, 1H, CH), 7.08–7.28 (m, 5H, Ar), 11.91 (s, 1H, OH).

1.2.2,2'-(2-nitrophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) (3b): The reaction was carried out according to the general experimental procedure using 2-nitrobenzaldehyde (100 mg, 0.0006mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013 mole), and SmCl3(16.9 mg, 10mol%)in water(1 mL). Conditions: room temperature in 30 minutes. The title compound 3bwas obtained (251 mg, 91%) as asolid. The spectral data for the compound 3b was in agreement with the values already reported in the literature[2] Mp: 244-246 0C. 1H NMR (400 MHz, CDCl3):  1.01 (s, 6H, 2 x CH3), 1.15 (s, 6H, 2 xCH3), 2.17–2.47 (m, 8H, 4 x CH2), 6.03 (s, 1H, CH), 7.23–7.55 (m, 4H, Ar), 11.58 (s, 1H, OH).

1.3. 2,2'-(3-nitrophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3c):The reaction was carried out according to the general experimental procedure using 3-nitrobenzaldehyde (100 mg,0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013 mole) and SmCl3(16.9 mg, 10mol%)in water (1 mL).Conditions: room temperature,

30 minutes. The title compound 3cwas obtained (251 mg, 91%) as a whitesolid. The spectral data for the compound 3c was in agreement with the values already reported in the literature [1].Mp:201-2030C.1H NMR (400 MHz, CDCl3):  1.05 (s, 6H, 2 x CH3), 1.20 (s, 6H, 2 x CH3), 2.24–2.45 (m, 8H, 4 x CH2), 5.47 (s, 1H, CH), 7.32–7.98 (m, 4H, Ar), 11.79 (s, 1H, OH).

1.4.2,2'-(4-nitrophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3d): The reaction was carried out according to the general experimental procedure using 4-nitrobenzaldehyde (100 mg, 0.0006mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013 mole) andSmCl3(16.9 mg, 10mol%)in water (1 mL).Conditions: room temperature,30 minutes. The title compound 3dwas obtained (251 mg, 91%) as asolid. The spectral data for the compound 3d was in agreement with the values already reported in the literature [1]. Mp: 194-1960C.1H NMR (400 MHz, CDCl3):  1.04 (s, 6H, 2 x CH3), 1.16 (s, 6H, 2 x CH3), 2.24–2.44 (m, 8H, 4 x CH2), 5.57 (s, 1H, CH), 7.03-7.51(m, 4H, Ar), 11.87 (s, 1H, OH).

1.5.2,2'-(2-bromophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3e):The reaction was carried out according to the general experimental procedure using 2-bromobenzaldehyde (100 mg, 0.0005 mole), 5,5-dimethyl-1,3-cyclohexanedione (138 mg, 0.0010 mole) andSmCl3(13.8 mg, 10mol%)in water (1 mL).Conditions: room temperature, 25 minutes. The title compound 3ewas obtained (241 mg, 97%) as asolid. The spectral data for the compound 3e was in agreement with the values already reported in the literature [3].

Mp: 238-2400C.1H NMR (400 MHz, CDCl3):  1.16 (s, 12H, 4 x CH3), 2.23–2.45 (m, 8H, 4 x CH2), 5.47 (s, 1H, CH),7.06(d, J = 10.4 Hz, 2H, Ar),8.03(d, J = 8.8 Hz, 2H, Ar), 11.73 (s, 1H, OH).

1.6. 2,2'-(2-chlorophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3f): The reaction was carried out according to the general experimental procedure using 2-chlorobenzaldehyde (100 mg, 0.0007mole), 5,5-dimethyl-1,3-cyclohexanedione (182 mg, 0.0014 mole) and SmCl3(18.3 mg, 10mol%)in water (1 mL).Conditions: room temperature, 20 minutes. The title compound 3f was obtained (276 mg, 95%) as a solid. The spectral data for the compound 3f was in agreement with the values already reported in the literature [1].

Mp: 200-2020C.1H NMR (400 MHz, CDCl3):  0.92 (s, 12H, 4 x CH3), 2.14 (s, 8H, 4 x CH2), 5.42 (s, 1H, CH), 6.85–7.15 (m, 4H, Ar).

