In the course of our investigations on the synthesis of original nitrogen heterocyclic derivatives, we were interested in the synthesis and study of original 1,4-dihydropyrazine rings. To this aim the desired bisvinylphosphate derivative was prepared from N-Boc piperazine-2,5-dione and then was engaged in palladium catalyzed reactions (reduction, Suzuki and Stille cross-coupling reactions). The 1,4-dihydropyrazine
the Pd-catalyzed P–Ccross-coupling reaction between enol phosphates and secondary phosphane–borane complexes or phosphane oxides. The reaction was performed under mild conditions, owing to Pd activation of the P–H bonds of the phosphane–boranes (or phosphane oxides) and to the powerful enol phosphate coupling reagents. New useful chiral and achiral α-β-alkenylphosphane derivatives bearing an amido
The synthesis of two marine natural products containing a 3-alkylidene-6-arylidene-2,5-diketopiperazine scaffold by employing two consecutive aldol condensations starting with 1,4-diacetyl-2,5-diketopiperazine is reported. The target compounds contain a phenol or an imidazole group as aryl substituents, respectively, and suitable conditions for the aldol condensation of 1-acyl-3-alkylidene-2,5-diketopiperazine
original stereocontrolled transannular rearrangement starting from activated 2,5-diketopiperazines has been developed, an opportunity for the medicinal chemistry field, which requests access to novel biological scaffolds. This powerful ring contraction, which can be related to a stereoselective aza-version of the Chan rearrangement, allows for example the one-step synthesis of various tetramic acids, access
The present invention relates to a drug-loaded emulsion, comprising a modified hydrophobic excipient having the following formula, a hydrophobic drug and a surfactant:
where R is a hydrophobic natural compound or a hydrophobic synthetic compound with one to three hydroxyl groups (n=1-3); and R1 is an α-amino protecting group, and R2 is an amino acid side chain, wherein, when m=0, R is reacted with an amino acid derivative with a protecting group by esterification to form a hydrophobic excipient carrying the amino acid derivative with a protecting group; or when m=1, R is firstly introduced with an amino acid linking arm of different chain lengths (l=1, 2, 4, 6) via an ester group, and then introduced with an amino acid derivative with a protecting group.