One-pot Cyclization Research Articles

Synthesis and characterization of new azo containing Schiff base macrocycle

Abstract Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition, a one-pot cyclization procedure of four-component without using a template. The condensation reaction of related bis (hydroxybenzaldehyde) with phenylenediamines to prepare a conjugated [2 + 2] Schiff base macrocycle has been investigated and fluorescent [2 + 2] Schiff base macrocycles with N 2 O 2 binding pockets has been prepared and characterized by elemental analysis, 1 H NMR, IR, Fluorescent, UV–visible and MALDI mass spectroscopies.

An efficient one-pot cyclization of quinoline thiosemicarbazones to quinolines derivatized with 1,3,4-thiadiazole as anticancer and anti-tubercular agents

A series of 6,7,8-substituted thiosemicarbazones (2a–j) of 2-chloro-3-formyl-quinoline derivatives were cyclized to the title compounds (3a–j) using acetic anhydride. The structures of the final compounds (3a–j) were confirmed by elemental and spectral (IR, 1H NMR and MS) analysis. Some of the title compounds have shown promising anticancer and antitubercular activities.

ChemInform Abstract: One-Pot Cyclization of Epoxy Olefins to Substituted Cycloalkanols via Free Radicals.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Regioselective Synthesis of 5‐(Arylsulfanyl)‐ and 5‐(Benzylsulfanyl)‐6‐phenylsalicylates by One‐Pot Cyclizations of 1,3‐Bis(silyloxy)buta‐1,3‐dienes with 2‐(Arylsulfanyl)‐ and 5‐(Benzylsulfanyl)‐3‐ethoxy‐1‐phenylprop‐2‐en‐1‐ones

Abstract5‐(Arylsulfanyl)‐6‐phenylsalicylates were prepared by one‐pot cyclizations of 1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes with 2‐(arylsulfanyl)‐3‐ethoxy‐1‐phenylprop‐2‐en‐1‐ones.

Single Bifunctional Ruthenium Catalyst for One‐Pot Cyclization and Hydration giving Functionalized Indoles and Benzofurans

DOI: 10.1002/chem.201001075 Single Bifunctional Ruthenium Catalyst for One-Pot Cyclization and Hydration giving Functionalized Indoles and Benzofurans Reji N. Nair, [a] Paul J. Lee, [a] Arnold L. Rheingold, [b] and Douglas B. Grotjahn* [a] Indole [1] and benzofuran [1d, 2] heterocycles are key structur- al units in a variety of biologically active natural products and unnatural synthetic materials. Over the last few years, transition-metal catalysts have been extensively used in the cyclization of o-alkynylarylamines [3a–l] and phenols [3m–p] to construct benzoheterocycles through intramolecular [3] and intermolecular reactions. [4] Many of these reactions required the use of a nitrogen protecting group in the case of indo- les [3g,i,k] or stoichiometric amounts of the metal. [3l] McLory and Trost [3d] synthesized both unprotected indoles or N- benzyl analogues by using rhodium–phosphine complexes, but to optimize the benzofuran synthesis, large amounts of phosphine (0.6 equiv) were needed. Saa and co-workers [3q] recently reported the use of 10 mol % catalyst and amine solvents in benzofuran synthesis at 90 8C. Herein, we report that the bifunctional ruthenium catalyst 1 which has been used for anti-Markovnikov alkyne hydration [5] emerges as a versatile choice for both indole and benzofuran formation, with a number of unique advantages, including the use of only 2 mol % catalyst in most cases and the unprecedented ability of a cycloisomerization catalyst to perform hydration or deuteration in the same reaction. We envisioned that the use of alkyne hydration catalyst 1 on substrates, such as 2, (Scheme 1) would generate the al- dehyde 3, on which cyclization and dehydration would then enable facile synthesis of heterocycles. Indeed, 2 a cyclized to hemiaminal 4 a, [5a] with some equilibrium amount of 3 a, [a] R. N. Nair, P. J. Lee, Prof. D. B. Grotjahn Department of Chemistry and Biochemistry San Diego State University 5500 Campanile Drive, San Diego, CA 92182-1030 (USA) Fax: (+ 1) 619-594-4634 E-mail: grotjahn@chemistry.sdsu.edu [b] Prof. A. L. Rheingold Department of Chemistry and Biochemistry University of California–San Diego La Jolla, CA 92093-0358 (USA) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201001075. Scheme 1. The use of bifunctional catalyst 1 for hydration and cycliza- tion; Cp = cyclopentadienyl. but elimination of water from 4 a required heating in second step, forming 5 a in 46 % overall yield. The same two-step process could be used on the homologous substrate 2 b, to form 5 b in 56 % overall yield. Encouraged by these results, and because of the impor- tance of indoles, we shifted our attention to substrates de- rived from o-ethynylaniline. The first four entries of Table 1 demonstrate that 1 cyclizes a wide range of aniline deriva- tives; most significantly, the simplest, unprotected parent compound 6 cyclized to indole 17 in 99 % yield (Table 1, entry 1). Sulfonamide 7 (Table 1, entry 2) was cyclized to give the N-tosyl (Ts) protected indole in just 2 h. Entries 3 and 4 in Table 1 show the ability of the catalyst to form ni- trogen analogues with different alkyl substituents. Especially notable is the selectivity of 1: the N-allyl group (Table 1, entry 3) is fully tolerated without the decomposition by iso- merization seen when using a Rh-based catalyst. [3d] The fact that a wide variety of nucleophilic nitrogen cen- ters could be used in indole formation encouraged us to ex- plore the scope of 1 not only in making more complex indole derivatives, but also in cyclizing phenol derivatives to benzofurans. Gratifyingly, 1 forms both 7-aza- and 6-nitroin- doles (Table 1, entries 5 and 6), showing tolerance of various ring substituents, including those that might coordinate to the catalyst. Furthermore, entry 9 (Table 1) shows the ability of 1 to form the benzofuran nucleus in essentially quantita- 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Chem. Eur. J. 2010, 16, 7992 – 7995

