DE2429248A1 - FURANDERIVATES AND PROCESS FOR THEIR PRODUCTION - Google Patents

Description

Dipl .-! Hg..E zeal Dipl.-Ing. K. Schieschke 8Müncheri 40, Elissbethstrasse 34

Aktieselskabet Grindstedvaerket 53, Jens Baggesens vej Srhus / DENMARK

Furan derivatives and processes for their preparation

The invention relates to new 2,5-furan derivatives and their Manufacturing and intermediates in manufacturing.

The new furan derivatives according to the invention are by the the following formula is shown:

.CH -CH-

. R.

R _{1 is} a lower alkyl group or a group of the formula

ROOC- (CH ₂ ) _- represents where R is hydrogen or a lower one

4098Ö3 / 1351

2 3
Alkyl group means, R and R each represent hydrogen

2 3

represent or R and R together represent a further bond between the carbon atoms, R and R each Mean hydrogen, hydroxy or a lower alkyl group,

4 5
or R and R together represent an oxygen atom, and

R "represents a group -CH _{2 1} , in which η is an integer from 1 to 10.

The lower alkyl groups of the instant compounds are preferably those containing 1-4 carbon have atoms, d. H. Methyl, ethyl, propyl, isopropyl,

Butyl, isobutyl and tert-butyl. The group R is preferably a pentyl group.

The compounds according to the invention have valuable biological properties in connection with a relatively low toxicity. So they have a controlling effect on hormone production of the corpus luteum and are almost as effective in this regard as the prostaglandin PGF - / ^ ' but without showing any side effects.

The following reaction schemes illustrate the preparation of the connections according to the invention:

40 ^ 883/135

CHO + C ₅ H ₁₁ COCH ₃ NaOH

HO-C- (CHp)

Il

I I

.CH = CHCOC ₅ H ₁₁ BF ₃ (C ₂ H ₅ ) _{2 O}

II

.CH = CHCOC ₅ H ₁₁

III

+ CH, (CH ₉ ) - C-CH ₉ -P (OCHo), III

II + C ₂ H ₅ OH

0

ff ti N t ~ \

C ₂ H ₅ OC- (CH ₂

NaBH,

-CH = CH ₂ COC ₅ H ₁₁

IV

.CH = CH ₂ CHOHC ₅ H ₁₁

IVa

Raney-CU

C ₂ H ₅ OC- (CH ₂

LcH ₉ CH ₉ COCcH ₁ NaBH.

I I

VI

409883/1351

X ₂ CO

It

'J

Via

K ₉ CO

HO-C- (CH

VII

CH ₃ -P Jj-CHO + C ₅ H ₁₁ COCH ₃ VIII

I I

_ CH = CH-COC ₁ -H, _Ί

5

IX

I I

.CH = CH-CHOHC ₁ -H

11

VII TMCS, HMDS

CH

1. CH ₃ MgBr

2. H ₃ O ⁺

XII CH ₃ -C-OH

CH ₃ OH - BF ₃

^ CH ₃ OC (CH ₂ ) ₇ _JTJL (CH ₃ ) ₂ -

0 ir-r-r-r

CH-I ³

P -

XIII

409883/1351

-C ₂ H ₅

cho

-CH (CH ₃ ) ₂

XIV
XV

,OH

R ⁷ J I I R ⁷ : i ~ -CH = CHCOC ₅ H -CH ₃ -C ₂ H ₅ • .XVI -CH XVII XVIII

H ₂ , Raney Ni
"a R ⁷ J ί N) '
R ⁷ : -CH ₃ -C ₂ H ₅

-CH (CH ₃ ) ₂

XXI

NaBH

R ⁷ :

-CH,

-C ₂ H ₅

-CH (CH ₃ ) ₂ XXII XXIII XXIV

409883 / 13S1

The starting materials for the preparation of the compounds according to the invention are furan derivatives of the formula

.CHO

wherein R is as previously defined, those from known compounds of the formula

for example produced by formylation according to Vilsmeyer can be.

