New Approaches for the Synthesis of Heterocyclic Compounds Derived from Cyclohexan-1,3-dione with Anti-proliferative Activities.

In the present work a series of heterocyclization reactions were adopted using cyclohexan-1,3-dione through its reaction with either furan-2-carbaldehyde or thiophene-2-carbaldehyde to give the corresponding ylidene derivatives 3a,b. The latter compounds underwent heterocyclization reactions to give thiophene and pyran derivatives 5a-d and 6a-d, respectively. Moreover, compounds 3a,b reacted with elemental sulfur and phenyl isothiocyanate to give the fused thiazole derivatives 8a,b. In addition, the reaction with either of hydrazine hydrate or phenylhydrazine has given the 4-hydrazono-4,5,6,7-tetrahydro-2H-indazole derivatives 10a-d, respectively. Similarly, the reaction of either 3a or 3b with hydroxylamine hydrochloride gave the 6,7-dihydrobenzo[c]isoxazol-4(5H)-one oxime derivatives 12a and 12b, respectively. Other fused heterocyclic compounds were produced and their structures were elucidated. Evaluation of the synthesized compounds against selected cancer cell lines was performed. The most active compounds were further evaluated against tyrosine kinases and Pim-1 kinase inhibitions.

Selectivity switch between FAK and Pyk2: Macrocyclization of FAK inhibitors improves Pyk2 potency.

Herein, we describe the synthesis of Pyk2 inhibitors via macrocyclization of FAK and dual Pyk2-FAK inhibitors. We identified macrocycle 25a as a highly potent Pyk2 inhibitor (IC50=0.7nM), with ∼175-fold improvement in Pyk2 potency as compared to its acyclic counterpart. In many cases, macrocyclization improved Pyk2 potency while weakening FAK potency, thereby improving the Pyk2/FAK selectivity ratio for this structural class of inhibitors. Various macrocyclic linkers were studied in an attempt to optimize Pyk2 selectivity. We observed macrocyclic atropisomerism during the synthesis of 19-membered macrocycles 10a-d, and successfully obtained crystallographic evidence of one atropisomer (10a-AtropB) preferentially bound to Pyk2.

[Synthesis and biological activity of tyrosine protein kinase inhibitors].

Four classes of 25 tyrosine protein kinase (TPK) inhibitors were designed and synthesized. Compounds 1-10 were tested to inhibit TPK of HL-60 leukemia cell using 32P-ATP method, and some of them exhibit evident inhibitory activities. Their structure-activity relationship is similar to that of TPK inhibitors reported in literatures. Compounds 11-25 were tested to inhibit TPK of normal rat spleen cell using ELISA method and their SAR is different from that using 32P-ATP method.

A new approach to phosphoserine, phosphothreonine and phosphotyrosine synthons and to thiophospho analogs. Stepwise synthesis of mono- and multiphosphorylated phosphopeptides related to src-protein kinase.

Several phosphoserine, phosphothreonine and phosphotyrosine synthons suitable for the stepwise synthesis of phosphopeptides were prepared. Treatment of methylthiomethyl (MTM) esters of either Z-, Boc-, Allocserine and threonine with phosphochloridate in pyridine followed by MgBr2 cleavage of MTM in diethyl ether afforded the title compounds in good yield. Thiophosphoserine and phosphotyrosine synthons were also obtained by the phosphoramidite method using di-(2,2,2-trichloroethyl)-N,N-diisopropylphosphoramidite and MCPBA as oxidizing reagent. Trichloroethyl proved valuable as phosphate protecting group especially in phosphotyrosine derivatives owing to its stability in acidic conditions. These synthons were involved in the liquid-phase synthesis of several phospho and/or thiophosphopeptides related to either src-protein kinase or rat liver pyruvate kinase.

Chemical synthesis of human papillomavirus type 16 E7 oncoprotein: autonomous protein domains for induction of cellular DNA synthesis and for trans activation.

The human papillomavirus type 16 E7 protein belongs to a family of nuclear oncoproteins that share amino acid sequences and functional homology. To localize biochemical activities associated with E7, we chemically synthesized the full-length 98-amino-acid polypeptide and several deletion mutant peptides. We show that the E7 polypeptide is biologically active and possesses at least two functional domains; the first induces cellular DNA synthesis in quiescent rodent cells, and the second trans activates the adenovirus E1A-inducible early E2 promoter and binds zinc. Further, each domain is autonomous and can function on separate peptides. DNA synthesis induction activity maps within the N-terminal portion of the molecule, which contains sequences related to adenovirus E1A conserved domains 1 and 2 required for cell transformation and binding of the retinoblastoma gene product. trans-Activation and Zn-binding activities map within the C-terminal portion of the molecule, a region which contains Cys-X-X-Cys motifs. trans Activation does not require protein synthesis, implying a mechanism that involves interaction with a preexisting cellular factor(s). E7 trans activates the adenovirus E2 promoter but not other E1A-inducible viral promoters, suggesting the possibility that E7 trans activation involves interaction, directly or indirectly, with cellular transcription factor E2F.