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A short synthesis of 8-chloro[1,2,4]triazolo-[4,3-a]pyrazines (III) using a two-step, one-pot oxidative cyclization method is reported.

2-Furfural, 1H-indole-3-carbaldehyde and (3-formylphenyl)boronic acid lead to complex reaction mixtures and degradation.

Optimized reaction conditions for the Pd-catalyzed domino reaction between 2,3-dichloropyrazine and primary amides to form oxazolopyrazine derivatives are presented.

The synthesis of title compounds (V) is based on an intramolecular carbene-mediated C—H insertion in phenylpiperazine-derived tosylhydrazones.

A variety of novel 7-sulfanylpyrazinoindole derivatives (V) (11 examples) is synthesized using a new and improved ring-closing methodology for the assembly of the hexahydropyrazinol[1,2-α]indole scaffold.

Piperidin-4-ylphosphinic acid, methyl(piperidin-4-yl)phosphinic acid and piperidin-4-ylphosphonic acid analogues of the GABAA agonist piperidin-4-ylcarboxylic acid (isonipecotic acid) were synthesised. The acid groups were introduced using a sequential Pudovik addition followed by a Barton deoxygenation procedure and finally followed by acidic hydrolysis. The mild and efficient procedure gave the target amino acids in good yields.

Novel racemic 4-amino-1-, 2-, and 3-hydroxybutylphosphinic acids and the corresponding 4-amino-1-, 2-, and 3-hydroxybutyl methylphosphinic acids have been synthesized. The phosphinic acid groups are bioisosteres of the carboxylic acid group, and some of these hydroxy amino acids are GABA B antagonists. The novel phosphinic acids were evaluated for their GABA A and GABA B receptor binding properties using rat brain synaptosomes and were also tested for GABAergic activity in a guinea pig ileum model. None of the phosphinic acids tested were found to be active.

The first seleninic acid analogues of γ-aminobutyric acid (GABA) and of the specific GABAA agonist piperidine-4-carboxylic acid (isonipecotic acid), 1 and 2, respectively, have been synthesized and shown to be potent agonists at the GABA receptors.

We have developed a novel and versatile synthesis of racemic 3-arylindan-1-ones by palladium-catalyzed intramolecular reductive cyclization of bromochalcones. This method is especially attractive because it avoids strong acidic conditions and consequently a larger number of sensitive functional groups are accepted during synthesis compared with existing methods.