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Synthesis of 9,10-dihydro-9,10-ethanoanthracene-11,12-trans-dicarboxylic acid diethyl ester |
| Reaction type: | cycloaddition, Diels-Alder reaction |
| Substance classes: | alkene, aromatics, carboxylic acid ester, diene, dienophile, acid catalyst |
| Techniques: | working with moisture exclusion, heating under reflux, stirring with magnetic stir bar, filtering, evaporating with rotary evaporator, recrystallizing, use of an ice cooling bath, heating with oil bath |
Operating scheme |
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Equipment |
 | three-necked flask 100 mL |  | adapter with ground-glass joint and hose coupling | |
 | protective gas piping |  | reflux condenser | |
 | drying tube |  | bubble counter | |
 | powder funnel |  | heatable magnetic stirrer with magnetic stir bar | |
 | rotary evaporator |  | ice bath | |
 | exsiccator with drying agent |  | oil bath |
| 1H-NMR: 9,10-Dihydro-9,10-ethanoanthracene-11,12-trans-dicarboxylic acid diethyl ester | |||
| 250 MHz, CDCl3 | |||
| delta [ppm] | mult. | atoms | assignment |
| 1.23 | t (3J = 7.2 Hz) | 6 H | CH3 ethyl |
| 3.45 | m | 2 H | 11-H, 12-H (-CH-COO-) |
| 4.08 | m | 4 H | CH2 ethyl |
| 4.75 | m | 2 H | 9-H, 10-H |
| 7.09-7.38 | m | 8 H | CH (arom.) |
| >7.4 | CH (arom., educt) | ||
| 13C-NMR: 9,10-Dihydro-9,10-ethanoanthracene-11,12-trans-dicarboxylic acid diethyl ester | |||
| 62.5 MHz, CDCl3 | |||
| delta [ppm] | assignment | ||
| 14.2 | CH3 (ethyl ester) | ||
| 46.7 | C9, C10 (CH) | ||
| 47.7 | C11, C12 (CH-COO) | ||
| 60.9 | CH2 (ethyl ester) | ||
| 123.8 | CH arom. | ||
| 124.5 | CH arom. | ||
| 126.2 | CH arom. | ||
| 126.3 | CH arom. | ||
| 140.3 | C quart. arom. | ||
| 142.0 | C quart. arom. | ||
| 172.3 | C(=O)O- | ||
| 76.5-77.5 | CDCl3 | ||
| IR: 9,10-Dihydro-9,10-ethanoanthracene-11,12-trans-dicarboxylic acid diethyl ester | |||
| [KBr, T%, cm-1] | |||
| [cm-1] | assignment | ||
| 3074, 3026 | arom. C-H valence | ||
| 2981 | aliph. C-H valence | ||
| 2935, 2897 | aliph. C-H valence | ||
| 1739 | C=O valence, ester | ||
| 1467 | arom. C=C valence | ||
Instruction (batch scale 100 mmol)
Equipment
1000 mL three-neck flask, adapter with ground glass joint and hose coupling, protective gas
supply, reflux condenser, drying tube, bubble counter, powder funnel, heatable magnetic
stirrer, magnetic stir bar, rotary evaporator , ice bath, desiccator, oil bath
Substances
anthracene (mp 215-217 °C9 17.8 g (100 mmol)
fumaric acid diethyl ester (bp 219 °C) 17.2 g (16.4 mL, 100 mmol)
aluminium chloride (water free) 13.3 g (100 mmol)
cyclohexane (water free) (bp 81 °C) 500 mL
cyclohexane (bp 81 °C) 200 mL
sodium carbonate decahydrate 24.9 g (150 mmol)
sodium carbonate (water free) 25.0 g (236 mmol)
ethanol (bp 78 °C) 150 mL
Reaction
The reaction apparatus consists of a thoroughly dried 1000 mL three-neck flask with reflux
condenser, drying tube and magnetic stir bar. On one opening of the flask is placed an adapter
with ground glass joint and hose coupling as inlet for nitrogen. This adapter is replaced
through a glass stopper after the addition of aluminium chloride to the flask. The reaction
apparatus is flushed with nitrogen. Then under stirring 17.8 g (100 mmol) anthracene and
17.2 g (16.4 mL, 100 mmol) fumaric acid diethyl ester are dissolved in the flask in 500 mL
absolute cyclohexane. After cooling down in the ice bath 13.3 g (100 mmol) water-free
aluminium chloride are added in one portion over a powder funnel under nitrogen counter
flow. The reaction mixture is heated under stirring for four hours under reflux.
Work up
The reaction mixture is cooled down to room temperature, then 24.9 g (150 mmol) sodium
carbonate decahydrate are added. The drying tube is replaced through a bubble counter filled
with paraffin oil and the mixture is stirred until no more gas is formed. Then 25 g (236 mmol)
sodium carbonate (water free) are added. The mixture is stirred for 10 minutes. The solid is
filtered off and washed in portions with a total of 200 mL cyclohexane. The solvent is
evaporated from the filtrate at a rotary evaporator. A solid residue remains as crude product,
which is dried in the desiccator. Crude yield: 32.6 g
The crude product is recrystallized from about 150 mL ethanol.
Yield: 30.8 g (87.9 mmol, 88%); colourless crystals, mp 103 °C
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