The starting aldehydes are condensed with the appropriate alkan-2-one, for example 2-heptanone, or a 2-oxoalkylphosphonic acid dimethyl ester, to form a 3-oxy-1-alkenyl group at the 5-position of the furan ring and hydrogenate if desired catalytically removes the double bond in the 1-position of the side chain and reduces the keto group with sodium borohydride or subjects the keto group to one Grignardation using alkyl magnesium halide as the Grignard reagent.

If R denotes the group ROOC- (CH ₂ ) ₇ ~, where R is hydrogen, the carboxyl group can then be esterified, whereby esters according to the invention are obtained, or if the compound obtained is an ester, it can be saponified to give the corresponding acid to deliver.

The introduction of the side chain in the 5-position is preferably carried out at room temperature in solution in an alkanol, for example Methanol or ethanol.

409883 / 13S1

_ 7 -

Suitable catalysts for hydrogenation are Raney nickel, Raney copper and noble metal catalysts, for example

The following examples illustrate the preparation of the present Compounds, the various compounds being identified by the numbering in the reaction schemes above are identified.

example 1

8 * -15- (3-Oxo-i -octenyl) -2-furyl. 7 -octanoic acid (II)

(G 9.17, 0.0364 mol) by formylating furyl-2-octanoic acid prepared compound I is dissolved in 60 ml of methanol and the solution is cooled to -5 ⁰ C. 9.1 g of aqueous 20% sodium hydroxide are added all at once with stirring. To the resulting mixture was added 5.05 g (0.0444 mole) of 2-heptanone with stirring in the course of 10 minutes at a temperature of 18-20 ⁰ C to. The mixture is stirred for a further 1 hour at the same temperature and for a further 16 hours at room temperature. The reaction mixture is poured into 130 ml of water and adjusted to pH 7.2 with 3 η acetic acid (9.2 ml). The yellow crystals obtained are isolated by filtration and washed with 30 ml of water. The filtrate (F) is collected. The moist crystal cake is suspended in a mixture of 80 ml of water and 80 ml of ether and stirred. The emulsion obtained is neutralized to pH 7 with 3 η acetic acid. The ether layer is separated. The aqueous layer is extracted with 50 ml of ether. The combined ether extracts are washed with 50 ml of water and then dried over magnesium sulfate. The dried ether solution is evaporated on a water bath (60 ⁰ C) for closure to 15 mm Hg to dryness to obtain 6.21 g of crude compound II is obtained as a yellow oil which is solid at room temperature.

409.883 / 1351

The above filtrate (F) is stirred with 50 ml of ether and the pH of the emulsion is adjusted to 7 with 3 η acetic acid. The ether layer is separated and the aqueous layer is extracted with 50 ml of ether. The combined ether extracts are washed with 50 ml of water, dried over magnesium sulfate and the ether is ^{removed by distillation on a water bath (60 °} C.), finally below 15 mm Hg. Chromatography of the yellow, oily residue (5.30 g) on silica gel (150 g, 0.25-0.125 mm (60-120 mesh), BDH Chemical Ltd.) and eluting with increasing concentration of acetone in η-hexane gives 2, 20 g crude compound II.

The combined crude products are crystallized from 250 ml of η-hexane to give 7.45 g (61%) of compound II as pale yellow crystals of melting point 58 - 59 ⁰ C is obtained.

analysis
(334.4)

^C 20 ^H 30 ° 4 C. 8th 9 H 71 7th 9 , 0 ber .: 71 , 0 found :

Example 2

8- / 5- (3-Oxo-i-octenyl) -2-furyl7-octanoic acid methyl ester (III)

A. 2.52 g (0.00755 mol) of compound II, 30 ml of methanol and 0.24 g of ethyl ether boron trifluoride complex are stirred and refluxed for 1 hour. After cooling, the reaction mixture is poured into 150 ml of ice-water and extracted with two 80 ml portions of ether. The combined ether extracts are washed with 50 ml of cold 10% sodium carbonate and then with two 50 ml portions of cold water. The ether solution is evaporated and dried over magnesium sulfate, on a water bath (60 ⁰ C) and finally under 15 mm Hg to dryness. Distillation of the residual oil (2.46 g) under nitrogen yields 2.07 g (79%) of Compound III, _Q Kp _3202-204 C ^0, n £ ⁵ 1.5262.