1.7. 2,2'-(4-chlorophenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3g): The reaction was carried out according to the general experimental procedure using 4-chlorobenzaldehyde (100 mg, 0.0007mole), 5,5-dimethyl-1,3-cyclohexanedione (182 mg, 0.0014 mole) andSmCl3(18.3 mg, 10mol%)in water (1mL).Conditions: room temperature, 20 minutes. The title compound 3gwas obtained (276 mg, 95%) as asolid. The spectral data for the compound 3g was in agreement with the values already reported in the literature [1].

Mp: 142-1440C.1H NMR (400 MHz, CDCl3):  1.02 (s, 6H, 2 x CH3), 1.14 (s, 6H, 2 x CH3), 2.21–2.41 (m, 8H, 4 x CH2), 5.40 (s, 1H, CH),6.95 (d, J = 8.4 Hz, 2H, Ar),7.14 (d, J = 8.4 Hz, 2H, Ar), 11.80 (s, 1H, OH).

1.8. 2,2'-(4-methylphenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3h): The reaction was carried out according to the general experimental procedure using 4-methylbenzaldehyde (100 mg, 0.0008 mole), 5,5-dimethyl-1,3-cyclohexanedione (213 mg, 0.0014 mole) and SmCl3(21 mg, 10mol%)in water(1mL).Conditions: room temperature,30 minutes. The title compound 3hwas obtained (306 mg, 95%) as asolid. The spectral data for the compound 3h was in agreement with the values already reported in the literature [1].

Mp: 139-1410C.1H NMR (400 MHz, CDCl3):  1.02 (s, 6H, 2 x CH3), 1.15 (s, 6H, 2 x CH3), 2.22 (s, 3H, CH3), 2.25–2.40 (m, 8H, 4 x CH2), 5.42 (s, 1H, CH),6.91 (d, J = 8.0 Hz, 2H, Ar),7.19 (d, J = 8.0 Hz, 2H, Ar), 11.83 (s, 1H, OH).

1.9.2,2'-(4-methoxyphenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3i): The reaction was carried out according to the general experimental procedure using 4-methoxybenzaldehyde (100 mg, 0.0007 mole), 5,5-dimethyl-1,3-cyclohexanedione (188 mg, 0.0014 mole) andSmCl3(18.8 mg, 10mol%) in water(1 mL) .Conditions: room temperature, 30minutes.The title compound 3iwas obtained (242 mg, 82%) as asolid. The spectral data for the compound 3i was in agreement with the values already reported in the literature [1].

Mp: 146-148 0C.1H NMR (400 MHz, CDCl3):  1.02 (s, 6H, 2 x CH3), 1.15 (s, 6H, 2 x CH3), 2.21–2.40 (m, 8H, 4 x CH2), 3.70 (s, 3H, OCH3), 5.41 (s, 1H, CH),6.75 (d, J = 8.8 Hz, 2H, Ar),6.93 (d, J = 8.0 Hz, 2H, Ar), 11.84 (s, 1H, OH).

1.10.2,2'-(4-hydroxyphenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3j):The reaction was carried out according to the general experimental procedure using 4-hydroxybenzaldehyde (100 mg, 0.0008 mole), 5,5-dimethyl-1,3-cyclohexanedione (210 mg, 0.0016 mole) and SmCl3(21mg, 10mol%)in water (1 mL).Conditions: room temperature, 30 minutes. The title compound 3jwas obtained (281mg, 88%) as asolid. The spectral data for the compound 3j was in agreement with the values already reported in the literature [1].

Mp: 188-1900C.1H NMR (400 MHz, CDCl3):  1.02 (s, 6H, 2 x CH3), 1.49 (s, 6H, 2 x CH3), 2.21–2.40 (m, 8H, 4 x CH2), 5.39 (s, 1H, CH),6.64 (d, J = 8 Hz, 2H, Ar),6.84 (d, J = 8.4 Hz, 2H, Ar), 11.81 (s, 1H, OH).

