DE566693C - Process for the preparation of pyridine derivatives - Google Patents

Description

Process for the preparation of pyridine derivatives By the '336 patent 891 a process for the preparation of pyridine derivatives is protected. It exists in that one pyridine by the action of thionyl chloride to .f-Pyridvlpyridiniunidichlorid converts and optionally the latter by treatment with alkaline agents Converts agents to .1-aminopyridine.

The subject of the first additional patent 554 702 is a process in which 4-pyridylpyridinium chloride or its hydrochloric acid salt is caused by the action of water. Alcohols or phenols - optionally in the presence of acid-binding agents - are converted into d.-olivpyridine or its ether.

According to the second additional patent j63 32o, you can also use Thionvlbromid zti a -1-Pyridvlpyridinittmverbindungen arrive and this, how given above, decompose to 4-pyridine derivatives.

In further processing it has now been found that you can also get through The action of sulfur chloride or thione chloride in statu nascendi d.-pyridylpyridinium compounds gain and through the action of alkaline agents to .1-aminopyridines or through Action of water, alcohol or phenols, optionally with the addition of a acid-binding agent, to 4.-oxypyridine or its ethers. example Molecular amounts of pyridine and sulfur chloride are heated for a few hours the water bath or let stand for a few days at ordinary temperature. That The reaction product is then dissolved in water, the solution of sulfur and others insoluble by-products sucked off and in a vacuum with the addition of a few cubic centimeters dilute hydrochloric acid evaporated to dryness. The residue is then used for purification redissolved from alcohol or rubbed with a mixture of alcohol et al. You get so in good yield the d.-pyridylpyridiniutndichlorid with those described in the main patent Properties. It can be found in that described in the main patent and the additional patents Manner by the action of alkaline agents in-I aminopyridine or by the action of water, Convert alcohols or phenols into 4-OZ_vpyridiii or its ether.

For the production of 4-Oxvpyridins can also the above-mentioned solution obtainable when the reaction mixture is taken up immediately use.

For the preparation of the i-aminopyridine one can expediently proceed as follows that the reaction mixture is rubbed with a little ice-cold alcohol, filtered off with suction, with Carbon disulfide extracted and the extraction residue according to the main patent specified procedure further processed.

The conversion of the pyridine into the 4-pyridylpyridinium dichloride succeeds even when using more than r mole of chlorosulfur per z mole of pyridine and in the presence of indifferent solvents, such as B. benzene.

Example e 1319 phosphorus pentachloride is covered with a solution of 259 pyridine in 40o ccm benzene. Sulphurous acid is then passed into the mixture. After the reaction has ended, ie when a homogeneous solution has formed, the volatile constituents are removed by vacuum distillation; the solid residue is digested with ice-cold alcohol and filtered off with suction. The 4-pyridylpyridinium dichloride obtained in this way can be processed further as described in the main patent or its additional patents.

Claims (1)

PATENT CLAIM: Modification of patent 536 891 and its additional patents 554 7o-2 and 565 32o protected process for the preparation of pyridine derivatives, characterized in that here pyridine under the action of sulfur chloride or subjected to thionyl chloride in statu nascendi and the q.-pyridylpyridinium compound obtained thereby by the action of alkaline agents or by the action of water. Alcohols or Phenols, optionally with the addition of an acid-binding agent, to 4-pyridine derivative data is dismantled.