DE858551C - Process for the preparation of piperidine derivatives - Google Patents

Description

Process for the preparation of piperidine derivatives It has been found that piperidine derivatives are obtained if z, 5-dihalopentanes with at least equimolecular amounts of primary amines which contain a further alkylatable group contain, treated in the presence of hydrogen halide binding agents.

It is surprising that the halogen atoms of r, 5-dihalopentane and its substitution product2 are practically only associated with the primary. Amino group or react with one of two primary amino groups and not also with the other alkylatable group still present, after it is known that diamines, when treated with other haloalkylenes, give mixtures of different alkylation products which contain alkyl groups in b-ides alkylatable groups . The implementation proceeds according to the scheme where R is an optionally substituted alkyl, ary-1, aralkyl or cycloalkyl radical, Y is an alkylatable radical and the pentane chain can also contain further substituents. Examples of amines of the type used here are: aliphatic diamines, such as ethylenediamine, hexamethylenediamine, decamethylenediamine, the aliphatic chain also being interrupted by heteroatoms, as in diaminodiethyl ether; aromatic diamines such as p-phenylenediamine, tolylenediamine, diaminodiphenylmethane, methyl-m-phenylenediamine; Oxyamines, such as ethanolamine, aminophenols, aminonaphthols.

The reaction is highly exothermic and will after initial warming carried out with suitable cooling at the lowest possible temperature. Often is to achieve a better mixing and cooling effect the use of a Solvent advantageous. Used to bind the released hydrogen halide it is expedient to use an excess of amine or other hydrogen halide binding agents Agents such as alkali, alkaline earth oxide or a tertiary base.

In the case of the use of excess amine, the reaction product is by adding strong alkali and fractional distillation or crystallization won. It is useful here to remove the precipitated water after the water has been distilled off Separate the salt by suction. You can also add methanol or fuel bring the salt to the reaction product for separation before distillation.

The compounds that are very easily accessible by this method are partly new, partly so far only in a complicated way, starting from others Piperidine compounds. They are of the most diverse commercial Recyclable accessible and can z. B. as intermediate products for dyes, plastics, Find textile auxiliaries and pharmaceuticals use.

The parts mentioned in the examples are parts by weight.

EXAMPLE 1 232 parts of hexamethylenediamine are heated to 0 ° and 23o parts of 1,5-dibromopentane are slowly added dropwise with vigorous stirring. The temperature should not rise above g5 °. The mixture is stirred at 95 to 100 ° for 1 hour and the temperature is increased to 10 ° over the course of the next hour, then an equivalent amount of strong alkali lye is added and the water is distilled off under reduced pressure. The residue is separated off from the precipitated salt and distilled in vacuo. First the excess hexamethylenediamine passes over as a forerun, then the N- (6-aminohexyl) piperidine (bp 128 to 130 °, hydrochloride mp 208 °) as a colorless oil.

In addition, a very small amount of i, 6-dipiperidinohexane is obtained (Kplo Zoo up to 21o °, hydrochloride F. 263 °). Example 2 For a mixture initially taken from 232 parts of hexamethylenediamine, 246 parts of caustic potash and 300 parts of water 282 parts of i, 5-dichloropentane slowly flow in while stirring at 0 to 100 °. The mixture is then stirred for 3 hours at 100 to 100 ° and, after cooling to 60 °, left 150 parts Run in methanol and stir until it cools. The excreted by suction Removed potassium chloride and distilled the filtrate in vacuo. You get that in Example i, described N- (6-aminohexyl) piperidine.

Example 3 162 parts of p-phenylenediamine are suspended in 50 parts of toluene and 115 parts of i, 5-dibromopentane are added at 0 ° with stirring. The mixture is stirred at 95 to 100 ° for 2 hours. After cooling, the crystallized hydrochloric acid p-phenylenediamine and part of the excess, likewise crystallized p-phenylenediamine are suctioned off and the filtrate is distilled in vacuo.

The N- (p-aminophenyl) piperidine formed in good yield goes at bp 154 to 160 ° as a colorless oil, which after prolonged standing in the cold becomes large in the air browning crystals solidified with a temperature of 22 °.

Example 4 For a mixture initially introduced and heated to 60 ° 134 parts of ethanolamine and 45o parts of 50% potassium hydroxide solution are left under vigorous Stirring 46o parts of 1, 5-dibromopentane are added dropwise, immediately after the start of the dropping keep the temperature at 6o to 70 ° by intensive cooling and then slowly increases to ioo °. After cooling, the reaction product is mixed with 10000 parts of fuel diluted, filtered off with suction and the filtrate is distilled under reduced pressure. At Kp " 8o to 82 ° the N-oxyethylpiperidine goes over as a colorless liquid.

Claims (2)

PATENT CLAIMS: i. Process for the preparation of piperidine derivatives, characterized in that 1, 5-dihalopentanes or their substitution products are treated with at least equimolecular amounts of primary amines which contain a further alkylatable group, especially diamines or oxyamines, in the presence of hydrogen halide binding agents. 2. The method according to claim i, characterized in that that an excess of the applied as hydrogen halide binding agent primary amine used.