Organocatalytic Michael addition-lactonisation of carboxylic acids using α,ß-unsaturated trichloromethyl ketones as α,ß-unsaturated ester equivalents.

Isothiourea HBTM-2.1 catalyses the Michael addition-lactonisation of 2-aryl and 2-alkenylacetic acids and α,ß-unsaturated trichloromethyl ketones. Ring-opening of the resulting dihydropyranones and subsequent alcoholysis of the CCl3 ketone with an excess of methanol gives a range of diesters in high diastereo- and enantioselectivity (up to 95 : 5 dr and >99% ee). Sequential addition of two different nucleophiles to a dihydropyranone gives the corresponding differentially substituted diacid derivative.

Azetidinimines as a novel series of non-covalent broad-spectrum inhibitors of ß-lactamases with submicromolar activities against carbapenemases KPC-2 (class A), NDM-1 (class B) and OXA-48 (class D).

The occurrence of resistances in Gram negative bacteria is steadily increasing to reach extremely worrying levels and one of the main causes of resistance is the massive spread of very efficient ß-lactamases which render most ß-lactam antibiotics useless. Herein, we report the development of a series of imino-analogues of ß-lactams (namely azetidinimines) as efficient non-covalent inhibitors of ß-lactamases. Despite the structural and mechanistic differences between serine-ß-lactamases KPC-2 and OXA-48 and metallo-ß-lactamase NDM-1, all three enzymes can be inhibited at a submicromolar level by compound 7dfm, which can also repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1. We show that 7dfm can efficiently inhibit not only the three main clinically-relevant carbapenemases of Ambler classes A (KPC-2), B (NDM-1) and D (OXA-48) with Ki's below 0.3 µM, but also the cephalosporinase CMY-2 (class C, 86% inhibition at 10 µM). Our results pave the way for the development of a new structurally original family of non-covalent broad-spectrum inhibitors of ß-lactamases.

A DHODH inhibitor increases p53 synthesis and enhances tumor cell killing by p53 degradation blockage.

The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect.

Publisher Correction: A DHODH inhibitor increases p53 synthesis and enhances tumor cell killing by p53 degradation blockage.

The original PDF version of this Article listed the authors as "Marcus J.G.W. Ladds," where it should have read "Marcus J. G. W. Ladds, Ingeborg M. M. van Leeuwen, Catherine J. Drummond et al.#".Also in the PDF version, it was incorrectly stated that "Correspondence and requests for materials should be addressed to S. Lín.", instead of the correct "Correspondence and requests for materials should be addressed to S. Laín."This has been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.