409883/1351

analysis
(348.5) ^C 21 ^H 32 ° 4 ber .: C. 4th 9 H one OCH ^ found: 72, 5 9 , 3 S ₁ 72, , 2 8th, , 9 , 9-

B. 0.96 g (0.02 mol) of 50% sodium hydride in mineral oil are suspended in 200 ml of 1,2-dimethoxyethane. The slurry is cooled to 15 ° C and stirred vigorously with a mechanical stirrer. Is added dropwise in the course of 30 minutes 4.44 g (0.02 mol) of (2-oxoheptyl) -phosphorsäuredimethylester to, wherein the reaction temperature at 15 (Wadsworth et al .: JACS 8J3 (1961) 1733rd) - 20 ⁰ C holds. After the addition, the suspension of a white, voluminous precipitate is stirred for 1 hour at room temperature. A solution of 5.04 g (0.02 mol) of compound I in 30 ml of 1,2-dimethoxyethane was added over 30 minutes dropwise to the stirred suspension, wherein they are kept below 25 ⁰ C. The cloudy, yellow solution obtained is stirred at room temperature for 1.5 hours. The solvent (200 ml) is ^{distilled off from a water bath (70 °} C.) under reduced pressure (40 mm Hg). After cooling, the oily residue is diluted with 300 ml of cold water and extracted with two 200 ml portions of ether. The combined ether extracts are washed with two 100 ml portions of water and then dried over magnesium sulfate. The dried ether solution is finally evaporated on a water bath (60 ⁰ C) under 15 mm Hg to dryness. The yellow oil that remains is purified by distillation under nitrogen. Is obtained as 6.34 "g" (91% ■) Compound III as a yellow liquid, bp _Q, 194 -. 200 ⁰ C, n ^ ⁵ 1.5256. In thin-layer chromatography, it has the same R ^ values in different solvents as the compound obtained according to method A. ·

409883/1351

Example 3

8- / 5- (3-OXO-1-octenyl) -2-furyU-octanoic acid ethyl ester (IV)

A mixture of 9.94 g (0.0298 mol) of compound II, 190 ml of ethanol and 0.97 g of ethyl ether boron trifluoride complex is stirred and refluxed for 1.5 hours. After cooling, the reaction mixture is poured into 600 ml of ice-water and extracted with three 300 ml portions of ether. The combined ether extracts are washed with 100 ml of cold 10% sodium carbonate and then with two 200 ml portions of cold water. The ether solution is evaporated and dried over magnesium sulfate, on a water bath (60 ⁰ C), and finally at 15 mm Hg, to dryness. The residual yellow oil (9.84 g) is purified by distillation under nitrogen from a coated piston potassium acetate to give 8.57 g (79%) of Compound IV, bp _no 198-201 ⁰ C, n ^ 1.5217, receives.

analysis Example 4 C ₂₂ I. I. H ^OC 2 ^H 5 (362.5) 8- / 5- (3-oxooctyl) 9.5 12.4 C. 9.5. 12.3 ber .: 72, found: 73, Ethyl -2-furyl7-octanoate (V) ^ ₄ ⁰ . , 9 , 0

1.74 g (0.0048 mol) of compound IV, 25 ml of ethanol and 0.75 g of Raney-copper (Ponomarev et al., J. Gen. Chem. USSR 3J) (1960) 584) are 6 hours at 30 ⁰ C shaken under 80 atmospheres of hydrogen. After filtration, the ethanol is distilled off under reduced pressure from a water bath of (6O ⁰ C). 30 ml of ether are added to the residue and the cloudy solution is filtered (G4, Celite). The ether solution is evaporated on a water bath (50 ⁰ C) under reduced pressure, finally at 15 mm Hg, to dryness. The remaining oil is purified by distillation under nitrogen.

