Saleh M. Al-Mousawi

Polyfunctional Nitriles in Organic Syntheses: A Novel Route to Aminopyrroles, Pyridazines and Pyrazolo[3,4-c]pyridazines

Phenacylmalononitrile 1 reacts with dimethylformamide dimethyl acetal to yield an enaminone which could be readily converted into a pyrrole or an aminopyridazine by treating with ammonium acetate and hydrazine hydrate, respectively. Compound 1 reacted with hydrazine hydrate in ethanol at room temperature to yield the dihydropyridazine 9 as a single product. In refluxing ethanol this product further reacted with hydrazine hydrate to yield the novel dihydropyrazolopyridazinamine 10.

A Microwave Assisted Diazo Coupling Reaction: The Synthesis of Alkylazines and Thienopyridazines

Heating diazoaminobenzene with active methylene compounds 1–3 in microwave oven in acetic acid, in the presence of hydrochloric acid, afforded the corresponding arylhydrazones 5–7. These reaction products were condensed with ethyl cyanoacetate in a domestic microwave oven after 1–2 minutes heating to yield the pyridazinones 8–12. Compounds 8c and 12 reacted with sulfur in basic DMF solution, in microwave oven using MORE technology to yield the thienopyridazinone 14 and 16 respectively. While 17 was produced when 8b was treated like wise with sulfur and DMF in the presence of piperidine. Compounds 16 coupled with aromatic diazonium salts to yield arylazo derivatives 21a–c.

Condensation Reactions of 3-Oxo-2-arylhydrazonopropanals with Active Methylene Reagents: Formation of 2-Hydroxy- and 2-Amino-6-substituted-5-arylazonicotinates and Pyrido(3,2-c)cinnolines via 6π-Electrocyclization Reactions

3-Oxo-3-phenyl-2-(p-tolylhydrazono)propanal (1a) undergoes condensation with ethyl cyanoacetate in acetic acid in the presence of ammonium acetate to yield either 2-hydroxy-6-phenyl-5-p-tolylazonicotinic acid ethyl ester (6a) or 2-amino-6-phenyl-5-p-tolyl-azonicotinic acid ethyl ester (8), depending on the reaction conditions. Similarly, other 3-oxo-3-aryl-2-arylhydrazonopropanals 1a,b condense with active methylene nitriles 2c,d to yield arylazonicotinates 6b,c. In contrast, 2-[(4-nitrophenyl)-hydrazono]-3-oxo-3-phenyl-propanal (1c) reacts with ethyl cyanoacetate to yield ethyl 6-(4-nitrophenyl)-2-oxo-2,6-dihydropyrido[3,2–c]cinnoline-3-carboxylate (11), via a novel 6π-electrocyclization pathway. Finally, 3-oxo-2-(phenylhydrazono)-3-p-tolylpropanal (1d) condenses with 2a–c to yield pyridazinones 13a–c.

Green synthetic approaches: solventless synthesis of polyfunctionally substituted aromatics as potential versatile building blocks in organic synthesis utilizing enaminones and enaminonitriles as precursors

Abstract A variety of 1,3,5-trisubstituted benzenes could be obtained upon heating enaminones in absence of solvent over montmorillonite-K-10. Heating mixtures of two different enaminones 2a–d have also afforded 1,3,5-trisubstituted benzenes 7b–d and 8b–d resulting from self-condensation of one enaminone with two molecules of the other enaminone. Heating enaminone 2b with ethyl propiolate afforded a mixture of triaroylbenzene 3b in addition to diaroylbenzoic acid esters 11 and 1,3,5-aroylbenzene dicarboxylate 12. On the other hand, reaction of enaminone derivative 2b with dimethyl acetylenedicarboxylate has afforded 2-oxopyran-4-carboxylic acid derivative 15. 2-Aminoprop-1-ene-1,1,3-tricarbonitrile 16 was reacted with enaminones to yield polysubstituted benzenes 19a–c. Likewise the reaction of 2-aminoprop-1-ene-1,1,3-tricarbonitrile 16 with benzylidenemalononitrile has afforded polysubstituted benzenes 24.

A Facile Synthesis of Arylazonicotinates for Dyeing Polyester Fabrics under Microwave Irradiation and Their Biological Activity Profiles

A as textile dyes and the fastness properties of the dyed samples were measured. Most of the dyed fabrics tested displayed very good washing and perspiration fastness and series of 2-hydroxy- and 2-amino-6-substituted-5-arylazonicotinate monoazo compounds 7a–e and 9a–c were prepared via condensation of 3-oxo-3-substituted-2-arylhydrazonals 2a–e with active methylene nitriles 3a–d using microwave irradiation as an energy source. These substances were then tested moderate light fastness. Finally, the biological activity of the synthesized compounds against Gram positive bacteria, Gram negative bacteria and yeast were evaluated.

Studies on enamines and azaenamines: 2-oxoarylhydrazonals as C-1 nucleophiles

2-Oxoarylhydrazonals la,b react with aldehydes; piperidine; morpholine and benzotriazole to yield the corresponding Mannich bases 2a,f, and 4. Formaldehyde reacts with la,b to yield the hydroxymethylarylhyrazons 5a,b together with bisarylhydrazones 6. The hydroxymethyl derivatives 5a are converted to arylhydrazonal 7 upon oxidation in refluxing nitrobenzene. The reaction of aldehydes and malononitrile with la,b in ethanolic solution in presence of chitozan as heterogeneous catalyst afforded 6-amino-1 ,4-dihydropyridazins 14a,b.

