Discovery and Characterization of SY-1365, a Selective, Covalent Inhibitor of CDK7.

Recent studies suggest that targeting transcriptional machinery can lead to potent and selective anticancer effects in cancers dependent on high and constant expression of certain transcription factors for growth and survival. Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of the CDK-activating kinase complex. Its function is required for both cell-cycle regulation and transcriptional control of gene expression. CDK7 has recently emerged as an attractive cancer target because its inhibition leads to decreased transcript levels of oncogenic transcription factors, especially those associated with super-enhancers. Here, we describe a selective CDK7 inhibitor SY-1365, which is currently in clinical trials in populations of patients with ovarian and breast cancer (NCT03134638). In vitro, SY-1365 inhibited cell growth of many different cancer types at nanomolar concentrations. SY-1365 treatment decreased MCL1 protein levels, and cancer cells with low BCL2L1 (BCL-XL) expression were found to be more sensitive to SY-1365. Transcriptional changes in acute myeloid leukemia (AML) cell lines were distinct from those following treatment with other transcriptional inhibitors. SY-1365 demonstrated substantial antitumor effects in multiple AML xenograft models as a single agent; SY-1365-induced growth inhibition was enhanced in combination with the BCL2 inhibitor venetoclax. Antitumor activity was also observed in xenograft models of ovarian cancer, suggesting the potential for exploring SY-1365 in the clinic in both hematologic and solid tumors. Our findings support targeting CDK7 as a new approach for treating transcriptionally addicted cancers. SIGNIFICANCE: These findings demonstrate the molecular mechanism of action and potent antitumor activity of SY-1365, the first selective CDK7 inhibitor to enter clinical investigation.

Discovery of a potent and orally bioavailable benzolactam-derived inhibitor of Polo-like kinase 1 (MLN0905).

This article describes the discovery of a series of potent inhibitors of Polo-like kinase 1 (PLK1). Optimization of this benzolactam-derived chemical series produced an orally bioavailable inhibitor of PLK1 (12c, MLN0905). In vivo pharmacokinetic-pharmacodynamic experiments demonstrated prolonged mitotic arrest after oral administration of 12c to tumor bearing nude mice. A subsequent efficacy study in nude mice achieved tumor growth inhibition or regression in a human colon tumor (HT29) xenograft model.

A new cationic, chiral catalyst for highly enantioselective Diels-Alder reactions.

[reaction: see text] The Diels-Alder reaction of cyclopentadiene and 2-methacrolein is catalyzed by a chiral Lewis acid to form the exo adduct in 96% yield and 96% ee.

A concise route to structurally diverse DMP 323 analogues via highly functionalized 1,4-diamines.

[reaction: see text] The utility of functionalized 1,4-diamines, produced via a temporary phosphorus tether (P-tether)/ring-closing metathesis (RCM)/hydrolysis sequence, is demonstrated in the synthesis of structurally diverse DMP 323 analogues. These 1,4-diamines are transformed into various seven-membered heterocycles via insertion of the appropriate nuclei "X". Subsequent derivatization generates heterocyclic diols that are similar in structure to DMP 323, a notable member of a class of highly potent inhibitors of HIV protease.

Conformationally constrained alpha-boc-aminophosphonates via transition metal-catalyzed/curtius rearrangement strategies.

A transition metal-catalyzed/Curtius rearrangement sequence toward the development of conformationally constrained alpha-Boc-aminophosphonates 2-6 is described. An approach using the versatile tert-butylphosphonoacetate moieties 1a and 1b to derive an array of mono- and bicyclic alpha-Boc-aminophosphonate systems is presented. Conformational constraint is incorporated using either the ring-closing metathesis reaction catalyzed by the first generation Grubbs catalyst or intramolecular cyclopropanation mediated by Rh2(OAc)4. Using the tert-butyl ester functionality in 1a or 1b as a potential amino group, the Curtius rearrangement provides an efficient route toward the target alpha-Boc-aminophosphonates.

Double diastereoselective intramolecular cyclopropanation to P-chiral [3.1.0]-bicyclic phosphonates.

[reaction: see text] A double diastereotopic differentiation strategy on a phosphonoacetate template is described. The approach utilizes Rh(2)(OAc)(4)-catalyzed intramolecular cyclopropanation (ICP) employing the (R)-pantolactone auxiliary in the ester functionality of the phosphonoacetate. The olefinic diastereofacial selectivity is governed by inherent electronic and steric interactions in the reacting carbene intermediate, while the group selectivity is dictated by the chiral auxiliary. This approach is being developed as an effective method to access bicyclic P-chiral phosphonates.