Abstract: To provide a taxoid derivative that has improved solubility in water and acts specifically with respect to tumors, thereby mitigating side effects. The present invention provides an anticancer agent comprises covalent bond compound of an antibody that reacts specifically with respect to cancer cells with a taxoid derivative and a method for preparing the anticancer agent according to claim 1, characterized by reacting, in the presence of reduction agent, an antibody that reacts specifically with respect to cancer cells with a reaction product obtained by allowing periodic acid or periodate to act on a taxoid derivative.

Abstract: The object of the invention is to develop baccatin derivatives useful for preparing taxoid compounds such as paclitaxel and a process for the producing the same. The invention provides baccatin derivatives represented by the general formula (I) as well as a process for producing baccatin derivatives represented by the general formula (I) above, which comprises allowing a baccatin represented by the general formula (II) to react with a &bgr;-ketoester in the absence of a catalyst or in the presence of a tin compound or an amine base, preferably under reduced pressure.

Abstract: A taxoid compound represented by general formula (I) ##STR1## where the symbols R.sup.1, R.sup.2, R.sup.3, R.sup.4, Bz, and Ac have specified meanings. Also, a method for producing the taxoid derivative from a baccatin derivative having a .beta.-ketoester group at the 13-position by transesterification and a method for producing taxoid compound such as paclitaxel from the taxoid derivative under mild condition are disclosed.

Abstract: Disclosed are ursodeoxycholic acid derivatives having an increased solubility in water, and methods for producing the derivatives. To produce the derivatives, ursodeoxycholic acid is protected at its carboxyl group with a benzyl group, then reacted with tetrabenzyl-acetic acid-oxyglucoside of the following formula (1), and de-benzylated; or ursodeoxycholic acid is protected at its hydroxyl group with a t-butyldimethylsilyl group, then reacted with tetrabenzyl-2-hydroxyethyloxyglucoside of the following formula (2), and de-t-butyldimethylsilylated and de-benzylated.