409883/1351

Are thus obtained 1.51 g (86%) of compound V in the form of an almost colorless oil, bp _{Q 2178-181} C ^0, n ^ ⁵ 1.4700.

analysis ber. Example 5 ^C 22 ^H 36 ° 4 1 H 0 OC 2 ^H 5 (364.5) found 1 O, 0 12th , 4 C. O, 12th , 4 : 72, 5 : 72, 3

Ethyl 8- / 5- (3-hydroxyoctyl) -2-f ury ^ -octanoate (VI)

Dissolve 1.25 g (0.00343 mol) of compound V in 70 mL of absolute ethanol and the solution is cooled to -5 ⁰ C. In the course of 3 minutes while stirring in portions 0.50 g (0.0132 mole) of sodium borohydride to. The cloudy solution is stirred for 15 minutes at 0 to 5 ° C. and then for 1 hour at room temperature. The colorless solution is poured into 250 ml of ice-water. 10 ml of 1.5 μm sodium hydroxide are added to the emulsion obtained with stirring. It is stirred for a further 15 minutes. The white emulsion is extracted with three 100 ml portions of ether. The combined ether extracts are washed with 100 ml of cold water, dried over magnesium sulfate, and the solvent is removed by distillation in a water bath (60 ° C.), below 15 mm Hg towards the end. Distillation of the remaining oil (1.34 g) gives 1.18 g (94%) of compound VI as a colorless oil, bp _Q 1172-175 ° C., n ^ ^{5 1.4731}

analysis ber. ^C 22 ^H 38 ° 4th 1 H 5 OC 2 ^H 5 (366.5) found C. 1 O, 5 12th , 3 : 72, 1 0, 12th , 4 72, 2

409883/1351

Example 6

8- / 5- (3-oxooctyl) -2-furylj-octanoic acid (VII)

A mixture of 5.10 g (0.014 mol) of compound V, 180 ml of methanol and 60 g of 20% strength potassium carbonate is stirred and heated under reflux for 1 hour. The cloudy solution is concentrated to a quarter of the volume by distillation on a water bath (60 ^° C.) under reduced pressure (60 mm Hg). The residue is diluted with 300 ml of water and the clear solution obtained is acidified to pH 6 with acetic acid. The emulsion is extracted with two 150 ml portions of ether. The combined ether extracts are washed with two 100 ml portions of water and then dried over magnesium sulfate. The ether is distilled off on a water bath (60 ^° C.), finally below 15 mm Hg. The yellow, oily residue, 4.62 g, solidifies at room temperature. Purification by crystallization from 40 ml of η-hexane gives 3.54 g (75%) of compound VII in the form of slightly yellowish crystals; Melting point 64 - 65 ⁰ C.

Analysis ^C 20 ^H 32 ^ 4
(336.5)

CH
calc .: 71.4 9.6

found: 71.2 9.6

Example 7

1- (S-methyl ^ -furyD-i-octen-S-ol (X)

The starting material, 1- (5-methyl-2-furyl) -1-octen-3-one (IX), which is known (Chem. Abstr. 74 (1971) 141, 418 g), is from Compound VIII (J. Org. Chem. 22. (1957) 1269) according to the in the literature (J.A.C.S. 2 £ (1948) 2695) given instructions manufactured.

1.65 g (0.008 mol) of compound IX are dissolved in 200 ml of absolute ethanol and the solution is cooled to 0.degree. With stirring, 0.70 g

A09883 / 1351

Sodium boronate (0.0185 mole) added all at once. The cloudy solution is stirred for 15 minutes at 0 to 5 ^° C. and then for 20 hours at room temperature. The solution is (50 mm Hg) by distillation on a water bath (4O ⁰ C) under reduced pressure to a quarter of the volume. The remaining solution is ^{cooled to 10 °} C. and then 800 ml of cold water and 25 ml of n-sodium hydroxide are added in succession with stirring. The mixture is stirred for a further 15 minutes at room temperature and the pH of the emulsion is then adjusted to 7.8 by adding 3 η acetic acid. The reaction mixture is extracted with two 150 ml portions of ether. The combined organic extracts are washed with 100 ml of water and dried over magnesium sulfate. The ether solution is evaporated on a water bath (60 ⁰ C) under reduced pressure, finally at 15 mm Hg to dryness. The remaining oil (1.67 g) is purified by distillation under nitrogen. This gives 1.13 g (68%) of compound 10 as a yellow liquid, bp _no 97-99 ° C, n * 1.5166.

