Benzocaine

Benzocaine is a topical anesthetic. It numbs any area to which it is applied. It is widely used in first-aid creams and sunburn remedies. 

Benzocaine is an ester, a compound made from the organic acid PABA (para-amino benzoic acid) and the alcohol ethanol. 

Other esters of PABA have similar anesthetic properties. 

Dentists use procaine (also called novocaine) to numb teeth and gums before dental work. 

Another topical anesthetic, similar to benzocaine, is lidocaine, which is used to relieve the pain of shingles (herpes zoster) infections. Lidocaine is called an amide anesthetic, because it is not an ester (the alcohol is replaced by an amide, the nitrogen group). Amide anesthetics are metabolized by the liver, and are less prone to cause allergic reactions. If an anesthetic has the letter i in the prefix (lidocaine, prilocaine, bupivacaine), it is an amide anesthetic. 

Benzocaine is a local anaesthetic with a range of applications (see box). It is manufactured froitf toluene in a few steps using some quite simple chemistry. 

Benzocaine has been used as a component of appetite suppressants astringents analgesics burn and sunburn remedies cough tablets, drops, and lozenges haemorrhoidal creams, suppositories, and enemas oral 

Formation of the acid chloride followed by reaction with the alcohol would not be suitable here, for chemical reasons as well as economical ones. Why not  

one of the classical reactions of aromatic chemistry the nitration of toluene. The methyl group directs the nitration to the para position, so we get the right substitution pattern for benzocaine. But we also get the wrong oxidation levels first, the nitro group needs reducing to NH2 this can be done with catalytic hydrogenation (Chapters 22 and 24). 

In this experiment, a procedure is given for the preparation of a local anesfhefic, benzocaine, by fhe direcf esferification of p-aminobenzoic acid wifh ethanol. At the instructor s option, you may test the prepared anesthetic on a frog s leg muscle. 

Techiuque 11 Crystallization, Sections 11.4 and 11.10 New Essay Local Anesthetics 

Sulfuric acid is corrosive. Do not allow it to touch your skin. 

Dispose of all filtrates into the container designated for nonhalogenated organic solvents. 

Place 0.120 g of p-aminobenzoic acid and 1.20 mL of absolute ethanol into a 3-mL conical vial. Add a magnetic spin vane and stir the mixture until the solid dissolves completely. While stirring, add 0.10 mL of concentrated sulfuric acid dropwise. A large amount of precipitate forms when you add the sulfuric acid, but this solid slowly dissolves during the reflux that follows. Attach a water-cooled condenser and heat the mixture at a gentle boil for 60-75 minufes with an aluminum block at about 105°C. Stir the mixture during this heating period. 

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Benzocaine (or anaesthesine) is conveniently prep>ared from p-nitrobenzoic acid by either of the following methods ... 

Medicinals. Many esters are used as pharmaceuticals (105,106). Of these, benzocaine, ethyl 4-aminobenzoate [94-09-7] is a topical anesthetic. Phenyl saHcylate [118-55-8] (1) has antipyretic, antirheumatic, and antiparasitic properties. 

Sulfonamides, 1,2-di-acetylhydrazine, procaine, benzocaine, etc Apply samples and dry, place TLC plate in a twin-trou chamber with fuming hydrochlonc acid and heat to 100°C Then remove the acid in a stream of cold air and chromatograph [39]... 

A chance observation made some time prior to the full structural elucidation of cocaine in fact led to one of the more important lasses of local anesthetics. It was found that the simple ethyl e. ter of p-aminobenzoic acid, benzocaine (25), showed activity. 1-. a local anesthetic. It is of interest to note that this drug, I 1rst introduced in 1903, is still in use today. Once the struc-iiire of cocaine was established, the presence of an alkanolamine iiiniety in cocaine prompted medicinal chemists to prepare esters "I aminobenzoic acids with acyclic alkanolamines. Formula 26 11 presents the putative relationship of the target substances with cocaine. 

Regeneration was based on removing ammonium dihydrogen phosphate, formed in hydrogenolysis of benzocaine, from the catalyst. The catalyst was... 

A. Ethyl 4-Amino-3-(methylthiomethyl)benzoate [Benzoic acid, 4-amino-3-[(methylthio)methyl]-]. A 1-1., three-necked, round-bottomed flask is fitted with a mechanical stirrer, a condenser topped with a gas-inlet tube, and a two-neckcd adapter holding a low-temperature thermometer and a 100-ml., pressure-equalizing dropping funnel. The flask is charged with 10.50 g. (0.10 mole) of ethyl p-aminobenzoate [Benzocaine Benzoic acid, 4-amino-, ethyl ester] (Note 1), 300 ml. of acetonitrile, and 100 ml. of dichloromethane, is flushed with nitrogen, and is then immersed in a 40% aqueous methanol-dry ice bath maintained between... 

Benzocaine was purchased from Mallinckrodt Chemical Works and was recrvstallized from absolute ethanol prior to use to give material of m.p. 91-92°. 

Benzocaine [Benzoic acid, 4-amino-, ethyl ester], 73... 

HBr and benzocaine Cough X, Vicks Formula 44 Cough of cough dextromethorphan HBr formulation take as directed on package... 

Topical anesthetics temporarily inhibit the conduction of impulses from sensory nerve fibers. These drug s may be used to relieve itching and pain due to skin conditions, such as minor bums, fungus infections, insect bites, rashes, sunburn, and plant poisoning, such as poison ivy. Some are applied to mucous membranes as local anesthetics. Examples of local anesthetics include benzocaine (Lanacane), dibucadne (Nupereainal), and lidocaine (Xylocadne). 

Denatonium benzoate is the bitterest-tasting substance known. It gets its name from denatured alcohol—alcohol that has been rendered unfit for drinking—and is often used in the denaturing process. Specially denatured alcohol 40, or SD-40, is ethanol that has been denatured by a tiny amount of denatonium benzoate. Denatonium benzoate is an ester of PABA, and is related to lidocaine, benzocaine, novocaine, and cocaine. 

You can see a resemblance between benzocaine, procaine, and the compound that gave Coca-Cola its first name. Cocaine also has a... 

AMR See aminomethyl propanol, cyclic aminomethyl propanol AMP-95. See aminomethyl propanol amphetamines, 160 amyl p-methoxy cinnamate, 5 amylase, 87, 155 amylopectin, 144-145 amylose, 31-32, 144-145, 152 analgesics. See pain relievers anesthesin. See benzocaine anesthetics, 60, 172-175, 229 annatto, 105-106, 107, 114, 117 antacids, 169 anthocyanins, 109-111 antibacterials, 13, 25, 26,42, 67, 86,... 

Among other uses, these polymers have been employed in a variety of biomedical applications. Poly(phosphazenes) containing organic side chains, derived from the anaesthetics procaine and benzocaine, have been used to prolong the anaesthetic effect of their precursor drugs. They have also been used as the bioerodable matrix for the controlled delivery of drugs. 

QH15NO2 5006-62-2) see Tiagabine a-ethyl-4-nitrobenzeneacetic acid (C (,H, N04 7463-53-8) see Indobufen ethyl 4-nitrobenzoate (C9H9NO4 99-77-4) see Benzocaine ethyl 3-nitro-benzylideneacetoacetate (CijHijNO, 39562-16-8) see Nitrendipine ethyl At-(2-nitro-6-chlorobenzyl)glycinate... 

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