1.11.2,2'-(4-hydroxy-3-methoxyphenylmethylene)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3k): The reaction was carried out according to the general experimental procedure using 4-hydroxy-3-methoxybenzaldehyde (100 mg, 0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (168 mg, 0.0013 mole) and SmCl3(16.8mg,10mol%)in water (1 mL).Conditions: room temperature,15 minutes. The title compound 3kwas obtained (259 mg, 94%) as asolid. The spectral data for the compound 3k was in agreement with the values already reported in the literature [1]. Mp:193-1950C.1H NMR (400 MHz, CDCl3):  1.03 (s, 6H, 2 x CH3), 1.16 (s, 6H, 2 x CH3), 2.22–2.39 (m, 8H, 4 x CH2), 3.69 (s, 3H, OCH3), 5.42 (s, 1H, CH), 6.49–6.74 (m, 3H, Ar), 11.90 (s, 1H, OH).

1.12.2,2'-(3,4-dimethoxyphenylmethylene)bis(3-hydroxy-5,5- dimethyl-2-cyclohexene-1-one)(3l):The reaction was carried out according to the general experimental procedure using 3,4-dimethoxybenzaldehyde (100 mg, 0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (154 mg,0.0012 mole) and SmCl3(15.4mg,10mol%) in water (1mL).Conditions: room temperature, 25 minutes. The title compound 3lwas obtained (242 mg, 96%) as asolid. The spectral data for the compound 3l was in agreement with the values already reported in the literature [1].Mp:178-1800C.1H NMR (400 MHz, CDCl3):  1.28 (s, 12H, 4 x CH3), 2.55(s, 8H, 4 x CH2), 3.85-3.92 (6H, 2 x OCH3), 6.06 (s, 1H, CH), 6.69–7.11 (m, 3H, Ar).

1.13. 2,2'-(3,4,5-trimethoxyphenylmethylene)bis(3-hydroxy-5,5- dimethyl-2-cyclohexene-1-one)(3m):The reaction was carried out according to the general experimental procedure using3,4,5-trimethoxybenzaldehyde(100mg,0.0005mole),5,5-dimethyl-1,3-cyclohexanedione(154 mg, 0.0012 mole) and SmCl3(13mg, 10mol%) in water (1 mL) .Conditions: room temperature, 15 minutes. The title compound 3mwas obtained (219 mg, 93%) as asolid. The spectral data for the compound 3m was in agreement with the values already reported in the literature [4]. Mp:203-2050C.1H NMR (400 MHz, CDCl3):  1.05 (s, 6H, 2 x CH3), 1.17 (s, 6H, 2 x CH3), 2.28–2.35 (m, 8H, 4 x CH2), 3.68 (s, 6H, 2 x OCH3),3.74 (s, 3H, OCH3),5.42 (s, 1H, CH), 6.27 (s, 2H, Ar), 11.96 (s, 1H, OH).

1.14. 2,2'-(furan-2-ylmethylene)bis(3-hydroxy-5,5- dimethyl-2-cyclohexene-1-one)(3n):

The reaction was carried out according to the general experimental procedure using 2-Furaldehyde (100 mg0.0014 mole), 5,5-dimethyl-1,3-cyclohexanedione (266 mg,0.0020mole) and SmCl3(26.7mg, 10mol%) in water(1 mL).Conditions: room temperature, 20 minutes.The title compound 3nwas obtained (351 mg, 93%) as asolid. The spectral data for the compound 3n was in agreement with the values already reported in the literature [3].

Mp: 139-1410C.1H NMR (400 MHz, CDCl3):  1.10 (d,J=30.8Hz,12H, 2 x CH3), 2.36 (s, 8H, 4 x CH2), 5.39 (s, 1H, CH), 5.95 (s, 1H, CH), 6.30 (s, 1H, CH), 7.26 (s, 1H, CH), 12.17 (s, 1H, OH).

1.15.2,2'-(3-phenylprop-2-ene-1,1-diyl)bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one)(3 o): The reaction was carried out according to the general experimental procedure using cinnamaldehyde(100mg,0.0007mole)5,5-dimethyl-1,3 cyclohexanedione(194mg,0.0015 mole) and SmCl3(19.4mg,10mol%) in water (1 mL).Conditions: room temperature, 25 minutes. The title compound 3owas obtained (289 mg, 96%) as asolid. The spectral data for the compound 3o was in agreement with the values already reported in the literature [5].

