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Phenacaine, also known as holocaine, is a
The condensation of
local anesthetic
A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...
. It is approved for ophthalmic use.
Synthesis
The condensation of P-Phenetidine
''p''-Phenetidine (4-ethoxyaniline) is a chemical compound with the molecular formula C8H11NO. It is one of the three isomers of phenetidine. It is used as an intermediate in the synthesis of pharmaceutical drugs, dyes, and the sweetener dulcin. ...
(1) with triethyl orthoacetate
Triethyl orthoacetate is the organic compound with the formula CH3C(OC2H5)3. It is the ethyl orthoester of acetic acid. It is a colorless oily liquid.
Triethyl orthoacetate is used in organic synthesis for acetylation.
It is also used in the Jo ...
8-39-7(2) to afford the imino ether (a so-called Pinner salt) (3). Reaction of that intermediate with a second equivalent of the aniline results (4) in a net displacement of ethanol, probably by an addition-elimination scheme. There is thus obtained the amidine, phenacaine (5).
In the patented synthesis,Dr Ernst Taeuber, (1894). phenacetin
Phenacetin (acetophenetidin, ''N''-(4-ethoxyphenyl)acetamide) is a pain-relieving and fever-reducing drug, which was widely used following its introduction in 1887. It was withdrawn from medicinal use as dangerous from the 1970s (e.g., withdrawn ...
was used as precursor. Treatment with PCl3 gave the enol chloride, and reaction of this intermediate with p-phenetidine then completed the synthesis of phenacaine.
References