Electronic Supporting Information (ESI)

Electronic Supporting Information (ESI)

Green and cost effective protocol for the synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines by using sawdust sulphonic acid

Shrikrishna Karhale1,2, Monika Patil1, Gajanan Rashinkar3, Vasant Helavi*1

1Department of Chemistry, Rajaram College, Kolhapur, Maharashtra, 416004, India.

2Abasaheb Marathe Arts & New Commerce, Science College, Rajapur, Ratnagiri, India.

3Department of Chemistry, Shivaji University, Kolhapur 416004, Maharashtra, India.

Address correspondence to Vasant B. Helavi, Department of Chemistry, Rajaram College, Kolhapur, 416004, M.S., India

E-mail:

Tel.: +91 231 2537840; fax: +91 231 2531989.

Experimental:

Dimedone (Thomas Baker), chlorosulphonic acid (Spectrochem), ammonium acetate (Thomas Baker) and aldehydes (Spectrochem and Thomas Baker) were used as received. Melting points were determined in an open capillary and are uncorrected. The NMR spectra were recorded on Bruker AC (300 MHz for 1H NMR and 75 MHz for 13C NMR) spectrometer using TMS as an internal standard in CDCl3. Chemical shifts (δ) are expressed in ppm. Solid state CP/MAS 13C-NMR spectrum was recorded on JEOL-ECX400 spectrometer under prescribed operating conditions. The Mass spectra were recorded on a Shimadzu QP2010 gas chromatograph mass spectrometer. The FT-IR spectra were measured on Bruker ALPHA FT-IR spectrometer in between the frequency range 500-4000 cm-1. The size and morphology of pristine sawdust and prepared catalyst were observed by using FE-SEM of MIRA3 TESCAN microscope with an accelerating voltage of 10 kV.

General procedure for synthesis of 1,8-dioxo-octahydroxanthenes:

A mixture dimedone (2 mmol), aromatic aldehyde (1 mmol) and sawdust sulphonic acid (0.05 g) was refluxed in ethanol (3 mL). After completion of reaction as indicated by thin layer chromatography (TLC), the reaction mixture was diluted with hot ethanol (5 mL) and filtered to remove the catalyst. After evaporation of solvent in vacuo, the crude product was recrystallized from ethanol to afford the desired 1,8-dioxo-octahydroxanthenes.

General procedure for synthesis of 1,8-dioxo-decahydroacridines:

To the well stirred mixture of benzaldehyde (1 mmol) and sawdust sulphonic acid (0.05 g) in ethanol (3 mL), dimedone (2 mmol) and NH4OAc (1.5 mmol) were added and the resultant reaction mixture was refluxed for appropriate time. After completion of reaction (monitored by TLC), the reaction mixture was diluted with hot ethanol (5 mL) and filtered to remove the catalyst. After evaporation of solvent in vacuo, the crude product was recrystallized from ethanol to afford corresponding 1,8-dioxo-decahydroacridines.

Spectral data of representative compounds:

3,3,6,6-Tetramethyl-9-phenyl-1,8-dioxo-octahydroxanthene (Table 3, entry 1):

Yield 88%, Mp. 200-202°C, (Mp. 201-203 °C)[1]; FT-IR (KBr) (cm-1): 3057, 2948, 1687, 1608, 1319, 1297, 1223, 1189, 962, 858, 783, 660, 609, 583, 555; 1H NMR (300 MHz, CDCl3): δ (ppm) 7.32 (d, J = 7.12 Hz, 2H), 7.24 (d, J = 7.19 Hz, 2H), 7.13 (s, 1H), 4.58 (s, 1H), 2.76 (s, 2H), 2.65 (s, 2H), 2.57 (s, 2H), 2.29 (s, 2H), 1.11 (s, 6H), 0.92 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 25.8, 27.3, 32.8, 32.2, 41.3, 51.7, 116.6, 127.4, 128.3, 145.1, 164.3, 195.2; MS(EI): m/z 350 [M+].

3,3,6,6-Tetramethyl-9-(4-cyanophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 2):

Yield 92%, Mp. 217-219 °C, (Mp. 217-218 °C)[1]; FT-IR (KBr) (cm-1): 3047, 2959, 2224, 1660, 1617, 1359, 1233, 1196, 1164, 934, 889, 858, 783, 660, 609, 583, 555; 1H NMR (300 MHz, CDCl3): δ (ppm) 7.53-7.55 (d, J = 8.4 Hz, 2H), 7.42-7.44 (d, J = 8.1 Hz, 2H), 4.79 (s, 1H), 2.49 (s, 4H), 2.24 (s, 2H), 2.20 (s, 2H), 1.13 (s, 6H), 1.00 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 27.3, 29.2, 32.2, 32.4, 40.8, 50.6, 110.2, 114.6, 119.1, 129.3, 131.9, 149.5, 162.9, 196.3; MS(EI): m/z 375 [M+].

