Amin F. M. Fahmy

Regioselective Condensation of Alkylidenephosphoranes with Bifunctionalized Compounds: New Approach to the Synthesis of Fused O- and N-Heterocycles

A series of fused pyran- (∼ 40% yield) and furan- (∼ 20% yield) derivatives were regioselectively prepared from the reactions of 5,6-difur-2′yl-3-oxo-2,3-dihydropyridazin-4-carbonitrile with ester- and keto phosphorus ylides, whereas new ylides were obtained, in addition to fused furans, in almost equal yields (33%) from the reaction of the same substrate with cyanomethylene(triphenyl)phosphorane. However, application of such Wittig reagents on 2-[(benzylidene)amino]-benzonitrile afforded, in all cases, 4-hydroxyquinolines in a ∼ 42% yield as major products. Moreover, 2-[(triphenylphosphoranylidene)amino] benzonitrile, with the corresponding alkene, was also isolated a side products.

Study of Insertion Reactions with Phosphorus Ylides − On Reactions between 4-(4-Methylphenyl)-2,3-benzoxazin-1-one and Alkylidene Phosphoranes

4-(4-Methylphenyl)-2,3-benzoxazin-1-one (1) reacts thermally with a series of alkylidene phosphoranes and the relevant salts to give mainly substituted isoquinolines. Thus, compound 1 reacts with ester ylides 2a and 2b to give isoquinolones 7a and 7b, whereas with benzoylmethylenetriphenylphosphorane (3a), compound 7c was obtained together with the corresponding ylide 9a. The latter compound was treated with K2CO3 and then with polyphosphoric acid to give the isoquinolone 7c. With acetyl ylide 3b, o-diacetyl-α-naphthol 13 and cycloheptenone 14 were also obtained, in addition to 7d. On the other hand, isoquinolone derivatives 18, 21a, and 21b were successfully prepared by treatment of 1 with moderately (4a) and more reactive (4b, 4c) phosphonium salts.

New Synthesis of Pyrido[2,3-d] and [3,2-d]Oxazines

Abstract N-Hydroxyquinolinimide 1 reacts with each of aromatic amines, hydrazine hydrate and aromatic hydrocarbons to give arylcarbamoyl pyridines 2, pyrrolopyridines 3, pyridopyridazines 4 and pyridooxazinones 5 and 6. The heterocycles 5 and 6 can be transformed to the condensed systems, triazolopyridopyridazines 14 and 15 through series of reactions.

REACTIONS WITH α, β-SPIROEPOXY-ALKANONES. PART I. SYNTHESIS AND REACTIONS OF OXASPIRO(2,5)OCTA-4-ONES

Abstract 2-Aryl-1-oxaspiro(2,5)octa-4-ones Ia,b were synthesized and reacted with thiourea in ethanol to give hydroxy cyclohexanone derivatives IIa,b. Compounds IIa,b were readily cyclised into the corresponding 5-hydroxy quinazolines IIIa,b and their dehydrated derivatives IVa,b. A mixture of compounds III and IV were also prepared directly from the reaction of compounds Ia,b with thiourea in alkaline medium. Compounds Va,b were produced by reduction of corresponding IV. Compounds III or and V reacted with chloroacetic acid to give resp. VI and VII, which condensed with aromatic aldehydes to form resp. VIII and IX.

Synthesis of Some New Triphenylphosphanylidenes, Alkylphosphonates, and Heterocycles of Pyrazole Derivatives and Their Antimicrobial Activity

Abstract The reaction of 5(4H)-pyrazolone with phosphorus ylides afforded new triphenylphosphanylidene alkanone derivatives. Moreover, its benzylidene derivative reacted with Wittig–Horner reagents to give the corresponding dialkoxyphosphoryl, alkyl phosphonate, and heterocyclic products. Treatment of pyrazole-4-carbaldehyde with Wittig–Horner reagents and trialkyl phosphites gave the respective alkyl phosphonate adducts. Mechanisms accounting for the formation of the new products are discussed. The biological activity of some of the newly synthesized compounds was also examined. GRAPHICAL ABSTRACT

