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A Convenient Synthesis of 1,2-Dihydro-1,2,4-triazolo[3,2-b]quinazolin-9(1H)-ones and Their 1,2,4-Triazolo Derivatives

Article - 1997, Vol.70, No.9

2209-2213

A Convenient Synthesis of 1,2-Dihydro-1,2,4-triazolo[3,2-b]quinazolin-9(1H)-ones and Their 1,2,4-Triazolo Derivatives

El-Hiti Gamal Abdel-Rahman ¹

¹ Chemistry Department, Faculty of Science, Tanta UniversityTanta, Egypt

https://doi.org/10.1246/bcsj.70.2209

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Abstract

A range of 1,2-dihydro-1,2,4-triazolo[3,2-b]quinazolin-9(1H)-ones (3) has been synthesized in very good yields by the reaction of 3-amino-2-anilino-4(3H)-quinazolinone (1) with aromatics aldehydes in the presence of excess piperidine as a base. The 1,2,4-triazolo[3,2-b]quinazolin-9(1H)-ones could be obtained in very good yields by dehydrogenation of compounds 3 with thionyl chloride. Reaction of 1 with active methylene compounds (diethyl malonate and acetylacetone) resulted in the production of condensed products. These condensed products could be cyclized to 1,2,4-triazolo[3,2-b]quinazolin-9(1H)-one by heating above the melting point. Acetylation of 1 by acetic anhydride was found to be dependent on the reaction conditions. The acetyl derivative 3-acetamido-2-anilino-4(3H)-quinazolinone formed under mild conditions, while dimerization took place under strong conditions to give a pentacyclic compound in very good yield.

bcsj 1992 - Vol.65 , No.2, pp. 546 - 552

Synthesis of 3-(Alditol-1-yl)triazolo[4′,3′:2,3]-1,2,4-triazino[5,6-b]indoles

Ahmed Mousaad, Hamida Abdel Hamid, Ahmed El Nemr, El Sayed H. El Ashry

A series of the hydrazones were prepared by the reaction of 3-hydrazino-5H-1,2,4-triazino[5,6-b]indole (1) with monosaccharides, and their acetylation was studied. Cyclodehydrogenation of the hydrazones gave 3-(substituted)-10H-1,2,4-triazolo[4′,3′:2,3][1,2,4]triazino[5,6-b]indole, whose acetylation and partial acetylation were carried out. The ring-chain tautomerism of the hydrazones promoted their heterocyclization. The linear structure, and not that of the angular isomer, has been selected for the products. This structure has been confirmed from a model study of the cyclization of the acetaldehyde derivative of 1, which was found to be identical with that product obtained from the reaction of 4,5-diamino-3-methyl-1,2,4-triazole with isatin. Periodate oxidation of the hydrazones and their cyclized products was also studied.

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bcsj 1994 - Vol.67 , No.1, pp. 149 - 155

Regioisomeric Formation of Acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazines and Their Acyclic C-Nucleoside Analogues

Nagwa Rashed, Mahmoud Shoukry, El Sayed H. El Ashry

The oxidative cyclization of the ethylidene derivative of 3-hydrazinoacenaphtho[1,2-e][1,2,4]triazine (2) gave regioselectively the angular isomer 1-methylacenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (5). Its linear isomer 10-methylacenaphtho[1,2-e][1,2,4]triazolo[4,3-b][1,2,4]triazine (4) was synthesized by the condensation of acenaphthenequinone (6) with 3,4-diamino-5-methyl-4H-1,2,4-triazole. Condensation of 2 with a number of monosaccharides afforded the respective hydrazones 9 whose oxidative cyclization gave the corresponding 1-(polyhydroxyalkyl)acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (10). Acetylation of 9 and 10 gave 3-[N-acetyl-N′-(polyacetoxyalkylidene)hydrazino]acenaphtho[1,2-e][1,2,4]triazine (11) and 1-(polyacetoxyalkyl)acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (13) respectively. Periodate oxidation of 9e gave 3-(2-oxoethylidenehydrazino)acenaphtho[1,2-e][1,2,4]triazine (14).

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bcsj 1983 - Vol.56 , No.4, pp. 1227 - 1230

Open Access

Synthesis of the 1,2,4-Triazolo[4,3-a]quinazolin-5-ones and Related Compounds

H. A. El-Sherief, A. E. Abdel-Rahman, G. M. El-Naggar, A. M. Mahmoud

2-Hydrazino-3-phenyl-4(3H)-quinazolinone (1) underwent ring closure with aliphatic acid, aldehydes, and carbon disulfide to 1-alkyl-, 1-aryl-, and 1-mercapto-4-phenyl-1,2,4-triazolo[4,3-a]quinazolin-5(4H)-ones (7) for instance. The 1-alkylthio-3-phenyl-1,2,4-triazolo[4,3-a]quinazolin-5(4H)-ones were readily obtained from 7 and alkyl halides. Reaction of 1 with ethyl acetoacetate gave the corresponding hydrazone which was readily converted into 2-(3-methyl-5-oxo-2-pyrazolin-1-yl)-3-phenyl-4(3H)-quinazolinone.

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bcsj 1993 - Vol.66 , No.9, pp. 2612 - 2616

Chemical Interactions between 1,2,4-Triazole-3-thiols and π-Acceptors

Alaa A. Hassan, Nasr K. Mohamed, Yusria R. Ibrahim, Kamal U. Sadek, Aboul-Fetouh E. Mourad

4-Amino-5-mercapto-5-substituted 4-amino-1,2,4-triazole-3-thiols 1a, b reacted with tetrachloro-, tetrafluoro-p-benzoquinone and 2,3-dichloro-1,4-naphthoquinone as well as 2-(dicyanomethylene)-1,3-indandione via charge-transfer (CT) complex formation giving naphthotriazolothiadiazinone 2a—d, bistriazolobenzobisthiadiazine 3a—d, triazolobenzothiadiazinone 4a, b, bistriazolonaphthobisthiadiazine 5a, b, and indenatriazolothiadiazepine 7a, b derivatives.

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bcsj 1992 - Vol.65 , No.6, pp. 1652 - 1656

Studies in Vilsmeier–Haack Reaction. IX. Synthesis and Application of Novel Heterocyclo-Substituted Furo[2,3-c:5,4-c′]dipyrazole Derivatives

Ibrahim M. A. Awad

The Vilsmeier-Haack reaction on 4,4′-bi-4H-pyrazole-5,5′(1H, 1H′)-dione brought about the formation of one methyl group, chloro substitution of a carbonyl group in the 5-position, and the cyclization of the 5-chloro-3-(2-amino-1-formylethenyl)derivative in one step to give the corresponding furo[2,3-c:5,4-c′]dipyrazole (3). Treatment of 3 with some secondary heterocyclic amines gave the aminomethylene derivatives 6–8. Interaction of 3 with hydroxylamine hydrochloride, hydrazine hydrate and phenylhydrazine afforded the corresponding isoxazolyl and pyrazolyl derivatives 9–11 which have been screened in vitro for antibacterial and antifungal activities.

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Article - 1997, Vol.70, No.9

A Convenient Synthesis of 1,2-Dihydro-1,2,4-triazolo[3,2-b]quinazolin-9(1H)-ones and Their 1,2,4-Triazolo Derivatives

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