K. M. Kondratyuk

Introduction of chiral 2-(aminoalkyl) substituents into 5-amino-1,3-oxazol-4-ylphosphonic acid derivatives and their use in phosphonodipeptide synthesis

Starting from phthalimidoalkanoylamines 1 (amino-protected derivatives of L-alanine, L-valine, and L-leucine), we have suggested a straightforward synthetic route to 5-amino-1,3-oxazol-4-ylphosphonic acid derivatives 5 containing a chiral aminoalkyl substituent on the 2-position of the oxazole ring. Compounds 5 have been further used to obtain phosphonodipeptides 8, 9, and 10 with the original optical purity retained.

A Facile Synthesis of 1,3-Thiazole-4-sulfonyl Chlorides

Abstract A four-step preparative-scale synthesis of eight 2-alkyl- and arylsubstituted thiazole-4-sulfonyl chlorides from chloralamides is reported. Good yields and easy availability of starting materials are valuable advantages of the procedure that gives access to formerly unattainable building blocks. GRAPHICAL ABSTRACT

Reaction of diethyl 1-acylamino-2,2-dichloroethenylphosphonates with amino acids esters

Reactions of available diethyl 1-acylamino-2,2-dichloroethenylphosphonates with amino acids esters were studied, which in the case of esters of proline, nipecotic and isonipecotic acids resulted in N-substituted derivatives of 5-amino-4-diethoxyphosphoryloxazol in high yields. Their behavior in the acidic and alkaline media was investigated by the example of methyl N-(4-diethoxyphosphoryl-2-R-oxazol-5-yl)isonipecotinate.

Synthesis of new 4-phosphorylated derivatives of 5-amino-1,3-oxazole

The N-1,1,1,2-Tetrachloroethylamides were found to react with diethyl amidophosphites via the Arbuzov reaction to afford N-substituted amides of ethyl 1-acylamino-2,2,2-trichloroethylphosphonic acids. A convenient method for the synthesis of new 4-phosphorylated 5-amino-1,3-oxazoles on their basis was developed.

New Heterocyclic Pyrano[2′,3′:5,6]Chromeno[3,2-c]Pyridin-4-Ones and Furo[2′,3′:5,6]Chromeno[3,2-c]Pyridin-3(2H)-Ones Synthesized Via a Hetero-Diels–Alder Reaction

The behavior of flavonoid Mannich bases in inverse electron-demand hetero-Diels–Alder reactions was studied. Isoflavones and aurones were used as examples to show that their Mannich bases reacted with 4-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)morpholine through an elimination mechanism and subsequent cycloaddition to form derivatives of the new heterocyclic systems pyrano[2′,3′:5,6]chromeno[3,2-c]pyridin-4-one and furo[2′,3′:5,6]chromeno[3,2-c]pyridin-3(2H)-one.

Synthesis of phosphorylated dehydrotyrosine-containing tripeptides from 5-amino-2-aminoalkyl-1,3-oxazole-4-phosphonic acids derivatives

Interaction of 4-phosphorylated derivatives of 5-amino-2-aminoalkyl-1,3-oxazole with 4-(4-acetoxybenzylidene)-2-phenyl-1,3-oxazol-5-one resulted in the formation of new 1,3-oxazole derivatives. The latter undergo 1,3-oxazole ring opening to give phosphorylated tripeptides with a dehydrotyrosine fragment.

Synthesis and some properties of 4-phosphorylated derivatives of 5-mercapto-1,3-oxazoles

Various approaches to the synthesis of new derivatives of diethyl 5-mercapto-2-R-1,3-oxazole-4-ylphosphonates were considered. The behavior of these compounds in the presence of mineral acids and alkalis resulting in the synthesis of previously unknown 5-mercapto-2-R-1,3-oxazole-4-ylphosphonic acids was studied.

A convenient approach to synthesis of benzoxazol-2-ylglycine and benzothiazol-2-ylglycicne derivatives

Introduction of pharmacophore heterocyclic moieties into the peptide chain is of particular interest because it results in a promising new bioregulators [1] with a significant anticonvulsant, neuropathic and analgesic activity [2–6], and also oxytocin antagonists [7]. However, the functionalization of α-amino acids with electron-acceptor heterocycles is a challenging task, due to their ease of decarboxylation. This substantially limits the use of such amino acids in peptide synthesis. In this work, we developed a convenient approach to the synthesis of glycine derivatives, which were modified at the α-position with benzoxazol-2-yl and benzothiazol-2-yl moieties. For the first time we used for this purpose available 2-phenyl-4-dichloromethylene-5(4H)-oxazolone [8], which was involved into the reactions sequence: I → III → V or VII. The reaction I → III has been previously described by an example of 2-aminothiophenol [9], and all the other reaction were investigated by us for the first time. The DOI: 10.1134/S1070363213060364

Aminomethylation of Afromosin, Cladrastin, and Their 2-Methyl Derivatives

Aminomethylation of the natural isoflavones afromosin and cladrastin and their 2-methyl derivatives was studied. Several new Mannich bases of 7-hydroxy-6-methoxyisoflavones were synthesized under Mannich reaction conditions using aminals of secondary amines.

1,3-oxazole derived cytisines

Reactions of 1-acylamino-2,2-dichloroacrylonitriles, diethyl 1-acylamino-2,2,2-trichloroethyl-phosphonates and 1-acylamino-2,2-dichloroethenylphosphonium salts with natural alkaloid cytisine have been studied. A series of novel multifunctional cytisine derivatives containing pharmacophore 1,3-oxazole moiety have been obtained. Composition and structure of the synthesized compounds have been confirmed by mass spectrometry and NMR spectroscopy data.