SAR studies of capsazepinoid bronchodilators. Part 2: Chlorination and catechol replacement in the A-ring

Benzyl Alcohol/Salicylaldehyde-Type Polyketide Metabolites of Fungi: Sources, Biosynthesis, Biological Activities, and Synthesis

Marine microorganisms are an important source of natural polyketides, which have become a significant reservoir of lead structures for drug design due to their diverse biological activities. In this review, we provide a summary of the resources, structures, biological activities, and proposed biosynthetic pathways of the benzyl alcohol/salicylaldehyde-type polyketides. In addition, the total syntheses of these secondary metabolites from their discoveries to the present day are presented. This review could be helpful for researchers in the total synthesis of complex natural products and the use of polyketide bioactive molecules for pharmacological purposes and applications in medicinal chemistry.

Palladium-Catalyzed Perfluoroalkylative Carbonylation of 2-Allylaryl Trifluoromethanesulfonates: Base-Controlled Selective Access to β-Perfluoroalkyl Amides

A palladium-catalyzed perfluoroalkylative carbonylation of 2-allylaryl trifluoromethanesulfonates has been developed. A range of 2-allyl trifluoromethanesulfonates, perfluoroalkyl halides, and amines were applied in this tandem procedure to provide the corresponding β-perfluoroalkyl amides with good functional group tolerance and high chemoselectivity. The final products were controlled by the base applied.

Deprotection of N-Boc Groups under Continuous-Flow High-Temperature Conditions

The scope of thermolytic, N-Boc deprotection was studied on 26 compounds from the Pfizer compound library, representing a diverse set of structural moieties. Among these compounds, 12 substrates resulted in clean (≥95% product) deprotection, and an additional three compounds gave ≥90% product. The thermal de-Boc conditions were found to be compatible with a large number of functional groups. A combination of computational modeling, statistical analysis, and kinetic model fitting was used to support an initial, slow, and concerted proton transfer with release of isobutylene, followed by a rapid decarboxylation. A strong correlation was found to exist between the electrophilicity of the N-Boc carbonyl group and the reaction rate.

Synthesis and SAR of novel capsazepine analogs with significant anti-cancer effects in multiple cancer types

We previously demonstrated that capsazepine (CPZ), a synthetic transient receptor potential Vanilloid subtype 1 (TRPV1) antagonist, has significant anti-cancer effects in vivo. The purpose of this study was to develop more potent analogs based upon CPZ pharmacophore and structure-activity relationships (SAR) across analogs. We generated 30 novel compounds and screened for their anti-proliferative effects in cultured HeLa cervical cancer cells. Cell viability assays identified multiple compounds with IC_50s < 15 μM and one compound, 29 with an IC₅₀ < 5 μM; six fold more potent than CPZ. We validated the anti-proliferative efficacy of two lead compounds, 17 and 29, in vivo using HeLa-derived xenografts in athymic nude mice. Both analogs significantly reduced tumor volumes by day 8 compared to control treated animals (p < 0.001) with no observable adverse effects. Calcium imaging determined that compound 17 activates TRPV1 whereas 29 neither activates nor inhibits TRPV1; indicating a unique mechanism-of-action that does not involve TRPV1 signaling. Cell viability assays using a panel of additional tumor types including oral squamous cell carcinoma, non-small cell lung cancer (NSCLC), breast cancer, and prostate cancer cell lines (HSC-3, H460, MDA-231, and PC-3 respectively) demonstrated that both lead compounds were efficacious against every cancer type tested. Compounds 29 displayed IC_50s of 1-2.5 μM in HSC-3and PC-3cells. Thus, we propose that these novel CPZ analogs may serve as efficacious therapeutic agents against multiple tumor types that warrant further development for clinical application.

Direct functionalization of (un)protected tetrahydroisoquinoline and isochroman under iron and copper catalysis: two metals, two mechanisms

A highly facile, straightforward synthesis of 1-(3-indolyl)-tetrahydroisoquinolines was developed using either simple copper or iron catalysts. N-protected and unprotected tetrahydroisoquinolines (THIQ) could be used as starting materials. Extension of the substrate scope of the pronucleophile from indoles to pyrroles and electron-rich arenes was realized. Additionally, methoxyphenylation is not limited to THIQ but can be carried out on isochroman as well, again employing iron and copper catalysis.

SAR studies of capsazepinoid bronchodilators. Part 1: The importance of the catechol moiety and aspects of the B-ring structure

Capsazepine as well as its derivatives and analogues are general inhibitors of constriction of human small airways. From a systematic variation of the capsazepine structure, divided into four regions, SARs were established. This part concerns the catechol moiety of the A-ring as well as the 2,3,4,5-tetrahydro-1H-2-azepine moiety (the B-ring) of capsazepine. It is revealed that a conformational constrain (as a fused ring) is important and that compounds with a six-membered B-ring (as a 1,2,3,4-tetrahydroisoquinoline) in general are more potent than the corresponding isoindoline, 2,3,4,5-tetrahydro-1H-2-benzazepine and 2,3,4,5-tetrahydro-1H-3-benzazepine derivatives.