Discovery of amide replacements that improve activity and metabolic stability of a bis-amide smoothened antagonist hit.

A bis-amide antagonist of Smoothened, a seven-transmembrane receptor in the Hedgehog signaling pathway, was discovered via high throughput screening. In vitro and in vivo experiments demonstrated that the bis-amide was susceptible to N-acyl transferase mediated amide scission. Several bioisosteric replacements of the labile amide that maintained in vitro potency were identified and shown to be metabolically stable in vitro and in vivo.

Reactivity of Enol Carbonates with Ozone.

Several dienes of varying steric bulk containing an enol carbonate have been synthesized and reacted selectively with ozone at the isolated double bonds. Rate measurements have been made for ozonolysis in a series of substituted cyclohexenes to demonstrate the unusually slow reactivity of the enol carbonate. Proton and carbon NMR chemical shifts have been presented to show that the enol carbonate is not particularly electron deficient in its double bond. Calculation of partial charges from the Mulliken population analysis shows good correlation with the NMR data. The results suggest a carbonate association with ozone that slows the rate of carbon-carbon bond cleavage.

An efficient and scalable one-pot double Michael addition-Dieckmann condensation for the synthesis of 4,4-disubstituted cyclohexane beta-keto esters.

A simple, scalable, and efficient one-pot methodology for the synthesis of 4,4-disubstituted cyclohexane beta-keto esters from benzylic nitriles or esters and methyl acrylate promoted by potassium tert-butoxide is described. The process relies on a tandem double Michael addition-Dieckmann condensation reaction, which results in the formation of three discrete carbon-carbon bonds in a single pot, including a quaternary center. The method allows for the convenient and rapid synthesis of a variety of 4-aryl-4-cyano-2-carbomethoxycyclohexanone and 4-aryl-2,4-biscarbomethoxycyclohexanone building blocks for use in natural products synthesis and medicinal chemistry.