Phenacaine, also known as holocaine,[1] is a local anesthetic. It is approved for ophthalmic use.[2]
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| Names | |
|---|---|
| IUPAC name (1E)-N,N′-Bis(4-ethoxyphenyl)ethanimidamide | |
| Identifiers | |
3D model (JSmol) | |
| ChEMBL | |
| ChemSpider | |
PubChem CID | |
| UNII | |
CompTox Dashboard (EPA) | |
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| Properties | |
| C18H22N2O2 | |
| Molar mass | 298.386 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Synthesis
The synthesis of phenacaine begins with the condensation of p-phenetidine (1) with triethyl orthoacetate (2) to afford the imino ether (a 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, producing the amidine, phenacaine (5).
In the patented synthesis,[4] phenacetin was used as precursor. Treatment with phosphorus trichloride (PCl3) gave the enol chloride, and reaction of this intermediate with p-phenetidine then completed the synthesis of phenacaine.