Rajab Abu-El-Halawa

Removal efficiency of Pb, Cd, Cu and Zn from polluted water using dithiocarbamate ligands

Abstract Presently, there is increased attention and focus on heavy metals, which are becoming one of the most serious environmental problems due to their adverse health effects. These toxic heavy metals are not easily degraded and require removal from polluted water to protect people and the environment. The purpose of this work was to prepare two types of dithiocarbamate ligands, one aliphatic (diethyldithiocarbamate) and the other aromatic (diphenyldithiocarbamate), and to use them as chelators to remove Pb, Cd, Cu and Zn from polluted water. Dithiocarbamates were selected because they have good binding ability and can precipitate metal ions as complexes. The metal removal efficiency is compared between both ligands and also compared to the efficiency of activated carbon in an adsorption process to remove the same metals. The investigation results indicated that the diphenyldithiocarbamate ligand was more efficient in removing the studied metals than the diethyldithiocarbamate analogues. Additionally, the metal removal efficiency of the diphenyldithiocarbamate ligand was more effective than using the activated carbon method.

Synthesis and Biological Activity of Some Nucleoside Analogs of Hydroquinoline-3-Carbonitrile

Hydroquinoline acyclonucleosides 2, 4, 6a,b, 8a,b, 9a,b, and their corresponding N-alkyl derivatives (10–12) were obtained by the reaction of 1a,b with acetoxybutylbromide, (2-acetoxyethoxy)methyl bromide, 3-chloropropanol, 1,3-dichloro-2-propanol, epichlorohydrin, propargyl/allyl bromides in the presence of K2CO3 in dry dimethylformamide (DMF). In a similar manner, reaction of 1a,b with glycosyl/galactosyl and lactosyl bromide afforded the corresponding N-nucloside derivatives 13a,b, 15a,b, and 17, respectively. Deacetylation of the N-nucleosides derivatives in the presence of Et3N/MeOH and few drops of water gave the deprotected derivatives 3, 5, 7a,b, 14a,b, 16a,b, and 18 in good yields, respectively. All the newly synthesized compounds are elucidated by infrared, 1H, 13C NMR and elemental analyses. Some of these compounds were screened for antimicrobial activities.

On the Reaction of Cyanamides with N-Alkylnitrilium and N,N-Dialkylcyanamidium Salts

N-Alkylnitrilium and N,N-dialkylcyanamidium salts 1 and 2 undergo ene reactions with cyanamides 4 to afford 2-azoniaallene salts 7 and 9 in which the N-alkylnitrilium salts 1 react as the ene, and the cyanamides 4 react as the enophile components. Competing with the ene reaction, N-alkylnitrilium salts 1 undergo [2++2+2] cycloaddition to furnish triazinium salts 8. 2-Azoniaallene salts react with alcohols to afford alkoxy amino derivatives 10 and 12, which yield iminium salts 11 and ketals/acetals upon further reaction with alcohols. The constitution of the 2-azoniaallene 7 and 9 and triazinium salts 8 was secured by elemental analyses and spectral properties (IR and NMR). Graphical Abstract On the Reaction of Cyanamides with N-Alkylnitrilium and N,N-Dialkylcyanamidium Salts

The Reaction of Cyanamidium Salts with Ylidenecyanamide Derivatives

Cyanamidium salts 1undergo ene reactions with ylidenecyanamide derivatives 5to afford conjugated iminium salts 12. The N,N,Nʹ-trialkylcyanamidium salts 1react as the ene, and the ylidenecyanamide derivatives 5react as the enophile components to form the 2-azoniaallene salts 11 followed by the formation of conjugated iminium salts 12 as cationic polynitrogen compounds with guanidine and amidine subgroups. The constitution of the new conjugated iminium salts 12 was secured by elemental analyses and spectroscopic data (IR and NMR). Graphical Abstract The Reaction of Cyanamidium Salts with Ylidenecyanamide Derivatives

One-Pot Synthesis of 2-Alkyl/arylamino-6-chlorothieno(3,2-e)-1,3- thiazin-4-one

Alkyl/arylamino-6-chlorothieno(3,2-e)-1,3-thiazin-3-one derivatives were prepared in one-pot synthesis by refluxing alky/arylisothiocyanates and 2,5-dichloro-3-thiophene- carboxamide. Alternatively, these derivatives were prepared by the intramolecular cyclization of the deprotonated 2,5-dichloro-N-(alkyl/arylaminocarbonothioyl)thiophene-3-carboxamides, which were obtained by the reaction of the deprotonated 2,5-dichloro-3-thiophene-carboxamide with alky/arylisothiocyanates. The structures of the newly synthesized bicyclic derivatives, and their acyclic precursors, were confirmed based on microanalytical and spectral (IR, MS, and NMR)

Concise Synthesis and Displacement Reactions of Model 3-(Alkylthio)- 6-chloro- and 2,6-Dichlorothieno[2,3-e][1,4,2]dithiazine 1,1-Dioxides

A series of 3-(alkylthio)-6-chlorothieno[2,3-e][1,4,2]dithiazine 1,1-dioxides (7a - e) were prepared via interaction of deprotonated 2,5-dichlorothiophene-3-sulfonamide with carbon disulfide under reflux, followed by alkylation with alkyl halides. Employment of dimethyl sulfate afforded the isomeric 2-methyl-3-thione derivative 8 together with the expected 3-(methylthio) derivative 7a in a molar ratio of 1 : 4. Treatment of 7a or 10 with ethylamine, aniline or p-chloroaniline produced the corresponding N-ethyl- (or N-phenyl)-6-chlorothieno[2,3-e][1,4,2]dithiazine-3-amine 1,1-dioxides 3a - c. Likewise, interaction of 7a with methylhydrazine (or phenylhydrazine) gave the respective 3-(1-methylhydrazinyl or 2-phenylhydrazinyl) 1,1-dioxides 9a, b. Desulfonation of 6-chloro-3-(methylthio)thieno[ 2,3-e][1,4,2]dithiazine 1,1-dioxide (7a) with sulfuryl chloride produced 3,6-dichlorothieno[2,3- e][1,4,2]dithiazine 1,1-dioxide (10). The latter compound was used as a substrate for the preparation of N-alkyl- (or aryl)-6-chlorothieno[2,3-e][1,4,2]dithiazin-3-amine 1,1-dioxides 3a - c representing a new approach for the synthesis of similar derivatives. Compounds 7a - e showed modest to low antibacterial activity against E. coli and S. aureus. Graphical Abstract Concise Synthesis and Displacement Reactions of Model 3-(Alkylthio)- 6-chloro- and 2,6-Dichlorothieno[2,3-e][1,4,2]dithiazine 1,1-Dioxides