The N-alkylation of N-(tert-butoxycarbonyl)glycine (I) with benzyl bromide (II) by means of NaH in THF gives N-benzyl-N-(tert-butoxycarbonyl)glycine (III), which is condensed with 4-aminoacetophenone (IV) by means of isobutyl chloroformate and TEA in dichloromethane yielding the corresponding glycinamide (V). The cyclization of (V) with thiourea (VI) by means of I2 in refluxing isopropanol affords, after work up, the N-benzyl-glycinamide (VII), which is finally acylated with pyridine-4-carbonyl chloride by means of TEA and DMAP in dichloromethane.

The acylation of N-[4-(4-aminophenyl)-2-thiazolyl]carbamic acid tert-butyl ester (I) with bromoacetyl bromide (II) gives the bromoacetamide (III), which is then condensed with (S)-alpha-methylbenzylamine (IV) to yield the glycinamide derivative (V). The acylation of (V) with 4-pyridylcarbonyl chloride affords the protected precursor (VI), which is finally deprotected to provide the target BILS 179 BS.

The acylation of N-[4-(4-aminophenyl)-2-thiazolyl]carbamic acid tert-butyl ester (I) with bromoacetyl bromide (II) gives the bromoacetamide (III), which is then condensed with 4-pyridylmethylamine (IV) to yield the glycinamide derivative (V). The acylation of (V) with cyclohexanecarbonyl chloride affords the protected precursor (VI), which is finally deprotected to provide the target BILS 103 BS.