Mp: 213-2150C.1H NMR (400 MHz, CDCl3):  1.00 (s, 6H, 2 x CH3), 1.04 (s, 6H, 2 x CH3), 2.19–2.32 (m, 8H, 4 x CH2), 4.82 (s, 1H, CH),6.44 (dd, J=11.2Hz, 2H, =CH), 7.11-7.25 (m, 5H, Ar), 12.14 (s, 1H, OH).

General Procedure B:

2. General Procedure for the Preparation of 3,3,6,6-Tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-2H-xanthene-1,8-dione (4) :

To a solution of an aldehyde (1mole) and 5,5-dimethyl-1,3-cyclohexanedione (2mole) in 1200 Cand SmCl3(20mol%) was added and stirred at 1200C. The progress of the reaction was monitored by TLC (Silica gel, 7:3, Hexane:EtOAc), after completion of the reaction, it was cooled to room temperature and water (5mL) was added to the reaction mixture, solid separated was filtered washed with water (5 mL) and dried under vacuum to get the desired Xanthenedione derivative.

2.1.3,3,6,6-tetramethyl-9-phenyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione(4a):Thereaction was carried out according to the general experimental procedure using benzaldehyde(100mg,0.0009mole),5,5-dimethyl1,3-cyclohexanedione(241mg,0.0018 mole),SmCl3(48.4 mg, 20mol%).Conditions: 1200C, 9h. The title compound 4a was obtained (328 mg, 98%) as asolid. The spectral data for the compound 4a was in agreement with the values already reported in the literature [6]. Mp: 203-205 0C. 1H NMR (400 MHz, CDCl3): 0.98 (s, 6H, 2 x CH3), 1.10 (s, 6H, 2 x CH3),2.21 (q, J=12Hz, 4H, 2 x CH2), 2.46(s, 4H, 2 x CH2),4.74 (s, 1H, CH),7.09 (t,J=14.4Hz, 1H, Ar),7.23 (t,J=16Hz, 2H, Ar),7.27 (d,J=12Hz,2H, Ar).13C NMR: (CDCl3,100 MHz) δ: 27.33, 29.27, 31.83, 32.2, 40.87, 50.74, 115.67, 126.36, 128.04, 128.37, 144.08, 162.24, 196.37.

2.2.3,3,6,6-tetramethyl-9-(2-nitrophenyl)-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4b):

The reaction was carried out according to the general experimental procedure using 2-nitrobenzaldehyde (100 mg, 0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013 mole) and SmCl3(33.9 mg, 20mol%).Conditions: 1200C, 10 h. The title compound 4bwas obtained (260 mg, 98%) as asolid. The spectral data for the compound 4b was in agreement with the values already reported in the literature [6].Mp:246-248 0C. 1H NMR (400 MHz, CDCl3):  1.00 (s, 6H, 2 x CH3), 1.09 (s, 6H, 2 x CH3),2.20 (q,J=12.4Hz, 4H, 2 x CH2), 2.46(s, 4H, 2 x CH2),5.50 (s, 1H, CH),7.24 (d, J=5.6Hz, 2H, Ar), 7.37-7.45 (m, 2H, Ar),7.74 (d,J=8Hz, 1H, Ar).

2.3. 3,3,6,6-tetramethyl-9-(3-nitrophenyl)-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4c): The reaction was carried out according to the general experimental procedure using 3-nitrobenzaldehyde (100 mg, 0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013mole)andSmCl3 (33.9mg,20mol%).Conditions: 1200C, 10h.The title compound 4c was obtained (257 mg, 97%) as a solid. The spectral data for the compound 4c was in agreement with the values already reported in the literature [6].Mp: 171-173 0C. 1H NMR (400 MHz, CDCl3):  1.00 (s, 6H, 2 x CH3), 1.11 (s, 6H, 2 x CH3),2.27 (q, J=16.8Hz, 4H, 2 x CH2), 2.50(s, 4H, 2 x CH2), 4.83 (s, 1H, CH),7.42(t, J=16.6Hz,1H, Ar),7.83 (d, J=8Hz, 1H, Ar),8.00 (t, J=10.4Hz, 2H, Ar).13C NMR (CDCl3, 100 MHz) : δ 27.31, 29.20, 32.08, 32.26, 40.84, 50.62, 114.55, 121.69, 122.48, 128.8, 146.28, 148.33, 163.02, 196.4.

