Prodrugs for colon-restricted delivery: Design, synthesis, and in vivo evaluation of colony stimulating factor 1 receptor (CSF1R) inhibitors.

The ability to restrict low molecular weight compounds to the gastrointestinal (GI) tract may enable an enhanced therapeutic index for molecular targets known to be associated with systemic toxicity. Using a triazolopyrazine CSF1R inhibitor scaffold, a broad range of prodrugs were synthesized and evaluated for enhanced delivery to the colon in mice. Subsequently, the preferred cyclodextrin prodrug moiety was appended to a number of CSF1R inhibitory active parent molecules, enabling GI-restricted delivery. Evaluation of a cyclodextrin prodrug in a dextran sodium sulfate (DSS)-induced mouse colitis model resulted in enhanced GI tissue levels of active parent. At a dose where no significant depletion of systemic monocytes were detected, the degree of pharmacodynamic effect-measured as reduction in macrophages in the colon-was inferior to that observed with a systemically available positive control. This suggests that a suitable therapeutic index cannot be achieved with CSF1R inhibition by using GI-restricted delivery in mice. However, these efforts provide a comprehensive frame-work in which to pursue additional gut-restricted delivery strategies for future GI targets.

Synthesis and optimization of furano[3,2-d]pyrimidines as selective spleen tyrosine kinase (Syk) inhibitors.

A series of furano[3,2-d]pyrimidine Syk inhibitors were synthesized and optimized for their enzyme potency and selectivity versus other kinases. In addition, ADME properties were assessed and compounds were prepared with optimized profiles for in vivo experiments. Compound 23 was identified as having acceptable pharmacokinetic properties and demonstrated efficacy in a rat collagen induced arthritis model.

Structure activity optimization of 6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazines as Jak1 kinase inhibitors.

Previous work investigating tricyclic pyrrolopyrazines as kinase cores led to the discovery that 1-cyclohexyl-6H-pyrrolo[2,3-e][1,2,4]triazolo[4,3-a]pyrazine (12) had Jak inhibitory activity. Herein we describe our initial efforts to develop orally bioavailable analogs of 12 with improved selectivity of Jak1 over Jak2.

One-pot synthesis of lactams using domino reactions: combination of Schmidt reaction with Sakurai and aldol reactions.

A series of domino reactions in which the intramolecular Schmidt reaction is combined with either a Sakurai reaction, an aldol reaction, or both is reported. The Sakurai reaction of an allylsilane with an azido-containing enone under Lewis acidic conditions followed by protonation of the resulting titanium enolate species allowed for a subsequent intramolecular Schmidt reaction. Alternatively, the intermediate titanium enolate could undergo an aldol reaction followed by the intramolecular Schmidt reaction to form lactam products with multiple stereogenic centers. The stereochemical features of the titanium enolate aldol reaction with several 3-azidoaldehyde substrates during this domino process is discussed.