Mark James Bamford

Functionalised pyrrolidinones derived from (S)-pyroglutamic acid

Abstract The generation of the lactam enolate derived from bicyclic lactams 2a-c, prepared from (S)-pyroglutamic acid 1a, and subsequent reaction with a range of electrophiles, is reported. Exo-diastereoselectivity is generally favoured. The deprotection of some of these adducts to give functionalised hydroxymethylpyrrolidinones is readily achieved by simple hemiaminal ether cleavage under acidic conditions.

Synthesis of (±)-2′-oxa-carbocyclic-2′,3′-dideoxynucleosides as potential anti-HIV agents

Abstract Novel 2′,3′-dideoxynucleosides, having the pentofuranosyl oxygen at the 2′-position, were obtained by a short synthetic route from diethyl malonate and bromoacetaldehyde dimethyl acetal. The results of biological testing against HIV-1 in vitro are presented.

Synthesis of the potent influenza neuraminidase inhibitor 4-guanidino Neu5Ac2en. X-Ray molecular structure of 5-acetamido-4-amino-2,6-anhydro-3,4,5-trideoxy-D-erythro-L-gluco-nononic acid

An efficient and high-yielding synthesis of 4-guanidino Neu5Ac2en, the potent anti-influenza A and B compound, is described. The route exploits a stereospecific introduction of the key nitrogen functionality at C-4 via an oxazoline intermediate. Three different methods for the final-step conversion of the 4-amino into 4-guanidino derivatives are described. To explore the structure–activity relationship in this region of the molecule, a series of substituted guanidino derivatives were synthesized and their activity is described.

SYNTHESIS OF A NOVEL ANALOGUE OF SIALYL LEWIS X

Abstract Two different strategies have been developed in order to synthesise an analogue and potential mimic of sialyl Lewis X that incorporates a carboxymethyl group and a C 2 -symmetric 2,3-butanediol unit as replacements for the sialic acid and the N-acetylglucosamine residues respectively.

FUNCTIONALISED PYRROLIDINONES DERIVED FROM (S)-PYROGLUTAMIC ACID BY CYCLOADDITION REACTIONS

Abstract The α,β-unsaturated bicyclic lactams 3a,c, prepared from (S)-pyroglutamic acid, are useful substrates for cycloaddition reactions, giving excellent regio- and diastereocontrol; however, lactam 3c has very superior reactivity with several dienes and dipoles under mild reaction conditions.

Synthesis and biological activity of conformationally constrained sialyl Lewis X analogues with reduced carbohydrate character

Abstract Two conformationally constrained analogues of sialyl Lewis X have been synthesised in which the GlcNAc residue has been replaced with cyclohexyl and phenyl rings. The cyclohexyl derived compound was equipotent to sLex and sLea in vitro, suggesting the main role of the GlcNAc residue in sLex is conformational, and represents a simplified inhibitor of adhesion.

A concise approach to functionalised, homochiral pyrrolidinones

Abstract Acylation of O , N -acetal 1 gives excellent yields of the C-7 substituted products 2a,b . Alkylation of 2a under mild conditions gives high yields of the exo- 3 and endo- 4 substituted products in varying ratios, depending on the alkylating agent. The unsaturated derivative 8 reacts in high yields under mild conditions with dienes and 1,3-dipoles to give the corresponding cycloadducts. Elaboration of these compounds by acidic deprotection to substituted pyroglutaminols, and oxidation to the corresponding pyroglutamates, can be readily achieved.

Synthesis of 6-, 7- and 8-carbon sugar analogues of potent anti-influenza 2,3-didehydro-2,3-dideoxy-N-acetylneuraminic acid derivatives

Analogues of the potent anti-influenza A and B compound, 4-guanidino-Neu5Ac2en, are described in which the stereochemically demanding C-6-glycerol side-chain is truncated. Syntheses of the one- and two-carbon side-chain analogues, of both 4-guanidino- and 4-amino-Neu5Ac2en, are presented, as well as the syntheses of analogues lacking any side-chain. Whilst complete removal of the C-6 side-chain abolishes activity, a stepwise increase in inhibition of influenza neuraminidase and influenza A and B in cell culture with increasing C-6 chain length is observed. The one-carbon, hydroxymethyl derivative retains significant activity to represent a suitable lead in the search for neuraminidase inhibitors of reduced stereochemical demand and synthetic complexity.

Pyrrolidinones derived from (S)-pyroglutamic acid. Part 1. Conformationally constrained glutamate

Novel conformationally constrained pyroglutaminols and pyroglutamates are readily available using an α,β-unsaturated bicyclic lactam as a template for diastereocontrolled enolate additions in the key step; zinc enolates are particularly effective in this regard. The bicyclic ring system both controls and permits the determination of ring stereochemistry. The utility of this methodology is demonstrated by a formal total synthesis of the NMDA receptor agonist, CPAA 11.

In search of a small molecule agonist of the relaxin receptor RXFP1 for the treatment of liver fibrosis

The peptide hormone human relaxin-2 (H2-RLX) has emerged as a potential therapy for cardiovascular and fibrotic diseases, but its short in vivo half-life is an obstacle to long-term administration. The discovery of ML290 demonstrated that it is possible to identify small molecule agonists of the cognate G-protein coupled receptor for H2-RLX (relaxin family peptide receptor-1 (RXFP1)). In our efforts to generate a new medicine for liver fibrosis, we sought to identify improved small molecule functional mimetics of H2-RLX with selective, full agonist or positive allosteric modulator activity against RXFP1. First, we confirmed expression of RXFP1 in human diseased liver. We developed a robust cellular cAMP reporter assay of RXFP1 signaling in HEK293 cells transiently expressing RXFP1. A high-throughput screen did not identify further specific agonists or positive allosteric modulators of RXFP1, affirming the low druggability of this receptor. As an alternative approach, we generated novel ML290 analogues and tested their activity in the HEK293-RXFP1 cAMP assay and the human hepatic cell line LX-2. Differences in activity of compounds on cAMP activation compared with changes in expression of fibrotic markers indicate the need to better understand cell- and tissue-specific signaling mechanisms and their disease-relevant phenotypes in order to enable drug discovery.