The polarographic behaviour of a series of arylazothiohydantoin derivatives has been investigated a t a dropping mercury electrode. Two waves were displayed. The first and predominant one is due to the reductive splitting of the azo-linkage by a 4e irreversible process. The second is assumed to be for the reduction of the CONHCO group in the resulting molecule. A mechanism for the electrode process covering a wide range of pH is proposed, discussed, and clarified via model compounds, identification of the resulting products of electrolysis, pK, determinations, and the interpretation of a-€3 plots.
The reaction of α‐cyanothioacetamide (1) or its methylthio derivative (2) with anthranilic acid led to the formation of 3,4‐dihydro‐4‐oxoquinazolin‐2‐yl acetonitrile (3). 3 condensed with aromatic aldehydes to give arylidene derivatives (4a‐d) which could be prepared also via the reaction of 2‐thiocarbamoylcinnamonitriles (5a‐d) or their methylthio derivatives (6a‐d) with anthranilic acid. 3 reacted with cinnamonitrile derivatives (7a‐h) and (12a‐d) to yield pyrido‐[1,2‐a]‐quinazoline derivatives (10a‐h) and (15a‐d) which could also be prepared by the reaction of (4a‐d) with malononitrile (11a), benzoyl acetonitrile (11b) and ethylcyanoacetate (16), respectively.
Abstract 5-Arylazo-2-thiohydantoin derivatives (2a,c) were cleaved and rearranged by aqueous sodium hydroxide to give the corresponding 1-aryl-⊿2-1,2,4-trazole-5-imino-3-carboxylic acids (3a-c). 3 a was decarboxylated to 1-phenyl-⊿2 -1,2,4-triazoline-5-imine (5). Hydrolysis of 5-arylazo-1-phenyl-2-thiohydantoins (6a-c) behaved in different manner affording 1-aryl-4-phenyl-⊿2 -1,2,4-triazoline-5-thione-3-carboxylic acids (7a-c). Fusing (2a-c) with aromatic amines at high temperature gave the corresponding anilides (8a-h). Treatment of 5-arylidene-2-thiohydantoin derivatives (9a-c) with hydrazine hydrate gave colourless products of thioureido cinnamic acid hydrazide derivatives (10a-c), while refluxing 5-arylidene-2-methylmercaptohydantoin (11a-d) with hydrazine hydrate and/or benzo-phenone hydrazone gave the corresponding glycocyamidine derivatives (12a-g).
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