Desorption of HMS-DBU-CO2
Elemental analysis: C, 66.44; H, 5.62. Calculated for C10H10O3:
C, 67.41; H, 5.66.
HMS-DBU-CO2 (6.67 g) was taken on the weighing moisture
analyzer pa◦n. The sample was heated slowly at constant heating
rate of 5 C min-1, under air. Weight of the sample was
recorded over a period of time and loss in weight was calculated
accordingly.
2-Oxo-indan-1-carboxylic acid methyl ester. 1H NMR, d
(ppm), 3.72 (s, 3H), 7.24 (m, 2H), 7.20 (d, 1H), 7.5 (d, 1H),
3.512 (d, 2H), 4.54 (t, 1H). MS (EI) m/z (rel. intensity) 191.19.
Elemental analysis: C, 69.43; H, 5.21. Calculated for C11H10O3:
C, 69.47; H, 5.30.
Carboxylation reaction using HMS-DBU
Dimethyl 2-oxocyclohexane-1,3-dicarboxylate. 1H NMR, d
(ppm), 3.71 (s, 6H), 1.58 (t, 1H), 1.41 (t, 1H), 1.93 (dd, 2H),
1.74 (t, 1H), 1.80 (dd, 1H), 3.74 (dd, 1H), 3.63 (dd, 1H). MS
(EI) m/z (rel. intensity) 215.21. Elemental analysis: C, 56.05; H,
6.55. Calculated for C10H14O5: C, 56.07; H, 6.59.
Methyl
2-oxocyclohexanecarboxylate. Cyclohexanone
(0.5 g, 5 mmol) CH3I (0.35 mL, 5.6 mmol) and RCC (0.25 g)
were taken in a round-bottom flask and 35 mL methanol
was added into the flask while CO2 was bubbled through
the solution at room temperature. Progress of reaction was
monitored by recording IR spectra (by following –COOMe
group). After stirring the reaction for 4 h, the RCC was removed
by filtration. The filtrate was then concentrated under reduced
pressure. Purity of the isolated product was determined by
HPLC comparing with authentic sample of cyclohexanone and
2-carboxy cyclohexanone. 1H NMR, d (ppm) 3.71 (1, 3H), 1.60
(4, 1H), 1.82 (4, 1H), 1.41 (m, 1H) 1.6 (m, 1H), 2.44 (4 1H), 2.53
(m, 1H), 1.94 (4, 1H) 1.81 (4, 1H) 3.53 (m, 1H). MS (EI) m/z
(rel. intensity) 157.17, Elemental analysis: C, 61.34; H, 7.72.
Calculated for C8H12O3. C, 61.52; H, 7.74.
Ethyl 4-nitrobenzoylacetate. 1H NMR, d (ppm), 3.69 (s, 3H),
8.134 (d, 2H) 8.15 (d, 2H), 4.02 (s, 2H). MS (EI) m/z (rel.
intensity) 224.19. Elemental analysis: C, 53.80; H, 4.00; N, 6.30.
Calculated for C10H9O5: C, 53.82; H, 4.06; N, 6.28.
Reaction using HMS-DBU
Preparation of 1-methoxynapthelene. In a round bottomed
flask 0.5 g (0.039 mmol DBU) of HMS-DBU, 6.1 mg
(0.042 mmol) of 1-napthol and 10 mL dimethyl carbonate were
taken along with a magnetic stir bar and placed over oil bath.
The mixture was heated at 90 ◦C for 16 h. The yield of the
product was determined after analyzing the reaction mixture by
Methyl 2-acetyl-3-oxobutanoate. 1H NMR, d (ppm) 3.74 (1,
3H), 2.21 (m, 6H), 4.87 (m, 1H). MS (EI) m/z (rel. intensity)
159.16 (M+, 19). Elemental analysis: C, 53.0; H, 6.34. Calculated
for C7H10O4: C, 53.16; H, 6.37.
1
HPLC. Yield, 98%, H NMR, d (ppm) 1.26 (3H), 7.31 (1H),
7.6 (1H), 7.4 (1H), 7.1 (1H), 7.98 (1H), 7.5 (2H)). MS (EI) m/z
(rel. intensity) 159.11. Elemental analysis: C, 83.24; H, 6.31.
Calculated for C11H10O: C, 83.52; H, 6.37.
