Wai Ming Kan

Selective N-debenzylation of amides with p-TsOH

Abstract N -Benzylamides were debenzylated efficiently with 4 equiv. of p -TsOH in refluxing toluene. Good to quantitative yields of the desired primary amides were obtained within 2–4 h from a wide variety of N -2,4-dimethoxybenzylamides. N -4-Methoxylbenzyl amides and N -benzylamides were also debenzylated cleanly. In the case of N -2,4-dimethoxylbenzylamides, selective N -debenzylation was possible in the presence of N -Fmoc, N - t -BOC or N -trityl-protection. Protected amino acid amides survived these conditions without any detectable epimerization.

Efficient Synthesis of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines

Abstract A general method for the preparation of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines is described. These heterocycles can be synthesized from their respective anilines with 2‐chloro‐2‐imidazoline or 2‐chloro‐1,4,5,6‐tetrahydropyrimidine, generated in situ from imidazolidin‐2‐one and tetrahydropyrimidin‐2(1H)‐one activated by dimethyl chlorophosphate, in good to excellent yields.

One‐Pot Synthesis of Ene‐Lactams via N‐Debenzylation of Keto‐Containing N‐2,4‐Dimethoxylbenzylamides

Abstract A general method of ene‐lactam preparation is described. Ene‐lactams can be prepared efficiently from keto‐containing N‐2,4‐dimethoxylbenzylamides in good to excellent yields. This method is applicable for the preparation of substituted δ‐, γ‐, and ϵ‐ene‐lactams and bicyclic ene‐lactams.

Synthesis of novel 7-oxabicyclo[2.2.1]-heptane thromboxane A2 derivatives containing substitution on positions one and two.

Tromboxane A2 is one of the most important arachidonic acid metabolites.(1) Its receptors appeared in many tissues and organs including platelet (2), endothelial cells (3), mesanglial cell (4). It is thought to be involved in a wide varieties of disorders such as atherosclerosis, thrombosis and angina (5). The receptor was cloned from human placenta. (6) An isoform (7) was also identified from vascular endothelial cells arising from alternative splicing of the gene.