2.4. 3,3,6,6-tetramethyl-9-(4-nitrophenyl)-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4d):

The reaction was carried out according to the general experimental procedure using 4-nitrobenzaldehyde (100 mg,0.0006mole), 5,5-dimethyl-1,3-cyclohexanedione (170 mg, 0.0013 mole) and SmCl3(33.9 mg, 20mol%).Conditions: Conditions: 1200C, 12 h. The title compound 4dwas obtained (257 mg, 97%) as asolid. The spectral data for the compound 4d was in agreement with the values already reported in the literature [6].

Mp: 225-226 0C. 1H NMR (400 MHz, CDCl3): 0.99 (s, 6H, 2 x CH3), 1.11 (s, 6H, 2 x CH3),2.18 (q, J=19.6Hz,4H, 2 x CH2), 2.49 (s, 4H, 2 x CH2), 4.82 (s, 1H, CH),7.47 (d, J=5.2Hz, 2H, Ar), 8.10(d,J=4.8 Hz, 2H, Ar).13C NMR (CDCl3,100 MHz) : δ 27.27, 29.25, 32.23, 32.35, 40.84, 50.59, 114.54, 123.44, 129.35, 146.48, 151.49, 162.93, 196.26.

2.5. 9-(2-bromophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4e): The reaction was carried out according to the general experimental procedure using 2-bromobenzaldehyde (100 mg, 0.0054 mole), 5,5-dimethyl-1,3-cyclohexanedione (138 mg, 0.0010 mole) andSmCl3(27.7 mg,20mol%).Conditions: 1200C,8 h. The title compound 4e was obtained (230 mg, 98%) as a solid. The spectral data for the compound 4e was in agreement with the values already reported in the literature [4].Mp: 226-229 0C. 1H NMR (400 MHz, CDCl3):  1.01 (s, 6H, 2 x CH3),1.09 (s, 6H, 2 x CH3),2.19 (q, J=12.4Hz, 4H, 2 x CH2), 2.44 (s, 4H, 2 x CH2), 5.01 (s, 1H, CH),6.95 (t,J=6.4Hz, 1H, Ar), 7.18 (t,J=6.8Hz, 1H, Ar), 7.32 (s, 1H, Ar), 7.42 (d,J=7.2Hz, 1H,Ar).

2.6. 9-(2-chlorophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4f): The reaction was carried out according to the general experimental procedure using 2-chlorobenzaldehyde (100 mg, 0.0007 mole), 5,5-dimethyl-1,3-cyclohexanedione (182 mg, 0.0014mole) and SmCl3(36.6 mg, 20mol%). Conditions: 1200C, 8 h. The title compound 4f was obtained (272 mg, 98%) as a solid. The spectral data for the compound 4f was in agreement with the values already reported in the literature [6]. Mp: 230-232 0C. 1H NMR (400 MHz, CDCl3): 1.01 (s, 6H, 2 x CH3), 1.09 (s, 6H, 2 x CH3),2.20 (q, J=12Hz, 4H, 2 x CH2), 2.44 (s, 4H, 2 x CH2), 4.99 (s, 1H, CH),7.06 (t, J=7.6Hz, 1H, Ar), 7.16 (t, J=7.2Hz, 1H, Ar), 7.23 (d, J=8Hz, 1H, Ar),7.44 (d, J=7.2Hz, 1H, Ar). 13C NMR (CDCl3,100 MHz) :δ 27.36, 29.28, 32.02, 40.81, 50.69, 113.67, 126.33, 127.81, 130.16, 133.42, 162.97, 196.5.

