Tarik E. Ali

Synthesis and antibacterial activity of some new thiadiaza/triazaphospholes, thiadiaza/triaza/tetrazaphosphinines and thiadiaza/tetrazaphosphepines containing 1,2,4-triazinone moiety

Some new thiadiaza/triazaphospholes, thiadiaza/triaza/tetrazaphosphinines and thiadiaza/tetrazaphosphepines fused with 6-methyl-1,2,4-triazin-5-one moiety were synthesized via reactions of alpha,beta-bifunctional compounds derived from 4-amino-3-mercapto-6-methyl-1,2,4-triazin-5(4H)-one (1) with various phosphorus reagents. The in vitro antibacterial activities of the synthesized compounds were evaluated against some bacterial strains. Compounds 16 and 21 exhibited good inhibitory activities against most the tested organisms with MIC values in the range 6.25-12.5 microg/mL and lower cytotoxicity in comparison with the reference drugs.

Synthesis and antimicrobial activity of chromone-linked 2-pyridone fused with 1,2,4-triazoles, 1,2,4-triazines and 1,2,4-triazepines ring systems

Three series of novel fused nitrogen heterocyclic systems such as 1,2,4-triazolo[1,5-α ] pyridines (5-7 and 9), pyrido[1,2-b][1,2,4]triazines (10, 11, 13 and 15), and pyrido[1,2-b][1,2,4]triazepines (17, 18, 20 and 22) linked with a chromone moiety were synthesized from the key intermediate 1,6-diamino-(6-chloro-4-oxo-4H-chromen-3-yl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (4) with some electrophilic reagents. The structures of the novel compounds were established by elemental analyses and spectral data. All the products were also screened invitro for their antimicrobial activity. Compounds 7, 9 and 15 showed the highest activities when compared with the reference drugs.

Synthesis and Fungicidal Activity of Some New 4H-Chromen-4-ones Containing Some 1,3-Thiazole, 1,3-Thiazine, 1,2,4-Triazole and 1,2,4-Triazine Moieties

The potassium salt of carbamodithioic acid derivative 3 reacted with some electrophiles reagents to afford the 2-thioxo-1,3-thiazoles 4–5 and 2-thioxo-1,3-thiazines 6–7 derivatives. Heterocyclization of compound 3 with amino-mercapto compounds 8–9 and/or hydrazine derivatives 12–13 yielded 3-thioxo-1,2,4-triazoles 10–11 and 3-thioxo-1,2,4-triazines 14–15 , respectively. Structures of the products have been determined by elemental and spectral methods. All the new compounds have been screened for their fungicidal activity.

Synthesis of Bioactive 4-Oxo-4H-Chromenes Bearing Heterocyclic Systems from Hydrazonecarbodithioic Acid and Thiocarbohydrazone

Condensation 4-oxo-4H-chromene-3-carboxaldehydes (1a,b) with acid hydrazine-carbodithioic acid and/or thiocarbohydrazide afforded hydrazonecarbodithioic acid 2, monothiocarbohydrazone 3a,b and bisthiocarbohydrazone 4, respectively. Heterocyclization of 2–4 via reaction with oxygen, sulfur and/or halogen reagents in different media yielded pyridazinethione 5; 1,3-thiazoles 7; pyrazoles 9–12; 1,2,4-thiadiazoles 8,13,14, and 23; 1,2,4-triazolethiones 15–17; 1,2,4-triazinethiones 18–22; imidazolethione 24 and pyrimidinethione 25 derivatives. Antifungal activity was screened for some the new synthesized compounds. Formulations of all products have been deduced by elemental analysis and spectral data (IR, 1H NMR and Mass spectroscopy).

Synthesis and biological evaluation of some new polyfluorinated 4-thiazolidinone and α-aminophosphonic acid derivatives

A simple route for the synthesis of new polyfluorinated 4-thiazolidinones and 1,4-bis(4-thiazolidinone)phenylenes was achieved from one-pot three-component reaction of fluorinated aniline, mono- and dialdehyde and thioglycolic acid followed by fluorination with trifluoroacetamide and 4-fluorobenzaldehyde. Also, some new fluorinated α-aminophosphonates, 1,4-bis(α-aminophosphonate)phenylenes and their corresponding acids were synthesized via one-pot three-component reaction of fluorinated aniline, mono- and dialdehyde and diethyl phosphite followed by fluorination with trifluoroacetic anhydride. All the synthesized compounds were screened for their antifungal activity against Alternaria alternate and Fusarium oxysporium. Also, their effects on the enzymatic effect of cellobiase produced from Alternaria alternate and Fusarium oxysporium were estimated. Compounds that have trifluoromethyl groups recorded good inhibition against the fungal strains and also enhanced the enzymatic effect of cellobiase.Graphical abstract.

