Cp*Ir(III)-Catalyzed C-H/O-H Functionalization of Salicylaldehydes for the Synthesis of Chromones at Room Temperature.

Herein, we report Cp*Ir(III)-catalyzed C-H/O-H-bond functionalization of salicylaldehydes with α-diazocarbonyl compounds for the synthesis of chromones under redox-neutral conditions. The reaction proceeds at room temperature and displays excellent functional group tolerance along with high yields of the corresponding products. The developed reaction protocol was successfully applied for the late-stage functionalization of estrone derivative.

Strategies towards the synthesis of anti-tuberculosis drugs.

Antituberculosis drugs have captured the attention of the scientific community due to the emergence of drug resistance. Hence, the development of new analogs and new drugs which can treat drug-resistant tuberculosis is required. In this report, we reviewed the strategies towards the synthesis of antituberculosis drugs. These strategies include semisynthetic approaches, resolution based strategies, microbial transformations, solid phase synthesis, and asymmetric synthesis. As stereochemistry is an important hallmark of many drugs, the strategies based on asymmetric synthesis are described in detail. The emphasis on semisynthetic approaches is given for aminoglycoside antibiotics.

Total Synthesis of Lamellarin D Trimethyl Ether, Lamellarin D, and Lamellarin H.

Total syntheses of three different lamellarins have been accomplished using a Ru(II)-catalyzed (3 + 2) annulation strategy to construct the central pyrrole ring. The striking features of this synthesis are the use of PEG-400 as a green solvent for the (3 + 2) annulation reaction and multiple catalytic reactions with excellent overall yield. The present route also enables the synthesis of various lamellarin analogues devoid of a B ring.

Cp*Co(III)-Catalyzed C-H/N-N Functionalization of Arylhydrazones for the Synthesis of Isoquinolines.

Cationic Co(III)-catalyzed C-H/N-N bond functionalization of arylhydrazones with internal alkynes has been developed for the synthesis of isoquinoline derivatives. The arylhydrazones are easy to prepare and require inexpensive and commercially available hydrazine hydrate. The reaction works well with a variety of internal alkynes and arylhydrazones and offers broad scope, good functional group tolerance, and high yields under redox-neutral conditions in the presence of air.

Cobalt(III)-catalyzed C-H halogenation of 6-arylpurines: facile entry into arylated, sulfenylated and alkoxylated 6-arylpurines.

Cobalt-catalyzed C-H halogenation of biologically important 6-arylpurines has been reported under mild conditions with good functional group tolerance. The regioselective halogenation of thiophenes, as well as the synthetic applicability of the present protocol for the synthesis of arylated, sulfenylated and alkoxylated purine analogues was also demonstrated.

Targeting SHP2 with an Active Site Inhibitor Blocks Signaling and Breast Cancer Cell Phenotypes.

The Src homology phosphotyrosyl phosphatase 2 (SHP2) is an oncogenic protein for which targeted therapies are being sought. In line with this idea, we have previously reported the development of a specific active site inhibitor named CNBDA that showed effectivity in suppressing the transformation phenotypes of breast cancer cells. To improve efficacy, we introduced limited modifications to the parent compound and tested potency in vitro and under cell culture conditions. Of these modifications, removal of one of the butyric acid groups led to the production of a compound named CNBCA, which showed a 5.7-fold better potency against the SHP2 enzyme activity in vitro. In addition, CNBCA showed better selectivity to SHP2 than the control PTPs (SHP1 and PTP1B) as determined by the phosphatase assay. Furthermore, CNBCA binds and inhibits enzyme activity of full-length SHP2 in cellular contexts, downregulates SHP2 mediated signaling, and suppresses breast cancer cell phenotypes, including cell proliferation, colony formation, and mammosphere growth. These findings show that targeting SHP2 with CNBCA is effective against the cancerous properties of breast cancer cells.

Design and synthesis of improved active-site SHP2 inhibitors with anti-breast cancer cell effects.

The Src homology containing phosphotyrosyl phosphatase 2 (SHP2) is a bona fide oncogene particularly in cancers driven by overexpression of receptor tyrosine kinases (RTKs). As such, there is a growing interest to target SHP2 in cancer. Based on these premises, several active site (type I) and allosteric site (type II) inhibitors have been developed, but no SHP2 targeting therapies have reached the clinic yet. In an effort to fill these gaps, we embarked on producing optimized versions of our parent active-site SHP2 inhibitor CNBDA. The objectives were to produce derivatives with increased inhibitory potential and improved selectivity. Accordingly, we designed derivatives around the CNBDA scaffold and predicted their binding property by in silico molecular modeling. Based on comparative differences in free energy of binding to the SHP2 versus the SHP1 active sites, ten were selected, chemically synthesized, and evaluated by NMR and mass spectroscopy for structural integrity. Among the ten derivatives, BPDA2 was found to be the most potent and highly selective compound, inhibiting the SHP2 enzyme activity with an IC50 of 92 nM when DiFMUP was used as a substrate and with an IC50 of 47 nM when pNPP was used as a substrate. Furthermore, enzyme kinetic analyses showed that BPDA2 is a competitive SHP2 inhibitor. Selectivity comparisons in a PTPase assay using DiFMUP as a substrate demonstrated that BPDA2 is more selective to SHP2 than to SHP1 and PTP1B by more than 369-fold and 442-fold, respectively. Evaluation with a cellular thermal shift assay (CETSA) confirmed that BPDA2 binds to wild-type SHP2 in a cellular context, and stabilizes it in solution. Treatment of cells with DBDA2 downregulates mitogenic and cell survival signaling and RTK expression in a concentration dependent manner. Furthermore, treatment of cells with BPDA2 suppresses anchorage independent growth and cancer stem cell properties of breast cancer cells. Overall, data described in this report show that BPDA2 is a more potent derivative of CNBDA with a highly improved selectivity for SHP2.

Cp*Ir(iii)-catalyzed C-H/N-H functionalization of sulfoximines for the synthesis of 1,2-benzothiazines at room temperature.

The first Cp*Ir(iii)-catalyzed C-H/N-H bond functionalization of sulfoximines with α-diazocarbonyl compounds has been developed for the synthesis of 1,2-benzothiazines under redox-neutral conditions. The reactions proceed at room temperature with excellent functional group tolerance and high yields without the requirement of any silver additive.