2.7. 9-(4-chlorophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4g): The reaction was carried out according to the general experimental procedure using 4-chlorobenzaldehyde (100 mg, 0.0007 mole), 5,5-dimethyl-1,3-cyclohexanedione (182 mg, 0.0014mole) and SmCl3(36.6mg, 20mol%).Conditions: 120 0C, 9 h. The title compound 4g was obtained (269 mg, 97%) as a solid. The spectral data for the compound 4g was in agreement with the values already reported in the literature [6].Mp: 230-233 0C. 1H NMR (400 MHz, CDCl3): 0.98 (s, 6H, 2 x CH3), 1.10 (s, 6H, 2 x CH3),2.18 (q, J=13.6 Hz, 4H, 2 x CH2), 2.46 (s, 4H, 2 x CH2), 4.70 (s, 1H, CH),7.17–7.26 (m, 4H, Ar). 13C NMR (CDCl3,100 MHz) :δ 27.29, 29.28, 31.46, 32.20, 40.84, 50.69, 115.27, 128.22, 129.77, 132.03, 142.69, 162.41, 196.35.

2.8. 3,3,6,6-tetramethyl-9-p-tolyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4h):

The reaction was carried out according to the general experimental procedure using 4-methylbenzaldehyde (100 mg, 0.0008 mole), 5,5-dimethyl-1,3-cyclohexanedione (213 mg, 0.0014mole) andSmCl3(42.7 mg, 20mol%).Conditions: 1200C,8h. The title compound 4h was obtained (301 mg, 98%) as a solid. The spectral data for the compound 4h was in agreement with the values already reported in the literature [6].Mp: 212-214 0C. 1H NMR (400 MHz, CDCl3): 0.99 (s, 6H, 2 x CH3), 1.10 (s, 6H, 2 x CH3),2.20 (q, J=411.6Hz, H, 2 x CH2), 2.24 (s, 3H, CH3), 2.45 (s, 4H, 2 x CH2), 4.70 (s, 1H, CH),7.02 (d,J=8Hz, 2H, Ar),7.18 (d,J=8Hz, 2H, Ar).13C NMR (CDCl3,100 MHz) : δ 21.05, 27.38, 29.26, 31.43, 32.2, 40.88, 50.76, 115.77, 128.24, 128.79, 135.77, 141.19, 162.09, 196.43.

2.9.9-(4-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione(4i):Thereactionwascarriedoutaccordingtothegeneralexperimental procedureusing4-methoxybenzaldehyde(100mg,0.0007mole),5,5dimethyl-1,3cyclohexanedione (188 mg, 0.014mole) and SmCl3(37.7 mg, 20mol%).Conditions: 1200C, 10 h. The title compound 4i was obtained (274 mg, 97%) as a solid. The spectral data for the compound 4i was in agreement with the values already reported in the literature [7]. Mp:242-245 0C. 1H NMR (400 MHz, CDCl3): 0.99 (s, 6H, 2 x CH3), 1.09 (s, 6H, 2 x CH3),2.18 (q, J=10.8 Hz, 4H, 2 x CH2), 2.45 (s, 4H, 2 x CH2), 3.73 (s, 3H, OCH3),4.69 (s, 1H, CH),6.76 (d, J=8.8Hz, 2H, Ar),7.21 (d, J=8.8Hz, 2H, Ar).13C NMR (CDCl3,100 MHz) :δ 27.34, 29.27, 30.96, 32.2, 40.86, 50.76, 55.11, 113.46, 115.79, 129.3, 136.48, 157.94, 162.06, 196.5.

2.10.9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4j): The reaction was carried out according to the general experimental procedureusing4-hydroxybenzaldehyde(100mg,0.0008mole),5,5-dimethyl-1,3-cyclohexanedione (210 mg, 0.0016 mole) and SmCl3(42mg, 20mol%).Conditions:1200C,9 h. The title compound 4j was obtained (298 mg, 98%) as a solid. The spectral data for the compound 4j was in agreement with the values already reported in the literature [6].Mp: 244-246 0C. 1H NMR (400 MHz, CDCl3): 0.99 (s, 6H, 2 x CH3), 1.09 (s, 6H, 2 x CH3),2.21 (q, J=8.8Hz, 4H, 2 x CH2), 2.45 (s, 4H, 2 x CH2), 4.67 (s, 1H, CH),6.61 (d, J=8Hz, 2H, Ar),7.11(d, J=8Hz, 2H, Ar).13C NMR (CDCl3,100 MHz): δ 27.37, 29.19, 30.96, 32.26, 40.85, 50.76, 115.18, 115.85, 129.39, 135.83, 154.5, 162.34, 197.08.

