Discovery of a 1-Methyl-3,4-dihydronaphthalene-Based Sphingosine-1-Phosphate (S1P) Receptor Agonist Ceralifimod (ONO-4641). A S1P1 and S1P5 Selective Agonist for the Treatment of Autoimmune Diseases.

The discovery of 1-({6-[(2-methoxy-4-propylbenzyl)oxy]-1-methyl-3,4-dihydronaphthalen-2-yl}methyl)azetidine-3-carboxylic acid 13n (ceralifimod, ONO-4641), a sphingosine-1-phosphate (S1P) receptor agonist selective for S1P1 and S1P5, is described. While it has been revealed that the modulation of the S1P1 receptor is an effective way to treat autoimmune diseases such as relapsing-remitting multiple sclerosis (RRMS), it was also reported that activation of the S1P3 receptor is implicated in some undesirable effects. We carried out a structure-activity relationship (SAR) study of hit compound 6 with an amino acid moiety in the hydrophilic head region. Following identification of a lead compound with a dihydronaphthalene central core by inducing conformational constraint, optimization of the lipophilic tail region led to the discovery of 13n as a clinical candidate that exhibited >30 000-fold selectivity for S1P1 over S1P3 and was potent in a peripheral lymphocyte lowering (PLL) test in mice (ED50 = 0.029 mg/kg, 24 h after oral dosing).

Identification of protein kinase CK2 inhibitors using solvent dipole ordering virtual screening.

Novel protein kinase CK2 inhibitors were identified using the solvent dipole ordering virtual screening method. A total of 26 compounds categorized in 15 distinct scaffold classes inhibited greater than 50% of enzyme activity at 50 µM, and eight exhibited IC50 values less than 10 µM. Most of the identified compounds are lead-like and dissimilar to known inhibitors. The crystal structures of two of the CK2 complexes revealed the high accuracy of the predicted binding modes.

Structure-activity relationship studies of S1P agonists with a dihydronaphthalene scaffold.

Structure-activity relationship (SAR) of sphingosine-1-phosphate receptor agonists with a dihydronaphthalene scaffold was investigated. Compound 1 was modified to improve S1P(1) agonistic activity and in vivo peripheral lymphocyte lowering (PLL) activity without impairing selectivity over S1P(3) agonistic activity. A detailed SAR study of the terminal lipophilic part revealed that the introduction of substituents on the propylene linker and the terminal benzene ring influences in vitro and PLL activities. Compound 6n bearing a (S)-methyl group at the 2-position on the propylene linker and chlorine at the para-position on the terminal benzene ring showed potent hS1P(1) agonistic activity with excellent selectivity over hS1P(3) and in vivo PLL activity in mice.

Discovery of S1P agonists with a dihydronaphthalene scaffold.

Structure-activity relationship of sphingosine-1-phosphate receptor agonists was examined. Cinnamyl derivative 1 was modified to improve S1P(1) agonistic activity as well as selectivity over S1P(3) agonistic activity. Dihydronaphthalene derivative 10d was identified as a potent S1P(1) receptor agonist with high selectivity against S1P(3) and enhanced efficacy in lowering peripheral lymphocyte counts in mice.

Structure-activity relationship studies of sphingosine-1-phosphate receptor agonists with N-cinnamyl-ß-alanine moiety.

Structure-activity relationship of sphingosine-1-phosphate receptor agonist was examined. In terms of reducing the flexibility of molecule, hit compound 1 was modified to improve S1P(1) agonistic activity as well as selectivity over S1P(3) agonistic activity. Novel S1P agonists with cinnamyl scaffold or 1,2,5,6-tetrahydropyridine scaffold were identified.

Protein phosphatase inhibitory activity of tautomycin photoaffinity probes evaluated at femto-molar level.

Herein we describe the further improvement of our in-house developed firefly bioluminescence assay system for the determination of inhibition of protein phosphatase (PP). The advantage with the new system is higher sensitivity as well as being time and sample efficient. The inhibition activity of tautomycin with PP1gamma was determined using the upgraded test system and Ki was found to be 4.5 nM, which compare favorably with the activity reported previously by others using different methods. The test system was then used in order to determine the activity of nine tautomycin (TTM) photoaffinity probes. One of the TTM photoaffinity probes (anti-10) was found to possess higher activity than the natural product itself with a Ki of 3.4 nM, while the remaining photoaffinity probes were found to possess Ki in the range of 8.0-213 nM.

Synthesis of [18,19,21,22-(13)C4]-labeled tautomycin as an NMR probe of protein phosphatase inhibitor.

We have accomplished the synthesis of 13C-labeled tautomycin at the C18, C19, C21, and C22 positions starting from 100% [13C]triethylphosphonoacetate for the purpose of elucidating the dynamics and conformation of the C17-C26 moiety. NMR spectroscopy of 13C-labeled tautomycin revealed strong binding with protein phosphatase type 1 and new features in the 13C NMR spectrum, such as the very small three-bond coupling constants (2J).

Preparation of bis(diazo) compounds incorporated into butadiyne and thiophene units and generation and characterization of their photoproducts.

(2,6-dimethyl-4-tert-butylphenyl)(2,4,6-tribromophenyl)diazomethane(-N(2)) was found to be stable enough to survive under Sonogashira coupling reaction conditions, and aryldiazomethyl substituents were introduced at the 1,4-positions of butadiyne (4-2N(2)) and the 2,5-positions of thiophene(5-2N(2)). Irradiation of those bis(diazo) compounds generated bis(carbenes), which were characterized by using ESR and UV/vis spectroscopic techniques in a matrix at low temperature as well as time-resolved UV/vis spectroscopy in solution at room temperature. These studies revealed that both of the bis(carbenes), 4 and 5, have singlet quinoidal diradical ground states with a very small singlet-triplet energy gap of less than 1 kcal mol(-1). A remarkable increase in the lifetime of bis(carbenes), as opposed to that of the monocarbene (2), was noted and was interpreted to indicate that bis(carbenes) are thermodynamically stabilized as a result of delocalization of unpaired electrons throughout the pi net framework. In spite of the stability, both bis(carbenes) are readily trapped by molecular oxygen to afford bis(ketones). Presumably, the reaction of the upper-lying localized quintet states with oxygen is much faster than that for lower-lying states.