ABSTRACT
The development of peptide-based pharmaceutics is a hot topic in the pharmaceutical industry and in basic research. However, from the research and development perspective there is an unmet need for new, alternative, solid-phase peptide synthesizers that are highly efficient, automated, robust, able to synthetize peptides in parallel, inexpensive (to obtain and operate), have potential to be scaled up, and even comply with the principles of green chemistry. Moreover, a peptide synthesizer of this type could also fill the gap in university research, and therefore speed the advancement of peptide-based pharmaceutical options. This paper presents a Tecan add-on peptide synthesizer (TaPSy), which has operational flexibility (coupling time: 15-30 min), can handle all manual synthesis methods, and is economical (solvent use: 34.5 mL/cycle, while handling 0.49 mmol scale/reactor, even with ≤3 equivalents of activated amino acid derivatives). Moreover, it can carry out parallel synthesis of up to 12 different peptides (0.49 mmol scale in each). TaPSy uses no heating or high pressure, while it is still resistant to external influences (operating conditions: atmospheric pressure, room temperature 20-40 ËC, including high [>70%] relative humidity). The system's solvent can also be switched from DMF to a green and biorenewable solvent, γ-valerolactone (GVL), without further adjustment. The designed TaPSy system can produce peptides with high purity (>70%), even with the green GVL solvent alternative. In this paper we demonstrate the optimization path of a newly developed peptide synthesizer in the context of coupling reagents, reaction time and reagent equivalents applying for a synthesis of a model peptide. We compare the results by analytical characteristics (purity of raw material, crude yield, yield) and calculated overall cost of the syntheses of one mg of crude peptide using a specified set of reaction conditions.
Subject(s)
Robotic Surgical Procedures , Solid-Phase Synthesis Techniques , Humans , Solid-Phase Synthesis Techniques/methods , Peptides , SolventsABSTRACT
A novel set of 1-substituted apomorphines as dopaminergic agonists were synthesized according to our new strategy employing the acid-catalyzed rearrangement of diversely functionalized 5ß-substituted-6-demethoxythebaines. The activities of new compounds for dopamine receptors subtypes were evaluated using HEK293 based stable cell lines expressing D1, D2L or D3 receptor subtypes. All studied compounds had affinities in nanomolar range for D2L and D3 receptors and the change of the nature of substituent in position 1 had only moderate effect. D1 receptors were sensitive to the introduction of the 4-OH-benzyl function resulting in an increased affinity. The small hydrophilic group (hydroxymethyl) highly reduced the agonist affinity and potency thereby increasing subtype selectivity. This strategy for selective modulation of affinities and potencies of 1-substituted apomorphines gives essential hints for future design of subtype selective dopaminergic ligands.
Subject(s)
Apomorphine/chemical synthesis , Apomorphine/pharmacology , Dopamine Agonists/chemical synthesis , Dopamine Agonists/pharmacology , Drug Design , Apomorphine/chemistry , Binding Sites , Dopamine Agonists/chemistry , HEK293 Cells , Humans , Molecular Structure , Protein Binding/drug effects , Receptors, Dopamine/metabolism , Structure-Activity RelationshipABSTRACT
Novel 6-ketolevorphanol analogs with diverse substitution patterns at ring C were synthesized and their binding affinities at the µ,δ and κ opioid receptors were investigated. The in vitro activity of the new analogs was then evaluated in the functional assay based on the electrically-stimulated contractions of the mouse ileum. It was shown that analogs with Δ7,8 bond had no significant potency at any of the opioid receptor types. In contrast, analogs with the saturated ring C were either potent κ agonist or antagonist depending on the absence or presence of the hydroxyl group in position 14.
Subject(s)
Analgesics, Opioid/chemical synthesis , Analgesics, Opioid/pharmacology , Muscle Contraction/drug effects , Analgesics, Opioid/chemistry , Animals , Crystallography, X-Ray , Dose-Response Relationship, Drug , Ileum/cytology , Ileum/drug effects , Ketones/chemical synthesis , Ketones/chemistry , Ketones/pharmacology , Levorphanol/chemical synthesis , Levorphanol/chemistry , Levorphanol/pharmacology , Male , Mice , Molecular Structure , Swiss 3T3 CellsABSTRACT
A set of novel apomorphine derivatives were synthesized with diversely functionalized side chains in the proximity of position 2 of the aporphine skeleton. Amino and/or carboxylic functions were introduced to this region of the backbone to test their pharmacological effects. During the synthesis of 2-(S-3-mercaptopropionic acid)-derivative a heteroring-fused congener was also isolated. The structural elucidation confirmed that the formation of this product was in accordance with our previous observations on the reaction of thebaine (2) with thiosalycilic acid. All the novel apomorphine congeners 4a-g were neuropharmacologically characterized to discover their dopaminergic profiles. Two derivatives were identified as D(2) full agonists equipotent with apomorphine (1) having significantly increased D(2)/D(1) selectivity ratios.
