DE75611C - Process for the preparation of D / 'acet-p-phenetidide - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

CLASS 12: Chemical apparatus and processes.

Process for the preparation of diacet- ρ-phenetidid. Patented in the German Empire by al. July 1893.

It is well known that the acid anilides - preferably the acetyl derivatives - have many excellent properties antipyretic effects. Diacetyl derivatives have not yet been investigated in this regard.

The inventors have now found that by introducing a second acetyl group into the monoacetamidophenol ethers, the antipyretic properties of the same are significantly increased. B. in the case of acetanilide - conversion into the diacetyl derivatives does not allow such an increase in the mode of action to be established, at least not to this extensive extent. For example, diacet-p-phenetidide is sufficient to produce the same effect, _{doses Y 4} lower than when using monoacet-p-phenetidide (phenacetin).

For the preparation of the diacet-p-phenetidids one proceeds in general in such a way that one Phenacetin at higher temperature (in open or closed vessels) with acetic anhydride or analogous acetylating agents and the crude product is treated with a suitable one Subjected to treatment with benzene and ligroin or similar solvents. Instead of The monoacetyl compound can of course also be used with p-phenetidine itself; in this In this case it is only necessary for a larger quantity of the acetylating agent to react allow.

Example 1.

ι Mol. Phenacetin is heated ^{to 200 0} with 4 Mol. Acetic anhydride for 8 to 10 hours in a closed vessel. The slightly brownish liquid obtained is freed from glacial acetic acid and excess anhydride by distilling the latter off in an oil bath heated to 180 °. The residue is poured into shallow dishes, mixed with approximately the same volume of benzene and left in the air for one night. The benzene evaporates and with it the last remains of the anhydride, which, if not removed, seem to make the subsequent crystallization more difficult. What remains is a viscous oil that sometimes solidifies almost completely voluntarily, usually only in a cold mixture. This solid crystalline mass is strongly pressed and boiled with a lot of ligroin (boiling point up to 100 °). It first melts under the ligroin to an oil, which then goes into solution, leaving behind small amounts of solid, unchanged phenacetin. The filtered ligroin solution first separates some phenacetin on cooling, from which it is poured off, then very abundantly, already quite pure diacetphenetidide, which after repeated recrystallization from benzene proves to be absolutely pure. When distilled off, the ligroin mother liquors yield further, albeit somewhat yellowish, amounts of diacetphenetidide. The same melts at 55 bis. 56 °. The 'yield is good.

The analysis showed:

Calculated for C ^ H _is NO _s

CH N

Found: 65.04 pCt. 7.00 pct. 6.32 pCt.

65.15-6.79. - 6.33 -

In this example one can start from the p-phenetidine itself and so on Conversion into the diacetyl product in one process. It is then used appropriately 6 to 8 moles of acetic anhydride.

The acetic anhydride can be "replaced by acetylating agents with a similar effect, and to isolate the diacetyl products from the reaction mixtures in question, it is also possible to use other solvents can be used.

Example 2.

Phenacetin (1 mol.) Is heated with acetyl chloride mol.) For 3 hours on a reflux condenser in a 180 to 190 ⁰ hot oil bath. The further processing takes place as in example 1.

Claims (1)

Patent claim: Process for the preparation of diacet-pphenetidide, which consists in using phenacetin or p-phenetidine is treated with acetylating agents at a higher temperature, and those thus formed Reaction mixtures of a suitable treatment with benzene and ligroin respectively. subject to similar solvents.