Befunolol (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway. Before the advent of motorized transportation, they also provided accomm ...

) is a

beta blocker Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms ( arrhythmia), and to protect the heart from a second heart attack after a first heart attack ( secondary prevention ...

with

intrinsic sympathomimetic activity Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms (arrhythmia), and to protect the heart from a second heart attack after a first heart attack (secondary prevention). ...

used in the management of

open-angle glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

. It also acts as a β adrenoreceptor

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given Receptor (biochemistry), receptor, but have only partial Intrinsic activity, efficacy at the receptor relative to a full agonist. They may also be considered Ligand (bio ...

. Befunolol was introduced in Japan in 1983 by Kakenyaku Kako Co. under the trade name Bentos.

Synthesis

The first reported synthesis of befunolol in 1974 used a benzofuran derivative (4) with

epichlorohydrin Epichlorohydrin (abbreviated ECH) is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscibility, miscible with most p ...

and then

isopropylamine Isopropylamine (also known as monoisopropyl amine, MIPA, or 2-propylamine) is an organic compound, an amine. It is a hygroscopic colorless liquid with ammonia-like odor. It is miscible with water and flammable. It is a valuable intermediate in c ...

to add the sidechain which was known to produce beta blockers, by analogy with drugs discovered by

Imperial Chemical Industries Imperial Chemical Industries (ICI) was a British Chemical industry, chemical company. It was, for much of its history, the largest manufacturer in Britain. Its headquarters were at Millbank in London. ICI was listed on the London Stock Exchange ...

, such as propanolol. The requisite intermediate was synthesized from ortho-vanillin (1) by a

condensation reaction In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a ...

with

chloroacetone Chloroacetone is a chemical compound with the chemical formula, formula . At Standard temperature and pressure, STP it is a colorless liquid with a pungent odor. On exposure to light, it turns to a dark yellow-amber color. It was used as a lachry ...

(2) in the presence of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

, giving 2-acetyl-7-methoxybenzofuran (3), which was

demethylated Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen at ...

using

hydrobromic acid Hydrobromic acid is an aqueous solution of hydrogen bromide. It is a strong acid formed by dissolving the diatomic molecule hydrogen bromide (HBr) in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at and contains ...

References

Benzofuran ethers at the benzene ring Beta blockers Catechol ethers N-isopropyl-phenoxypropanolamines Ophthalmology drugs {{Antihypertensive-stub