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From the carbolithiation of 6-N,N-dimethylamino fulvene (3a) and different lithiated N-heterocyclic compounds (N,N-dimethylaminomethylpyrrole, 1-methylimidazole and 2,4-[bis(N',N'-dimethylaminomethyl)]-N-methyl pyrrole), the corresponding lithium cyclopentadienide intermediate (4a-c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in dimethylamino-functionalised titanocenes 5a-c. When these titanocenes were tested against LLC-PK cells, the IC50 values obtained were of 13, and 63 microM for titanocenes 5b and 5c, respectively. The most cytotoxic titanocene in this paper (5a) with an IC50 value of 6.8 microM is found to be almost as cytotoxic as cis-platin, which showed an IC50 value of 3.3 microM, when tested on the epithelial pig kidney LLC-PK cell line, and titanocene 5c is approximately 400 times better than titanocene dichloride itself.

From the carbolithiation of 6-N,N-dimethylamino fulvene (3) and 2,4[bis(N,N-dimethylamino)methyl]-N-methylpyrrolyl lithium (2a), N-(N′,N′-dimethylaminomethyl)benzimidazolyl lithium (2b)' or p-(N,N-dimethylamino)methylphenyl lithium (2c), the corresponding lithium cyclopentadienide intermediate (4a–c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4' resulting in N,N-dimethylamino-functionalised titanocenes 5a–c. When these titanocenes were tested against a pig kidney epithelial cell line (LLC-PK), the IC50 values obtained were of 23, and 52 μM for titanocenes 5a and 5b, respectively. The most cytotoxic titanocene in this paper, 5c with an IC50 value of 13 μM, was found to be approximately two times less cytotoxic than its analogue Titanocene C (IC50=5.5 μM) and almost four times less cytotoxic than cisplatin, which showed an IC50 value of 3.3 μM when tested on the LLC-PK cell line.