Abd El-Hamid Ismail

An approach to acyclo-3-deazapyrimidine S-nucleosides via 3,5-dicyano-2(1H)-pyridinethiones

Abstract A series of different acyclo-3-deazapyrimidine nucleosides have been synthesized. The site of glycosylation was confirmed by 13 C NMR spectroscopy.

The ritter reaction of α-chlorocarbenium ions; a synthesis of chloro substituted 2-azoniaallene salts

Abstract α-Chlorocarbenium ions, 9 , stabilized by allylic resonance, react with nitriles, 10 , to give chloro substituted 2-azoniaallene salts, 12 . The cation 12k abstracts chloride from the counterion SbCl 6 − to furnish the chloroimine 13k together with SbCl 5 . The hexachloroantimonates 12 can be transformed into unpolar chlorides, 13b,1 , and 17 , with ammonium chlorides. Compounds 13 and 17 are hydrolyzed to give N-acyl imidoyl chlorides, 14a,b , respectively the allophanate 18 . Electron-rich nitriles insert into the CCl bond of the 2-azoniaallene salts 12 to afford imidoyl chlorides, 151-p,16 .

Synthesis of some new quinazolin-4(3H)-one derivatives and evaluation of their anticonvulsant activity

We reported the synthesis of a novel series of quinazolin-4(3H)-one derivatives bearing oxadiazole, thiadiazole, and other moieties in the 3-position of the quinazolinone nucleus using appropriate synthetic route. The compounds were evaluated for their anticonvulsant activity using picrotoxin model, GABA-A receptor antagonist. Five compounds showed significantly prolonged times for convulsions compared with the standard drug phenobarbital.Graphical abstract

SYNTHESIS OF 1-(2-NAPHTHYLSULFONYL)PYRAZOLE-C-GLYCOSIDES

ABSTRACT 2-Naphthylsulfonylhydrazine was reacted with aromatic aldehydes or aldehydo sugars to give the corresponding hydrazones which undergo Michael addition reactions with malononitrile or ethyl cyanoacetate to form pyrazole derivatives.

Synthesis of N 1- and N 3-quinazolin-(3H)- 4-thione non-nucleosides

Quinazolin-(3H)-4-thione non-nucleosides 7, 9 and 12 were obtained by the reaction of quinazolin-(3H)-4-thione 4 with compounds 5, 8 or 10 respectively. The structures of the synthesized non-nucleosides were confirmed by 1H and 13C NMR spectroscopy.

Synthesis of novel bicycloalkane ring-fused pyridines via Michael addition reaction of a,ß-Unsaturated Nitriles

Camphorylidene(cyano)thioacetamide (3) and camphorylidenemalononitrile (9) were easily prepared by the reaction of (+)-camphor (1) with cyanothioacetamide (2) and malononitrile (8), respectively, under solid-liquid phase-transfer catalyzed conditions. The reaction of the arylidene derivatives of malononitrile, cyanothioacetamide and cyanoacetamide with 3 and 9 leads to condensed 2-thioxo- and 2-oxo-pyridine derivatives. Treatment of the latter compounds with P4S10 causes transformation into the corresponding pyridinethiones.

On the Reaction of alpha,alpha-Dichlorocarbenium Ions with Isocyanates

Trichlormethanes 4 react with two equivalents of n-alkyl isocyanates R2-NCO in the presence of SbCl5 to furnish the 2,2-dichloro-5,6-dihydro-6-oxo2H-1,3,5-oxadiazinium salts (9). The structure of these heterocycles is confirmed by an X-ray analysis of 9d (R1 = ClC = CCl2, R2 = Et). p-Tolyl isocyanate is Friedel-Crafts alkylated by 4b in the presence of SbCl5. Subsequent ring closure affords the quinolinium salt 13, which is hydrolyzed to give inter alia the quinolone 16.