Abstract: The invention provides an improved process for preparing romidepsin. The process involves producing, purifying, or storing romidepsin under conditions that prevent the formation of undesired adducts. Purifying romidepsin at an apparent pH lower than approximately 6.0 (e.g., between an apparent pH of 4.0 and 6.0) has been discovered to prevent the reduction of the disulfide bond of romidepsin and the subsequent formation of dimerized, oligomerized, or polymerized adducts. The invention also provides compositions of monomeric romidepsin free of dimerized, oligomerized, or polymerized adducts.

Abstract: The present invention relates to a method for processing microbiologically produced, non-polar, cyclic oligopeptides comprising the step of a) extracting the entire fermentation broth incident to the microbiological production process using a liquid extractant that contains ether and is immiscible with water, wherein the amount of extractant is sufficient to form a two-phase system together with the total fermentation broth, and novel solvates of cyclosporin A and methyl-t-butyl ether.

Abstract: The present invention relates to a method for preparing microbiologically produced ergot alkaloids of the following formula (I), comprising the step of: a) extracting the fermentation product occurring during the biological production, said product containing at least one ergot alkaloid of formula (I), at a pH of 8-14 using an extractant with a solubility in water of 0.2 g/100 g of water to 25 g/100 g water at 20° C., wherein the amount of extractant is sufficient to form a 2-phase system together with the fermentation product.

Abstract: The present invention relates to a method for processing microbiologically produced, non-polar, cyclic oligopeptides comprising the step of a) extracting the entire fermentation broth incident to the microbiological production process using a liquid extractant that contains ether and is immiscible with water, wherein the amount of extractant is sufficient to form a two-phase system together with the total fermentation broth, and novel solvates of cyclosporin A and methyl-t-butyl ether.

Abstract: The invention provides an improved process for preparing romidepsin. The process involves producing, purifying, or storing romidepsin under conditions that prevent the formation of undesired adducts. Purifying romidepsin at an apparent pH lower than approximately 6.0 (e.g., between an apparent pH of 4.0 and 6.0) has been discovered to prevent the reduction of the disulfide bond of romidepsin and the subsequent formation of dimerized, oligomerized, or polymerized adducts. The invention also provides compositions of monomeric romidepsin free of dimerized, oligomerized, or polymerized adducts.

Abstract: The invention provides an improved process for preparing romidepsin. The process involves producing, purifying, or storing romidepsin under conditions that prevent the formation of undesired adducts. Purifying romidepsin at an apparent pH lower than approximately 6.0 (e.g., between an apparent pH of 4.0 and 6.0) has been discovered to prevent the reduction of the disulfide bond of romidepsin and the subsequent formation of dimerized, oligomerized, or polymerized adducts. The invention also provides compositions of monomeric romidepsin free of dimerized, oligomerized, or polymerized adducts.

Abstract: The present invention relates to novel processes for preparing certain aza cyclohexapeptide compounds, e.g. caspofungin, novel intermediates used in said processes and a process for preparing said intermediates. In particular, the intermediates have formula (II), wherein X is amino or substituted amino and contains a cyano/nitrile functionality.