Synthesis and spectral characterization of some new thiazolopyrimidine derivatives

Thiazolopyrimidnes are considered one of the most interesting classes in heterocyclic chemistry due to their pharmaceutical importance. Herein, we report the synthesis of some new heterocyclic compounds containing thiazolopyrimidine starting from compound (1) which was previously prepared in literature. The starting compound was allowed to react with different alkylating agents such as chloroacetone, chloroacetyl chloride, and phenacyl bromide to afford derivatives (2-4). Compound (5), benzylidene derivative, was obtained by the reaction of compound (2) with benzaldehyde while amino-dicarbonitrile compound (6) can be obtained by the reaction of compound (5) and malononitrile. Acetylation of amino group in compound (6) with chloroacetyl chloride led to formation of compound (7). Nucleophilic substitution of chlorine in compound (7) by aniline gave compound (8) which further subjected the Munich reaction to form compound (9). All new synthesized compounds were characterized using different elemental and spectral analysis.

Study of N-benzylidene derivatives synthesized as corrosion inhibitors for copper in HCl solution

Corrosion inhibition of the two N-benzylidene derivative compounds, as corrosion inhibitors for copper in HCl 6.0 M have been studied by electrochemical methods such as potentiodynamic polarization measurements and EIS.

Darstellung von 2,3,8-substituierten Perhydrooxazolo[3,2-a]pyridinen und die Kristallstruktur von (E)-3-(2-Fluorbenzyliden)-1-[1,2-bis(2-fluorphenyl)- 2-hydroxyethyl]-3,4,5,6-tetrahydropyridiniumchlorid

2-Fluorobenzaldehyde (1) and pipecolic acid (7) react in dimethyl sulfoxide with potassium carbonate to form benzylidene-oxaindolizidines 4. These diastereomers yield with acids uniform salts, so from 4 with hydrogen chloride results (E)-3-(2-fluorobenzylidene)-1-[1,2-bis(2-fluorophenyl)-2- hydroxyethyl]-3,4,5,6-tetrahydropyridinium chloride (6·Cl), elucidated by X-ray structural analysis. Treatment of 6·Cl with alkali hydroxide regenerates 4. Similarly proline (13), when treated with two equivalents of 1, gives rise to oxapyrrolizidines 14. From 14 in presence of 1 the perchlorate of the benzylidene derivative 15·ClO4 can be obtained which is transformed to benzylideneoxapyrrolizidines 15 by bases.

The life, death, and ROMP activity of ruthenium complexes containing the basic, chelating diphosphine bis(dicyclohexyl)-1,4-phosphinobutane

Reaction of RuCl2(PPh3)3 with bis(dicyclohexyl)-1,4-phosphinobutane (dcypb) under N2 affords access to a formerly elusive family of dcypb complexes based on the RuCl2(PP) core. Under Ar or vacuum atmosphere, decomposition occurs via Ru-promoted dehydrogenation of the dcypb ligand. While the N2-stabilized species [RuCl2(dcypb)]2(N2) (4a) is easily handled under N2 in nonchlorinated solvents, reaction with chlorinated solvents rapidly yields paramagnetic Ru2Cl5(dcypb)2 (5). The N2 ligand within 4a is readily displaced under H2 or CO atmosphere, yielding Ru2Cl4(dcypb)2(H2) (6) or RuCl2(dcypb)(CO)2, the latter as a mixture of ccc-(7) and tcc-(8) isomers. Benzylidene derivative RuCl2(dcypb)(CHPh) (1a), prepared in situ by reaction of 4a with PhCHN2, proves exceptionally active in ring-opening metathesis polymerization (ROMP) of norbornene. The X-ray crystal structure of 5 is reported: triclinic, a = 13.390(2), b = 15.726(2), c = 19.524(2) Å, α = 77.325(2), β = 70.964(2), γ = 73.478(2)°, with space group P[Formula: see text] and Z = 2.Key words: ruthenium, alkylphosphine, dehydrogenation, carbene, metathesis, crystal structure.