The study of preparation by classic and microwave irradiation methods, spectroscopic characterization of 3-Acyl-2-R-methylchromone derivatives(R = H, C6H5, ArO ). Some subsequent reactions of these products with hydroxylamine and by aldol condensation with 3-formylchromones have been studied.

Pseudo-Michael reaction of 2-aminoimidazolines bearing substituents in position 1 (aryl or alkyl) and 5 (hydrogen or aryl - respectively) can lead to isomeric enamines due to possibility of tautomeric shift of C=N double bond in and out of imidazoline ring

In a two-step reaction (pseudo-Michael/acylation) of 1-aryl-2-hydrazinoimidazolines with DEEM (diethyl ethoxymethylenemalonate) formation of 2,3-dihydroimidazo[2,1--c][1,2,4]triazepine system was observed. This type of reaction usually lead to formation of 5:6 or 6:6 membered fused hetero-cyclic systems whereas reaction of hydrazine derivatives (alkyl or aryl) or hydrazides and DEEM give pyrazoline carboxylates. In the literature formation of fused 1,2,4-tri-azepines in reaction of a-hydrazinoazoheterocycles is not mentioned. In first step of reaction of 1-aryl-2-hydrazinoimidazolines with Michael reagents chain enamine is formed.

New interpretation of the mechanism of CH-acid condensation with aldehydes using quantum chemical method is reported in this work.

The preparation of some sulfur bridged substituted pyrimidines, pyrazoles, and imidazoles is reported in this communication.

Naphthalene- or DTBB-catalyzed lithiation of chloroimines 1, deprotonated chlorobenzyl alcohols, mercaptanes or amines 4, and 3-phenylthiopropylamine 7 in THF at -78deg.C leads to the formation of the corresponding intermediates 2, 5 and 8, which by reaction with carbonyl compounds as electrophiles afford the expected bifunctionalized compounds 3, 6 and 9, respectively.

The preparation of N-Boc-protected (S)-6-isopropyl-5-phenyl-1,2,3,6-tetrahydro-2-pyrazinone from (S)-valine and glycine in seven steps and its reactivity with carbonyl compounds affording stereoselectively (Z)-didehydroamino acids derivatives is reported in this communication.

The nucleophilic addition of 2-furyllithium to esters derived from L-serine is described. The obtained furyl ketone 5 is stereoselectively reduced (ds>=95%) with sodium borohydride to afford the corresponding syn aminoalcohol 12 in enantiomerically pure form. Compound 12 was further converted into valuable a-hydroxy-[beta]-amino acids by means of the furan-to-acid equivalence.

The aza-Wittig reaction1 of iminophosphoranes ([lambda]5-phosphazenes, phosphine imines) with carbonyl compounds, when carried out inter- or intramolecularly, leads to the formation of C=N double bonds, usually under neutral and mild reaction conditions. Several review articles1,2 have appeared recently reporting the increasing significance of the aza-Wittig reaction in organic synthesis, basically in the preparation of nitrogen-containing heterocyclic compounds.

Cardiac glycosides of Digitalis species are well known heart-stimulating drugs, clinically used for treatment of congestive heart failure.2 In the steroidal moiety of the aglycons (cardenolides) the C/D cis ring junction, the 14b-OH and the 17b-butenolide could be recognized as three peculiar features for a potent pharmacological action, while the A/B ring junction can vary from cis (e.g. digitoxigenin) to trans (e.g. uzarigenin) (Fig. 1) without a dramatic loss of activity. As a part of our work aimed at searching new digitalis-like compounds with an improved pharmacological profile, we synthesized compound 9 (Fig. 1) in which the C/D part of the molecule was maintained while the A/B part was simplified in a 5b-cyclohexyl substituent.