Mohamed Lamine Benkhoud

NOUVELLE SYNTHÈSE DE [1,2-A]BENZIMIDAZOLO-1,3,5,2-TRIAZAPHOSPHORINES ET DE [1,2-A]BENZIMIDAZOLO-1,3,5,2- TRIAZAPHOSPHORINE-2-THIONES

The condensation of N1-benzimidazolyl amidines 1 with tris(dimethy- lamino)phosphine leads to the corresponding [1,2a]Benzimidazolo-1,3,5,2-triazaphosphorines 3 . The N2-phosphoroamidine intermediates 2′ are isolated and yielded the corresponding cyclic compounds 4 upon heating. The oxidation by sulfur of the compounds 3 gives the thiooxide derivatives 4 . The structure of these compounds is unambiguously confirmed by IR, 1H, 31P, and 13C NMR spectroscopy and by MS for some products.

A convenient synthesis of alkyl-2-(2-imino-4-oxothiazolidin-5-ylidene)acetate derivatives involving an electrogenerated base of acetonitrile

ABSTRACT We report a simple method for the synthesis of alkyl-2-(2-imino-4-oxothiazolidin-5-ylidene) acetate derivatives 3 in good yields under mild conditions. The electrogenerated cyanomethyl base (EGB), obtained from electroreduction of acetonitrile-0.1 M TBABF4, assists the reaction between thiourea derivatives 1 and dialkyl acetylene dicarboxylate 2. The expected products, 3/4, and the structure obtained from X-ray diffraction confirm that the main products are the five-membered heterocycles 3. Furthermore, a mechanism, to explain the reaction pathways, is proposed based on the thermodynamic and kinetic data obtained from quantum calculations. GRAPHICAL ABSTRACT

Reactivity of N-thioamido amidines with halogenated alkyl derivatives: synthesis of 4,5-disubstituted 2-alkylaminothiazoles

2-Bromoacetate ethyl ester 4, 2-chloroacetonitrile 5, 2-bromo-1-(4-nitrophenyl)ethanone 6, and 2-chloroacetone 7 react with N-thioamido amidines 3 to yield the corresponding 4,5-disubstituted 2-alkylamino thiazoles 8, 9, 10, and 11 after the release of an amine molecule. The reaction of the amidines 3 with benzyl bromide 12, 4-chlorobutyronitrile 13, 3-bromopropionate ethyl ester 14, 3-chloropropionate ethyl ester 15, and 4-nitrobenzyl chloride 16 does not lead to the cyclic derivatives but gives opened-ring intermediates 17, 18, 19, 20, and 21. The cyclization mechanism is discussed on the basis of the study of the opened-ring intermediates which have been isolated in some cases and the AM1 and PM3 semi-empirical energetic calculations.

Unexpected Reaction of Bis(Diethylamino)-Fluorophosphine with N-Benzimidazol-2-Yl-N′-Amidines

Bis(diethylamino)fluorophosphine reacts with N-benzimidazol-2-yl-N′-amidines to undergo the elimination of HF and diethylamine leading to the corresponding 2-substituted benzimidazolo-1,3,5,2-λ 3 -triazaphosphorines.

SYNTHESIS AND REACTVITY OF N-[N-PHOSPHORAMIDO-1H-BENZIMIDAZOL-2-YL] IMIDATES

N-(-1H-Benzimidazol-2-yl) imidates 1a–c react with chlorophosphoramide to give the N-[-1-N,N,N′,N′-tetramethylphosphoramidoyl-1H-benzimidazol-2-yl]-imidates 2a–c or with dichlorophosphoramide to yield the bis[(N-1-benzimidazol-2-yl)-imidate] phosphoramide derivatives 3a–b. The reaction of compounds 2a–c toward primary amines is studied. The obtained amidine derivatives 4a–b were unambiguously characterized by different spectroscopic techniques (IR, 1H, 13C, and 31P NMR, and in some cases MS).