a Abdel Hamid

Microwave‐Assisted Synthesis of Quinoline Derivatives from Isatin

Abstract Microwave irradiation has been used for a rapid and efficient synthesis of quinoline‐4‐carboxylic acids 5a–g and 1,2,3,4‐tetrahydroacridine‐9‐carboxylic acid (6) from the reaction of isatins 1–3 with acyclic and cyclic ketones in basic medium. 2‐Hydroxyquinoline‐4‐carboxylic acid (11) was also obtained by irradiating a mixture of isatin 1 and malonic acid in AcOH. The esters of 5f and 11 and their respective hydrazides 8 and 13 were also prepared under MWI.

Synthesis of Aryloxyacetic Acids, Esters, and Hydrazides Assisted by Microwave Irradiation

Abstract Under microwave irradiation on clay a series of transformations of a number of phenols into their aryloxyacetic acids 3 and then their methyl esters 4 and hydrazides 5 has been achieved efficiently in good yields.

Acyclo C-Nucleoside Analogs. Regioselective Annellation of a Triazole Ring to 5-Methyl-1,2,4-Triazino[5,6-b]Indole and Formation of Certain 3-Poly Hydroxyalkyl Derivatives

ABSTRACT Cyclodehydrogenation of the ethylidene derivative of (5-methyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazine (1) gave the angular isomer, 1,10-dimethyl-1,2,4-triazolo[3′,4′:3,4][1,2,4]triazino[5,6-b]indole (4). The linear isomer, 3,10-dimethyl-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole (7) could be prepared regioselectively by the cyclodehydration of the acetyl derivative of 1. The cyclodehydrogenation was extended to the monosaccharide derivatives of 1. The role of the N-methyl group on the site of annellation has been discussed.

Microwave irradiation for enhancing the regioselective synthesis of 6H-indolo[2,3-b]quinoxalines

Microwave irradiation (MWI) promotes the regioselective synthesis of 6H-indolo[2,3-b] quin oxaline (5) by condensation of isatin (1) with o-phenylenediamine. Ethyl indolo [2,3-b] quinoxaline-6-acetate (8) was prepared via the carbethoxymethylation of 5, or from the reaction of N-(ethoxycarbonylmethyl)isatin (6) with o-phenylenediamine under MWI. The reaction of 8 with hydrazine hydrate afforded the hydrazide 9, whose condensation with aromatic aldehydes and monosaccharides gave the hydrazones 10a–d.

A novel synthesis of acyclonucleosides via allylation of 3-[1-(phenylhydrazono)-l-threo-2,3,4-trihydroxybut-1-yl]quinoxalin-2(1H)one

The allylation of 3-[1-(phenylhydrazono)-L-threo-2,3,4-trihydroxybut-1-yl]quinoxalin-2(1H)one (1) gave, in addition to the anticipated 1-N-allyl derivative (2), a dehydrative cyclized product, 1-N-allyl-3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]quinoxalin-2-one (4) and its isomeric O-allyl derivative 3. The O-allyl group in 3 underwent acetolysis under acetylation conditions, in addition to the acetylation of the hydroxyl group, to afford 2-acetoxy-3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl]quinoxaline (8) instead of the O-acetyl derivative of 3. Allylation of the tri-O-acetyl derivative of 1 caused the elimination of a molecule of acetic acid in addition to N-allylation to give 1-N-allyl-3-[3,4-di-O-acetyl-2-deoxy-1-(phenylhydrazono)but-2-en-1-yl]quinoxalin-2-one (11). Hydroxylation of the allyl group gave a glycerol-1-yl acyclonucleoside which can be alternatively obtained by a displacement reaction of the tosyloxy group in 2,3-O-isopropylidene-1-O-(p-tolylsulfonyl)glycerol (14), followed by deisopropylidenation. 1-N-(2,3-Dibromopropyl)-3-[5-(hydroxymethyl)-1-(4-bromophenyl)pyrazol-3-yl]quinoxalin-2-one (15) underwent azidolysis to give a 2,3-diazido derivative. The assigned structures were based on spectral analysis. The activity of compounds 2, 4, 6, and 15 against hepatitis B virus was studied.

