Synthesis of some new aralkylsulfonyl carboxamides and hydrazones: with expected herbicidal and antibacterial activity

The outstanding antituberculous and herbicidal activities of 2-benzalhydrazonobenzothiazoles and 2-benzalhydrazonobenzoxazoles, and the high antibacterial activities of 4-substituted benzenesulfonylhydrazones, prompted us to synthesise compounds, possessing both sulfonyl and benzalhydrazono groups, which may have biological activities

Reactions with 2-phenylhydrazono-4-thiazolidinone

2 phenylhydrazono-4-thiazolidinone [1] reacted with acrylonitrile to yield the N[1]- Beta-cyanoethylphenylhydrazono derivative 2. The reaction of 1 with phenacyl bromide afforded the N[1]phenacyl-phenylhydrazono derivative 5 which can be readily cyclized into the new fused thiazolo [2,3-c]-l,2,4-triazine derivative 6. The reaction of 1 with ethyl bromoacetate afforded the thiazolo-[2,3-c] -1,2,4-triazinpne derivative 7. The reaction of 1 with phenylmethylenemalononitrile afforded the adduct 9

reaction of azides with active methylene reagents

The reaction of active methylene reagents with sulphonylazides is one of the best known methods for preparing polyfunctional diazo compounds. However, active methylene nitriles and active methylene ketones have been shown to afford in some cases cyclic 1,2,3-triazoles. Reactions of this type have been reviewed several times in literature .In connection with our interest in the synthesis of heterocyclic derivatives from activated nitriles we have investigated the reaction of p-tosylazide with several activated nitrile derivatives. It has been found that tosylazide reacts with benzoylacetonitrile in ether in the presence of sodium hydroxide to yield a product of molecular formula C[16]H[12]N[4]O[2]S. Structure 3 was readily established for the reaction product based on its IR spectrum which revealed the absence of diazo group absorption. Treatment of compound 3 with equimolecular amount of hydrazine hydrate at 100 degree in absence of a solvent afforded a mixture of two products of mp. 125 degree and 193 degree which were separated by fractional crystallization from ethanol. The product of the mp. 125 degree was shown to be the amidrazone 4 based on its analytical data and the absence of absorption for cyano- and diazo- functions in its IR spectrum. On the other hand, the other product revealed analytical data indicating that it is only an isomer for 3; its IR spectrum revealed the presence of cyano- and diazo- functions, consequently structure 5 was suggested for this product. Similar isomerisatian of 1, 2, 3-triazoles into diazo- compounds has been observed in literature and reactions of this type have been summarized by Regitz. The isomerisatian of 3 into the diazo- derivative 5 prompted us to try isomerisatian of the 1,2,3-triazole 6, prepared by Regitz et al by the reaction of malononitrile with 1, into the diazo- derivative 7. However, the reaction afforded the amidrazone on treatment with phenylhydrazine. Compound 1 also reacted with 1,1, 3-tricyano-2- aminopropene under similar conditions to yield the 1,2,3-triazole derivative 10. Attempts to convert this compound into the diazo- derivative 11 by our procedure or other reported procedures for isomerising 1, 2, 3-triazoles into diazo-derivatives, were unsuccessful. In contrast to the observed behaviour of active methylene nitriles, the aryl-hydrazononitriles 12a-c were treated with sodium azide in DMF to yield 1,2,3,4-tetrazole derivatives 13a-c. To our knowledge only few examples of the reaction of nitriles with azides to yield tetrazoles have been reported in literature Compound 1 reacted with 1, 3-diphenyl-5- aminopyrazole [14a] to yield the pyrazolo [4, 5-d] 1, 2, 3-triazole derivative 15. On the other hand, the aminopyrazole 14b reacted under the same conditions to yield the tetrazene derivative 16. Under a variety of conditions l-phenyl-3-methyl-2-pyrazolin-5-one reacted with tosylazide to yield the hydrazo derivative 18. The formation of 18 is assumed to proceed via intermediacy of the diazo derivative 19 formed through the triazine 20 [c.f. chart 2]. In order to get evidence for this assumption the reaction of 17 with 1 was conducted in the presence of [3-naphthol. The coupling product 21 was isolated in addition to 18 and the azo derivative 22

Cleavage reactions of 4-thiazolidinone-2-thiones: reactions with 5-arylhydrazono-4thiazolidinone-2-thiones