U, ί D

Example 8

8-ΖΓ5- (3-hydroxyoctyl) -2-furyl7-octanoic acid (VIa)

A mixture of 2.73 g (0.00745 mol) of compound VI, 100 ml of methanol and 30 ml of 20% strength aqueous potassium carbonate solution is stirred and refluxed for 1 hour. The cloudy solution is (60 mm Hg) by distillation on a water bath (6O ⁰ C) under reduced pressure to a quarter of the volume. The residue is diluted with 100 ml of water and adjusted to pH 7 with 2.7 ml of acetic acid. The emulsion obtained is extracted with two 80 ml portions of ether. The combined ether extracts are washed with 100 ml of water and dried over magnesium sulfate. The ether is distilled off on a water bath (50 ^° C.), at the end below 15 mm Hg. The yellow oily residue (2.58 g) is purified by crystallization from 450 ml of petroleum ether (boiling point below 5O ⁰ C). Are thus obtained 2.13 g (84%) of Compound VIa in the form of almost white crystals with melting point 43-45 ⁰ C.

409883/135

analysis Example 9 ^C 20 ^H 34 ° 4 1 0 H (338.5) 1 0 ,1 C. ,1 ber. : 71, 0 found : 70, 8th

8- / 5- (3-Oxooctyl) -2-furyl-7-octanoic acid methyl ester

11.37 g (0.0326 mol) of compound III, 150 ml of methanol and 2.5 g of Raney nickel are stirred at room temperature under 1 atmosphere of hydrogen until one molar equivalent of hydrogen has reacted. After filtration, the solvent is removed by distillation on a water bath (60 ^° C.) under reduced pressure, finally under 15 mm Hg. The residual slightly yellow oil (11.4 g) is purified by preparative thin layer chromatography (tlc) on silica gel (mixture of petroleum ether (b.p. <"50 ⁰ C) and ether (2: 1) as eluant) to give.

7.25 g of the title compound are obtained as a yellowish oil. Further purification by distillation under nitrogen gives 7.05 g (62%) of the title compound as an almost colorless oil, bp _{0 07} 172-18O ⁰ C, n ^ ⁵ 1.4723.

Analysis C- ₁
(350.5)
I. Example 10 34 4
C. H OCH ₃ ber .: 72.0 9.8 8.8 found: 71.8 9.9 9.0 8- / 5- (3-Hydroxyoctyl) -2-furyl-7-octanoic acid methyl ester

1.61 g (0.0046 mole) of the ester from Example 9 is dissolved in 30 ml of methanol and 0.80 g (0.021 mol) of sodium borohydride are added at -10 ⁰ C under stirring. Stirring is continued for 90 minutes, with the temperature of the reaction mixture to 22-25 ⁰ C Toggle

409883/1351

increases. The solution obtained is poured into 200 ml of ice-water. Then 10 ml of 1.5 η aqueous sodium hydroxide solution are added and the emulsion is stirred for 15 minutes. The reaction mixture is extracted with three 100 ml portions of ether. The combined organic extracts are washed with two 100 ml portions of water and dried over magnesium sulfate. The ÄtherIosung is evaporated on a water bath (60 ⁰ C) under reduced pressure (15 mm Hg) to dryness. The remaining oil (1.59 g) is purified by distillation under nitrogen. 1.50 g (93%) of the title compound are obtained as a colorless oil, boiling point _176-178 ° C,

25 '

n ^ ^D 1.4759.

analysis ber. Example 11 ^C 21 ^H 36 ° 4 . .... H OCH ₃ (352.5) found , 6 10.3 8.8 C. , 7 10.5 8.7 : 71 : 71 -2-furyl7-octanoic acid 8-ΖΊ5- (3-hydroxyoctyl)

