Evaluación de Impacto Ambiental

dark red and was stirred at 0°C for a further one hour then refluxed for one hour. The dark red solution was filtered hot and the

solution evaporated to dryness leaving a dark red residue identified by mass spectrometry as the required product.

Cyig + Fe(C0)5 + Me^NO ► C ^ F e t C O ^ + Me^N + CC>2 + CO

5.9.32) 1,5-PioxasPiro/ 4 » u n d e c a n e

Triethylor.thoformate (71.1g, 0.48 mole) was added at room temperature during five minutes to a solution of cycloheptanone (49.4g, 0.44 mole) and p-toluenesulphonic acid (0.19g, 1.1 mmole) in dry diethylene glycol (34*13g» 0.55 mole). The reaction mixture was heated on a steam bath and ethanol distilled from the mixture.

After four hours the reaction was complete and the mixture was

:z

cooled and dilute aqueous sodium hydroxide (4cm , 2M) added and stirred for five minutes. The mixture was extracted with

X

diethylether (2 x 100cm ) and the combined ether layer dried over anhydrous magnesium sulphate during sixteen hours. The filtered ether layer was reduced in volume by rotary evaporation and the residue distilled under vacuum, the required product boiling at

52-5°C/l.3mm Hg pressure, yield 44.4g, 0.28 mole (64.6%).

E tO \/O E t

+ CHOOEt EtO OEt

+ HOCH~CH~OH + 2 EtOH

5.9.33) 5«4-Cycloheptadienone

1,3-Dioxaspir0/ 4,6/undecane (31.24g, 0.2 mole) dissolved in absolute methanol (500cm^) was treated at 25°C whilst continuously stirred, with a small portion (100 drops) of bromine, giving a dark solution. On disappearance of the colouration the remainder was added (32.0g, 0.2 mole,in total) at a rate sufficient to maintain reaction, and leaving a slight excess on completion. The reaction mixture was heated to 40°C and treated again with bromine

(32.0g, 0.2 mole) as previously. On completion of addition the temperature was maintained for one hour then the reaction mixture was allowed to cool and stand during sixteen hours, at which time a small excess of bromine was still present as indicated by the colour. (An excess of bromine must be present throughout). The

X.

yellow reaction mixture was poured into stirred pentane (500cm ) containing anhydrous sodium carbonate (50g, 0.47 mole), with

effervescence, and stirred for five minutes. Following the addition

X

of water (500cm ), with stirring, the pentane layer was separated and dried over anhydrous magnesium sulphate^then filtered. The volume of the pentane layer was reduced by rotary evaporation at reduced pressure and the temperature raised gradually to 55°0 removing all solvent and resulting in a colourless oily pungent liquid. Freshly prepared sodium methoxide (38g, 1 mole) was added

X

to a stirred solution of the oil in dry dimethylsulphoxide (200cm ) whilst cooling to maintain the temperature below 60°C. After fifteen minutes the temperature of the reaction mixture was stable and

cooling was removed. The stirred mixture was allowed to stand for sixteen hours at room temperature. The reaction mixture was poured

X

into saturated brine (200cm ) and extracted with pentane. The whole mixture was filtered to remove flocculated sodium bromide which was washed on the filter with pentane. The combined liquors were

separated and the pentane layer dried over anhydrous magnesium sulphate for four hours. The filtered pentane solution was reduced in volume at atmospheric pressure and the oily product was then distilled under vacuum, boiling at 42°C/o.8mm Hg pressure. The distilled oil was split into 5g portions each of which was stirred at ambient temperature with aqueous sulphuric acid (lC^) for

sixteen hours. The mixtureswere extracted with pentane and the extracts were washed with aqueous sodium bicarbonate solution then dried over anhydrous magnesium sulphate. Evaporation of the

solvent from the combined extracts followed by vacuum distillation gave a colourless oil boiling at 60°C/6mm Hg pressure, yield 5g

{2j/o based on C^HgO). During sixteen hours the product darkened and resinified232 l/z Brv 0 Br OMe MeCT/DMSO 5.9.34) C.yclohexanonediethylene ketal

Cyclohexanone (40g, 0.41 mole), triethyl orthoformate (l85g, 4 mole) were refluxed together with p-toluene sulphonic acid (0.04g, 0.23 mmole) for ten minutes. The reaction mixture was cooled and then neutralised with potassium ethoxide (0.23 mmole). Fractionation under reduced pressure, removing excess alcohol and ethyl formate, allowed recovery of cyclohexanone diethylene ketal boiling at 60°C/9mm Hg pressure in high yield 67g, (9%) •

The diethylene ketal (l2g, 70 mmole) together with

and ethanol distilled from the mixture. On fractionation under reduced pressure a colourless oil boiling at 47-8°C/lOmm Hg pressure was recovered, yield J,6g (87%), and identified as 1-ethoxycyclohexene by 'H.N.M.R.

O

+ CH(OEt)3

EtO. .OEt

+ CHOOEt

EtO OEt OEt

H

4- EtOH

5-9-35) l-Ethoxy-7.7-dichloronorcarane

Ethyltrichloroacetate (126.4s* 0.66 mole) was added dropwise to a stirred slurry of sodium ethoxide (44.8g, 0.66m) and

1-ethoxycyclohex-l-ene (80g, 0.63 mole) in sodium dried pentane

3 o

(50cm ) at 0 C. A vigorous exothermic reaction ensued and after maintaining the reaction at 5°C for one hour after completion of addition the mixture was allowed to warm to room temperature

A

during sixteen hours. The reaction mixture was poured into water (200cm^), extracted with pentane (2 x 200cm^) and the combined extract dried over anhydrous magnesium sulphate. The filtered dry extract was reduced in volume and the residue distilled under vacuum (bpt 64°C, 1mm Hg) yielding 27.3g* 0.13 mole (21%) of the required product, identified by

OEt EtO Cl _Cl

6

5.9*36) 1-Ethoxycyclohepta-l.5.5-triene

l-Ethoxy-7>7-dichloronorcarane (27g, 0.129 mole) was heated

reaction mixture was then distilled giving a low yield of crude product, redistillation of which yielded lg, 7*3 mmole (5*7%). The product was identified by infrared spectroscopy and ^H.N.M.R.

5.9.37) 3.5-Cycloheptadienone

1-Ethoxycyclohepta-l,5»5-triene (lg, 7*3 mmole) was dissolved hydrochloric acid was added. The solution was warmed to reflux for ten minutes then cooled. The acidic solution was neutralised with pentane extract was dried over anhydrous magnesium sulphate then filtered. On evaporation to recover the required product,

decomposition was found to have occurred, neither product nor starting material being recoverable. Previous attempts at room temperature had resulted in recovery of the starting material.

■Z

under nitrogen atmosphere in dry, redistilled quinoline (100cm ) to l60°C for two hours, and then at 180°C for one hour. The viscous

Quinoline _{+ 2 HCI}

■z :z

in methanol (lOcm ) and water (2cm ) to which 1 drop of concentrated

sodium carbonate then extracted with pentane (3 x 10cm^). The

OEt O

+ EtOH

5.9.38) Tropolone methyl ether

A solution of diazomethane was prepared and reacted with tropolone as follows.

A solution of p-tolysulphonyl methyl nitrosamide (4.3g»

3 o

0.02 mole) in anhydrous diethylether (60cm ) was ice cooled to 0 C