Leonid G. Menchikov

A Straightforward Approach toward Multifunctionalized Pyridazines via Imination/Electrocyclization

A facile synthesis of functionalized 3-carbamide pyridazines starting from readily available chlorovinyl aldehydes and oxamic acid thiohydrazides via cascade imination/electrocyclization is reported. In the presence of p-toluenesulfuric acid, various ketones have been efficiently incorporated into the pyridazine derivatives through a two-step sequence involving a Vilsmeier-Haack reaction and imination. The synthetic value of this method has been demonstrated by efficient synthesis of steroidal pyridazines.

Access to steroidal pyridazines via modified thiohydrazides

An approach to steroids annulated with pyridazines via cascade imination/electrocyclization of chlorovinyl aldehydes with oxamic acid thiohydrazides is disclosed. A mechanistic rationalization was performed using real-time 1H NMR spectroscopy and computational studies. A series of 18-nor-5α-androsta-2,13-diene[3,2-d]pyridazines, androsta-2-ene[3,2-d]pyridazines and Δ1,3,5(10)-estratrieno[16,17-d]pyridazines were synthesized from native hormones. These compounds were screened for cytotoxicity against the human estrogen-responsive breast cancer cell line MCF-7 and the estrogen-independent breast cancer cell line MDA-MB-231. The structure–activity relationship analysis revealed that the annulation of the pyridazine moiety to the A-ring of the 17β-hydroxy-5α-androsta-2-ene core provides high antiproliferative activity. Compounds 7a and 10b exhibited higher antiproliferative potency than the drug cisplatin. 5α-Androsta-2-ene[3,2-d]pyridazine 10c showed good selectivity against the MCF-7 breast cancer cells.

Influence of surfactants on laser-induced copper deposition from solution

The influence of surfactants on the result of laser induced copper deposition from solution on the dielectric surface was studied. The dependences of the topology of the copper structures on the hydrophilic—lipophilic balance of non-ionogenic surfactants was found. The surface tension at the gas phase—solution interface was measured. The best results of laser deposition are obtained by the use of non-ionogenic surfactants with low values of hydrophilic—lipophilic balance.

Ambiguousness of GC-MS identification of spiro[2.4]hepta-4,6-diene in natural objects

The publications on the GC-MS identification of spiro[2.4]hepta-4,6-diene in various natural objects were critically considered. Significant similarity of the mass spectra and coincidence of the GC retention indices on standard nonpolar phases of spiro[2.4]hepta-4,6-diene (761±3) and its isomer (toluene, 760±8) do not allow one to assert that the spirocyclic hydrocarbon was found in all the cases. Additional analytical parameters should be applied to differentiate such isomers.

CCDC 1402494: Experimental Crystal Structure Determination

Related Article: Alexander V. Komkov, Anna S. Komendantova, Leonid G. Menchikov, Elena I. Chernoburova, Yulia A. Volkova, Igor V. Zavarzin|2015|Org.Lett.|17|3734|doi:10.1021/acs.orglett.5b01718

The Warburg Effect Is a Guide to Multipurpose Cancer Therapy Including Trace Element Delivery

The Nobel Prize Winner (1931) Dr. Otto H. Warburg had established that the main energy source of the cancer cell is aerobic glycolysis (the Warburg effect). He also postulated the hypothesis about “the prime cause of cancer”, which is a matter of debate till nowadays. On the contrary to the hypothesis, his discovery was completely recognized. However, the discovery had been almost vanished in the heat of battle about the hypothesis. The prime cause of cancer is important for the prevention and diagnosis, and yet the effects that influence on tumor growth are more important for cancer treatment. As a consequence of the Warburg effect, the recovery of the oxygen respiration of cancer cells can inhibit the tumor growth and lead to a remission. Here, we review the current knowledge of the inhibition of abnormal glycolysis and normalization of oxygen respiration of malignant tumor and a potential role of ultra trace element germanium in this process. Efficiency of different Ge-delivery molecules is also discussed.