ABSTRACT
The action of Janus kinases (JAKs) is required for multiple cytokine signaling pathways, and as such, JAK inhibitors hold promise for treatment of autoimmune disorders, including rheumatoid arthritis, inflammatory bowel disease, and psoriasis. However, due to high similarity in the active sites of the four members (Jak1, Jak2, Jak3, and Tyk2), developing selective inhibitors within this family is challenging. We have designed and characterized substituted, tricyclic Jak3 inhibitors that selectively avoid inhibition of the other JAKs. This is accomplished through a covalent interaction between an inhibitor containing a terminal electrophile and an active site cysteine (Cys-909). We found that these ATP competitive compounds are irreversible inhibitors of Jak3 enzyme activity in vitro. They possess high selectivity against other kinases and can potently (IC50 < 100 nm) inhibit Jak3 activity in cell-based assays. These results suggest irreversible inhibitors of this class may be useful selective agents, both as tools to probe Jak3 biology and potentially as therapies for autoimmune diseases.
Subject(s)
Janus Kinase 3/antagonists & inhibitors , Janus Kinase 3/chemistry , Janus Kinase 3/metabolism , Protein Kinase Inhibitors , Adenosine Triphosphate/analogs & derivatives , Adenosine Triphosphate/chemistry , Adenosine Triphosphate/pharmacology , Autoimmune Diseases/drug therapy , Autoimmune Diseases/enzymology , Autoimmune Diseases/genetics , Catalytic Domain , Cell Line , Humans , Janus Kinase 3/genetics , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacologyABSTRACT
Irradiation of a tryptamine linked through its side-chain nitrogen to an alkylidene malonate residue results in an intramolecular [2 + 2] cycloaddition to the indole 2,3-double bond. The resultant cyclobutane undergoes spontaneous retro-Mannich fission to produce a spiro[indoline-3,3'-pyrrolenine] with relative configuration defined by the orientation of substituents in the transient cyclobutane. The tandem intramolecular photocycloaddition-retro-Mannich process, abbreviated as TIPCARM, leads to a spiropyrrolidine which is poised to undergo a second retro-Mannich fragmentation that expels the malonate unit and generates transiently an indolenine. The latter undergoes rearrangement to a beta-carboline, which upon brominative oxidation undergoes further rearrangement to an oxindole. With tryptamine as starting material, the entire sequence leads to the alkaloid (+/-)-coerulescine. Starting from 5-methoxytryptamine, a parallel series affords (+/-)-horsfiline. Modification of the malonylidene unit to include an isobutyl substituent at C3 affords a photosubstrate which also undergoes the TIPCARM process. In this case, a 2'-isobutyl-substituted spiro[indoline-3,3'-pyrrolenine] results. This undergoes stereoselective hydride reduction to give a product with relative orientation at the spiro carbon and the new stereocenter bearing the isobutyl appendage corresponding to that of the alkaloid elacomine. From tryptamine, the sequence paralleling that leading to coerulescine and horsfiline terminates at 6-deoxyelacomine, whereas 6-methoxytryptamine as starting material affords (+/-)-elacomine itself.
Subject(s)
Aniline Compounds/chemical synthesis , Indoles/chemical synthesis , Photochemical Processes , Spiro Compounds/chemical synthesisABSTRACT
[reaction: see text] Intramolecular [2 + 2] photocycloaddition of beta-aminoalkylidene malonates gives transiently a cyclobutane which undergoes retro-Mannich fragmentation to a Delta(1)-pyrroline. The tandem sequence, exemplified in two series based on tryptamine and aminoethyl-1,4-cyclohexadiene, leads to a spiroindolopyrroline skeleton and to the nonindolenine portion of koumine.