A mixture of 2.73 g (0.0077 mol) of the ester from Example 10, 100 ml of methanol and 30 ml of 20% strength potassium carbonate is stirred and refluxed for 1 hour. The colorless solution is concentrated by distillation to a water bath (6O ⁰ C), under reduced pressure (60 mm Hg) to a quarter of the initial volume. The residue is diluted with 100 ml of water and the cloudy solution obtained is acidified to pH 6 with acetic acid. The emulsion is extracted with two 100 ml portions of ether. The combined ether extracts are washed with two 100 ml portions of water and then dried over magnesium sulfate. The ether is on a water bath (6O ⁰ C), at the end of below 15 mm Hg, distilled off. The yellow oily residue (2.58 g) solidifies

409883/1351

at 10 ⁰ C. Purification by crystallization from 450 ml of petroleum ether (b.p. <50 ° C) yields 2.13 g (81%) of the title compound as white crystals with melting point 43 to 45 ° C.

analysis ber. ^C 20 ^H 34 ° 4 1 H 1 (338.5) found 1 O, 1 ■ c O, : 71, 0 : 70, 8th

Example 12

8-L5- Q-Hydroxy-S-methyloctyl) ^ - furylj-octanoic acid methyl ester (XIII)

4.50 g (0.0133 mol) of compound VII, 25 ml of pyridine, 7.2 ml of hexamethyldisilazane (HMDS) and 2.4 ml of trimethylsilyl chloride (TMCS) are mixed and the mixture is left to stand overnight, protected from moisture. The suspension is then filtered in a dry atmosphere, and the filtrate is ^{evaporated on a water bath (80 °} C.) under reduced pressure (10 mm Hg). The residue is mixed with 50 ml of dry ether and the mixture is filtered to remove a small amount of insoluble material. The filtrate is cooled to 2 ⁰ C in a dry nitrogen atmosphere and a 3.7 m ether solution of methylmagnesium bromide (7.8 mL, 0.0289 mol) is added with stirring over a period of 25 minutes at about 10 ⁰ C dropwise. The suspension obtained is stirred at room temperature overnight. It is then added to a mixture of 32 ml of n HCl and 120 ml of water, the temperature of which is 5 ° C., and the mixture obtained is stirred for 90 minutes. The ether layer is then separated off and the aqueous phase is extracted with 30 ml of ether. The combined ether extracts are extracted with 40 ml of 0.5 η aqueous sodium hydroxide. The aqueous extract is acidified with 42 ml of 0.5 η hydrochloric acid and extracted with two 25 ml portions of ether. The Ver-

409883/1351

agreed ether extracts are evaporated dried with magnesium sulfate and on a water bath "(7O ⁰ C), and finally at 15 mm Hg, to dryness. The residual crude acid XII (4.23-g) in a mixture of 50 ml of methanol and 0 , 5 ml of ethyl ether boron trifluoride complex, as described in Example 2, esterified to give the crude methyl ester XIII (4.2 g). This crude ester is purified by chromatography, using a column of silica gel and petroleum ether-ether (1: 1) as eluent, yielding 2.1 g of crude oil. distillation of this crude oil under nitrogen yields 1.83 g (37%) of compound XIII, Kp ₀ ^ _3178-180 ⁰ C, n ^ ⁵ 1, 4749,

analysis ^C 22 ^H 38 ° 4 10 H OCH ₃ (366.5) 10 , 5 8.5 C. , 4 8.6 ber .: 72 ,1 found .: 71 , 5.

The NMR spectrum is consistent with that assumed Structure for compound XIII.

