Haider Behbehani

Wastewater Reuse Practices in Kuwait

Water is a scarce commodity in Kuwait. With rapid growth of population coupled with increasing urbanization and agriculture, the demand for water in Kuwait is continually on the increase. The main water source in the country is from desalination with small quantities from underground aquifers. Wastewater effluent at least for irrigation purposes, could be a valuable source to augment this dwindling water supply, and should not continue to be wasted. Reuse of wastewater effluent could both minimize the disposal of water to the environment and reduce the demand on fresh water supplies. This paper discusses the features of reuse, the processes used and standards adopted. Design data, operational results, and physical characteristics for the three wastewater treatment plants (Ardiya, Jahra, and Riqqa) in Kuwait are discussed. In addition, the paper reports on the results of a research study undertaken to determine the willingness, level of awareness and knowledge among the people of Kuwait in using wastewater effluent for different purposes. Cost and benefit analyses were conducted on wastewater effluent and reuse. The study concludes with useful recommendations to both the authorities and the citizens of Kuwait.

Applications of 2-arylhydrazononitriles in synthesis: Preparation of new indole containing 1,2,3-triazole, pyrazole and pyrazolo[1,5-a]pyrimidine derivatives and evaluation of their antimicrobial activities

In this effort, 2-arylhdrazononitriles were used as key synthons for the preparation of wide variety of new, uniquely substituted heterocyclic substances. In addition, the results of biological evaluations demonstrate that members of the group prepared have promising antimicrobial activities against Gram negative bacteria, Gram positive bacteria and Yeast. In the synthetic sequences, 3-(1-methyl-1H-indol-3-yl)-3-oxo-2-(phenylhydrazono)propanenitrile 2a and its 2-methyl derivative 2b were found to react with hydroxylamine hydrochloride to yield the corresponding indolyl-5-amino-2-phenyl-1,2,3-triazoles 4a,b. These amines react with cyanoacetic acid in presence of acetic anhydride either thermally or under microwave irradiation conditions to yield the corresponding cyanoacetamides 5a,b, which condensed readily with dimethylformamide dimethylacetal to yield the enaminonitriles 6a,b. Whereas heating of 6a,b with hydrazine hydrate affords compound 8, compound 12 is produced when these reactants are subjected to microwave irradiation. We observed that the aminopyrazole 9 reacts with enaminal 13 to yield 14 and that its reactions with enaminones 15 afford 17. Finally, compound 5 reacts with cinnamaldehyde to yield the corresponding Schiffs base 18 that does not undergo cyclization to form the pyridine derivative 19. The activities of all new substances synthesized in this investigation were evaluated against a panel of microbial organisms. The results show that 4a, 4b, 5b and 9b display strong antimicrobial activities against all of the tested organisms.

2-Aminothiophenes as building blocks in heterocyclic synthesis: Synthesis and antimicrobial evaluation of a new class of pyrido[1,2-a]thieno[3,2-e]pyrimidine, quinoline and pyridin-2-one derivatives

Multisubstituted 2-aminothiophenes 1a-c can be readily cyanoacylated via reaction with cyanoacetic acid in presence of acetic anhydride under a microwave irradiation to form the corresponding cyanoacetamides 2a-c, which condensed with DMF-DMA to form the corresponding enamines 4 that reacted with hydrazine hydrate to yield the aminopyrazoles 5. Moreover the cyanoacetamides 2a-c reacted with a variety of arylidenmalononitrile to afford a novel pyrido[1,2-a]thieno[3,2-e]pyrimidine derivatives 12a-o. In addition the enamines 4a,b reacted with malononitrile to afford the pyrido[1,2-a]thieno[3,2-e]pyrimidine derivatives 19a,b. The cyanoacetamides 2a,b reacted also with salicylaldehyde to afford the quinoline derivatives 24a,b. Moreover the cyanoacetamides 2a,b reacted with the enaminones 25a-c to form the corresponding Pyridin-2-one derivatives 29a-c. Reactions of 2a,c with bezenediazonium chloride afford the arylhydrazones 30a,b that reacted with chloroacetonitrile to form the acyclic product 31 which could not be further cyclized to the corresponding 4-aminopyrazole. The X-ray crystallographic analyses of seven products could be obtained thus establishing with certainty the proposed structures in this work. Most of the synthesized compounds in this investigation were tested and evaluated as antimicrobial agents.

Efficient atom economic approaches towards macrocyclic crownamides via ring closure metathesis

RCM of suitable 1,ω-dienes led to efficient atom economic synthetic approaches towards azacrown ether derivatives with eight- to twenty four-membered ring sizes.

4-Thiazolidinones in heterocyclic synthesis: synthesis of novel enaminones, azolopyrimidines and 2-arylimino-5-arylidene-4-thiazolidinones.

The 4-thiazolidinones 3a–d were used as a key intermediates for the synthesis of 2-arylimino-5-arylidene-4-thiazolidinones derivatives 7a–p via nucleophilic addition reactions with the arylidene malononitrile. Moreover the 4-thiazolidinones 3a and 3c condensed with the DMF-DMA to form the corresponding enamines 8 and 9 depending on the reaction conditions. Otherwise the 4-thiazolidinone 3b reacts regioselectively with DMF-DMA to afford the enaminones 10 and 11, respectively. The latter reacts with many heterocyclic amines affording polyfunctionally substituted fused pyrimidine derivatives 13–18. The enamine 8b was also reacted with the 3-amino-1,2,4-triazole to afford the acyclic product 19, which could not be further cyclized to the corresponding tricyclic system 20. Moreover the 4-thiazolidinone 3c reacted with the benzenediazonium chloride to afford the arylhydrazones 12. The X-ray single crystal technique was employed in this study for structure elucidation and Z/E potential isomerism configuration determination. The X-ray crystallographic analyses of eight products could be obtained, thus establishing with certainty the structures proposed in this work.

