H. A. Daboun

Novel Rearrangement of 5-Arylazo-2-thiohydantoin Derivatives with Alkali and Aromatic Amines

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).

Electrochemical behaviour of some 2,3-dihydrothiazolo[3,2-a]benzimidazol-3-one derivatives—II. Polarographic reduction of a series of 2-arylidene-2, 3-dihydrothiazolo[3, 2-a]-benzimidazol-3-one

The polarographic behaviour of a series of the titled compound in 50% by volume ethanolic aqueous buffers covering a wide range of Ph are reported and discussed. A mechanism interpreting the electrode process is proposed and confirmed via the identification of the resulting products of electrolysis and Hammetts δ—E12 relations.

Reactions with 2-Thiohydantoin, Synthesis of Imidazothiazolone Derivatives and Mannich Bases of 5-Arylidene-2-thiohydantoin

Treatment of 5-arylidene-2-thiohydantoin (1a-d) with alkyl bromoacetate and chloroacetic acid gave the esters 2a-f and the acids 2g-j, respectively. 2a was refluxed with concentrated hydrochloric acid to give 5-benzylidene hydantoin. 2 was cyclized with acetic anhydride to give the bicyclic product 3. 5-Arylidene-2-thiohydantoin derivatives (1a, b) and (8a) condense with formaldehyde and primary or secondary amines to give the corresponding Mannich bases 6a-f and 8c-e, respectively. The assigned structure 6 and 8 finds support from the chemical evidences

Reactions of Amino Acids on 2-Methylmercaptohydantoin Derivatives. Synthesis of Imidazoimidazoline and Imidazoquinazoline Derivatives

Treatment of 5-arylidene-2-methylmercaptohydantoins (1a-d) and 5-arylazo-2-methyl- mercaptohydantoins (3a, b) with glycine in acetic acid gave 5-arylidene-N2-carboxy- methylglycocyamidines (2a-d) and 5-arylazo-N2-carboxymethylglycocyamidines (4a, b) respectively. 2 a, b, d were cyclised with acetic anhydride to give imidazoimidazoline derivatives (5a-c). 2-Methylmercapto-3-phenylhydantoin (7) reacted with anthranilic acid to give 9 which previously prepared by the action of aniline on ethyl 2-methylthio-4-oxo- 3,4-dihydro-3-quinazolinylacetate (8). Arylidenes 1 a-c, 10 a-c and arylazo derivatives 3 a, b reacted with anthranilic acid to give imidazoquinazoline derivatives 11a-f and 12 a, b, respectively.

Chemical Reactivity of 2-Thiohydantoin Derivatives

Treatment of 5-arylazo-2-thiohydantoins (2 a-c) with formaldehyde and the appropriate amine in ethyl alcohol led to the formation of the corresponding Mannich bases 3a-i. 2 a-c reacted with methyl bromoacetate and/or chloroacetic acid to give the esters 5 a-c and/or the free acids 5d-f, respectively. 5e also obtained by treating 5 b with aqueous sodium hydroxide (2%). 5 a-c were cyclised with acetic anhydride to give the bicyclic products 6 a-c. 5-Arylidene-2-thiohydantoins (7 a-e) reacted with acrylonitrile in pyridine to give 5-arylidene-3-β-cyano-ethyl-2-thiohydantoins (8a-e). 8 a-c were hydrolysed with a mixture of acetic-hydrochloric acid to give the corresponding acids 8f-h. Compounds 8a, b, d were alkylated with alkyl halides to give 10 a-e which when hydrolysed with acids gave compounds 13 a-c.

Electrochemical behaviour of some thiazolo[3,2-a]benzimidazol-3(2H)-one derivatives. Part 1. Electroreduction of a series of 2-arylazothiazolo[3,2-a]benzimidazol-3(2H)-ones

The electrochemical reduction of a series of 2-arylazothiazolo[3,2-a]benzimidazol-3(2H)-ones has been investigated. A mechanism for the electrode process covering a wide range of pH values is proposed, discussed, and clarified via model compounds, polarographic analysis, pKa determination, and interpretation of Hammetts σ/E½ relations. Large-scale preparative electrolysis of the title and model compounds was carried out and the products were isolated and identified.

NOVAL REARRANGEMENT OF 5-ARYLAZO-2-THIOHYANTOIN DERIVATIVES WITH ALKALI AND AROMATIC AMINES

Abstract Treatment of 5-arylazo-2-thiohydantoins with aqueous sodium hydroxide affected hetero-ring opening followed by recyclization via the loss of hydrogen sulphide with the formation of 1-aryl-Δ2 -1, 2, 4-triazole-5-imino-3-carboxylic acids.