2.11.9-(4-hydroxy-3-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione(4k): The reaction was carried out according to the general experimental procedure using 4-hydroxy-3-methoxybenzaldehyde (100 mg, 0.0006 mole), 5,5-dimethyl-1,3-cyclohexanedione (168 mg, 0.0013 mole) and SmCl3(33.7mg, 20mol%).Conditions: 1200C, 8 h. The title compound 4k was obtained (258 mg, 98%) as a solid. The spectral data for the compound 4k was in agreement with the values already reported in the literature [7].Mp: 224-225 0C. 1H NMR (400 MHz, CDCl3):  1.00 (s, 6H, 2 x CH3), 1.10 (s, 6H, 2 x CH3),2.20 (q, J=7.2Hz, 4H, 2 x CH2), 2.45 (s, 4H, 2 x CH2), 3.89 (s, 3H, OCH3),4.66 (s, 1H, CH),5.46 (s, 1H, OH),6.58 (d, J=8Hz,1H, Ar),6.74 (d, J=8Hz,1H, Ar), 7.00 (s, 1H, Ar).13C NMR (CDCl3, 100 MHz): δ 27.28, 29.31, 31.30, 32.20, 40.86, 50.77, 55.88, 112.26, 113.91, 115.81, 120.01, 136.46, 144, 145.87, 162.08.

2.12. 9-(3,4-dimethoxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (4l): The reaction was carried out according to the general experimental procedureusing3,4-dimethoxybenzaldehyde(100mg,0.0006mole) 5,5-dimethyl-1,3-cyclohexanedione (154 mg, 0.0012 mole) and SmCl3 (30.9mg, 20mol%).Conditions: 1200C, 9 h. The title compound 4l was obtained (233 mg, 97%) as a solid. The spectral data for the compound 4l was in agreement with the values already reported in the literature [8].Mp: 179-181 0C. 1H NMR (400 MHz, CDCl3):  1.00 (s, 6H, 2 x CH3),1.10 (s, 6H, 2 x CH3), 2.20 (q, J=7.6Hz, 4H, 2 x CH2), 2.46 (s, 4H, 2 x CH2),3.79 (s, 3H, OCH3),3.85 (s,3H, OCH3), 4.70 (s, 1H, CH),6.70–6.77 (m, 2H, Ar), 6.90 (s, 1H, Ar).13C NMR (CDCl3, 100 MHz) :δ 27.26, 29.34, 31.22, 32.19, 40.89, 50.75, 55.75, 55.88, 110.83, 112.29, 115.76, 120.11, 136.98, 147.46, 148.45, 162.11, 196.5.

2.13.3,3,6,6-tetramethyl-9-(3,4,5-trimethoxyphenyl)-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione(4m):The reaction was carried out according to the general experimental procedure using 3,4,5-trimethoxybenzaldehyde (100 mg, 0.0005 mole), 5,5-dimethyl-1,3-cyclohexanedione (154mg,0.0010mole) and SmCl3(26.1mg, 20mol%).Conditions: 1200C,10 h. The title compound 4m was obtained (222 mg, 98%) as a solid. The spectral data for the compound 4m was in agreement with the values already reported in the literature [6].Mp: 186-188 0C. 1H NMR (400 MHz, CDCl3):  1.03 (s, 6H, 2 x CH3), 1.11 (s, 6H, 2 x CH3), 2.23–2.24 (m, 8H, 4 x CH2),3.77 (s, 3H, OCH3), 3.80 (s, 6H, 2 x OCH3),4.71(s, 1H, CH), 6.51 (s, 2H, Ar).13C NMR (CDCl3, 100 MHz) : δ 27.19, 29.37, 31.8, 32.19, 40.9, 50.73, 56.09, 60.7, 105.7, 115.57, 136.55, 139.73, 152.79, 162.35, 196.52.

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