3,3,6,6-Tetramethyl-9-(4-chlorophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 3):

Yield 81%, Mp. 230-233 °C, (Mp. 230-232 °C)[1]; FT-IR (KBr) (cm-1): 3064, 2960, 2929, 1664, 1595, 1380, 1166, 981, 844, 762, 611, 523; 1H NMR (300 MHz, CDCl3): δ (ppm) 7.38-7.23 (m, 4H), 4.73 (s, 1H), 2.44 (s, 4H), 2.26 (s, 4H), 1.11 (s, 6H), 0.96 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 27.2, 29.3, 32.3, 41.7, 51.6, 114.9, 129.6, 131.2, 133.4, 144.1, 164.8, 196.4; MS(EI): m/z 384 [M+].

3,3,6,6-Tetramethyl-9-(4-bromophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 4):

Yield 85%, Mp. 238-240 °C, (Mp. 240-242 °C)[1]; FT-IR (KBr) (cm-1): 3022, 2955, 1610, 1363, 1222, 978, 843, 742, 654, 533; 1H NMR (300 MHz, CDCl3): δ (ppm) 7.49-7.11 (m, 4H), 4.89 (s, 1H), 2.45 (s, 4H), 2.19 (d, 4H, J = 8.0 Hz), 1.17 (s, 6H), 1.01 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 27.3, 29.5, 32.1, 32.5, 42.2, 51.3, 112.7, 123.0, 125.3, 127.4, 132.0, 1421.2, 163.4, 196.7; MS(EI): m/z 429 [M+].

3,3,6,6-Tetramethyl-9-(4-nitrophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 5):

Yield 94%, Mp. 227-230 °C, (Mp. 228-230 °C)[1]; FT-IR (KBr) (cm-1): 3022, 2928, 1686, 1655, 1530, 1368, 1188, 1033, 855, 756, 633, 513; 1H NMR (300 MHz, CDCl3): δ (ppm) 8.11 (d, J = 8.4 Hz, 2H), 7.38 (d, J = 8.2 Hz, 2H), 4.85 (s, 1H), 2.88 (s, 4H), 2.33 (s, 4H), 1.14 (s, 6H), 0.98 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 27.4, 27.6, 29.5, 30.1, 43.6, 43.9, 51.8, 114.4, 115.7, 126.8, 128.3, 131.4, 133.1, 148.6, 164.8, 197.2; MS (EI): m/z 395 [M+].

3,3,6,6-Tetramethyl-9-(4-hydroxyphenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 6):

Yield 88%, Mp. 252-255 °C, (Mp. 250-251 °C)[2]; FT-IR (KBr) (cm-1): 3340, 3065, 2975, 1671, 1664, 1162, 1083, 987, 888, 774, 622, 534; 1H NMR (300 MHz, CDCl3): δ (ppm) 9.88 (bs, 1H), 7.14-7.31 (m, 4H), 4.67 (s, 1H), 2.44 (m, 4H), 2.22 (m, 4H), 1.11 (s, 6H), 0.93 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 21.6, 25.9, 28.3, 30.2, 33.3, 51.5, 57.4, 115.9, 128.4, 129.4, 134.6, 142.8, 164.5, 196.7; MS(EI): m/z 366 [M]+.

3,3,6,6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 7):

Yield 88%, Mp. 217-220 °C, (Mp. 219-221 °C)[1]; FT-IR (KBr) (cm-1): 3037, 2958, 2876, 1677, 1660, 1387, 1355, 1248, 1135, 1019, 997, 930, 886, 822, 775, 684, 655, 569, 518; 1H NMR (300 MHz, CDCl3): δ (ppm) 6.99-7.06 (m, 4H), 4.47 (s, 1H), 3.37 (s, 3H), 2.46-2.60 (m, 4H), 2.20-2.28 (m, 2H), 2.03-2.09 (m, 2H), 1.03 (s, 6H), 0.89 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 21.0, 26.9, 29.1, 31.2, 32.3, 50.5, 56.4, 114.9, 128.4, 128.9, 135.6, 141.8, 163.2, 196.5; MS(EI): m/z 364 [M+].

3,3,6,6-Tetramethyl-9-(2-nitrophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 10):

Yield 86%, Mp. 248-251 °C, (Mp. 249-250 °C)[3]; FT-IR (KBr) (cm-1): 3085, 2964, 1689, 1685, 1531, 1362, 1088, 885, 744, 673, 512; 1H NMR (300 MHz, CDCl3): δ (ppm) 8.08 (m, 1H), 7.58-7.44 (m, 3H), 4.78 (s, 1H), 2.82 (s, 4H), 2.44 (s, 4H), 1.12 (s, 6H), 0.97 (s, 6H); 13C NMR (75 MHz, CDCl3): δ (ppm) 27.5, 27.9, 30.6, 32.3, 44.9, 52.2, 115.6, 124.0, 126.7, 130.8, 131.9, 149.6, 162.4, 198.2; MS (EI): m/z 395 [M]+.

