Deen Tulshian

Discovery of orally active pyrazoloquinolines as potent PDE10 inhibitors for the management of schizophrenia.

A series of pyrazoloquinoline analogs have been synthesized and shown to bind to PDE10 with high affinity. From the SAR study and our lead optimization efforts, compounds 16 and 27 were found to possess potent oral antipsychotic activity in the MK-801 induced hyperactive rat model.

The SAR development of dihydroimidazoisoquinoline derivatives as phosphodiesterase 10A inhibitors for the treatment of schizophrenia

The identification of potent and orally active dihydroimidazoisoquinolines as PDE 10A inhibitors is reported. The SAR development led to the discovery of compound 35 as a potent, selective, and orally active PDE10A inhibitor. Compound 35 inhibited MK-801-induced hyperactivity at 3mg/kg and displayed a 10-fold separation between the minimal effective doses for inhibition of MK-801-induced hyperactivity and hypolocomotion in rats.

Pyrazoloquinolines as PDE10A inhibitors: discovery of a tool compound.

A series of pyrazoloquinolines, possessing (hetero)arylhydroxymethyl substituents at the quinoline C-4 position were evaluated as PDE10A inhibitors. Among these, methylpyrimidyl analogue 15 was identified as having good rodent and monkey exposure, and a MED of 10 mg/kg in an in vivo model.

Fused tricyclic mGluR1 antagonists for the treatment of neuropathic pain

A series of fused tricyclic mGluR1 antagonists containing a pyridone ring were synthesized. In vitro, these antagonists were potent against both human and rat isozymes, as well as selective for inhibiting mGluR1 over mGluR5. When dosed orally, several examples were active in vivo in a rat SNL test.

The discovery of potent, selective, and orally active pyrazoloquinolines as PDE10A inhibitors for the treatment of Schizophrenia.

High-throughput screening identified a series of pyrazoloquinolines as PDE10A inhibitors. The SAR development led to the discovery of compound 27 as a potent, selective, and orally active PDE10A inhibitor. Compound 27 inhibits MK-801 induced hyperactivity at 3mg/kg with an ED(50) of 4mg/kg and displays a ∼6-fold separation between the ED(50) for inhibition of MK-801 induced hyperactivity and hypolocomotion in rats.

The anxiolytic-like profile of the nociceptin receptor agonist, endo-8-[bis(2-chlorophenyl)methyl]-3-phenyl-8-azabicyclo[3.2.1] octane-3-carboxamide (SCH 655842): Comparison of efficacy and side effects across rodent species

The endogenous opioid-like peptide, nociceptin, produces anxiolytic-like effects that are mediated via the nociceptin (NOP) receptor. Similarly, synthetic, non-peptide NOP agonists produce robust anxiolytic-like effects although these effects are limited by marked side effects. In the present studies, the effects of a novel NOP receptor agonist, SCH 655842, were examined in rodent models sensitive to anxiolytic drugs and tests measuring potential adverse affects. Oral administration of SCH 655842 produced robust, anxiolytic-like effects in three species, i.e., rat, guinea pig, and mouse. Specifically, SCH 655842 was effective in rat conditioned lick suppression (3-10 mg/kg) and fear-potentiated startle (3-10 mg/kg) tests, a guinea pig pup vocalization test (1-3 mg/kg), as well as in mouse Geller-Seifter (30 mg/kg) and marble burying (30 mg/kg) tests. The anxiolytic-like effect of SCH 655842 in the conditioned lick suppression test was attenuated by the NOP antagonist, J-113397. In mice, SCH 655842 reduced locomotor activity and body temperature at doses similar to the anxiolytic-like dose and these effects were absent in NOP receptor knockout mice. In rats, SCH 655842 did not produce adverse behavioral effects up to doses of 70-100 mg/kg. Pharmacokinetic studies in the rat confirmed dose-related increases in plasma and brain levels of SCH 655842 across a wide oral dose range. Taken together, SCH 655842 may represent a NOP receptor agonist with improved tolerability compared to other members of this class although further studies are necessary to establish whether this extends to higher species.

T-type calcium channel blockers: spiro-piperidine azetidines and azetidinones-optimization, design and synthesis.

A series of spiro-azetidines and azetidinones has been evaluated as novel blockers of the T-type calcium channel (Ca(V)3.2) which is a new therapeutic target for the potential treatment of both inflammatory and neuropathic pain. Confirmation and optimization of the potency, selectivity and DMPK properties of leads will be described.

Discovery and hit-to-lead optimization of 2,6-diaminopyrimidine inhibitors of interleukin-1 receptor-associated kinase 4.

Interleukin receptor-associated kinase 4 (IRAK4) is a critical element of the Toll-like/interleukin-1 receptor inflammation signaling pathway. A screening campaign identified a novel diaminopyrimidine hit that exhibits weak IRAK4 inhibitory activity and a ligand efficiency of 0.25. Hit-to-lead activities were conducted through independent SAR studies of each of the four pyrimidine substituents. Optimal activity was observed upon removal of the pyrimidine C-4 chloro substituent. The intact C-6 carboribose is required for IRAK4 inhibition. Numerous heteroaryls were tolerated at the C-5 position, with azabenzothiazoles conferring the best activities. Aminoheteroaryls were preferred at the C-2 position. These studies led to the discovery of inhibitors 35, 36, and 38 that exhibit nanomolar inhibition of IRAK4, improved ligand efficiencies, and modest kinase selectivities.

Synthesis and SAR development of novel P2X7 receptor antagonists for the treatment of pain: Part 1

Structure-activity relationship (SAR) efforts around our initial lead compound 1 led to the identification of potent P2X(7) receptor antagonists with improved pharmacokinetic profiles. These compounds were potent and selective at the P2X(7) receptor in both human and rodent. Compound (entry 31) exhibited oral efficacy in the rat MIA and CCI pain models.

Structure–activity relationships of 2,4-diphenyl-1H-imidazole analogs as CB2 receptor agonists for the treatment of chronic pain

A series of 2,4-diphenyl-1H-imidazole analogs have been synthesized and displayed potent human CB2 agonist activity. Many of these analogs showed high functional selectivity over human CB1 receptors. The syntheses, structure-activity relationships, and selected pharmacokinetic data of these analogs are described.