Selective α-Methylation of Ketones

The convenient and scalable preparative approach for the two-step α-methylation of ketones is described. The optimized protocols for regioselective preparation of enaminones with further diastereoselective and functional groups tolerant hydrogenation to α-methylketones are developed. The scope and limitations of the proposed methodology are discussed. The advantages compared to known procedures are demonstrated. The unexpected role of acetone in the hydrogenation is suggested. The evaluation of the method for both early building block synthesis and late-stage CH-functionalization is shown. The elaborate procedures' preparability and scalability are demonstrated by the synthesis of several α-methyl ketones up to 100 g amount.

A cascade reaction of cinnamyl azides with vinyl sulfones directly generates dihydro-pyrrolo-pyrazole heterocycles

This report describes the direct synthesis of dihydro-pyrrolo-pyrazole heterocycles from allylic azides and methyl vinyl sulfone. The product results from a complex cascade reaction that is operationally straightforward, with aromatization being the result of a concomitant elimination step. A variety of azides could participate in this reaction (12 examples) and the isolated yields of the desired product ranged from 51%-72%. Lastly the ethylene sulfone group could be removed by heating the product in pyrrolidine.

2,4-Diamino-8-quinazoline carboxamides as novel, potent inhibitors of the NAD hydrolyzing enzyme CD38: Exploration of the 2-position structure-activity relationships

Starting from 4-amino-8-quinoline carboxamide lead 1a and scaffold hopping to the chemically more tractable quinazoline, a systematic exploration of the 2-substituents of the quinazoline ring, utilizing structure activity relationships and conformational constraint, resulted in the identification of 39 novel CD38 inhibitors. Eight of these analogs were 10-100-fold more potent human CD38 inhibitors, including the single digit nanomolar inhibitor 1am. Several of these molecules also exhibited improved therapeutic indices relative to hERG activity. A representative analog 1r exhibited suitable pharmacokinetic parameters for in vivo animal studies, including moderate clearance and good oral bioavailability. These inhibitor compounds will aid in the exploration of the enzymatic functions of CD38, as well as furthering the study of the therapeutic implications of NAD enhancement in metabolic disease models.

Probing for improved selectivity with dipeptide-derived inhibitors of dipeptidyl peptidases 8 and 9: the impact of P1-variation

The influence of P1-variation on DPP8/9 inhibitor selectivity is investigated.

Synthesis and biological evaluation of 4-(aminomethyl)-1-hydroxypyrazole analogues of muscimol as γ-aminobutyric acid(a) receptor agonists

A series of bioisosteric 4-(aminomethyl)-1-hydroxypyrazole (4-AHP) analogues of muscimol, a GABA(A) receptor agonist, has been synthesized and pharmacologically characterized at native and selected recombinant GABA(A) receptors. The unsubstituted 4-AHP analogue (2a) (EC(50) 19 μM, R(max) 69%) was a moderately potent agonist at human α(1)β(2)γ(2) GABA(A) receptors, and in SAR studies substitutions in the 3- and/or 5-position were found to be detrimental to binding affinities. Ligand-receptor docking in an α(1)β(2)γ(2) GABA(A) receptor homology model along with the obtained SAR indicate that 2a and muscimol share a common binding mode, which deviates from the binding mode of the structurally related antagonist series based on 4-(piperidin-4-yl)-1-hydroxypyrazole (4-PHP, 1). Selectivity for α(1)β(2)γ(2) over ρ(1) GABA(A) receptors was observed for the 5-chloro, 5-bromo, and 5-methyl substituted analogues of 2a illustrating that even small differences in structure can give rise to subtype selectivity.

Synthesis and antiproliferative activity of novel diaryl ureas possessing a 4H-pyrido[1,2-a]pyrimidin-4-one group

We herein disclose a series of novel diaryl urea derivatives possessing a 4H-pyrido[1,2-a]pyrimidin-4-one group as novel potent anticancer compounds. The structures were confirmed by IR,(1)H-NMR, and MS. All the compounds were screened for their antiproliferative activity against the human breast cancer cell line (MDA-MB-231). The pharmacological results indicated that most of the compounds showed moderate activity. The best of this series is compound 4c (IC(50)= 0.7 micromol/L), with a potency 3.6-fold higher than Sorafenib (IC(50) = 2.5 micromol/L), which was approved in 2005.