Synthesis of Some New 1,3,2-Oxazaphosphinine, 1,3,2-Diazaphosphinine, Acyclic, and/or Cyclic α-Aminophosphonate Derivatives Containing the Chromone Moiety

The synthesis of some new 1,3,2-oxazaphosphinine 18, 1,3,2-diazaphosphinine 19, acyclic, and cyclic α-aminophosphonate derivatives 3–17 containing the chromone moiety have been achieved via reaction of 3-(phenyliminomethyl)chromone (1), 3-(phenylaminomethylene)-2-hydroxychromanone (4), and/or 3-(phenylamino-methylene)-2-(phenylamino)chromanone (5) with diethyl phosphite, tris(2-chloroethyl)phosphite, and phenylphosphonic dichloride. Structures of the products were verified on the basis of their elemental analyses, IR, 1H, and 31P NMR spectral data.

Synthesis and Molluscicidal Activity of Phosphorus-Containing Heterocyclic Compounds Derived from 5,6-Bis (4-bromophenyl)-3-hydrazino-1,2,4-triazine

Novel N1-(phosphoryl moiety)-N2-(1,2,4-triazin-3-yl)hydrazines 4, 6, 8, 9 and 12, iminophosphorane 3, iminophosphane 5, 1,2,4-triazinyldiazaphospholine 7, 1,2,4,3-triazaphospholinotriazines 2, 10, 11, and 1,2,4-triazino[3,2-c][1,2,4,5] triazaphosphine 13 have been obtained via treatment 5,6-bis(4-bromophenyl)-3-hydrazino-1,2,4-triazine (1) with various polyfunctional phosphorus reagents by stirring at room temperature or refluxing for long time in tetrahydrofuran. Structures of these compounds have been deduced upon the basis of elemental and spectral data. Molluscicidal activity of the prepared compounds against Biomphalaria Alexandrina snails (the intermediate host of Schistosoma mansoni) showed considerable activities.

Cleavage of Diethyl Chromonyl α-Aminophosponate with Nitrogen and Carbon Nucleophiles: A Synthetic Approach and Biological Evaluations of a Series of Novel Azoles, Azines, and Azepines Containing α-Aminophosphonate and Phosphonate Groups

Abstract A convenient synthetic approach leading to a series of novel substituted azoles, azines, and azepines linked to the α-aminophosphonate moiety was achieved. The methodology depends on ring opening and ring closure (RORC) of the chromone ring of diethyl chromonyl α-aminophosphonate 1 via its reaction with nitrogen nucleophiles such as primary amines and 1,2-, 1,3-, and 1,4-bi-nucleophiles in ethanolic sodium ethoxide. Also, treatment of compound 1 with some acyclic and cyclic active methylene compounds under the same reaction conditions afforded interesting novel isolated and fused pyridine systems bearing phosphonate groups at the α-position. The screening of antimicrobial activity for the synthesized compounds indicates that connection of pyrazole, oxazepine, and benzodiazepine rings with α-aminophosphonate moiety exhibited good antimicrobial effects. Also, evaluation of their antioxidant properties shows that the compounds having 1,5-benzoxazepinyl and 1,5-benzodiazepinyl units in combination with α-aminophosphonic diester moiety are the most powerful antioxidant agents. GRAPHICAL ABSTRACT

Synthesis of Biologically Active 4-Oxo-4H-Chromene Derivatives Containing Sulfur-Nitrogen Heterocycles

The synthesis of 4-oxo-4H-chromenes containing sulfur-nitrogen heterocyclic rings as well as their biological activities are reviewed.

A convenient synthesis and biological evaluation of some novel linear and cyclic α-aminophosphonic acid derivatives containing a quinazolinone ring

Synthesis of some novel linear and cyclic α-aminophosphonic acids and their esters bearing a quinazolin-4(3H)-one ring was achieved. The methodology depends on Pudovik reaction conditions in which using 3-(benzylideneamino)-2-phenyl-quinazolin-4(3H)-one (2) with phosphorous acid, diethyl phosphite and tris(2-chloroethyl) phosphite gives the corresponding linear α-aminophosphonic acid derivatives 3, 5 and 7, respectively, in good yields. Heterocyclization of the linear compounds to 1,4,2-oxazaphosphinanes as cyclic α-aminophosphonic acid derivatives 4, 6 and 8, respectively, was carried out. The synthesized compounds were evaluated for their antimicrobial and antioxidant activities. The cyclic α-aminophosphonic acids and their esters showed better antimicrobial and antioxidant activities than the corresponding linear α-aminophosphonic acids and their esters.Graphical AbstractSynthesis of some novel linear and cyclic α-aminophosphonic acids and their esters bearing a quinazolin-4(3H)-one ring as antimicrobial and antioxidant agents from 3-(benzylideneamino)-2-phenyl-quinazolin-4(3H)-one was achieved.