3,3,6,6-Tetramethyl-9-(2,5-dimethoxyphenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 11):

Yield 80%, Mp. 171-173 °C, (Mp. 172-174 °C)[4]; FT-IR (KBr) (cm-1): 2955, 2930, 1679, 1655, 1586, 1370, 1237, 1127, 1043, 823, 774, 750, 620, 608, 582; 1H NMR (300 MHz, CDCl3): δ (ppm) 6.79-6.82 (d, J = 9 Hz, 1H, Ar-H), 6.71-6.72 (d, J = 2.4 Hz, 1H, Ar-H), 6.58-6.59 (d, J = 3 Hz, 1H, Ar-H), 4.80 (s, 1H, CH), 3.77 (s, 3H, OCH3), 3.68 (s, 3H, OCH3), 2.31-2.39 (m, 8H, CH2), 1.17 (s, 3H, CH3), 1.10 (s, 3H, CH3), 1.06 (s, 3H, CH3), 0.93 (s, 3H, CH3); 13C NMR (75 MHz, CDCl3): δ (ppm) 26.3, 27.2, 29.4, 31.2, 32.8, 42.8, 46.7, 48.8, 50.8, 55.5, 111.4, 113.9, 116.3, 131.1, 150.9, 153.9, 166.9, 189.1, 196.2.

3,3,6,6-Tetramethyl-9-(phenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 1):

Yield 88%, Mp. 190-192 °C, (Mp. 190-191 °C)[5]; FT-IR (KBr) (cm-1): 3313, 3073 2939, 1632, 1595, 855, 749; Mp: 190-192°C, 1H NMR (400 MHz, CDCl3): δ (ppm) 11.75 (s, 1H, NH), 7.19-7.28 (m, 5H, Ar-H), 5.52 (s, 1H, CH), 2.36 (s, 8H, CH2), 1.13 (s, 12H, CH3).

3,3,6,6-Tetramethyl-9-(4-nitrophenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 5):

Yield 90%, Mp. 283-285 °C, (Mp. 284-286 °C)[5]; FT-IR (KBr) (cm-1): 3108, 2957, 2866, 1658, 1582, 850, 733, 587; 1H NMR (400 MHz, CDCl3): δ (ppm) 11.78 (s, 1H, NH), 8.12-8.14 (d, J = 8Hz, 2H, Ar-H), 7.23-7.26 (m, 2H, Ar-H), 5.54 (s, 1H, CH), 2.30-2.51 (m, 8H, CH2), 1.61 (s, 6H, CH3), 1.23 (s, 6H, CH3).

3,3,6,6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 7):

Yield 86%, Mp. <300 °C, (Mp. 300 °C)[6]; FT-IR (KBr) (cm-1): 3315, 2953, 2876, 1658, 1584, 811, 653; 1H NMR (400 MHz, CDCl3): δ (ppm) 11.93 (s, 1H, NH), 7.22-7.24 (d, J = 8 Hz, 1H, Ar-H), 7.08-7.10 (d, J = 8 Hz, 1H, Ar-H), 6.98-7.02 (m, 2H, Ar-H), 5.52 (s, 1H, CH), 2.21-2.45 (m, 8H, CH2), 2.19 (s, 3H, Ar-CH3), 1.25 (s, 6H, CH3), 1.09 (s, 6H, CH3).

3,3,6,6-Tetramethyl-9-(3,4,5-trimethoxyphenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 9):

Yield 81%, Mp. 260-262 °C, (Mp. 258-261 °C)[7]; FT-IR (KBr) (cm-1): 3376, 2987, 2948, 1640, 1601, 840, 708, 609; 1H NMR (400 MHz, CDCl3): δ (ppm) 12.01 (s, 1H, NH), 6.34-6.38 (m, 2H, Ar-H), 5.49 (s, 1H, CH), 3.80 (s, 9H, OCH3), 2.25-2.47 (m, 8H, CH2), 1.24 (s, 6H, CH3), 1.12 (s, 6H, CH3).

FT-IR, 1H-NMR, 13C-NMR and Mass Spectra of 3,3,6,6-Tetramethyl-9-(4-cyanophenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 2):

FT-IR, 1H-NMR, 13C-NMR and Mass Spectra of 3,3,6,6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 7):

FT-IR, 1H-NMR and 13C-NMR Spectra of 3,3,6,6-Tetramethyl-9-(2,5-dimethoxyphenyl)-1,8-dioxo-octahydroxanthene (Table 3, entry 11):

FT-IR, 1H-NMR and 13C-NMR Spectra of 3,3,6,6-Tetramethyl-9-(phenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 1):

FT-IR and 1H-NMR Spectra of 3, 3, 6, 6-Tetramethyl-9-(4-nitrophenyl)-1, 8-dioxo-decahydroacridine (Table 4, entry 5):

FT-IR and 1H-NMR Spectra of 3, 3, 6, 6-Tetramethyl-9-(4-methylphenyl)-1,8-dioxo-decahydroacridine (Table 4, entry 7):

FT-IR and 1H-NMR Spectra of 3,3,6,6-Tetramethyl-9-(3,4,5-trimethoxyphenyl)-1,8-dioxo-decahydroacridine (Table 3, entry 9):

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