Total syntheses of polyamine amides PhTX-4.3.3 and PhTX-3.4.3: Reductive alkylation is a rapid, practical route to philanthotoxins

Syntheses of pseudoceramines A-D and a new synthesis of spermatinamine, bromotyrosine natural products from marine sponges

Herein we report the total syntheses of pseudoceramine A-D (2-5) and spermatinamine (1) isolated from the marine sponge Pseudoceratina sp. Direct acyl substitution of α-hydroxyiminoesters with amine nucleophiles was developed as a key transformation. The synthetic compounds confirm the reported structures and importantly gives access to non-symmetrical spermine based natural products carrying two different bromotyrosine building blocks. Our new synthesis of spermatinamine is two steps shorter and more efficient than the previously reported sequence.

Polymethyleneamine alkaloids of animal origin: II. polyamine neurotoxins

Information on the structure and biological activity of animal alkaloids, polymethyleneamine components of spider and wasp venoms, is considered and systematized. These natural compounds are used for the development and modification of medicines for treating the functional disturbances in the central nervous system of humans.

Monitoring the synthetic reaction of a polyamide/peptide conjugate using electrospray ionization mass spectrometry

Recently, the chemical structures of a series of monoimidazole/polyamine conjugates were studied in this laboratory using electrospray ionization mass spectrometry (ESI-MS) combined with tandem mass spectrometry (ESI-MS/MS). The method was found to be a powerful tool for the identification of this class of compounds. During the synthesis of targeted polyamide/peptide conjugates as derivatives or analogues of netropsin and distamycin, the method was applied to analyze and track the coupling reaction for the formation of the polyamide, which was difficult to achieve using thin layer chromatography (TLC). Characteristic fragmentation pathways for a nitro-monoimidazole conjugate, an amino-monoimidazole conjugate, and the final product (a nitro-diimidazole conjugate) were explored. The fragmentations of these conjugates were strongly affected by the presence of an amino group instead of a nitro group in the molecule, and led to the identification of the three compounds in the reacting solution or in the final reaction mixture. Consequently, the reaction could be monitored successfully and the synthetic route optimized.

Effect of spermine conjugation on the cytotoxicity and cellular transport of acridine

Polyamines are believed to be potent vectors for the selective delivery of chemotherapeutic agents into cancer cells. In this paper, we report the effect of spermine conjugation on the cytotoxic and transport properties of acridine. Six derivatives, composed of a spermine chain attached at its N(1) position to an acridine via an aliphatic chain, were synthesized. The aliphatic linker, comprised of 3-5 methylene units, was connected to the position-9 of the heterocycle through either an amide (amidoacridines 8-10) or an amine (aminoacridines 11-13) linkage. Independently of their architecture, all ligands showed a high affinity for DNA binding but a limited DNA sequence selectivity. In a whole cell assay with L1210 and Chinese hamster ovary (CHO) cells, the aminoacridines (IC(50) values around 2 microM) were more potent than the amidoacridines (IC(50) values between 20 and 40 microM). This was related to a less efficient transport for the latter. As determined from competitive uptake studies with [(14)C]spermidine, all conjugates had a high affinity for the polyamine transport system (PTS). However, on the basis of competitive studies with an excess of spermidine and on the differential effect on cell growth and accumulation in CHO and in the mutant PTS deficient CHO-MG cells, the accumulation of the conjugates through the PTS was found to be poor but still more efficient for the aminoacridines. alpha-Difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, which induces an up-regulation of the activity of the PTS, enhanced accumulation of all acridine conjugates through the PTS and had a synergistic effect on the potency of the acridine conjugates to inhibit cell growth. Despite their high affinity for the PTS, the low amount of derivatives transiting through the PTS is likely to be related to their ability to repress rapidly and efficiently the activity of the PTS and, consequently, to inhibit their own uptake via this system.

Electrospray ionization mass spectra of monoimidazole/polyamine conjugates

Imidazole/polyamine amides are biologically important molecules due to their specific DNA binding activity, and much attention has been attracted to the synthesis of their derivatives or analogues. In the present studies, the fragmentation of a series of synthetic monoimidazole/polyamine amides was investigated using electrospray ionization mass spectrometry (ESI-MS) combined with tandem mass spectrometry (ESI-MS/MS). All of the monoimidazole/polyamine amides produced the fragment ion m/z 183 except for the monoimidazole/ethyldiamine amide. The diamine amides produced this ion after the elimination of an alkene, the triamine amides produced it via their corresponding diamine amide fragments, and the tetraamine amide via its triamine and then diamine amide fragments. The characterization of the mass spectra for the different polyamine amides allowed identification of a specific product from the N-acylation of spermidine, and should assist further study of the polyamine amides in DNA binding action.

Analogues of neuroactive polyamine wasp toxins that lack inner basic sites exhibit enhanced antagonism toward a muscle-type mammalian nicotinic acetylcholine receptor

Philanthotoxin-433 (PhTX-433), a natural polyamine wasp toxin, is a noncompetitive antagonist of certain ionotropic receptors. Six analogues of PhTX-343 (a synthetic analogue of the natural product), in which the secondary amino groups are systematically replaced by oxygen or methylene groups, have been synthesized by coupling of N-(1-oxobutyl)tyrosine with 1,12-dodecanediamine, 4,9-dioxa-1, 12-dodecanediamine, or appropriately protected di- and triamines, the latter being obtained by multistep syntheses. The resulting PhTX-343 analogues were purified and characterized, and their protolytic properties (stepwise macroscopic pK(a) values) were determined by (13)C NMR titrations. All analogues are fully protonated at physiological pH. The effects of these compounds on acetylcholine-induced currents in TE671 cells clamped at various holding potentials were determined. All of the analogues noncompetitively antagonized the nicotinic acetylcholine receptor (nAChR) in a concentration-, time-, and voltage-dependent manner. The amplitudes of acetylcholine-induced currents were compared at their peaks and at the end of a 1 s application in the presence or absence of the analogues. Most of the analogues were equipotent with or more potent than PhTX-343. The dideaza analogue PhTX-12 [IC(50) of 0.3 microM (final current value)] was the most potent, representing the highest potency improvement (about 50-fold) yet achieved by modification of the parent compound (PhTX-343). Thus, the presence of multiple positive charges in the PhTX-343 molecule is not necessary for antagonism of nAChR. In contrast, the compounds were much less potent than PhTX-343 at locust muscle ionotropic glutamate receptors sensitive to quisqualate (qGluR). The results demonstrate that the selectivity for different types of ionotropic receptors can be achieved by manipulating the polyamine moiety of PhTX-343.