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A new reagent, 9-fluorenylmethoxy-carbonyl- N -hydroxy-3-azaspiro[5,5]undecane-2,4-dione ester (Fmoc-OASUD) for the preparation of Fmoc-amino acids is described. The Fmoc-OASUD reacts with amino acids at room temperature in the presence of a base and gives Fmoc-amino acids in high yields and purity. The Fmoc-amino acids prepared using Fmoc-OASUD are free from impurities due to Lossen rearrangement, which are generally present when Fmoc-OSu is used. This is mainly because of the higher stability of Fmoc-OASUD compared to Fmoc-OSu.

Coupling of 2-pyridones with aldehydes, amines, and activated alkenes is found to allow access to pharmacologically interesting ring-fused isoquinuclidines.

3-Azaspiro-[5,5]-undecane-2, 4-dione (2, Scheme 1 ) is an important intermediate for the preparation of gabapentin, 1 – 3 which is widely used in the treatment of epilepsy and other various cerebra...

The synthesis and evaluation of the mesomorphic properties of the first trimesogen consisting of three non-identical calamitic mesogenic entities have been described.

Two new phenylethanoids, basalethanoid A (1) and B (2), and one new ceramide, basalamide A (3), together with eleven known compounds (4-14) were isolated from the MeOH extract of the stem barks of Basalmocitrus cameroonensis. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral (EI and ESI) data, chemical reactions, and comparison with previously known analogs. Compounds 1, 2, 5, and 7-10 demonstrated a strong inhibition on reactive Oxygen species (ROS) production in the oxidative burst activity of whole blood on activation with serum opsonized zymosan in the range of IC50 = 0.06-12.30 mu g mL(-1).

The plants of the family Buxaceae are widely used in traditional medicine and constitute rich sources of terpenoidal alkaloids. Compounds of this family have been the subject of numerous chemical and pharmacological studies over past decades because of their interesting biological activities such as cholinesterase inhibition, as well as antibacterial and antileishmanial activities. The chemical and biological properties of these alkaloids, including data relevant to straightforward structure determination and information on biosynthesis, are highlighted in this review, with 144 references being cited.

Bioguided phytochemical investigation of Sarcococca hookeriana with respect to the cholinesterase enzyme inhibitory assay yielded two new pregnane-type steriodal alkaloids hookerianamide H (1) and hookerianamide I (2), along with three known alkaloids N(a)-methylepipachysamine D (3), sarcovagine C (4) and dictyophlebine (5). Their structures were determined with the aid of extensive spectroscopic analysis. All compounds showed good inhibitory activities against the enzymes acetylcholinesterase (IC(50) 2.9-34.1 microM) and butyrylcholinesterase (IC(50) 0.3-3.6 microM). These compounds also showed moderate antiplasmodial activity (IC(50) 2.4-10.3 microM) against the Plasmodium falciparum chloroquine resistant W2 strain.

The acetyl- and butyrylcholinesterase inhibiting natural product dictyophlebine 1 was subjected to different N-alkylation and hydrochlorination reactions by which five new and bioactive chemical derivatives (2-6) with pentyl, pent-4-en-1-yl, hex-5-en-1-yl, 4-chloropentyl and 5-chlorohexyl substituents at the 3-N position were obtained with high yield. The alkylated and chlorinated products 3 - 6 were found to have significantly higher inhibitory potential towards cholinesterase than the parent compound 1.

A homologous series of optically inactive banana-shaped liquid crystals, synthesised by covalently linking two chemically different as well as thermally stable rod-like cores to the central 1,3-phenylene ring, display either a rectangular columnar phase or an electrically switchable smectic fluid phase having antiferroelectric ground state that was evidenced by optical, calorimetric, electrical switching and X-ray diffraction studies.