N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide DL-lactate monohydrate

Panobinostat lactate is a histone deacetylase (HDAC) inhibitor that was approved by the FDA for the treatment of multiple myeloma. It was also approved for the same indication in Japan, and the EU approved its use in combination with bortezomib and dexamethasone for the treatment of adults with relapsed and/or refractory multiple myeloma. Panobinostat was discovered and developed by Novartis and is currently being investigated for a number of hematological cancers as well as other indications.

Grandberg synthesis of 2-methyltryptamine (223) was accomplished in 47% yield by heating phenylhydrazine (221) with 5-chloro-2-pentanone (222). Reductive amination of 223 with (E)-3-(4-formyl-phenyl)-acrylic acid methyl ester (224) and sodium borohydride followed by formation of the hydrochloride salt provided amine hydrochloride 225 in high purity. Saponification of the methyl ester followed by reaction with hydroxylamine provided panobinostat in high overall yield. The free base was treated with racemic lactic acid and recrystallized in water to give panobinostat lactate (XXVIII).