Improved processes for the preparation of tubulysin compounds, tubulysin drug linker compounds, and their intermediates are disclosed.

A PSMA-specific agent comprising a compound according to Formula I or Formula II: wherein S.sub.1 is absent or is an organic spacer group comprising 3-10 carbons; A is an amino acid chain comprising 1 to 5 amino acids wherein at least one of the amino acids is selected from glutamic acid and aspartic acid; S2 is absent or is an organic spacer group comprising 1 to 15 carbons and/or 0 to 2 amino acids; I.sub.1 is an imaging group; and I.sub.2 is absent or is an imaging group. The PSMA-specific agents can be used to image PSMA within a tissue region and/or for the treatment of a cancer, such as prostate cancer.

##STR00001##

A preparation method of a novel natural bioactive peptide Tubulysin U includes: dissolving a compound 2 in trifluoroacetic acid, heating under reflux to prepare an intermediate, reacting with a compound 3 and N,N-diisopropylethylamine to obtain a product, reacting the product with 2, 6-dimethylpyridine and tert-butyldimethylsilyl trifluoromethanesulfonate, adding sodium hydroxide after the reaction to prepare an intermediate acid, reacting the intermediate acid with a compound 6, HATU and N,N-diisopropylethylamine to obtain a product, adding triphenylphosphine to prepare an intermediate amine, adding a compound 8 and HATU to react, adding ammonium fluoride to prepare a first intermediate, adding sodium hydroxide to the first intermediate to prepare a second intermediate, adding acetic anhydride to the second intermediate to prepare a third intermediate, adding trifluoroacetic acid to the third intermediate to prepare a fourth intermediate, and adding formaldehyde and sodium cyanoborohydride to the fourth intermediate to react, thereby obtaining a target product.

The present invention belongs to the field of medical technology and relates to a class of functional small molecules targeting proteolysis pathways, a preparation and an application thereof. Specifically, the present invention relates to functional small molecules represented by formula (M) and pharmaceutically acceptable salts thereof, as well as the application of said compounds and pharmaceutical compositions thereof in the preparation of tumor-treating drugs. The functional small molecules are obtained by means of linking a compound containing a peroxide bridge linkage and a substrate of an E3 ubiquitin ligase complex. The related functional molecules can promiscuously target and bind to multiple proteins comprising functional proteins in the proteolysis pathway and have anti-tumor biological activity.

##STR00001##

A preparation method of a novel natural bioactive peptide Tubulysin U includes: dissolving a compound 2 in trifluoroacetic acid, heating under reflux to prepare an intermediate, reacting with a compound 3 and N,N-diisopropylethylamine to obtain a product, reacting the product with 2, 6-dimethylpyridine and tert-butyldimethylsilyl trifluoromethanesulfonate, adding sodium hydroxide after the reaction to prepare an intermediate acid, reacting the intermediate acid with a compound 6, HATU and N,N-diisopropylethylamine to obtain a product, adding triphenylphosphine to prepare an intermediate amine, adding a compound 8 and HATU to react, adding ammonium fluoride to prepare a first intermediate, adding sodium hydroxide to the first intermediate to prepare a second intermediate, adding acetic anhydride to the second intermediate to prepare a third intermediate, adding trifluoroacetic acid to the third intermediate to prepare a fourth intermediate, and adding formaldehyde and sodium cyanoborohydride to the fourth intermediate to react, thereby obtaining a target product.

Provided herein are compounds, compositions, and methods for the treatment of diseases and disorders associated with cancer, including tubulysins and protein (e.g., antibody) drug conjugates thereof.

The drug component of an antibody-drug conjugate having a structure according to formula (II), where Ab, m, n, R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are as defined in the application, exhibits unexpectedly improved stability.

##STR00001##

Processes are described for the preparation of tubulysins. The processes are useful for preparing predetermined mixtures of tubulysins, preparing single tubulysins from mixtures of tubulysins, and for converting one tubulysin into a different tubulysin. The tubulysins described herein are useful in treating diseases and disease states that include pathogenic cell populations.

The invention described herein pertains to the diagnosis, imaging, and/or treatment of pathogenic cell populations. In particular, the invention described herein pertains to the diagnosis, imaging, and/or treatment of diseases caused by PSMA expressing cells, such as prostate cancer cells, using compounds capable of targeting PSMA expressing cells.

Compounds and compositions are disclosed in which a quaternized drug unit is linked to a targeting ligand unit from which a tertiary amine-containing drug is released at the targeted site of action. Methods for treating diseases characterized by the targeted abnormal cells, such as cancer or an autoimmune disease using the compounds and compositions of the invention are also disclosed.