alpha-Alkyl-alpha-amino-beta-sulphone hydroxamates as potent MMP inhibitors that spare MMP-1

Photo-induced imino functionalizations of alkenes via intermolecular charge transfer

A catalyst-free photosensitized strategy has been developed for regioselective imino functionalizations of alkenes via the formation of an EDA complex. This photo-induced protocol facilitates the construction of structurally diverse β-imino sulfones and vinyl sulfones in moderate to high yields. Mechanistic studies reveal that the reaction is initiated with an intermolecular charge transfer between oximes and sulfinates, followed by fragmentation to generate a persistent iminyl radical and transient sulfonyl radical. This catalyst-free protocol also features excellent regioselectivity, broad functional group tolerance and mild reaction conditions. The late stage functionalization of natural product derived compounds and total synthesis of some bioactive molecules have been demonstrated to highlight the utility of this protocol. Meanwhile, the compatibility of different donors has proved the generality of this strategy.

EnT-Mediated Amino-Sulfonylation of Alkenes with Bifunctional Sulfonamides: Access to β-Amino Sulfone Derivatives

β-Amino sulfones are commonly found structural motifs in biologically active compounds. Herein, we report a direct photocatalyzed amino-sulfonylation reaction of alkenes for the efficicient production of important compounds by simple hydrolysis without the need for additional oxidants and reductants. In this transformation, the sulfonamides worked as bifunctional reagents, simultaneously generating sulfonyl radicals and N-centered radicals which were added to alkene in a highly atom-economical fashion with high regioselectivity and diastereoselectivity. This approach showed high functional group tolerance and compatibility, facilitating the late-stage modification of some bioactive alkenes and sulfonamide molecules, thereby expanding the biologically relevant chemical space. Scaling up this reaction led to an efficient green synthesis of apremilast, one of the best-selling pharmceuticals, demonstrating the synthetic utility of the applied method. Moreover, mechanistic investigations suggest that an energy transfer (EnT) process was in operation.

Photocatalytic 1,2-Iminosulfonylation and Remote 1,6-Iminosulfonylation of Olefins

A new class of iminosulfonylation reagents were developed and extensively used in the 1,2-iminosulfonylation of various olefins. Olefins containing bioactive molecules, such as indomethacin, gemfibrozil, clofibrate, and fenbufen, afforded the desired iminosulfonylation products in synthetically useful yields. Furthermore, the first remote 1,6-iminosulfonylation of alkenes was realized by using oxime ester bifunctionalization reagents. Overall, more than 40 structurally diverse β-imine sulfones were obtained in moderate to excellent yields.

Generating Stereodiversity: Diastereoselective Fluorination and Highly Diastereoselective Epimerization of α-Amino Acid Building Blocks

Diastereoselective fluorination of N-Boc ( R)- and ( S)-2,2-dimethyl-4-((arylsulfonyl)methyl)oxazolidines and a previously unknown diastereoselective epimerization at the fluorine-bearing carbon atom α to the sulfone was realized. Diastereoselectivities of both reactions were excellent for benzothiazolyl sulfones, allowing access to two enantiomerically pure diastereomers from one chiral precursor. To demonstrate synthetic utility, the benzothiazolyl sulfones were converted to diastereomerically pure ( S, S)- and ( R, S)-benzyl sulfones via sulfinate salts and to amino acids. To understand the diastereoselectivities, DFT analysis was performed.

Orally active MMP-1 sparing α-tetrahydropyranyl and α-piperidinyl sulfone matrix metalloproteinase (MMP) inhibitors with efficacy in cancer, arthritis, and cardiovascular disease

α-Sulfone-α-piperidine and α-tetrahydropyranyl hydroxamates were explored that are potent inhibitors of MMP's-2, -9, and -13 that spare MMP-1, with oral efficacy in inhibiting tumor growth in mice and left-ventricular hypertrophy in rats and in the bovine cartilage degradation ex vivo explant system. α-Piperidine 19v (SC-78080/SD-2590) was selected for development toward the initial indication of cancer, while α-piperidine and α-tetrahydropyranyl hydroxamates 19w (SC-77964) and 9i (SC-77774), respectively, were identified as backup compounds.

beta-N-Biaryl ether sulfonamide hydroxamates as potent gelatinase inhibitors: part 2. Optimization of alpha-amino substituents

The introduction and the optimization of an alpha-amino substituent based on a series of alpha-hydroxy-beta-N-biaryl ether sulfonamide hydroxamates is described. The modification leads to a new series of MMP-2/MMP-9 inhibitors with enhanced inhibitory activities and improved ADME properties. An efficacy study on reducing the ischemia-induced brain edema in the rat transient middle cerebral artery occlusion (tMCAo) model is also demonstrated.

Phosphinic acid-based MMP-13 inhibitors that spare MMP-1 and MMP-3

Phosphinic acid-based inhibitors of MMP-13 have been investigated with the aim of identifying potent inhibitors with high selectivity versus MMP-1. Independent variation of the substituents on a P(1)' phenethyl group and a P(2) benzyl group improved potencies in both cases around 3-fold over the unsubstituted parent. Combining improved P(1)' and P(2) groups into a single molecule gave an inhibitor with a 4.5 nM IC(50) against MMP-13 and which is 270-fold selective over MMP-1.