Example 13

8-Zs- (3-hydroxy-3-methyloctyl) -2-furyl7-octanoic acid (XII)

A mixture of 0.91 g (0.0025 mol) of compound XIII, 10 ml of methanol, and 5 ml of 20% strength potassium carbonate is stirred and refluxed for 90 minutes. The clear yellow solution is mixed with 15 ml of water and acidified to pH 5 to 6 with acetic acid. The emulsion is extracted with two 15 ml portions of ether. The combined ether extracts are dried over magnesium sulfate. The ether is distilled off on a water bath (60 ^° C.), at the end below 0.1 mm Hg. The yellow, oily residue (0.86 g) is purified by chromatography on three 20 × 20 cm preparative thin-layer chromatography plates (Merck silica gel 60F ₂₅₄ ~ 2 mm layer) and the

409883/1351

therefrom insulated pipes compound XII is distilled at 175 to 185 ⁰ C and 0.03 mm Hg to give 0.63 g (71%) of Compound XII as a slightly yellowish oil, n ^ ⁵ 1.4844 receives.

Analysis C ber .: Example 14 21 ^H 36 ° 4 H (352.5) found: 10.3 C. 10.3 71.6 71.7 (XVII, XVIII) 1- (5-Alkyl-2-furyl) -octen-3-ones

(G 7.58, 0.0666 mol) to the stirred solution of 0.0666 mole of a 5-Alkylfuraldehyds and 9.3 ml, 2-heptanone in 25 ml of methanol are added over 10 minutes at 10 to 12 ⁰ C was added dropwise 1.8 ml of aqueous 20% sodium hydroxide. The clear yellow solution is stirred at the same temperature for 1 hour, then for 18 hours at room temperature. The pH of the mixture obtained is adjusted to 7 by adding acetic acid. The reaction mixture is poured into 100 ml of water and extracted with two 70 ml portions of ether. The combined organic extracts are washed with three 50 ml portions of water and dried over magnesium sulfate. The ether solution is evaporated on a water bath (70 ⁰ C) under reduced pressure, finally at 15 mm Hg to dryness. The remaining oil is purified by distillation below 10 mm Hg.

^RK Pi0 mm ⁿ D ^{5 Fp} * yield

⁰ C ⁰ C%

C ₂ H ₅ 166-174 41-64

CH (CH -.) - 174-182 1.5415 57

409883/1351

R formula found molecularly calculated

^C 14 ^H 20 ° 2 weight C. H 2 C. 2 9 H ^C 2 ^H 5 ^C 15 22 ^υ 2 220.3 76 , 3 9, 5 76 6th 9 , 2 CH (CH ₃ ) ₂ 15th 234.3 76 , 9 9, 76 , 4 example 1- (5-alkyl-2-furyl) -3-octanone (XIX - XXI)

0.03 mol of a 1- (5-alkyl-2-furyl) -1-octen-3-one, 150 ml

Methanol and Raney nickel (10 percent by weight of the olefin) are stirred at room temperature under 1 atmosphere of hydrogen until one molar equivalent of hydrogen has reacted. After filtration, the solvent is removed by distillation on a water bath (60 ^° C.) under reduced pressure, at the end, below 15 mm Hg. The slightly yellow oil that remains is purified by preparative thin-layer chromatography. Silica gel is used as the adsorbent and a mixture of ether and petroleum ether (bp <50 ° C.) (1: 8) as the developing solvent. The adsorbent is scraped off the glass plates and stirred with ether for 1 hour. After filtering, the solution is ^{evaporated to dryness on a water bath (60 °} C.) under reduced pressure, finally under 15 mm Hg. The remaining oil is purified by distillation under reduced pressure.

R Kp _1n n_ yield

Tu mm D

CH ₃ 140-142 1.4687 (2O ⁰ C) 71

C ₂ H ₅ 147-150 1.4675 86

CH (CH ₃ ) ₂ 158-159 1.4651 71

409883/1351

242S248

R. C ₁ formula Molecular
weight calculated
C- H 9.7 found
CH , 3 9, 8th CH ₃ C ₁ 3 ^H 20 ° 2 208, 75.0 10.0 74 , 5 10, 1 C ₂ H ₅ ^C 1 4 ^H 22 ° 2 222 75.6 10.2 75 ,1 10, 3 CH (CH ₃ ) ₂ 1 5 ^H 24 ° 2 236, 76.2 76 example ö £ 6th - XXIV) 5-alkyl , 3 -pentyl-2-furanpropanole (XXII , 3 , 3

