Synthesis and Biological Evaluation of 3,7-Diazabicyclo[4.3.0]nonan-8-ones as Potential Nootropic and Analgesic Drugs

Piperazines as nootropic agents: New derivatives of the potent cognition-enhancer DM235 carrying hydrophilic substituents

The piperazine ring of the potent nootropic drug DM235 has been decorated with H-bond donor and acceptor groups (CH₂OH, CH₂OMe, CH₂OCOMe, COOEt); the aim was to insert new functional groups, suitable for further chemical manipulation. The influence of these modifications on nootropic activity was assessed by means of the mouse passive avoidance test; some of the newly synthesized molecules (alcohol 7b, acetate 8b and ester 10d) showed interesting in vivo potency. This makes it possible to use these functional groups for adding other residues, in order to increase molecular diversity, or for anchoring a biotin group, to obtain compounds useful to capture the biological target. Moreover, the new compounds will improve our knowledge of structure activity relationships of this family of drugs.

Unifi nootropics from the lab to the web: a story of academic (and industrial) shortcomings

This paper is a review of the work of my former academic group of research in the past 15 years, in the field of cognition enhancers (also called nootropics) that identified two very potent molecules: Unifiram and Sunifiram that for a variety of reasons were not protected by a patent. Some 12 years after their disclosure (2000) I casually found that on the web, there were dozens of sites offering Unifiram and Sunifiram as drugs that improve cognition in healthy individuals even if only few preclinical studies were done and their long-term toxicity was unknown.

Preparation and structural analysis of (±)-cis-ethyl 2-sulfanylidenedecahydro-1,6-naphthyridine-6-carboxylate and (±)-trans-ethyl 2-oxooctahydro-1H-pyrrolo[3,2-c]pyridine-5-carboxylate

Bicycle ring closure on a mixture of (4aS,8aR)- and (4aR,8aS)-ethyl 2-oxodecahydro-1,6-naphthyridine-6-carboxylate, followed by conversion of the separatedcisandtransisomers to the corresponding thioamide derivatives, gave (4aSR,8aRS)-ethyl 2-sulfanylidenedecahydro-1,6-naphthyridine-6-carboxylate, C11H18N2O2S. Structural analysis of this thioamide revealed a structure with two crystallographically independent conformers per asymmetric unit (Z′ = 2). The reciprocal bicycle ring closure on (3aRS,7aRS)-ethyl 2-oxooctahydro-1H-pyrrolo[3,2-c]pyridine-5-carboxylate, C10H16N2O3, was also accomplished in good overall yield. Here the five-membered ring is disordered over two positions, so that both enantiomers are represented in the asymmetric unit. The compounds act as key intermediates towards the synthesis of potential new polycyclic medicinal chemical structures.

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

In a simple procedure, the intramolecular hydroarylation of N-propargyl-pyrrole-2-carboxamides was accomplished with the aid of gold(III) catalysis. The reaction led to differently substituted pyrrolo[2,3-c]pyridine and pyrrolo[3,2-c]pyridine derivatives arising either from direct cyclization or from a formal rearrangement of the carboxamide group. Terminal alkynes are essential to achieve bicyclic pyrrolo-fused pyridinones by a 6-exo-dig process, while the presence of a phenyl group at the C–C triple bond promotes the 7-endo-dig cyclization giving pyrrolo-azepines.