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This paper describes the Cu(OTf)2-mediated coupling of aryl and heteroaryl trifluoroborates with tetrabutylammonium or alkali metal salts to form C-O, C-N, and C-halogen bonds. The reactions proceed under mild conditions (often room temperature over 16 hours) with carboxylate, halide, and azide salts, all nucleophiles that have been underrepresented in the copper cross-coupling literature. Preliminary results show that copper salts bearing weakly coordinating X-type ligands are essential for enabling these transformations to proceed under mild conditions. [ABSTRACT FROM AUTHOR]

Starting from common intermediate methyl 1-hydroxy-9Hcarbazole- 3-carboxylate, synthetic routes toward murrayaquinone A, olivacine, and N-methylcalothrixin B were developed. [ABSTRACT FROM AUTHOR]

New pyrazino[2',3':4,5]thieno[2,3-e][1,2,3]triazolo[1,5-a]-pyrimidin-5(4H)-ones were synthesized in an efficient, fast, and mild one-pot procedure from methyl 7-azidothieno[2,3-b]pyrazine-6-carboxylate. From the latter, some triazolothieno[2,3-b]pyrazine-6-carboxylates were also obtained with total regioselectivity by [2+3] cycloaddition with alkynes without any metal catalyst. [ABSTRACT FROM AUTHOR]

The palladium-catalyzed oxidation-hydroxylation and oxidation- methoxylation of N-Boc indoles for the synthesis of tert-butyl 2-hydroxy(methoxy)-3-oxoindoline-1-carboxylates and their derivatives is developed. The process occurs readily using PdCl2 as the catalyst and acetonitrile as the solvent to afford 3-oxoindolines in moderate to high yields. A mechanism for this Pd-catalyzed oxidation-hydroxylation and oxidation-methoxylation of N-Boc indoles is proposed. [ABSTRACT FROM AUTHOR]

We report the synthesis of a new series of 2-oxo-1,2,4,9-tetrahydro-3H-pyrimido[4,5-b]indole derivatives and diethyl 4-hydroxyquinoline-2,3-dicarboxylate starting from ethyl 3-(2-ethoxy-2-oxoethyl)-1H-indole-2-carboxylate. Intramolecular cyclization formed the target ring systems. The key substrates featuring both acyl azide and isocyanate functionalities were prepared from bis(acyl azide) intermediate. The acyl azide functionalities directly connected to methylene groups were regiospecifically converted into urea and urethanes via the reactive isocyanate intermediates. Thermal treatment of urea and urethanes provided the target 2-oxo-1,2,4,9-tetrahydro-3H-pyrimido[4,5-b]indoles. Furthermore, ozonolysis of the starting indolediester substrate and subsequent base treatment to diethyl 4-hydroxyquinoline-2,3-dicarboxylate are described. [ABSTRACT FROM AUTHOR]

1-Sulfonylhydrazine-1,2-dicarboxylates are efficiently prepared via nucleophilic addition of thiols/thiophenols to dialkyl azodicarboxylates and subsequent oxidation with MCPBA. The protocol represents the first application of sulfenylhydrazines as precursors to sulfonylhydrazine derivatives, leading to a novel and effective method for the synthesis of sulfonylhydrazines. [ABSTRACT FROM AUTHOR]

An efficient and scalable synthesis of the antiepileptic drug (R)-lacosamide and its derivatives has been achieved from commercially available aziridine-(2R)-carboxylate in three simple sequential steps, including regioselective aziridine ring opening, debenzylation followed by acetylation in one pot, and amide formation. The advantage of this protocol is that the starting material and reagents are commercially available and a single purification by recrystallization is required after all the chemical transformations, providing the final drug in >99.9% ee. [ABSTRACT FROM AUTHOR]

Alkyl 4,5-dihydrofuran-2-carboxylates can be efficiently obtained via an enantioselective organocatalyzed consecutive reaction between α-keto esters and (Z)-(2-chloro-2-nitroethenyl)benzenes. The overall sequence combines a (R,R)-TUC-catalyzed Michael addition with a DABCO-promoted intramolecular O-alkylation leading to the title products as single diastereomers with enantiomeric excesses from 86% up to 97%. [ABSTRACT FROM AUTHOR]

3-Substituted 2-(phenylthio)acrylates prepared from aldol condensation using titanium tetrachloride were employed to synthesize benzo[b]thiophenes. The acrylates containing aryls and alkyls generated the desired benzo[b]thiophenes in reasonable yields under the optimized Heck condition, but acrylates having heteroaryls gave the desired products in poor yields or no products under the condition. [ABSTRACT FROM AUTHOR]

The synthesis of a new and versatile polyfunctionalised pyrimidine- 4-carboxylate, along with the study of its reactivity against 1,2-dinucleophiles and 1,4-dinucleophiles, is reported. These simple and efficient methodologies allowed for the synthesis of novel pyrimidine derivatives such as pyrimido[4,5-d]pyridazin-8-one-5-carboxylates and their corresponding carbohydrazides and N-acylhydrazone (NAH) derivatives, pyrimido[4,5-d][1,2]oxazin-8-one and its corresponding carbohydrazide derivative, and 3-pyrimidinylquinoxaline-2-one and its corresponding carbohydrazide. Furthermore, pyrimidine hydroxyimino derivatives were also prepared. [ABSTRACT FROM AUTHOR]

