A novel strategy for the manufacture of idelalisib: controlling the formation of an enantiomerElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ra00407b

A novel and scalable synthesis of 5-fluoro-3-phenyl-2-[(1 S )-1-(9 H -purin-6-ylamino)propyl]-4(3 H )-quinazolinone, idelalisib 1 , has been developed. This strategy controls the desfluoro impurity of 13 during reduction of nitro intermediate 4 , and also arrests the formation of the enantiomer during cyclisation of diamide 17 , without affecting the neighbouring chiral centre. This process is demonstrated on a larger scale in the laboratory and achieved good chemical and chiral purities coupled with good yields. A novel and scalable synthesis of 5-fluoro-3-phenyl-2-[(1 S )-1-(9 H -purin-6-ylamino)propyl]-4(3 H )-quinazolinone, idelalisib 1 , has been developed.