Design and Synthesis of Isoquinolidinobenzodiazepine Dimers, a Novel Class of Antibody-Drug Conjugate Payload.

Antibody-drug conjugates (ADCs) represent an important class of emerging cancer therapeutics. Recent ADC development efforts highlighted the use of pyrrolobenzodiazepine (PBD) dimer payload for the treatment of several cancers. We identified the isoquinolidinobenzodiazepine (IQB) payload (D211), a new class of PBD dimer family of DNA damaging payloads. We have successfully synthesized all three IQB stereoisomers, experimentally showed that the purified (S,S)-D211 isomer is functionally more active than (R,R)-D221 and (S,R)-D231 isomers by >50,000-fold and ∼200-fold, respectively. We also synthesized a linker-payload (D212) that uses (S,S)-D211 payload with a cathepsin cleavable linker, a hydrophilic PEG8 spacer, and a thiol reactive maleimide. In addition, homogeneous ADCs generated using D212 linker-payload exhibited ideal physicochemical properties, and anti-CD33 ADC displayed a robust target-specific potency on AML cell lines. These results demonstrate that D212 linker-payload described here can be utilized for developing novel ADC therapeutics for targeted cancer therapy.

Discovery of a potent thiadiazole class of histamine h3 receptor antagonist for the treatment of diabetes.

A series of novel 2-piperidinopiperidine thiadiazoles were synthesized and evaluated as new leads of histamine H3 receptor antagonists. The 4-(5-([1,4'-bipiperidin]-1'-yl)-1,3,4-thiadiazol-2-yl)-2-(pyridin-2-yl)morpholine (5u) displayed excellent potency and ex vivo receptor occupancy. Compound 5u was also evaluated in vivo for antidiabetic efficacy in STZ diet-induced obesity type 2 diabetic mice for 2 or 12 days. Non-fasting glucose levels were significantly reduced as compared with vehicle-treated mice. In addition, 5u dose dependently blocked the increase of HbA1c after 12 days of treatment.

Efficient cu-catalyzed asymmetric conjugate additions of alkylzincs to trisubstituted cyclic enones.

The first examples of efficient catalytic asymmetric conjugate addition (ACA) of alkylzincs to trisubstituted cyclic enones is disclosed. These Cu-catalyzed reactions proceed efficiently with five- and seven-membered ring substrates to afford the desired products in >/=95% ee. Intermediate enolates can be trapped with alkyl halides to generate a quaternary stereogenic center. The requisite chiral ligand is prepared from commercially available materials and can be used in situ without further purification in the presence of commercial grade (CuOTf)2.PhMe.

Cu-catalyzed asymmetric conjugate additions of alkylzinc reagents to acyclic aliphatic enones.

Cu-catalyzed enantioselective conjugate additions to acyclic aliphatic enones are reported. The resulting enolates may be functionalized intra- and intermolecularly, leading to the formation of an additional C-C bond. The utility of the present method is not limited to reactions involving Et2Zn; a variety of alkylzincs may be used. Moreover, many of the requisite substrates can be easily accessed through catalytic olefin cross metathesis.