Mohamed Refat H. Mahran

ORGANOPHOSPHORUS CHEMISTRY, 11.1 THE 1:2 ADDITION OF ALKYL PHOSPHITES TO 3-METHYLENE-OXINDOLES. A NEW TYPE OF ATTACK BY TERVALENT PHOSPHITE ESTERS ON α,β-UNSATURATED CARBONYL COMPOUNDS

Abstract The addition of trialkyl phosphites 2a,b to 3-methylene-oxindoles, &,b proceeded according to the 1:2 pattern to give 13a-d as major products. Compounds 14s-d (<10%) were also isolated and identified from the same reactions. Compounds 14 were exclusively obtained when controlled amounts of water were present in the reaction medium or when &,b were reacted with the appropriate dialkyl phosphite (15). Analytical and spectroscopic (IR, 1H, 31P, 13C NMR and MS) measurements are compatible with the proposed structures.

ORGANOPHOSPHORUS CHEMISTRY, 271. THE REACTION OF ISATIN, 5-METHYLISATIN AND THEIR MONOXIMES WITH ALKYL PHOSPHITES, TRIPHENYLPHOSPHINE AND PHOSPHORUS YLIDES

Abstract 5-Methylisatin ( 1b) reacts with TAP ( 4a–c) and/or DAP ( 3a-c) to give the respective dialkyl α-hydroxyphosphonates (8a-c). Isatin-monoxime ( 5a) and 5-methyl isatin-monoxime ( 5b) react with alkyl phosphites to give dialkyl 2-oxo-indolyl phosphorates ( 8a–c, 12a–f, 15a–c) as major products. The carbonyl-group at position – 3 in 1b is deoxygenated by triphenylphosphine to give a new phosphorus ylide ( 17 ) and by methylenetriphenylphosphoranes (Wittig-reagents, 7a-c) to afford the respective 3- substituted methylenes ( 19a-c) in good yields. Possible reaction mechanisms were considered and structural assignments were based upon analytical, chemical and spectroscopic (IR, 1H NMR, 31P NMR and MS) results.

On the Synthesis of Pyrazino[2,3-b]phenazine and 1H-Imidazo[4,5-b]phenazine Derivatives

Summary. Several pyrazino[2,3-b]phenazine derivatives were prepared by the reaction of 2,3-diaminophenazine with different 1,2-diketones. Nucleophilic substitution of 2,3-dibromomethyl-pyrazino[2,3-b]phenazine with propanol, morpholine, and potassium thiocyanate gave 2,3-bis-(propoxymethyl)-pyrazino[2,3-b]phenazine, 2,3-bis-(4-morpholinylmethyl)-pyrazino[2,3-b]phenazine, and 2,3-bis-(cyanosulfanylmethyl)-pyrazino[2,3-b]phenazine. 2-Aryl-1H-imidazo[4,5-b]phenazine derivatives were synthesized by a one-pot reaction of 2,3-diaminophenazine with different aromatic aldehydes or acids. Reaction of 2,3-diaminophenazine with acetic anhydride and formic acid afforded 1H-imidazo[4,5-b]phenazine and 2-methyl-1H-imidazo[4,5-b]phenazine. Chemical and spectroscopic evidences for the product structures of the new compounds are presented.Zusammenfassung. Einige Pyrazino[2,3-b]phenazinderivate wurden durch Reaktion von 2,3-Diaminophenazin mit verschiedenen 1,2-Diketonen dargestellt. Nucleophile Substitution von 2,3-Dibrommethyl-pyrazino[2,3-b]phenazin mit Propanol, Morpholin und Kaliumthiocyanat ergab 2,3-Bis(propoxymethyl)-pyrazino[2,3-b]phenazin, 2,3-Bis-(4-morpholinylmethyl)-pyrazino[2,3-b]phenazin und 2,3-Bis-(cyanosulfanylmethyl)-pyrazino[2,3-b]phenazin. 2-Aryl-1H-imidazo[4,5-b]phenazinderivate wurden in einer Eintopfreaktion aus 2,3-Diaminophenazin mit verschiedenen aromatischen Aldehyden oder Carbonsäuren hergestellt. Reaktion von 2,3-Diaminophenazin mit Essigsäureanhydrid oder Ameisensäure lieferte 1H-Imidazo[4,5-b]phenazin und 2-Methyl-1H-imidazo[4,5-b]phenazin. Chemische und spektroskopische Nachweise für die Struktruren der neuen Verbindungen werden mitgeteilt.

ORGANOPHOSPHORUS CHEMISTRY, 21.1 THE BEHAVIOUR OF 1-DICYANOMETHYLENE-ACENAPHTHEN-2-ONE AND 1-DICYANOMETHYLENE-3-INDANONE TOWARD ATTACK BY ALKYL PHOSPHITES

Abstract Trialkyl phosphites (Ia-c) and dialkyl phosphonates (11a-c) attacked 1-dicyanomethylene-acenaphthen-2-one (9) at the α-carbon atom with respect to the nitrile group, to give phosphonate adducts 13a–c and 14a–c, respectively. The reaction proceeded according to 1:2 addition. On the other hand, 1 reacts with 1-dicyanomethylene-3-indanone (10) to give the respective O-alkylated products 17, while 11 attacked 10 at the β-carbon atom with respect to the nitrile group to give the corresponding phosphonates 18. Structures of the new compounds were confirmed on the basis of elemental analyses and spectral studies.

