Benzocaine CAS 94-09-7
Introduction：Basic information about Benzocaine CAS 94-09-7, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.
Benzocaine Basic informationIndications and Usage Uses synthesis
| Product Name: | Benzocaine |
| Synonyms: | NSC 4688;Benzocaine(See B197952 for Labelled);Benzocaine, USP, EP;Ethyl 4-aMinobenzoate, 98% 100GR;Ethyl 4-aMinobenzoate, 98% 500GR;(p-(Ethoxycarbonyl)phenylaMine;4-(Ethoxycarbonyl)phenylaMine;4-Aminobenzoic Acid Ethyl EsterBenzocaine |
| CAS: | 94-09-7 |
| MF: | C9H11NO2 |
| MW: | 165.19 |
| EINECS: | 202-303-5 |
| Product Categories: | C8 to C9;Carbonyl Compounds;Esters;Aromatic Esters;Amines;Aromatics;Benzocaine;medical intermediate;organic interme;Intermediate of Tetracaine hydrochloride;Pharma materials;API;Pharmaceutical intermediate;Intermediates & Fine Chemicals;Pharmaceuticals;Research Chemical;94-09-7 |
| Mol File: | 94-09-7.mol |
Benzocaine Chemical Properties
| Melting point | 88-90 °C |
| Boiling point | 172 °C (12.7517 mmHg) |
| density | 1.17 |
| refractive index | 1.5600 (estimate) |
| Fp | 172°C/13mm |
| storage temp. | 2-8°C |
| solubility | alcohol: soluble1 gm in 5 ml |
| pka | 2.5(at 25℃) |
| form | Crystalline Powder |
| color | White |
| Odor | odorless |
| Water Solubility | Soluble in ethanol, chloroform, ethyl ether and dilute acids. Sparingly soluble in water |
| Merck | 14,1086 |
| BRN | 638434 |
| Stability: | Stable. Combustible. Incompatible with strong oxidizing agents. |
| Cosmetics Ingredients Functions | UV ABSORBER ORAL CARE |
| InChI | 1S/C9H11NO2/c1-2-12-9(11)7-3-5-8(10)6-4-7/h3-6H,2,10H2,1H3 |
| InChIKey | BLFLLBZGZJTVJG-UHFFFAOYSA-N |
| SMILES | CCOC(=O)c1ccc(N)cc1 |
| LogP | 1.860 |
| CAS DataBase Reference | 94-09-7(CAS DataBase Reference) |
| NIST Chemistry Reference | Benzoic acid, 4-amino-, ethyl ester(94-09-7) |
| EPA Substance Registry System | Benzocaine (94-09-7) |
Safety Information
| Hazard Codes | Xi,T,F |
| Risk Statements | 43-36/37/38-39/23/24/25-23/24/25-11 |
| Safety Statements | 22-24/25-37/39-26-24-45-36/37-16-7 |
| RIDADR | 3077 |
| WGK Germany | 2 |
| RTECS | DG2450000 |
| TSCA | TSCA listed |
| HazardClass | 9 |
| PackingGroup | III |
| HS Code | 29224995 |
| Storage Class | 11 - Combustible Solids |
| Hazard Classifications | Skin Sens. 1 |
| Hazardous Substances Data | 94-09-7(Hazardous Substances Data) |
| Toxicity | LD50 oral in rat: 3042mg/kg |
| Indications and Usage | Benzocaine is a colorless trapezial crystal. Its melting point is 92℃ (88-90℃), boiling point is 183-184°C (1.87kPa). 1g of this drug is soluble in about 2500ml water, 5ml ethanol, 2ml chloroform, 4ml ether or 30-50ml almond oil and olive oil, and it is also soluble in dilute acid. It is stable in air, odorless, and slightly bitter. Benzocaine is a lipid-soluble surface anesthetic, and it weaker than other local anesthetics such as lidocaine and tetracaine, so it will not cause any discomfort due to its anesthetizing effects when acting on mucosa. Benzocaine is a type of drug with relatively strong lipid-solubility and will bind with mucosa and the fatty layer of skin, but it will not easily penetrate into the body and cause poisoning. Benzocaine can be used as a precursor for Ossur imitation, orthocaine, and procaine. It is also used as a local anesthetic and can stop pain and itching. It is mainly used in pain and itch prevention on wounds, ulcer surfaces, mucous membrane surfaces and hemorrhoids. Its paste form can also lubricate and stop pain for the nasopharynx and endoscope. Benzocaine’s aural solution is used to alleviate acute congestion, concentrated otitis externa, and the pain and itching of swimming otitis. Benzocaine is also effective for toothaches, sore throat, oral ulcers, all kinds of hemorrhoids, anal fissures, and vulvar itching. Benzocaine can be used as a male sex organ numbing agent to slow ejaculation. It can also be used as a numbing lubricant for the pharynx and endoscope, and it can be used as a UV absorbing agent for cosmetics. |