Regioselective Synthesis of 5-Chlorosalicylates by One-Pot Cyclization of 1,3-Bis(trimethylsilyloxy)buta-1,3-dienes with 2-Chloro-3-ethoxy-2-alken-1-ones

A variety of 5-chlorosalicylates were prepared by regioselective one-pot cyclizations of 1,3-bis(trimethylsilyloxy)buta-1,3-dienes with novel 2-chloro-3-ethoxy-2-alken-1-ones.

Iron-Catalyzed Domino Process for the Synthesis of α-Carbonyl Furan Derivatives via One-Pot Cyclization Reaction

The Fe(ClO(4))(3)-catalyzed intramolecular rearrangement/cyclization/oxidation reaction sequence for the synthesis of alpha-carbonyl furan derivatives from electron-deficient alkynes and 2-yn-1-ols is reported.

ChemInform Abstract: Chirospecific Synthesis of 1,4-Dideoxy-1,4-imino-D-arabinitol and 1,4-Dideoxy-1,4-imino-L-xylitol via One-Pot Cyclization.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of biobased N-methylpyrrolidone by one-pot cyclization and methylation of γ-aminobutyric acid

N-Methylpyrrolidone (NMP) is an industrial solvent that is currently based on fossil resources. In order to prepare it in a biobased way, the possibility to synthesize NMP from γ-aminobutyric acid (GABA) was investigated, since GABA can be obtained from glutamic acid, an amino acid that is present in many plant proteins. Cyclization of GABA to 2-pyrrolidone and subsequent methylation of 2-pyrrolidone to NMP was achieved in a one-pot procedure, using methanol as the methylating agent and a halogen salt (i.e. ammonium bromide) as a catalyst. A selectivity above 90% was achieved, as well as a high conversion. Methylation of 2-pyrrolidone could also be done with dimethyl carbonate, but then the selectivity for NMP was less (67%).

Expedient access to fused quinoxalines via Dess–Martin periodinane-mediated cyclization of unsymmetrical phenylenediamide derivatives

Abstract One-pot cyclization of various 2- N -amido-homoallylanilides mediated by 4 equiv of Dess–Martin periodinane produced pyrrolo[1,2- a ]quinoxalines (11 examples, up to 93% yield).

Diversity‐Oriented Synthesis of Chlorinated Arenes by One‐Pot Cyclizations of 4‐Chloro‐1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes

AbstractA variety of 3‐chlorosalicylates were prepared by one‐potcyclizations of the first reported 4‐chloro‐1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes with various 1,3‐dielectrophiles. These include cyclizations with 3‐silyloxy‐2‐en‐1‐ones, 3‐aryl‐3‐silyloxy‐2‐en‐1‐ones, 1‐methoxy‐1‐en‐3‐ones, 1,1‐bis(methylthio)‐1‐en‐3‐ones, 3‐oxo orthoesters, 1,1,3,3‐tetraethoxypropanes, 1,1‐diacetylcyclopropane, and 3‐formylchromones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis of 2-(2-Aminophenyl)-4-arylquinazoline Derivatives by Reaction of 2-Aminoarylbenzimidamides with Isatoic Anhydride

A series of 2-(2-aminophenyl)-4-arylquinazoline derivatives (5a - j), with various 4-substituents, have been synthesized by one-pot cyclization in 66 - 79% yield by heating 2-aminoarylbenzimidamides 3a - j with isatoic anhydride (4). The high yield and simplified workup procedure, in addition to the neutral reaction conditions, are the main advantages of our approach. The structure of the product 5e was further confirmed by single-crystal X-ray structure analysis

Synthesis of Fluorinated Arenes and Hetarenes Based on One-Pot Cyclizations of 1,3-Bis(trimethylsilyloxy)-1,3-butadienes

One-pot cyclizations of fluorinated 1,3-bis(silyloxy)-1,3-butadienes and 3-alkoxy- and 3-silyloxy-2-en-1-ones provide a convenient access to various fluoro-, trifluoromethyl- and perfluoroalkyl-substituted arenes and hetarenes.