Studies with Condensed Azines: New Routes toPyrazolo[3,4-b]pyridines andPyrrolo[3,2-b]pyridines

Several condensed pyrazole derivatives are obtainedfrom the reaction of 3-methyl-1-phenylpyrazol-5-amine (1) withα,β-unsaturated ketones, α,β-unsaturatednitriles and isothiocyanates.

Antimicrobial activities of some novel thiazoles

Abstract2-(4-Phenylthiazol-2(3H)-ylidene)-malononitrile was synthesized by treating 1-phenyl-2-thiocyanatoethanone with malononitrile. Reaction of 2-(4-phenylthiazol-2(3H)-ylidene)-malononitrile with hydrazine hydrate afforded 4-(4-phenylthiazol-2-yl)-1H-pyrazole-3,5-diamine, reaction with benzylidenemalononitrile yielded 2-(5-benzylidene-4-phenyl-5H-thiazol-2-ylidene)-malononitrile, and coupling with benzenediazonium chloride gave 2-(4-phenyl-5-phenylazo-3H-thiazol-2-ylidene)-malononitrile. Diaminopyrazole reacted with enaminonitrile to yield the 3-(4-phenylthiazol-2-yl)pyrazolo[1,5-a]pyrimidine-2,7-diamine. All synthesized compounds showed significant antimicrobial activities with MIC range of 5–750 µg/mL. The results demonstrated a correlation of the hydrophobicity of the compounds with their antimicrobial activity. The most potent antimicrobial compound was 2-(4-phenylthiazol-2(3H)-ylidene)-malononitrile.

Hydroxycinnamic Acids: Natural Sources, Biosynthesis, Possible Biological Activities, and Roles in Islamic Medicine

Hydroxycinnamic acids are the most widely distributed phenolic acids in plants. Broadly speaking, they can be defined as compounds derived from cinnamic acid. They are present at high concentrations in many food products, including fruits, vegetables, tea, cocoa, and wine. Cinnamic acid has received great attention in oriental research where it has been used as an antioxidant in food additives in Asia and especially in medical studies in China after being proven to be an effective component of medicinal herbs used by traditional medicine. Cinnamic acid is a phenolic acid widely distributed in the plant kingdom. It presents a wide range of potential therapeutic effects useful in the treatments of cancer, diabetes, lung, and cardiovascular diseases, as well as hepatic, neuro-, and photoprotective effects and antimicrobial and antiinflammatory activities. Overall, the pharmaceutical potential of cinnamic acid can be attributed to its ability to scavenge free radicals. However, recent studies have revealed that cinnamic acid presents pharmacological properties beyond those related to its antioxidant activity, such as the ability to competitively inhibit HMG-CoA reductase and activate glucokinase, contributing to reduce hypercholesterolemia and hyperglycemia, respectively. A diet rich in hydroxycinnamic acids is thought to be associated with beneficial health effects such as a reduced risk of cardiovascular disease. The impact of hydroxycinnamic acids on health depends on their intake and pharmacokinetic properties. It can be found free, dimerized or esterified with proteins and polysaccharides in the cell wall, such as arabinoxylans in grasses and xyloglucans in bamboo. Cinnamic acid is an important biological and structural component of the plant cell wall. Due to its ability to stop radical chain reactions by resonance followed by polymerization, cinnamic acid offers protection against UV radiation and is responsible for cross-linking polysaccharides and other cell wall polymers. Cinnamic acid can be absorbed by the small intestine and excreted in the urine, where therapeutic efficacy is dependent on its physiological concentrations and pharmacokinetic properties, which include absorption, distribution, metabolism, and excretion of metabolites. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy, especially 2D NMR (COSY, NOESY, HMQC, and HMBC), are the most useful analytical techniques for the structural elucidation of hydroxycinnamic acids besides UV, IR, CD, X-ray analysis, and chemical degradation. In this chapter, we update the reader about the therapeutic properties of cinnamic acid, reviewing its dietary sources, the pharmacokinetic profile, antioxidant action mechanisms, and therapeutic effects in the treatment and prevention of various diseases, in order to provide a basis for understanding its pharmaceutical potential.

Synthesis of N-substituted arylhydrazones: applying to polyester fabric as disperse dyes

Purpose The purpose of this paper is to prepare new disperse dyes and apply for dying polyester fabrics. Design/methodology/approach The synthetic reaction was carried out through two steps: preparation of arylhydrazones and alkylation using enaminone and dimethylaminovinyl-pyridazine. The high temperature method was used to apply these dyes to polyester fibres. Findings The study revealed that there is a significant effect of the new prepared disperse dyes on polyester fabrics. The structures of the prepared dyes were established based on elemental analysis and spectral data (infra red (IR), mass spectrometry (MS) and proton nuclear magnetic resonance (1H-NMR), carbon 13th nuclear magnetic resonance (13C-NMR)). Research limitations/implications Disperse dyes containing heterocyclic moiety have attracted great academic and industrial attention owing to their significant. The potential of using disperse dyes easily prepared from arylhydrazones are promise broad applications for these dyes. Practical implications The presence of N-thienyl and N-pyridazinyl in the structure of the synthesised disperse dyes would be expected to add the bioactivity advantage. Also, it can be used in formulating the antimicrobial fabrics. Social implications The N-thienyl and N-pyrdiazinyl derivatives of azo dyes are expected to be superior to in the application for fabrics. It may be useful for other applications like painting. Originality/value This paper helps to synthesise novel thiophene or pyridazine-based dyestuff for application in dying properties on polyester fabric and study their fastness properties.