Ethylacetoacetate-2-carboxylic acid methylester. 1H NMR,
1
d (ppm) H NMR, 1.15 (1, 3H), 3.73 (2, 3H), 2.23 (3, 3H),
Preparation of 2-hydroxyphenylmethylacrylate (Baylis–
Hillman adduct of methyl acrylate and benzaldehyde). In a
round bottomed flask 0.05 g (0.0039 mmol DBU) of HMS-DBU,
3.5 mg (0.04 mmol) of methyl acrylate, 4.2 mg (0.04 mmol)
benzaldehyde were taken in 10 mL dichloromethane and
stirred for 24 h at room temperature under nitrogen. At end
of the reaction the mixture was acidified with aqueous HCl
(2 M, 20 mL) and separated the organic layer and dried over
anhydrous NaSO4. The mixture was concentrated using a rotary
evaporator below 50 ◦C and analyzed by HPLC. Yield, 72%. 1H
NMR, d (ppm) 5.9 (1H), 6.29 (1H), 3.71 (3H), 7.28 (1H), 7.4
(2H), 7.43 (2H), 6.01 (1H). MS (EI) m/z (rel. intensity) 193.15.
Elemental analysi: C, 68.24; H, 6.01. Calculated for C11H12O3:
C, 68.74; H, 6.29.
4.15 (m, 2H), 5.23 (m, 1H). MS (EI) m/z (rel. intensity) 189.18
(M+, 35). Elemental analysis: C, 51.02.; H, 6.32. Calculated for
C8H12O5: C, 51.06; H, 6.38.
1-Oxo-indan-2-carboxylic acid methyl ester. 1H NMR, d
1
(ppm) H NMR (CDCl3), 3.717 (s, 3H), 7.24 (dd, 1H), 7.20
(dd, 1H), 7.27 (dd, 1H), 7.50 (m, 1H), 3.512 (m, 1H), 3.51 (m,
1H), 4.54 (m, 1H). MS (EI) m/z (rel. intensity) 191.19. Elemental
analysis: C, 69.41; H, 5.34. Calculated for C11H10O3: C, 69.47;
H, 5.30.
Methylcyclopentanone-2-carboxylate. 1H NMR, d (ppm),
1H NMR 3.710 (1, 3H), 1.916 (m, 1H), 1.97 (4, 1H), 2.51 (m,
1H), 2.46 (m, 1H), 1.96 (m, 1H), 2.13 (m, 1H), 3.74 (m, 1H). MS
(EI) m/z (rel. intensity) 143.15. Elemental analysis: C, 59.12; H,
7.11. Calculated for C7H10O3: C, 59.14; H, 7.09.
Preparation of 2-oxocyclohexanecarboxylic acid
Methyl 4-chlorobenzoylacetate. 1H NMR, d (ppm), 3.69 (s,
3H), 7.523 (dd 2H), 7.847 (dd 2H), 3.86 (m 2H). MS (EI) m/z
(rel. intensity) 213.63. C 56.49, H 4.27, Cl 16.67. Elemental
analysis: C, 56.48; H, 4.28; Cl, 16.66. Calculated for C10H9O3Cl:
C, 56.49; H, 4.27; Cl, 16.67.
Cyclohexanone (0.5 g, 5 mmol) and RCC (0.25 g) were taken
in a round-bottom flask that was placed in a cold bath
maintaining temperature ~18–20 ◦C. 35 mL of methanol was
added into the flask while CO2 was bubbled through the solution
under constant stirring. Progress of reaction was monitored
by recording IR spectra (by following –COOH group). After
stirring the reaction for 4 h, the RCC was removed by filtration.
10 mL of ice cold water was then added into the mixture. A
white precipitate of the product settled at bottom which was
3-(4-Methoxyphenyl)-3-oxo-propionic acid methylester. 3.69
(s 3H), 3.794 (s, 3H), 7.054 (dd, 2H), 7.98 (d 2H), 3.82 (s, 2H).
MS (EI) m/z (rel. intensity) 209.21. Elemental analysis: C, 63.44;
H, 5.82. Calculated for C11H12O4: C, 63.45; H, 5.81.
1
then filtered and stored under dark and cold atmosphere. H
NMR, d (ppm) 1.810 (1H), 1.596 (2H), 1.405 (1H), 2.529 (1H),
2.434 (1H), 1.807 (1H), 1.947 (1H), 3.509 (1H). MS (EI) m/z
Methylbenzoylacetate. 1H NMR, d (ppm), 3.69 (s, 3H), 7.62
(t, 1H) 7.531 (dd 2H), 7.97 (dd, 2H), 3.87 (s, 2H). m/z 179.18.
382 | Green Chem., 2011, 13, 376–383
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The Royal Society of Chemistry 2011
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