الفهرس 
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Abstract
The study involving the synthesis of new heterocyclic compounds by using linear compounds as electron donors and some π-deficient compounds. Reactions of N,N’’-(1,ω-alkanediyl)bis(N’-organylthiourea) derivatives 1a-h with dimethyl acetylenedicarboxylate (DMAD, 3).
To obtain new bis(thiazolidin-4-ones) 8a-h, a mixture of a doubled molar amount of dimethyl acetylenedicarboxylate (DMAD, 3) with one mole of the respective bithiourea derivatives 1a-h was heated for 4-12 h at reflux in absolute ethanol. A yellow solid of 8a-h was obtained, which after spectroscopic characterization as well as single crystal X-ray analysis of one product 8g confirmed the proposed compounds (Scheme 1).
Reactions of N,N’’-(1,ω-alkanediyl)bis(N’-organylthiourea) derivatives 1a-h with dicyanomethylene compounds.
2.2.1. Reactions of N,N’’-(1,ω-alkanediyl)bis(N’-organylthiourea) derivatives 1a-d,g with 2-oxo-(3H)-indol-3-ylidene malononitrile (4).
The reaction of N,N”-1,ω-alkanediyl-bis[N’-organylthiourea] derivatives 1a-d,g with isatylidene malononitrile 4 [the analogues of (dioxoindenylidene)propane- dinitrile] under conventional thermal or microwave assisted in EtOH/pip/DMF as a solvent, an unexpected process leading of the functionalized (substituted amino-2-oxoindolin-3-ylidene)acetonitriles 9a-d, 2-thioxoimidazolidine-1-carbothioamides 10a-d or 2-thioxoperhydropyrimidine-1-carbothioamide 11, instead of the anticipated spiro-indolone derivatives 12a-d and 13a-d (Scheme 3).
The formation of 2-(2-oxoindolin-3-ylidene)-2-(substituted amino)acetonitriles
9a-d and imidazolidine as well as dihydropyrimidine derivatives (10a-d and 11) can be rationalized as depicted in Scheme 4.
An initial attack by HN-R of 1a-d,g on the C=C double bond of 4 afforded the intermediate 14, since the cyclization to 10a-d and 11 involves intramolecular nucleophile attack of the thioamide-NH on the thiocarbonyl group with elimination (oxoindolin-3-ylidene)-2-(substituted amino)acetonitriles 9a-d (Scheme 4).Treatment of 1a,b,e,g,h with two molecular equivalents of 5 in THF as solvent under reflux, nearly quantitative conversions were achieved already after 10-14 hours. Bis-oxathioaaza[3.3.3]propellanes 17a-e were precipitated as colourless major products. from the filtrate, imidazolthione or primidinethione 18a,b together with 1,3-dihydroxyindan-2-ylidenepropandinitrile 19 was formed in yields varying between 5-7 % (Scheme 5). The products 17a-b was elucidated by using spectral data as well as single crystal X-ray analysis.In order to rationalize the formation of propellanes 17a-e (Scheme 6), the formation of the radicals 20 and 21 may be regarded as the initial event via the formation of pair of radicals (1a,b,e,g,h•+ + 5•-). The nucleophilic addition of 20 to 21 followed by addition another molecule of 5 afforded the adduct 23. Intramolecular nucleophilic attack of NH on C≡N triple bond afforded the intermediate 24, which transformed to the more stable propellane 17a-e.
Since, the cyclization to imidazolethione or pyrimidinethione 18a,b involves intramolecular nucleophilic attack on thiocarbonyl group, it is conceivable that 5 accelerates the process in the sense of a proton or a Lewis acid, possible through the intermediate 22 (Scheme 7), activating the respective C=S bond toward nucleophilic addition. After cyclization, 5 are released and elimination a molecule of amine and another of substituted isothiocyanate to give the heterocyclic 18a,b (Scheme 7).
On the other hand, the anion 21 abstract a proton (may be from the start 1 as a source) afforded the (dihydroxyindan-2-ylidene)propanedinitrile 19 (Scheme 7).
Reactions of (Z)-2-amino-N’-arylbenzamidines derivatives 2a-d with both 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 6) and 2,3,5,6-tetrachloro-1,4-benzoqinone (CHL-p, 7).
When (Z)-2-amino-N′-arylbenzamidines 2a–d were left to react with DDQ 6 or with CHL-p 7 in dry ethyl acetate at room temperature, dibenzo[1,4]diazepines 27a–h were obtained as shown in (Scheme 8). The structure of the products 27a–h was substantiated by their elemental composition and spectroscopic data. These products have to be regarded as 1:1 combinations of the starting materials 2 and 6,7 with loss of two molecules of HCl giving rise to compounds 27a–h.