Dicyanomethylene compounds and heterocyclization of acylthiosemicarbazides

(1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile ( 1 , in ethyl acetate solution), 3‐(dicyano‐methylene)‐2‐indolone ( 2 , in ethanol/piperidine solution) and 7,7′,8,8′‐tetracyanoquinodimethane ( 3 , in pyridine solution) act on substituted acylthiosemicarbazides 4a‐d , forming the derivatives of oxoindeno‐pyrrolylidenehydrazide ( 5a‐d and 7a‐d ), thiazoloindolylidenehydrazide ( 12a‐d ), pyrroloindolylidene‐hydrazide ( 13a‐d ) and spiro[pyrrolylidene‐4,1′(cyclohexa‐2′,5′‐dienylidene)]propanedinitrile ( 18a‐d ). Rationales for these conversiones involving the nucleophilic addition on dicyanomethylene carbon atom are presented.     

Heterocyclization of N-propionylaminoindoline

Treatment of N-propionylaminoindine with a solution of phosgene in benzene gives the 1-[(indolin-1-yl)imino]propyl ester of 7-(1-cyanoethyl)indoline-1-carboxylic acid. The structure of the compound was proved using¹H and¹³C NMR spectroscopy.All-Russian Science Center for the Safety of Biologically Active Materials, Staraya Kupavna, Moscow Region 142450. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 168–170, February, 1995. Original article submitted January 11, 1995.     

Heterocyclization of 1,3-Butadienethiolates

Condensation of derivatives of ethoxymethylenecyanoacetic acid with cyanothioacetamide with base catalysis gave butadienethiolates and mercaptopyridines. On interaction with alkyl halides, butadienethiolates are cyclized into alkylthiopyridines, but their reactions with phenacyl bromides give substituted thiazoles.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 589–596, April, 2005.     

Heterocyclization reactions involving thiols

Information on the syntheses of sulfur-containing heterocycles involving thiols is systematized and generalized. Data on biological action of some among these systems are mentioned.     

Arylbiguanides in Heterocyclization Reactions

The reactions of arylbiguanides with acetyacetone derivatives were used to obtain N-(pyrimidin-2-yl)-N′-arylguanidines, and the reactions with acetoacetic ester derivatives (depending on the structure of the keto esters), N-aryl-N′-(4-oxo-3,4-dihydropyrimidin-2-yl)guanidines or 2-amino-4-arylamino-6-aryl(heteryl)-sulfanylmethylene-1,3,5-triazines. The N-aryl-N′-heterylguanidines formed by the reactions with anhydrides, acyl halides, and aryl isocyanates give rise to the corresponding triaza derivatives.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 331–339.Original Russian Text Copyright © 2005 by Kryl’skii, Shikhaliev, Shestakov, Liberman.     

Reaction of 1‐acylthiosemicarbazides with ethenetetracarbonitrile

1‐Acylthiosemicarbazides 9a‐d reacted with ethenetetracarbonitrile (TCNE, 2 ) in ethyl acetate with formation of N′‐(4‐amino‐5,6‐dicyano‐2H‐1,3‐thiazin‐2‐ylidene) substituted hydrazide 10a‐d , N′‐(5‐amino‐3,4‐dicyano‐2H‐pyrrol‐2‐ylidene)‐2‐substituted hydrazide 11a‐d and 2‐substituted imidazo[2,1‐b][1,3,4]‐oxadiazole‐5,6‐dicarbonitrile 12a‐d . Rationales for the conversions observed are presented.     

Heterocyclization of Amidophenacylation Products of Uracil

When uracil is reacted with benzoylamino(chloro)acetophenone, we obtain two amidophenacylation products depending on the condensation conditions. The first product contains an amidophenacyl moiety at the N¹ center, and in the second product two such moieties are located at the N¹ and N³ centers of the uracil. Treatment of these accessible uracil derivatives with phosphorus oxychloride, thionyl chloride, or phosphorus pentasulfide leads to cyclization of the amidophenacyl side group, which is used to synthesize a number of modified pyrimidine bases with 2,5-diphenyloxazole or 2,5-diphenylthiazole residues.     

2-Aminothiophene. Heterocyclization of benzylthionitriles

Synthesis of unstable 2-aminothiophene by way of its hydrochloride salt has been achieved in excellent yield. The key reaction in the scheme involves a novel heterocyclization of benzylthionitriles, which would appear to have general utility. Spectral and physical properties are tabulated and a possible mechanism is proposed.     

