DE2114219C3 - Process for the preparation of 2,3-dihydrofluoranthene from fluoranthene - Google Patents

Description

35

The formation of 2,3-dihydrofluoranthene (H) by metalation of fluoranthene (formula I) ^: n liquid ammonia (Birch reduction) is known. However, the intermediate II is immediately converted to resins and dimers. Only in one case was it possible to isolate II in substance, albeit in a very low yield (2%) (A. Streitwieser and S. S u ζ uki, Tetrahedron 1961, Vol. 16, pp. 153 to 168).

Thereby - after metallation of tetrahydro-fluorine anthen with ButylUthium in heptane under nitrogen - the reaction solution for one hour with oxygen gassed and then vigorously stirred with saturated aqueous sodium bisulfite solution. After peeling the organic phase is chromatographed (aluminum oxide), whereby an eluate is first obtained, das It, UV spectrography of a mixture of 2,3-dihydrofluoranthene and lOb-hydroxy-tetrahydrofluoranthene is then followed by further impure 1 Ob hydroxide eluted, which is dehydrated with hydrogen chloride in boiling glacial acetic acid. Man receives crude 2,3-dihydrofluoranthene, which is recrystallized by column chromatography together with the following is purified from ethanol.

According to another method, which is based on the above, the lOb-hydroxide and therefrom the compound II apparently obtained by treating tetrahydrofluoranthene-lithium with oxygen gassed and the reaction mixture acidified (C rombi e, Dean and Shaw, Chemistry and Industry 1970, 1469). The crude 1 Ob hydroxide is isolated. Sodium sulfite, which in Suzuki et al. to reduce the Intermediate formed hydroperoxide is explicitly seen, does not seem despite the analogy to have been used. There are no yield data. On the other hand, the authors recommend one allegedly improved method of the preparation of 10b-hydroxide or compound IL which in turn according to the gassing of a solution of tetrahydrofluoranthene and "Triton B" in pyridine provides for the addition of sodium bisulfite solution

R = H (1)

R = H (IUa). R = -NR- (111b).

R H

The object of the present invention was to provide a technically simpler process for the production of To find 2,3-Dihydrofluoranthene, in which the undesired resin formation and dimerization reaction can be suppressed and the yield is significantly increased

This is surprisingly achieved according to the invention by reacting fluoranthene in hydrocarbons at 100 protection to 14O ⁰ C under nitrogen, treated with sodium, then decomposes the reaction product with an excess of alcoholic acid and separating off the organic phase and optionally, the reaction mixture separates

In the metalation, preference is given to stoichiometric required amount of two equivalents of sodium metal is used

After decomposition with alcoholic acid and distillation in vacuo, a distillate (80%) is obtained which according to the gas chromatogram to 25% each of fluoranthene (I) and tetrahydrofluoranthene (formula IHa) and 50% of 2,3-dihydrofluoranthene (II) consists in a high vacuum, which has a lower bottom temperature permitted, the distillate consists of only 15% each of fluoranthene and tetrahydrofluoranthene and 70% from 2,3-dihydrofluoranthene.

To obtain pure dihydrofluoranthene from the mixture of the metalation reaction, one can use the add secondary amines such as piperidine, morpholine or pyrrolidine to the separated organic phase, with formation of adducts of the formula IHb taking place. The adducts which form in high yield can be isolate themselves by filtering off from the reaction mixture and deliver on thermal decomposition in the Vacuum (5 to 18 Torr) at temperatures between 80 and 130 ° or when heated with acid dihydrofluoranthene back in high yield. In another embodiment, one can use the one containing the adduct Reaction solution first with dilute inorganic

heat the insoluble components separate, liberate the adduct from the aqueous solution by adding alkali and then as above in base and decompose dihydrofluoranthene.