0.015 mole of a 1- (5-alkyl-2-furyl) -3-octanons (XIX - XXI) are dissolved in 90 ml of ethanol and is added at -10 ⁰ C with stirring 2.40 g (0.064 mol) of sodium borohydride to. Stirring is continued for 90 minutes, the temperature of the reaction mixture rising to 23-25 ^{° C.} The colorless solution is poured into 300 ml of ice-water, then 20 ml of 1.5 η aqueous sodium hydroxide are added and the emulsion is stirred for 10 minutes. The reaction mixture is extracted with three 100 ml portions of ether. The combined organic extracts are washed with two 100 ml portions of water and dried over magnesium sulfate. The ether solution is evaporated on a water bath (60 ⁰ C) under reduced pressure at the end of under 15 mm Hg to dryness. The remaining oil is purified by distillation under reduced pressure.

25th

Kp

10 mm ⁰ C

yield
%

CH ₃
C ₂ H ₅

148-160 152-155 160

1.4744 (2O ⁰ C)

1.4725

1.4701

95
93 91

formula

Molecularly calculated found weight C HC H

CH ₃ ^C 1 2 3 ^H 22 ° 2 210 , 3 C ₂ H ₅ ^C 1 4 ^H 24 ° 2 224 , 3 CH (CH ₃ ) ^C 15 ^H 26 ° 2 238 , 4

409883/1351

74.2 10.5 74.1 10.5 75.0 10/8 74.8 10.7 75.6 11.0 75.4 11.2

Dip! - Ing. E. Eder Dipl -Inn. K. Sehechke

8 Munich 40, Elisübst.it ε-ße 34

Claims (8)

Claims wherein: R * represents a lower alkyl group or a group of the formula ROOC- (CH ₉ ) _Ί , wherein R represents hydrogen or a 2 3 is lower alkyl, R and R are each hydrogen 2 3
mean, or R and R together form a further bond 4 5 between the carbon atoms, R and R each represent hydrogen, hydroxy or a lower alkyl group 4 5
or R and R together represent an oxygen atom, and R represents a group -CH ₂ .., where η is an integer from 1 to 10. 2. Compounds according to claim 1, wherein R is an alkyl group having T to 4 carbonä
means n "-Penty! group. with T represents up to 4 carbon atoms and R represents the 3. Compounds according to claim 1, wherein R is the group HOOC- (CH ₂ ) r, - and R is the n-pentyl group, and their esters with alkanols of 1 to 4 carbon atoms. 4. Compounds according to claim 1, wherein R is methyl, 2 3 R and R together form another bond between the . Represent carbon atoms, R and R together represent oxygen and R has the meaning n-pentyl. 5. Compounds according to claim 1, wherein R is methyl, 2 3 ■ R and R another bond between the carbon 409883/1351 4 5 represent atoms, R is hydrogen, R is hydroxy and R is n-pentyl. 6. Compounds according to claim 1, wherein R is methyl 2 3 4 5 tet, R and R represent hydrogen, R and R together Mean oxygen and R has the meaning n-pentyl. 7. Compounds according to claim 1, wherein R is the group 2 3
HOOC- (CH ₀ ) - means, R and R represent another bond between the carbon atoms, R and R together stand for oxygen and R has the meaning n-pentyl, and their esters with alkanols of 1-4 carbon atoms. 8. Process for the preparation of the compounds according to Claims 1 to 7, characterized in that one compounds the general formula .CHO worxn R _{1 has} the meanings given in claim 1, condensed with the appropriate alkan-2-one or a 2-oxoalkyl- phosphoric acid ester, a 3-oxy-1-alkenyl group being formed at the 5-position of the furan ring, and optionally the in The double bond in the 1-position of the side chain is catalytically hydrogenated, the keto group is reduced with sodium borohydride or the keto group is subjected to Grignardation using an alkyl magnesium halide as a Grignard reagent. Patent attorneys Dipl.-Ing. E Eder Dip! -hg. K. Schieschke 8 MQnchen 40, SisabeÖisfraße 3 4 409883/1351