A promising structural zinc enzyme model for CO2 fixation and calcification

A new ligand, namely, N-{tris([2-[(1-methylbenzimidazol-2-yl)ethyl]methyl]amino)-2-oxoethyl}iminodiacetic acid is synthesized and characterized and used to prepare a zinc complex as a promising model for the active site of the nacreous protein in mollusc shells. Preliminary investigation of CO₂ fixation and calcification is studied with regard to the influence of the pK_a value of the coordinated water molecule and the carboxylate groups.     

Synthesis,spectroscopic characterization,and in vitro antimicrobial activity of fused pyrazolo[4′,3′:4,5]thieno[3,2-d]pyrimidine

4-Amino-3-methyl-1-phenyl-1H-thieno[2,3-c]pyrazole-5-carboxamide ( 1 ), which had been previously synthesized according to literature, was used for synthesizing pyrazolothieno-pyrimidine ( 2 ) in the presence of triethyl orthoformate and acetic acid. Chlorination of the latter compound upon reflux with phosphorus oxychloride afforded the chloropyrazolothienopyrimidine ( 3 ), which underwent heterocyclization reaction with sodium azide to produce the tetrazolo-pyrazolothienopyrimidine ( 6 ). The chloropyrimidine ( 3 ) reacted with hydrazine hydrate to give the hydrazinopyrimidine derivative ( 4 ), which in turn underwent intramolecular condensation reactions with various 1,3-dicarbonyl compounds, namely ethyl acetoacetate, ethyl benzoylacetate, ethyl cyanoacetate, acetylacetone, diethyl malonate, and ethyl (ethoxymethylene) cyanoacetate, yielding new pyrazolyl pyrazolothienopyrimidine ring systems. Also triazolopyrazolothieno-pyrimidines and benzylidene Schiff's base compounds were obtained as a result of the reactions with carbon disulfide in pyridine and benzaldehyde, respectively. The chemical structures of the newly synthesized compounds were elucidated using elemental and spectroscopic analyses (FT-IR, ¹ H-NMR, ¹³ C-NMR, and mass spectroscopy). Some of the synthesized compounds possess high antibacterial and antifungal activities.     

Synthesis,reactions, and spectral characterization of some new biologically active compounds derived from thieno[2,3-c]pyrazole-5-carboxamide

The starting compound 4-amino-3-methyl-1-phenyl-1H-thieno[2,3-c]pyrazole-5-carboxamide (1) , that has been previously synthesized according to the literature procedure, underwent a reaction with the anhydride of phthalic acid either in AcOH or DMF to give isoindolinylpyrazole-5-carboxamide 3 and pyrazolothienopyrimidoisoindoledione 4 , respectively. Also, it was subjected to react with diethylmalonate followed by hydrazinolysis by hydrazine hydrate to yield the pyrazolothienopyrimidinyl acetohydrazide 5 . The carbohydrazide derivative 5 was used as a key intermediate for the preparation of other new heterocyclic systems containing pyrazolylacetyl pyrazolothienopyrimidines and pyrazolothieno-pyrimidotriazepine compounds 6–11 . The structures of these new heterocycles have been characterized by using analytical and spectroscopic analyses (IR, ¹H-NMR, ¹³C-NMR and MS). Some derivatives of the synthesized compounds exhibited remarkable antibacterial and antifungal activities against many bacterial and fungal strains.     

Synthesis and antimicrobial activity of some new coumarin and dicoumarol derivatives

PTC reaction of coumarin derivative 1 with alkyl halides afforded C₄ oxygen alkylation products 2a-d in appreciative yield, whereas with phenyl isothiocyanate gives the C₃ addition product 4 ; also, one-pot three-component PTC reaction was investigated. Treatment of coumarin 1 with aromatic aldehydes in different molar ratios gives 3-arylidene derivatives 7a,b and the dicoumarol derivatives 8a,b . Pyrano chromene 9 and pyrano pyridine 10 were obtained by reaction of arylidene 7a with ethyl acetoacetate through Michael cycloaddition reaction. The stability of pyrone ring in 3-arylidene 7 and dicoumarol 8 towards different nucleophilic reagents under reflux and/or fusion conditions has been studied by the action of hydrazine hydrate, ammonium acetate, methyl amine, and p-toluidine afforded compounds 11 and 13a-c . The antimicrobial activity of some synthesized compounds has been investigated.     