23-Dihydrofluoranthene claims interest Starting product for the production of pharmacologically interesting compounds, e.g. derivatives of j3-Phenyläthylamins, for which the adducts from IVp HIb are an example. Preferred embodiments of the invention are described in the following examples

example 1

200 parts of fluoranthene (I) are dissolved in 1000 parts of decalin and treated at 110 ⁰ C under vigorous stirring and nitrogen protection for 6 hrs with 50 parts of sodium Upon completion of metallation is cooled to 10 ⁰ C and decomposed with stirring under nitrogen protection by slow dropwise addition of a Mixture of 500 parts of ethanol and 120 parts of conc. Hydrochloric acid. It is then poured into 500 parts of water, the organic phase is separated off, dried with calcium chloride and decalin is distilled off in vacuo at 0.5 to 2 mm.

According to the gas chromatogram, the residue contains 80% (166 parts) of dihydrofluoranthene (II) and 10% (20 parts) each Fluoranthene (I) and tetrahydrofluoranthene (HIa).

After distillation at 140 to 150 ⁰ C under 0.01 Torr, the distillate to 15% each (30 parts) consisting of I and IIIa and 70% (140TeHe) from H.

R ': CsHio) from: 6.3 parts (88% dTh, m.p. 142-146 ⁰ C).
The analytically pure product melts at 1613 bis

Example 2

10 parts of the dihydrofluoranthene-rich organic phase according to Example 1, Paragraph 1 with 50% dihydrofluoranthene are ^{heated to 45 to 50 °} C. for 3 hours together with 15 parts of piperidine. The mixture is then allowed to cool and, after 3 days, almost colorless l-piperidino-1,2, 3,10b-tetrahydrofluoranthene (HIb, elemental analysis for C21H23N (289.42):
Calculated: C 87.15, H & 01, N 4.89%;
found: C 87.39, H 7.83, N 4.61%.

Breakdown of the piperidine adduct

a) thermal: 10 parts of l-piperidino-l ^ .lOb-tetrahydrofluoranthene are heated in vacuo (2 to 20 Torr) to 100 ° C for 5 hours, leaving 6.8 parts (97% of theory) pale yellow colored, oily Dihydrofluorasthens back, which crystallize on cooling, mp. 65 to 68 ⁰ C.

b) catalytic: 10 parts of l-piperidino-l ^ lOb-tetrahydrofluoranthene are heated in 100 parts of ethanol together with 1 part of 50% sulfuric acid under reflux for 5 hours then hot filtered and treated with two parts of distilled water at 70 to 75 ° C. On cooling, 5 parts are obtained (71% & th.) Dihydrofluoranthene from melting point 67 to 68.5 ° C

Example 3

10 parts of the dihydrofluoranthene-rich organic phase with 50% dihydrofluoranthene (see example 2) are converted into the adduct with 10 parts of piperidine - as in Example 2. The reaction mixture is then stirred vigorously with 50 parts of 25% strength sulfuric acid at 45 ° C. for 4 hours clear, acidic phase and this is mixed with 15 parts of 40% sodium hydroxide solution while stirring.

6.5 parts of l-piperidino-LÄS.lOb-tetrahydrofluoranthene are obtained (IHb, R ': C5H10), which are sucked off or centrifuged and according to Example 2a or 2b can be converted into pure dihydrofluoranthene.

Claims (4)

Patent claims: 1. Process for the preparation of 23-dihydrofluoranthene from fluoranthene, characterized in that fluoranthene is used in hydrocarbons Treated with sodium at 100 to 140 ° C under nitrogen protection, the reaction product then decomposed with an excess of alcoholic acid and the organic phase separated and optionally separating the reaction mixture 2. The method according to claim 1, characterized in that that the 23-dihydrofluoranthene-containing, separated and dried organisehe Phase distilled after removal of the solvent in a high vacuum 3. The method according to claim I _1, characterized in that the 2,3-dihydrofluoranthene-containing, separated organic phase is reacted with secondary amines and the formed and isolated adduct of 23-dihydrofluoranthene is decomposed at 80 to 130 "C and 5 to 18 Torr 4. The method according to claim 3, characterized in that one containing the adduct Reaction solution first with dilute inorganic acid heats the insoluble constituents is separated and the adduct is then released from the aqueous solution by adding alkalis is decomposed with strong acid at elevated temperature.