| Uses |
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| synthesis | Benzocaine is produced by reduction of ethyl 4-nitrobenzoate with iron or by the acid-catalyzed esterification of 4-aminobenzoic acid with ethanol: In a 5-mL round bottom flask, add 120 mg of 4-aminobenzoic acid (often called PABA for paminobenzoic acid), 1.5 mL of absolute ethanol (absolute ethanol is completely free of water and can be found on the hooded shevles), and 3 boiling chips. Heat this mixture on a sand bath until all the solid dissolves. Cool in ice and then add 0.25 mL of concentrated sulfuric acid dropwise. (One drop at a time.) A large amount of precipitate will form when the sulfuric acid is added, but this will dissolve during the reflux that follows. Attach an air condenser from the microscale kit, and reflux gently for 60- 75 min. Check periodically to be sure that the mixture is refluxing gently, and that the ring of condensation of solvent lies somewhere along the inner surface of the air condenser; loss of solvent will cause overheating and a significant decrease in yield. |
| Description | Benzocaine (ethyl p-aminobenzoate) is used topically by itself or in combination with menthol orphenol in nonprescription dosage forms such as gels, creams, ointments, lotions, aerosols, andlozenges to relieve pain or irritation caused by such conditions as sunburn, insect bites,toothache, teething, cold sores or canker sores in or around the mouth, and fever blisters.Benzocaine is a lipophilic local anesthetic agent with a short duration of action. Like most amino ester-type local anesthetics, it is easily hydrolyzed by plasma cholinesterase.Because of its low pKa, however, it is un-ionized under most physiological conditions and, therefore, can only bindto the lipid side of the local anesthetic receptor. It also can easily cross membranesinto systemic circulation to cause systemic toxicities. Furthermore, being a PABA derivative, ithas similar allergenic properties to procaine and is contraindicated with sulfonamide antibacterialagents. |
| Chemical Properties | Benzocaine is a white odourless needle-like crystal, slightly soluble in water and easily soluble in organic solvents. For example: ethanol, chloroform, ether, soluble in almond oil, olive oil. |
| Uses | Benzocaine is used as an anesthetic (Local and topical) that in products such as burn and sunburn remedies, hemorrhoidal creams, suppositories, creams for treatment of poison ivy, oral and gingival products, sore-throat sprays/lozenges, astringents, appetite suppressants, callus and wart remedies, athlete's-foot remedies, toothache- and denture-irritation products. |
| Definition | ChEBI: Benzocaine is a benzoate ester having 4-aminobenzoic acid as the acid component and ethanol as the alcohol component. A surface anaesthetic, it is used to suppress the gag reflex, and as a lubricant and topical anaesthetic on the larynx, mouth, nasal cavity, respiratory tract, oesophagus, rectum, urinary tract, and vagina. It has a role as a topical anaesthetic, an antipruritic drug, an allergen and a sensitiser. It is a benzoate ester and a substituted aniline. |
