Synthesis of 4- and 5-arylthiazolinethiones as inhibitors of indoleamine 2,3-dioxygenase.

Docking studies of 4-phenylthiazolinethione on human IDO1 suggest complexation of the heme iron by the exocyclic sulfur atom further reinforced by hydrophobic interactions of the phenyl ring within pocket A of the enzyme. On this basis, chemical modifications were proposed to increase inhibition activity. Synthetic routes had to be adapted and optimized to yield the desired substituted 4- and 5-arylthiazolinethiones. Their biological evaluation shows that 5-aryl regioisomers are systematically less potent than the corresponding 4-aryl analogs. Substitution on the phenyl ring does not significantly increase inhibition potency, except for 4-Br and 4-Cl derivatives.

Palladium-Catalyzed Amination of N-Free 2-Chloro-7-azaindole.

A simple and efficient procedure for the Pd-catalyzed amination of N-free 2-chloro-7-azaindole is described, using either primary or secondary amines. An optimized combination of Brettphos, a Brettphos precatalyst, and LiHMDS in THF led us to a novel methodology, applied to various functionalized amines to study the scope of the reaction. This is the first report of cross-coupling amination on N-free 2-chloro-7-azaindole.

Efficient synthesis of ß'-amino-α,ß-unsaturated ketones.

A general and simple procedure to access chiral ß'-amino-α,ß-enones, in seven steps, from an α,ß unsaturated ester has been described. The use of a Horner-Wadsworth-Emmons reaction as a key step for generating the ß'-amino-α,ß-enones, permits access to a range of substrates under mild conditions and in moderate to high yield.

Access to 2,6-disubstituted piperidines: control of the diastereoselectivity, scope, and limitations. Applications to the stereoselective synthesis of (-)-solenopsine A and alkaloid (+)-241D.

Scope and limitations in the diastereoselective preparation of 2,6-cis or 2,6-trans disubstituted piperidines are described, through intramolecular reaction of chiral ß'-carbamate-α,ß-unsaturated ketone. This methodology has been applied to the total synthesis of a few well chosen examples, such as (-)-solenopsine A and alkaloid (+)-241D.