Efficient highly stereoselective synthesis of olefinic macrocyclic crown-formazans with the Z-configuration via ring-closure metathesis

Abstract RCM of 1,5-bis- o -allyloxyphenylformazans with the suitably located 1,ω-dienes leads to an efficient, highly stereoselective, synthetic approach towards Z -olefinic 15-membered ring macrocyclic crown-formazans with potential applications. A novel reduction of pyridine N -oxides to pyridines by the action of Grubbs’ catalyst has been discovered.

Tetra and octa(2,6-di-iso-propylphenoxy)-substituted phthalocyanines: a comparative study among their photophysicochemical properties

This work reports on the synthesis of novel metal free, zinc, aluminum, gallium and indium tetra and octa (2,6-di-iso-propylphenoxy)-substituted phthalocyanine derivatives. UV-visible and 1H NMR analyses confirm that a non-planar conformation, adapted by the phenoxy substituents due to steric interaction in both derivative series, perfectly discourage cofacial aggregation. Fluorescence quantum yields vary as a function of the number of substituents on the ring periphery, while the fluorescence lifetimes display no distinct trend. Triplet quantum yields are significantly larger for the tetra 2,6-di-iso-propylphenoxy- substituted derivatives relative to their corresponding octa-substituted species. However there was no overall trend in the triplet lifetime values. For almost all of the phthalocyanine derivatives, singlet oxygen was produced with relatively good quantum yields. This study explores the possibility of fine-tuning their physicochemical properties by simple structural modification.

Approaches towards the synthesis of a novel class of 2-amino-5-arylazonicotinate, pyridazinone and pyrido[2,3-d]pyrimidine derivatives as potent antimicrobial agents

BackgroundDespite significant progresses in antimicrobial therapy, infectious diseases caused by bacteria and fungi remain a major worldwide health problem because of the rapid development of resistance to existing antimicrobial drugs. Therefore, there is a constant need for new antimicrobial agents. There are a large number of heterocyclic derivatives containing nitrogen atoms that possess a broad spectrum of biological activities including pyridine and pyridazine, which are two of the most important heterocycles in medicinal chemistry.ResultsThe reaction of 3-oxo-2-arylhydrazonopropanals 2 with ethyl cyanoacetate and malononitrile 3a,b has led to the formation of 2-amino-5-arylazo-6-aryl substituted nicotinates 8a-k as sole isolable products when the aryl group in the arylazo moiety was substituted with an electron-withdrawing group like Cl, Br, NO2. The pyridazinones 10 were formed from the same reaction when the arylazo moiety was phenyl or phenyl substituted with an electron-donating group. The 2-aminoazonicotinates 8 were condensed with DMF-DMA to afford the amidines 13a,b, which then were cyclized to afford the targeted pyrido[2,3-d]pyrimidine derivatives 15a,b, respectively. The structures of all new substances prepared in this investigation were determined by using X-ray crystallographic analysis and spectroscopic methods. Most of the synthesized compounds were tested and evaluated as antimicrobial agents and the results indicated that many of the obtained compounds exhibited high antimicrobial activity comparable to ampicillin, which was used as the reference compound.ConclusionA general rule for the synthesis of 2-amino-5-arylazo-6-aryl substituted nicotinic acid and pyridazinone was established using 3-oxo-2-arylhydrazonopropanal as a precursor. Moreover, a novel route to pyrido[2,3-d]pyrimidine was achieved. Most of the synthesized compounds were found to exhibit strong inhibitory effects on the growth of Gram-positive bacteria especially Bacillus subtilis. Compounds 1a, 8a-h, 10a-c, 15b and 16 showed a broad spectrum of antimicrobial activity against B. subtilis.

Ultrasound-assisted regio- and stereoselective synthesis of bis-[1′,4′-diaryl-1-oxo-spiro-benzosuberane-2,5′-pyrazoline] derivatives via 1,3-dipolar cycloaddition

The 1,3-dipolar cycloaddition reaction of the bis-hydrazonoyl chlorides with 2-arylidene-1-benzosuberone derivatives afforded the corresponding bis-[1′,4′-diaryl-1-oxo-spiro-benzosuberane-2,5′-pyrazoline] derivatives. The reaction is carried out under ultrasonic irradiation as well as under conventional heating. The factors affecting the optimization of the cycloaddition reaction are examined in detail. X-ray crystallographic analysis was used in the establishment of the regio- and stereochemistry of the cycloaddition products.

Acylation of Heteroaromatic Amines: Facile and Efficient Synthesis of a New Class of 1,2,3-Triazolo[4,5-b]pyridine and Pyrazolo[4,3-b]pyridine Derivatives

1,2,3-Triazolo[4,5-b]pyridines and pyrazolo[4,3-b]pyridines can be readily prepared via cyanoacetylation reactions of 5-amino-1,2,3-triazoles 1a,b and 4-amino- pyrazole 2 followed by subsequent cyclization of the formed cyanoacetamides. Reactions of amines 1a,b with a mixture of p-nitrophenylacetic acid and acetic anhydride under microwave irradiation conditions afforded the corresponding amides 15a,b that underwent cyclization to form 1,2,3-triazolo[4,5-b]pyridines 16a,b upon heating in DMF solutions containing sodium acetate. Reactions of 1a,b with active methylene compounds, including 17a-c, in the presence of zeolites as catalyst also afforded 1,2,3-triazolo[4,5-b]pyridine derivatives 20a-f via the intermediacy of triazole derivatives 19 and not 18.