ORGANOPHOSPHORUS CHEMISTRY 31[1]

Abstract 3-(Aryliminomethyl)chromones ( 5a, b ) produce the respective phosphonates (8a-f) upon reaction with the appropriate dialkyl phosphite ( 2a-c ) and/or trialkyl phosphhite ( 3a-c ). New complex ylidenetriphenyl-phosphoranes ( 13a, b ) were obtained directly and in good yield via condensing arylimines 5a, b with the resonance stabilized methylenetriphenylphosphoranes (4a, b) in boiling toluene. The reaction mechanism of 5a, b with trialkyl phosphites ( 3a-c ) was discussed. Compatible elementary and spectroscopic measurements were recorded for the new products.

ORGANOPHOSPHORUS CHEMISTRY 221. REACTION OF 3-FORMYL-4-CHROMONE WITH TER- AND PENTA-VALENT PHOSPHORUS COMPOUNDS

Abstract Trialkyl phosphites (2) and dialkyl phosphonates (5) attack the aldehydic carbonyl-carbon of 3-formyl-4-chromone (1), yielding the corresponding α-alkoxy (4), and α-hydroxy-phosphonates (6), respectively. On the other hand, the reaction of 1 with ylide-phosphoranes (10) proceeded according to the Wittig reaction mechanism, to give the respective ethylenes 13. Identity of the isolated products are based on analytical, chemical and spectroscopic data.

ORGANOPHOSPHORUS CHEMISTRY 25.1 THE UTILIZATION OF WITTIG REAGENTS IN LACTONE RING FORMATION. APPLICATION TO THE SYNTHESIS OF LINEAR FUROCOUMARINS AND PYRANOCOUMARINS

Abstract A new and improved method for the preparation of linear furocoumarins (7a,b) and pyranocoumarins (10a,b) in high yields, is described. It depends upon reacting ylid-phosphoranes (5) with suitably substituted benzofuran-, (3) or the benzo-γ-pyrone-(4) moiety. Formation of the target compounds (7 and 10) is assumed to proceed via lactonization of cis alkyl α-hydroxycinnamate intermediates of types 6 and 9, respectively. The trans analogues 8 do not lactonize to 10 even upon heating in boiling toluene. The new compounds have been characterized by their spectroscopic data (IR, PMR, 13C NMR) and elementary analyses.

ORGANOPHOSPHORUS CHEMISTRY, 20.1 THE BEHAVIOUR OF CERTAIN γ-PYRONE DERIVATIVES TOWARD 2,4-BIS-(4-METHOXYPHENYL)-1,3,2,4-DITHIAPHOSPHETAN-2,4-DISULPHIDE (LAWESSON REAGENT)

Abstract Lawesson reagent LR,1 converts 2.6-dimethyl-y-pyrone 2a. flavone 3a into their corresponding thioketones 2b and 3b in high yields. Thiation of flavone 3a with Lawesson reagent LR,1 can be also induced photochemically to give thioflavone 3b together with the ring phosphorane product 6A. Thiation of khellin 4a by LR to give 4b is accompanied by demethylation of 4b to give desmethylthiokhellin 4c. The behaviour of γ-pyrones 2a, 3a and 4a toward thiation with LR,1 was discussed in the light of the principle of vinylogy.

ORGANOPHOSPHORUS COMPOUNDS, 9.1 THE REACTION OF YLID-PHOSPHORANES WITH NITROSONAPHTHOLS

Abstract α-Nitroso-β-naphthol (1a) reacts with ylid-phosphoranes 3a-c to give the corresponding imines 4a-c. On the other hand, β-nitroso-α-naphthol (1b) undergoes deoxygenative dimerization by the same reagents to yield the azo-derivative 6. The appropriate symmetrically disubstituted ethylene 7 was also isolated and identified in each reaction. Structures 4, 6 and 7 were attested by compatible analytical and spectroscopic results.

ORGANOPHOSPHORUS CHEMISTRY 10. THE BEHAVIOUR OF β-AROYLACRYLIC ACIDS TOWARD NUCLEOPHILIC PHOSPHORUS COMPOUNDS

Abstract The reaction of alkyl phosphites and thiolphosphoric acids with β-aroylacrylic acids 1a,b has been investigated. Dialkyl phosphites (DAP) attacked 1 at the β-carbon atom with respect to the aroyl-carbonyl function, to give phosphonate 1:1 adducts assigned structure 2A. Thiolphosphoric acids (7) attacked 1 at the same centre to give adducts 8. On the other hand, trialkyl phosphites (TAP) converted 1 into the respective esters 5, almost exclusively. Structures of the new products were assigned according to consistent analytical and spectroscopic measurements.