| Brand name | Americaine (Fisons); BabyAnbesol (Whitehall-Robins). |
| Biological Functions | Benzocaine is a PABA derivative used primarily fortopical application to skin and mucous membranes. Itslow aqueous solubility allows it to stay at the site of applicationfor long periods. Its minimal rate of absorptionafter topical administration is associated with a low incidenceof systemic toxicity. Benzocaine is contraindicatedin patients with known sensitivity to ester-linkedanesthetics or PABA-containing compounds. |
| Synthesis Reference(s) | Journal of the American Chemical Society, 71, p. 4154, 1949 DOI: 10.1021/ja01180a513 Chemical and Pharmaceutical Bulletin, 29, p. 1443, 1981 DOI: 10.1248/cpb.29.1443 |
| General Description | Benzocaine is a unique local anesthetic because it does notcontain a tertiary amine. The pKa of the aromatic amine is 3.5ensuring that benzocaine is uncharged at physiological pH.Because it is uncharged, it is not water soluble but is ideal fortopical applications. The onset of action is within 30 secondsand the duration of drug action is 10 to 15 minutes. |
| Biochem/physiol Actions | Benzocaine is the ethyl ester of p-aminobenzoic acid (PABA). Benzocaine acts to inhibit the voltage-dependent sodium channels (VDSCs) on the nerve membrane, stopping the propagation of the action potential. |
| Clinical Use | Benzocaine is used for endoscopy, bronchoscopy, and topicalanesthesia. Benzocaine is available as a 20% solution topicalspray, in a 1% gel for mucous membrane application, and a14% glycerin suspension for topical use in the outer ear.Toxicity to benzocaine can occur when the topical doseexceeds 200 to 300 mg resulting in methemoglobinemia.Infants and children are more susceptible to this and methemoglobinemiahas been reported after benzocaine lubricationof endotracheal tubes and after topical administration to treata painful diaper rash. |
| Safety Profile | Poison by ingestion and intraperitoneal routes. Human systemic effects by rectal route: methemoglobinemia/carboxyhemoglobinem ia in infants. A skin irritant and a mild sensitizer. Local contact may cause contact dermatitis. Used as a topical anesthetic and as a sun-screening agent. When heated to decomposition it emits highly toxic fumes of NOx. See also ETHYL ALCOHOL and ESTERS |
| Synthesis | Benzocaine is the ethyl ester of 4-aminobenzoic acid (2.3.1). The classic,optimal way of benzocaine synthesis is the reduction of the nitro group of the ethyl esterof 4-nitrobenzoic acid to benzocaine by hydrogen, which generates directly in the reactionmedium by the reaction of iron filings with dilute acids [24¨C26]. |
| Purification Methods | Crystallise Benzocaine from EtOH/H2O or EtOH (m 93-94o), and dry it in air. [Beilstein 14 H 422, 14 IV 1129.] |
| Structure and conformation | Ethyl aminobenzoate, a para-aminobenzoate derivative (PABA) |
Benzocaine Preparation Products And Raw materials
| Raw materials | 4-Aminobenzoic acid-->4-Aminophthalic acid-->Ethyl p-nitrobenzoate |
| Preparation Products | 4-Fluorobenzoic acid-->Benzonatate-->Ethyl 4-(butylamino)benzoate-->Ethyl 4-dimethylaminobenzoate-->Methyl isopropyl ether-->ETHYL 4-(5-FORMYL-2-FURYL)BENZOATE-->Diethyl (hydroxymethyl)phosphonate-->TRIMETHYLENE BIS(4-AMINOBENZOATE)-->4-AZIDOBENZOIC ACID-->ETHYL 4-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)BENZOATE-->BOC-4-AMINOBENZYLALCOHOL-->Viaminate-->SGI-1027-->4-(2-OXO-PROPYL)-BENZOIC ACID ETHYL ESTER-->Benzocaine hydrochloride-->2-Aminobenzothiazole-6-carboxylic acid-->C.I.Disperse Yellow 102 |