Synthesis and Heterocyclization of 3-Arylaminothiocrotonanilides

Reactions of acetylthioacetanilide with arylamines in acetic acid in the presence of sodium acetate give 3-arylaminothiocrotonanilides in good yields. When treated with -bromoacetophenone in acetone, these products are converted to substituted 4-hydroxy-²-thiazolinium bromides, one of which was dehydrated to obtain the corresponding thiazolium bromide. The structure of the heterocyclization products was confirmed by single crystal X-ray diffraction and NMR study of 2-acetonylidene-3,4-diphenyl-2,3-dihydrothiazole formed by dehydration of the corresponding ²-thiazolinium salt with simultaneous hydrolysis.     

Heterocyclization of functionalized vinylic derivatives of imidazo

Heterocyclization of functionalized vinylic derivatives of imidazo[1,2-a]pyridines was explored experimentally and theoretically using semiempirical AM1 and ab initio methods. A range of functionalized vinylic derivatives (azido, amino, and carbodiimide groups) were prepared for conversion into pyrroloazaindoles 19-22, imidazo[1,x]-, (x = 5, 6, 7, 8), [2,6]-, and [2,7]naphthyridines 28-30, 35-38 by thermal reaction. In the case of vinylic groups in the 5 position, peri annulation also was observed. The experimental and theoretical data are compared and discussed.     

Heterocyclization of 2,4-disubstituted thiosemicarbazides with haloketones

2,4-Disubstituted thiosemicarbazides were allowed to react with α-bromoacetophenone to give the anticipated 2,3-dihydro-6H-1,3,4-thiadiazines, whereas with β-propiophenone and γ-butyrophenone to afford the unexpected 2,3-dihydro-1,3,4-thiadiazole. The reaction mechanism was also discussed.     

Heterocyclization of Allyloxyiodination Products of Halogen-Substituted Styrenes

Russian Journal of Organic Chemistry - A procedure has been proposed for the synthesis of 2-aryl-5-methyl-1,4-dioxanes by alkoxyiodination of halogen-substituted styrenes with allyl alcohol in the...     

Radical Heterocyclization and Heterocyclization Cascades Triggered by Electron Transfer to Amide‐Type Carbonyl Compounds

Radical heterocyclizations triggered by electron transfer to amide‐type carbonyls, using SmI₂‐H₂O, provide straightforward access to bicyclic heterocyclic scaffolds containing bridgehead nitrogen centers. Furthermore, the first radical heterocyclization cascade triggered by reduction of amide‐type carbonyls delivers novel, complex tetracyclic architectures containing five contiguous stereocenters with excellent diastereocontrol.     

Heterocyclization of acetylketeneN,S-acetals with benzoyl cyanamide

N-Unsubstituted mono- and diacetylketeneN,S-acetals undergo cyclization with benzoyl cyanamide to form 2-amino-4-methylthiopyrimidine derivatives. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2073–2075, November, 1997.     

Some Heterocyclization Reactions of N,N'-Dimethoxycarbonyl-o-benzoquinone Diimine

Russian Journal of Organic Chemistry -     

Oxidative Heterocyclization of 1,4-Butanediol to 4-Butanolide

Russian Journal of Organic Chemistry -     

Regioselectivity and tautomerism of novel five-membered ring nitrogen heterocycles formed via cyclocondensation of acylthiosemicarbazides

A series of 1-acyl-4-phenyl/(acridin-9-yl)thiosemicarbazides 3, including four new compounds, were prepared in order to study substituent effects on cyclization reactions with oxalyl chloride (producing imidazolidine-4,5-diones 4), dimethyl acetylenedicarboxylate (to give thiazolidin-4-ones 7 and 8) and autocondensation under alkaline conditions (to yield 1,2,4-triazoles 9). A positional isomer, 10 of compound 3f was also prepared. Altogether, twenty new compounds characterized and identified by IR, UV,1H, 13C and 2D NMR and quantum chemical calculations are described. The tautomerism of the products and regioselectivity of the reactions were evaluated. Compounds 3f-h,3h.2HCl, 7b,d and 10 were screened for cytotoxic activity against the L1210 leukemia cell line and all compounds, except for 3f, exhibited promising inhibitions of cell growth.