Tulobuterol

Tulobuterol (INN) is a long-acting beta2-adrenergic receptor agonist, marketed in Japan as a transdermal patch under the name Hokunalin tape (ホクナリンテープ).

Currently, it is only legal in 7 countries: Japan, Germany, China, South Korea, Bangladesh, Pakistan, and Venezuela. It is available in India also.

Synthesis

 * Tulobuterol synthesis.svg

The oxidation of 2'-chloroacetophenone (1) with selenium dioxide gives o-chlorophenylglyoxal (2). Condensation with tert-butylamine gives the imine (3). Reduction with sodium borohydride completes the synthesis of tulobuterol.