2-Isocyanatobenzonitrile and 2-Isothiocyanatobenzonitrile - Versatile Building Blocks in Organic Synthesis

2-Isothiocyanatobenzonitrile (ITCB) and isocyanatobenzonitrile (ICB) represent versatile difunctional building blocks containing a nitrile and an isothiocyanate or an isocyanate function, respectively. The present review provides an account of the chemistry of ITCB and ICB. This includes a number of one-pot cyclizations which provide a convenient access to a variety of pharmacologically important heterocycles.

Synthesis of Highly Functionalized Allene-Appended Oxindoles and 2-Oxo-1,2-dihydroindol-3-ylidene-2,5-dihydrofurans via Claisen Rearrangement and Cyclization

Synthesis of highly functionalized allene appended oxindole derivatives from vinyl propargyl ether derivatives of Morita-Baylis-Hillman adducts of isatin via Claisen rearrangement has been achieved. Synthetic utility of the allene derivatives obtained has been demonstrated with the synthesis of methyl 2,5-dihydro-5-methyl-2-(1-methyl-2-oxoindolin-3-ylidene)furan-3-carboxylates in a one-pot cyclization reaction under basic conditions. A plausible mechanism of the reaction is presented.

ChemInform Abstract: An InCl3‐Catalyzed Facile One‐Pot Synthesis of Novel Dispiro[cyclopent‐3′‐ene]bisoxindoles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Efficient access to 2,5-substituted tetrahydrofurans via a one-pot cyclization of di- and triepoxides

The one-pot addition and cyclization of 1,5-diepoxyhexane with a range of organolithium species provides efficient access to 2,5-substituted tetrahydrofurans (THFs), common structural motifs found in a range of natural products and pharmaceutical ingredients. Extension of this reaction to triepoxides has also been demonstrated to access adjacently linked bis-THF motifs in a single step.

A one-pot tandem oxidation–reduction protocol for the synthesis of cyclic ethers from their diols

A novel and an efficient one-pot cyclization method for the preparation of cyclic ethers from their diols via a tandem oxidation–reduction protocol using a cocktail of MnO 2/Et 3SiH/CF 3COOH is reported.

Microwave-Assisted Multicomponent Synthesis of Aza-, Diaza-, Benzo-, and Dibenzofluorenedione Derivatives

A microwave procedure was efficiently applied to the synthesis of a series of heteropolycyclic compounds with known or potential biological activities. Antitumor amide 3was obtained in a few minutes and with high yields through a solventless, one-pot cyclization, followed by treatment with the suitable amine. This method was also used to access tetracyclic aza-compounds 5/6, where their selective formation as N,N-syn and N,N-anti regioisomers was investigated under a solventless condition, or by changing the solvent, in the presence of solid supports and a catalytic amount of ecofriendly metal salts. Thermal access to similar polycyclic compounds recently reported under conventional heating by using the preformed pyridinium or isoquinolinium ylides was improved in this instance by microwave irradiation and extended to the synthesis of diaza-esters. In any case, the one-pot, three-component cyclization was more atom-efficient than the N-ylide sequence.

Design, synthesis, and antimicrobial activity of fused triheterocyclic nitrogen systems involving tetrazolo[1,5-b][1,2,4]triazines [1

Dehydrogenative cyclization of the 6-substituted 7-arylidenehydrazinotetrazolo[1,5-b][1,2,4]triazines derived from 6-methyl and 6-phenyl derivatives of 7-hydrazinotetrazolo[1,5-b][1,2,4]triazines and aromatic aldehydes gave the corresponding 6-substituted 9-aryl-[1,2,4]triazolo[4,3-d]tetrazolo-[1,5-b][1,2,4]triazines. The latter compounds were also obtained by an alternative route involving dehydrative cyclization of 6-methyl and 6-phenyl derivatives of 7-chlorotetrazolo[1,5-b][1,2,4]triazines with aromatic hydrazides through the isolable aroylhydrazino intermediates. Also, the triazolotetrazolotriazine rings were accomplished by one-pot cyclization of cyclic amidrazones with aromatic acid chlorides. The ditetrazolo[1,5-b:1′,5′-d][1,2,4]triazine systems were synthesized by cyclization of the former cyclic amidrazones with nitrous acid, or cyclic imidoyl chlorides with sodium azide. The bis-triazolotetrazolotriazine derivatives were synthesized by cyclization of two equivalents of each cyclic imidoyl chloride with acid dihydrazides through the isolable bis-hydrazide products. The antimicrobial activity of representative compounds was studied.