Tadeusz Bieg

Double bond migration in Sallyl systems catalysed by [RuClH(CO)(PPh3)3]

Abstract Reactions of S allyl systems (allyl sulphides of RSallyl type, where R=Et, allyl, Ph, Me 3 C, Ph 3 C, as well as of allyl phenyl sulphoxide, allyl phenyl sulphone, 2,5-dihydro-1,1-dioxothiophene) with [RuClH(CO)(PPh 3 ) 3 ] and other ruthenium compounds have been investigated. Double-bond migration was observed in the case of allyl trityl sulphide, allyl t -butyl sulphide and both sulphones, that is, where co-ordinating properties of sulphur were not too strong. High-yielded syntheses of ( E )- and ( Z )-RSCHCHCH 3 (R=Me 3 C, Z : E =96:4 and Ph 3 C, Z : E =92:8), ( E )PhS(O 2 )CHCHCH 3 and 2,3-dihydro-1,1-dioxothiophene from respective allyl systems are described. The binuclear Ru complex, formed in the model reaction of allyl phenyl sulphide with [RuClH(CO)(PPh 3 ) 3 ] has been isolated and its structure has been resolved. The mechanism of the reaction between S allyl systems and [RuClH(CO(PPh 3 ) 3 ] is proposed.

Highly selective synthesis of (E)-N-aryl-N-(1-propenyl) ethanamides via isomerization of N-allyl ethanamides catalyzed by ruthenium complexes

Abstract A convenient and highly selective method of synthesis of (E)-N-aryl-N-(1-propenyl)ethanamides via isomerization of respective N-allyl-N-arylethanamides catalyzed by [RuClH(CO)(PPh3)3] has been described. N-Allyl-N-arylethanamides have been obtained by allylation of respective N-arylethanamides under PTC conditions. It is proposed that the observed selectivity of the double bond migration to (E)-enamides is due to the interaction of the arene ring with the Ru atom in the transition state.

Synthesis of 2-deoxy-hexopyranosyl derivatives of uridine as donor substrate analogues for glycosyltransferases

A series of 2-deoxy-hexopyranosyl derivatives of uridine have been synthesized as analogues of UDP-sugar. These compounds were tested as inhibitors against bovine beta-1,4-galactosyltransferase I in fluorescent assays and showed no significant inhibition.

Simultaneous Removal of Benzyl and Benzyloxycarbonyl Protective Groups in 5′-O-(2-Deoxy-α-D-Glucopyranosyl)Uridine by Catalytic Transfer Hydrogenolysis

Synthesis of N 3,2′,3′-O-tris-(benzyloxycarbonyl)uridine and its use in the synthesis of 5′-O-(2-deoxy-α-d-glucopyranosyl)uridine is described. Simultaneous removal of benzyl and benzyloxycarbonyl groups was accomplished by catalytic transfer hydrogenolysis in the presence of Pearlmans catalyst without competing side reactions.

Cleavage of different ether bonds in butyl glycidyl ether and allyl glycidyl ether by K−, K+(15-crown-5)2

Abstract The kind of substituent in alkyl glycidyl ethers affects the course of their reaction with K−, K+(15-crown-5)2. The cyclic oxirane ring is exclusively cleaved in the case of butyl glycidyl ether whereas the presence of the unsaturated allyl group in the glycidyl ether molecule unexpectedly prefers the scission of the linear ether bond. In both the systems organometallic intermediates are formed. They react with crown ether causing its ring opening. Allylpotassium formed from allyl glycidyl ether reacts also with another glycidyl ether molecule; the oxirane ring is opened in this case.

5-Amino-2-pyridyl 1-thioglycosides in synthesis of analogs of glycosyltransferases substrates.

We present the synthesis of 1-thioglycosyl derivatives of uridine, which were designed to act as potential donor substrates for glycosyltransferases. We constructed such analogs using 5-amino-2-pyridyl 1-thioglycosides as glycosyl units which were connected to uridine via succinic linker. For preparation of the amide bonds we applied different condensation procedures.

Microwave-Assisted Regioselective Benzylation: An Access to Glycal Derivatives with a Free Hydroxyl Group at C4

D-glucal, D-galactal, and their 6-O-TBDMS derivatives were benzylated in a two-step procedure under microwave conditions. In the first step glycals were converted into dibutylstannylene acetal or tributyltin ether intermediates, which were next alkylated with benzyl bromide in the presence of Bu4NBr. In all cases the 4-OH group stayed unsubstituted. Microwave-assisted benzylation contributes to a significant reduction of the reaction time in comparison with the classical synthesis, which requires several hours of heating. Supplemental materials are available for this article. Go to the publishers online edition of Journal of Carbohydrate Chemistry to view the free supplemental file.

Synthesis and cytotoxicity of 2,3-enopyranosyl C-linked conjugates of genistein.

A series of glycoconjugates, derivatives of genistein containing a C-glycosylated carbohydrate moiety, were synthesized and their anticancer activity was tested in vitro in the human cell lines HCT 116 and DU 145. The target compounds 15–17 were synthesized by treating ω-bromoalkyl C-glycosides derived from l-rhamnal (1) with a tetrabutylammonium salt of genistein. The new, metabolically stable analogs of previously studied O-glycosidic genistein derivatives inhibited proliferation of cancer cell lines through inhibition of the cell cycle.

Synthesis and preliminary biological evaluations of 5'-substituted derivatives of uridine as glycosyltransferase inhibitors.

New derivatives of uridine which contain a β-ketoenol motif were synthesized, characterized and biologically tested. Synthesized compounds 1–4 showed no activity against bovine milk β-1,4-galactosyltransferase I at concentrations up to 2.0 mM and were not active against Candida albicans and Aspergilus fumigatus up to the maximum tested concentration of 1,000 µg/mL.

New N-substituted hydrazones, derivatives of uridyl aldehyde

ABSTRACT N-substituted isomeric hydrazones of uridyl aldehyde have been synthesized. The occurrence of the dominant E isomers with respect to the azomethine group was confirmed by means of NMR spectroscopy. Synthesized hydrazones feature an acetonide moiety as a protection of two hydroxyl groups on the ribose part. The attempt to remove the protecting group resulted in an azo-hydrazone tautomeric mixture. The described compounds may be valuable chiral ligands for metal chelation. Assessment of manganese(II) ion affinity to one selected hydrazone was performed.