Synthesis and Reactions of 1‐Amino‐5‐morpholin‐4‐yl‐6,7,8,9‐tetrahydrothieno[2,3‐c]isoquinoline

The pyrazolone derivative 4 was synthesized by reaction of carbohydrazide 2 with ethyl benzoylacetate in ethanol and p‐toluene sulphonic acid followed by cyclization upon heating in acetic acid. Chloroacylation of amino ester and amino benzoyl compounds 1 , 19 gave the chloro acetylamino derivatives 5 and 20 respectively which both of them react with different amines to afford compounds 6 , 23a‐d . Hydrolysis and decarboxlation of compound 1 yielded the aminothienotetrahydroisoquinoline 8 which was used as versatile material for synthesizing other heterocyclic compounds 9‐18 . Compound 20 react with hexamethylenetetramine and malononitrile yielded thediazepino and pyrrolo derivatives 21 , 22 respectively.     

SYNTHESIS OF NEW RING SYSTEMS: ISOMERIC 1,2,4-TRIAZOLOPYRIMIDO [4″,5″:4′,5′]THIENO[3′,2′:5,6]PYRIDO[3,2C]CINNOLINES AND OTHER RELATED SYSTEMS

3-Amino-2-Cyano-4-(p-tolyl)thieno[3′,2′:5,6]pyrido[3,2-c]cinnoline 1 underwent ring closures with formamide and carbon disulphide to afford pyrimidothienopyridocinnaline 2 and its pyrimido-9,11-thione derivative 3, respectively. Treatment of 1 with triethylorthoformate followed by hydrazine hydrate produced 10-amino-11-imino-pyrimido system 5, which in turn reacted with triethylorthoformate, acetic acid, carbon disulphide, and acetylacetone to cyclize into the systems, 1,2,4-triazolo, 2-methyltriazolo, triazolo-2-thione, and 1,2,4-triazepinopyrimido thienopyridocinnolines 6– 8, 11, respectively. Similarly, 3-amino-2-carboxamido-thienopyridocinnoline 12 was reacted with triethylorthoformate to give pyrimidothienopyridocinnoline-11-one 13, which was treated with phosphorous oxychloride and then hydrazine hydrate to produce 11-hydrazinopyrimido system 16. Treatment of 16 with triethylorthoformate, acetic anhydride, carbon disulphide, and ethyl chloroformate afforded the systems, 1,2,4-triazolopyrimidothienopyrido-cinnoline derivatives 16– 18, 20, respectively.     

Synthesis and some reactions of 7-methyl-5-phenyl-5H-pyrazolo[3,4-e]1,2,4-triazine-3-thiol

The title compound II has been prepared by the reaction of 3-methyl-1-phenyl-4-oxo-5-pyrazolone with thiosemicarbazide in aqueous potassium carbonate. Alkylation of II on the sulfur atom in aqueous sodium hydroxide afforded the 3-alkylthio derivatives III. Interaction of II or III with different amines yielded the 3-amino derivatives IV. The 3-hydrazino derivative IVa condensed with aromatic aldehydes in ethanol or acetic acid giving the corresponding hydrazones V.     

Synthesis of 3-(Tetritol-1-YL)-6-Phenyl-1,2,4-Triazolo[3,4-a]Phthalazines and Conformational Analysis of their Acetates

ABSTRACT

Condensation of 1-hydrazino-4-phenylphthalazine with D-arabinose, L-arabinose, D-lyxose, and D-xylose gave the corresponding 3-(tetritol-l-yl)-6-phenyl-1,2,4-triazolo[3,4-a]phthalazines (acyclic C-nucleoside analogs). D-Ribose, on the other hand, reacted with the same hydrazine to give the corresponding aldehydo-D-ribo-(4-phenyl-1-phthalazinyl) hydrazone. Catalytic dehydrogenative cyclization of this hydrazone with palladium-on-charcoal affected its transformation into the corresponding triazolophthalazine. Acetylation of the prepared acyclic C-nucleoside analogs gave the corresponding tetra-O-acetyl derivatives, the conformational analysis of which has been studied using proton magnetic resonance spectroscopy. Results of some biological activities of the prepared compounds are reported.