Utility of Phthalimidoacyl Isothiocyanate in Synthesis of Quinazolines, Benzoxazoles, Benzimidazoles, 1,2,4-Triazoles, and Oxatriazepines

Abstract Phthalimidoacyl isothiocyanates 1a,b participated in a wide range of addition–cyclization reactions. Simultaneous or subsequent cyclization of the obtained adducts gave derivatives of quinazoline, benzoxazole, benzimidazole, 1,2,4-triazole, and oxatriazepine. The structures of all the products were confirmed by microanalytical and spectroscopic data. GRAPHICAL ABSTRACT

The Utility of p-N-Succinimidobenzoyl Isothiocyanate in Synthesis of Benzoxazole, Quinazoline, Pyrimidine, 1,2,4-Triazoline, 1,3-Thiazolidine, and Thiourea Derivatives

Reactions of p-N-succinimidobenzoyl isothiocyanate (1) with different nucleophilic reagents afforded adducts. Simultaneous or subsequent cyclization of these adducts gave access to a variety of different heterocycles, including benzoxazole, quinazoline, pyrimidine, 1,2,4-triazoline, 1,3-thiazolidine and others. The structures of the new products were confirmed by their micro-analytical and spectral data. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Synthesis and antimicrobial study of 1,2,4-triazole, quinazoline and benzothiazole derivatives from 1-naphthoylisothiocyanate

1-Naphthoylisothiocyanate (1) is used as a building block in the synthesis of 1,2,4-triazole, quinazoline, benzothiazole and thiourea derivatives. The antimicrobial activity of some of the synthesised compounds was tested.

On the Redox Reaction of 1,2-Bis(diphenylphosphino) Alkanes Toward o-, and p-Quinones

Abstract The reaction of 1,2-bis(diphenylphosphino)ethane with substituted o-benzo-quinones afforded new bis(6-hydroxycyclohexa-2,4-dienone) derivatives. Treatment of the same reagent with o-naphthoquinone, phenanthrenequinone, and acenaphthenequinone gave the respective bis(diphenylphosphoryl)ethylidenes or diacenaphthylenone derivatives. On the other hand, p-quinones react with 1,2-bis(diphenylphosphino)methane to yield the corresponding 4-hydroxycyclohexa-2,5-dien-1-ones. Possible reaction mechanisms are considered and the structural assignments are based on compatible analytical and spectroscopic data. GRAPHICAL ABSTRACT

Multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)-oxazolones (azlactones) using a mechanochemical approach

BackgroundMechano heterocyclic chemistry (MCH) is a recent quickly growing technique in the synthesis of heterocycles and draws the attention of heterocyclic chemists towards the uses of grindstone technique in a solvent free green efficient synthesis of many heterocyclic systems. On the other hand, multicomponent approach has opened the door for the rapid and efficient one-step procedures to synthesize a wide range of complex targets. Azlactones have been reported to exhibit a wide range of pharmaceutical properties including immune suppressive, anticancer. Antimicrobial, antitumor, anti-inflammatory and antiviral. It also used as useful synthons in the synthesis of several small molecules, including amino acids and peptides.ResultsThe present work describes an efficient one step green synthesis of 4-arylidene-2-phenyl-5(4H)-oxazolones (azlactones) via the multi-component synthesis by the mechanochemical grinding of glycine, benzoyl chloride, an aromatic aldehyde and fused sodium acetate in the presence of drops of acetic anhydride. This process is green, simple to handle, step and atom efficient, economical and environmentally friendly, because it does not require a reaction solvent or heating, we introduced the yield economy [YE] as a metric to assess the conversion efficiency of grinding and conventional synthetic reactions of azlactones. The structures of the newly synthesized compounds were elucidated by elemental and spectral analyses.ConclusionIn conclusion, we have developed a simple, efficient and eco-friendly strategy for facile synthesis of azlactones. The key advantages of this strategy, over conventional approach, include its simple, solvent free conditions, as well as its facile work-up, high yield economy and environmental friendliness. It is also successful in achieving three of the green chemistry objectives of a solvent free operation, high atom economy and step efficient. Thus, combining the features of both economic and environmental advantages.Graphical abstractAn efficient one step green synthesis of azlactones via multicomponent synthesis by a mechanochemical grinding.