In continuation to our interest in the chemistry of thiazolidinone ring systems, owing to their considerable biological activities, we re-Port here on the behaviour of 5-arylhydrazono-4-thiazolodinone-2-thiones [6] la and b toward the action of a variety of nucleophilic reagents. Thus, subjecting la and b to the action of aliphetic amines affected elimination of the arylhydrazono group with concomitant ring cleavage to afford the thiooxalic acid amides 2a-c. This is in analogy with arylhydrazono group elimination in 4-arylhydrazono5-imino-3-pyrazolinones by amines

Heterodyne synthesis: synthesis of fused thiopyrano [2,3-d] thiazole, [1] benzopyrano ['3,'4: 4,5] thiopyrano [2,3-d] thiazole and thiazolo [3,4-c] -triazine derivatives

The biological and medicinal activities of substituted thiazolidines have been well reviewed, besides, the use of thiopyrano derivatives as anti-malarial drugs has prompted us to synthesize compounds having both thiazolidine and thiopyrano moieties of expected biological activities. The reactions of the highly coloured 5- salicylidenethiazolidine -2, 4-dithione and acrylonitrile at room temperature, in acetic acid, afforded a colourless 1:1 adduct, as inferred from its analytical data, which may have any of the structures 2-5. structures 3-5 were ruled out based on the 1H NMR data of the adduct which can be readily interpreted in terms of 6- cyano-7-o-hydroxyphenyll-5, 6-dihydrothiopyrano [2,3-d] thiazolidine-2 thione. The region-chemical assignment was based on proton chemical shift, which is in agreement with the favourable interaction between the sulphur atom of the heterodyne component, >C=C-C=S, and the Beta carbon atom of the dienophile. On the other hand, when 1 was reached with either acrylonitrile and/or ethyl acrylate in refluxing acetic acid, one and the same product was obtained; a fused benzopyrano- ['3, '4: 4,5] thiopyrano [2,3-d] thiazole- 2-thioxo 6[H]- one [6] as inferred from its analytical and spectral data. The formation of 6 is assumed to proceed through cycloaddition followed by concomitant loss of ethanol. The reaction of 1 with N-phenylmaleimide, maleic anhydride and dimethyl acetylenedicarboxylate in acetic acid, afford the colourless 1:1 adducts 7, 8 and 9, respectively. The gross structures of compounds 7-9 were assigned on the vasis of their analytical and spectral data; the sterochemical assignment of 7 and 8 was a consequence of proton coupling constants. Subjecting the anhydride 8 to the action of aniline in benzene afforded the amide 10, which is readily dehydrated by the action of acetic acid containing anhydrous sodium acetate to afford 7. The behaviour of 1 toward the action of malononitrile has also been investigated. Thus, treatment of 1 with malononitrile, at room temperature, in absolute ethanol, and in the presence of triethylamine afforded the colourless adduct 11. The structure of 11 was based on its analytical and spectral data, besides its unambiguous synthesis, by the reaction between thiazolidine 2, 4- dithione and salicylidenemalononitrile. On the other hand, when the reaction of 1 with malononitrile was carried out in refluxing ethanol, a fused benzopyraro ['3, '4: 4,5] thiopyrano [2,3-d] thiazole - 2 thione derivative 12 was based on its analytical and spectral data; furthermore, compound 12 was found to be identical with the product obtained by refluxing 11 in absolute ethanol in the presence of thriethlamine. Attempts to S-alkylate the potassium salt of 1 by the action of methyl iodide, ethyl bromoacetate and/or phenacyl bromide were unsuccessful, and instead, one and the same product was isolated. Structure 13 was assigned for the product based on its analytical and IR data; besides, its alkaline hydrolysis afforded 3-meracaptocoumarin, proved to be identical via its S-benzyl derivative with an authentic sample [8]. The reaction of 1 phenylhdrazine at room temperature, effected saliclidene group cleavage, with the formation of 4- phenylhydrazono-2-thiazolidinethione[9] [14]. The raction of 14 with acetyl chloride afforded 4-N1- acetylphenylhydrazono-2-thiazolidinethione [15]. Subjecting 14 to the action of ethyl bromoacetate and phenacyl bromide, in refluxing ethanol, and in the presence of few drops of triethylamine, afforded the fused thiazole [3,4-c]- triazine derivatives 16 and 17, respectively. The structures of 15-17 were based on their analytical and spectral data; besides, the acid hydrolysis of 15 and 16 yielded 4-thiazolidinone-2-thione[10]. This is in analogy with the reported behaviour of 2-phenylhydrazono-4-thiazolidinone derivatives toward the action of the same reagents[11]