ChemInform Abstract: Preparation of 3‐Amino‐2‐arylamino‐4(3H)‐quinazolinones.

Abstract

ChemInform Abstract Twenty-five thioxoquinazolinones such as (I) are S-alkylated with ethyl bromide (II) and subsequently coupled and rearranged with hydrazine hydrate (IV) to produce the title compounds (V).

Synthesis of acyclo C-Nucleosides of H1-antihistaminic 4-substituted [1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones

“…Elemental analyses were carried out by the Microanalytical Centre of Cairo University, Giza, Egypt. The starting 2-hydrazino-3-phenylquinazolin-4(3H)-one (3) 23 and its 3-cyclohexyl analog (4) 24 were prepared by hydrazinolysis of the respective 3-substituted-2-thioxo-1,2-dihydroquinazoline-4(3H)-ones 1 and 2 according to literature method.…”

New Efficient Synthesis of 1,2,4‐Triazolo[5,1‐b]quinazolin‐9(3H)‐ones via a Tandem Aza‐Wittig/Heterocumulene‐Mediated Annulation

“…The methods described so far for the preparation of some representative derivatives of this ring system involve either reaction of anthranilic acid with 3‐mercapto‐ s ‐triazoles18 or cyclization of 3‐amino‐2‐arylaminoquinazolin‐4(3 H )‐ones with carboxylic acids, acyl chlorides or aldehydes 20−22. However, these methods often require relatively harsh acid, dehydrating conditions or heating at high temperature.…”

Domino Cyclization of 2-Isothiocyanatobenzonitrile with Carboxylic Hydrazides − One-Pot Synthesis of 1,2,4-Triazolo[1,5-c]quinazoline-5(6H)-thiones

“…For example, 1,2,4‐triazolo[5,1‐ b ]quinazolines show antihypertonic activity 1. Antirheumatic and antianaphylactic activity has been recognized for 3‐heteroaryl‐1,2,4‐triazolo[5,1‐ b ]quinazolines,2 while 1,2,4‐triazolo[1,5‐ c ]quinazolines possess antiasthmatic, tranquilizing, and neuro‐stimulating activity 3. Aryl‐ and heteroaryl‐substituted derivatives have been shown to possess benzodiazepine binding activity 4.…”