Synthesis and Reactions of Acenaphthenequinones-Part-2. The Reactions of Acenaphthenequinones

The reactions of acenaphthenequinone and its derivatives with different nucleophiles, organic and inorganic reagents are reviewed. This survey also covers their oxidation and reduction reactions, in addition to many known reactions such as Friedel Crafts, Diels-Alder, bromination and thiolation.

Synthesis of Organofluorine Compounds Utilizing 3-[1-(3-Fluorophenylhydrazono)-D-erythro-2,3,4-trihydroxybutyl]quinoxalin-2(1H)-one as a Precursor

The reaction of D-erythro-2,3-hexodiulosono-1,4-lactone with 1,2-diaminobenzene followed by 3-fluorophenylhydrazine and the reaction of the product with dimethyl sulfate, sodium metaperiodate and acetic anhydride in pyridine have been investigated. The isopropylidenation of 3-[1-(3-fluorophenylhydrazono)-D-erythro-2,3,4-trihydroxybutyl]quinoxalin-2(1H)-one under thermodynamic controlled conditions has been studied. Compounds 3-[1-(3-fluorophenylhydrazono)-D-erythro-2,3,4-trihydroxybutyl]quinoxalin-2(1H)-one and its N-methyl derivative undergo dehydrative cyclisation in boiling acetic anhydride to the corresponding pyrazolylquinoxalinones

Mode of formation of quinoxaline versus 2[1 H]-quinoxalinone rings from dehydro-d-erythorbic acid

The mode of formation of the quinoxaline versus 2[1H]-quinoxalinone rings by the reaction of o-diamines with dehydro-D-erythorbic acid has been investigated. The study was carried out by using one and two molar equivalents of 1,2-diamino-4,5-dimethylbenzene (3b) to give 6,7-dimethyl-3-(1-oxo-D-erythro-2,3,4-trihydroxybutyl)-2[1H]-quino xalinone (4b) and 2-(2-amino-4,5-dimethylphenylcarbamoyl)-3-(D-erythro-glycerol-1-yl )- 6,7-dimethylquinoxaline (6), respectively. The former product exists predominantly as the two furanosyl anomers. Sequential reaction of 4a with 3b has been studied, and the location of each diamine in the product was deduced by using 1H-n.m.r. spectroscopy. A mechanism for the reaction is proposed. Acetate and acetal derivatives of the compound are prepared.

Synthesis and reactions of some hydrazones of dehydro-l-ascorbic acid☆

Abstract l - threo -2,3-Hexodiulosono-1,4-lactone 2-(3-chlorophenylhydrazone) and 4- (2-acetoxyethylidene)-4-hydroxy-2,3-dioxobutano-1,4-lactone 2-(3-chlorophenylhydrazone) were prepared. The two geometric isomers of the corresponding bis(hydrazone) underwent an intramolecular rearrangement to 1-(3-chlorophenyl)- 3-( l - threo -glycerol-1-yl)-4,5-pyrazoledione 4-(3-chlorophenylhydrazone), which gave a tri- O -acetyl derivative upon acetylation and the anticipated formyl derivative upon periodate oxidation. Oxidation of the bis(hydrazone) with cupric chloride afforded the bicyclic compound 3,6-anhydro-3- C -(3-chlorophenylazo)- l - xylo -2-hexulosono-1,4-lactone 2-(3-chlorophenylhydrazone), whose acetylation afforded the mono- O -acetyl derivative.

Functionalised 1,2,4-triazino[5,6-b]indoles

3-Ethoxycarbonylmethylthio-5H-1,2,4-triazino[5,6-b]indole (2) and 5-ethoxycarbonylmethyl-3-ethoxycarbonyl-methylthio-5H-1,2,4-triazino[5,6-b]indole (4) have been prepared from 2,5-dihydro-3H-1,2,4-triazino[5,6-b]indole-3-thione (1). The reaction of 2 and 4 with hydrazine hydrate gave the respective mono- and bishydrazide derivatives 3 and 5. Reaction of the monohydrazide 3 with acetylacetone, various carbonyl compounds and monosaccharides afforded the respective hydrazones 6 and 8–14. Dehydrative cyclization of 6 and 9 with boiling acetic anhydride afforded the pyrazole and 1,3,4-oxadiazoline derivatives 7 and 15, and reaction of 3 with CS2/KOH followed by hydrazinolysis afforded 16.