Catalytic cyclization of allyl amides of ethenetricarboxylate leading to pyrrolidines has been examined. Reaction of allyl amides of ethenetricarboxylate with Sc(OTf)3 (0.2 equiv) gave 4-hydroxymethyl- 2-oxopyrrolidine derivatives as major products. The formation of hydroxymethylpyrrolidines may arise from participation of adventitious water in situ. Sc(OTf)3-catalyzed cyclization reactions of the allyl amides with TMSX (X = Cl, Br) proceeded efficiently to give halogenated 2-oxopyrrolidine derivatives. Sc(OTf)3-catalyzed cyclization reactions of the allyl ester with TMSX (X= Cl, Br) also proceeded to give halogenated 2- oxotetrahydrofuran derivatives. [ABSTRACT FROM AUTHOR]

Indole-carboxylates are N-arylated with 2-bromopyridines using stoichiometric copper(II) oxide/potassium carbonate to give various N-(2-pyridyl)-substituted indole-2-carboxylates and with bromobenzenes using stoichiometric copper(I) iodide/N,N'-dimethylethylenediamine to give various N-(substituted phenyl)-substituted indole-2- carboxylates. These results expand the scope of metal-catalyzed N-arylation using heterocyclic amines with steric bulk and weak nucleophilicity. [ABSTRACT FROM AUTHOR]

A study of cyclopropanations of oxy-substituted ethenes with ethyl α-aroyl-α-diazoacetates is described. The reaction of ethyl α-aroyl-a-diazoacetates with trimethylsilyl vinyl ether or ethyl vinyl ether gave dihydrofuran products, but when vinyl acetate was used the products were stable cyclopropanes, ethyl 2-acetoxy-1-aroylcyclopropanecarboxylates, which were isolated in 16-87% yield depending on the nature and position of the aryl-ring substituent. [ABSTRACT FROM AUTHOR]

Reaction of 3-formylchromones, 2-aminobenzimidazole, and acetonedicarboxylates under ultrasound irradiation afforded alkyl 2-(1H-benzimidazol-2-ylamino)-5-(2-hydroxyaroyl)isophthalates as the only reaction product in almost quantitative yields. However, when 2-aminobenzimidazole was replaced by aromatic amines novel alkyl 1-aryl-2-[(E)-2-alkoxy-2-oxoethylidene]-5-(2-hydroxyaroyl)-(1H)-pyridine-3-carboxylates were isolated in good yields. A plausible mechanistic scheme for the formation of the isolated isophthalates and pyridine carboxylates is proposed, and full assignment of all their 1H and 13C NMR chemical shifts has been unambiguously achieved. In addition, the lipid peroxidation inhibition of the novel isophthalate derivatives was evaluated, and it was found that one such derivative presents an interesting antilipid peroxidation activity. [ABSTRACT FROM AUTHOR]

A simple and efficient procedure for the synthesis of ethyl 2- methylthio- and ethyl 2-benzylthio-6-methyl(aryl)-pyrimidine-4-carboxylates and their corresponding acid derivatives is reported. The products are obtained in good yields via the cyclocondensation reaction of ethyl 4-alkoxy-2-oxo-4-methyl(aryl)-but-3-enoates with 2-methylisothiourea sulfate or 2-benzylisothiourea hydrochloride, under mild, basic, aqueous conditions. [ABSTRACT FROM AUTHOR]

The synthesis of postulated 2H,6H-1,5-dithiocines from isonitriles and acetylenedicarboxylates or dibenzoylacetylene in the presence of elemental sulfur was repeated. The products do not possess the structure of eight-membered sulfur heterocycles, but isothiazole-3(2H)-thiones were formed instead. This structural corrigendum was confirmed not only by a critical consideration of the 13C NMR spectroscopic data and by the correction of the MS spectra and the values of the elemental analyses but also by X-ray crystallographic structure determination. Several reaction mechanisms are discussed to explain the generation of the observed isothiazole-3(2H)-thiones. [ABSTRACT FROM AUTHOR]

We have earlier shown how the Wittig chemistry can be done using novel Eigenbase phosphonium carboxylate reagents. Here we discuss the phenomenon of ion pairing, their solution tautomerism, solid-state structure, and mechanistic aspects of olefination. The results point to a complex process involving unfamiliar H-bond-driven ion-pair equilibria followed by standard Wittig reaction steps. [ABSTRACT FROM AUTHOR]

Synthetic approach to fused azasultams with 1,2,4-thiadi-azepine framework via base promoted protocols has been developed. 1 H -Azole-2-carboxylates and N -(chloromethyl)- N -methylmethanesulfonamide were used as ambiphilic building blocks in the one-pot and two-step reaction sequences. Chemical behavior of the obtained azasultams in reactions with amines, hydrazine, DMFDMA, and NaBH4 was investigated. An enamino ketone derived from an azasultam was exploited in the synthesis of new pyrazole and pyrimidine heterocycles. [ABSTRACT FROM AUTHOR]

An efficient approach to the preparation of pyridine carboxylates fused with 5- or 6-membered heteroaromatic rings is described. The method relied on the Combes-type condensation of the low-molecular--weight β-alkoxyvinyl glyoxylates as CCC bis-electrophiles and with heteroaromatic amines as NCC binucleophiles. In most experiments-, β-alkoxyvinyl glyoxylates without additional substituent at the β position led to the corresponding α-pyridine carboxylates (67–87% yield). In the case of β-methyl-substituted derivative, γ-pyridine carboxylates were obtained in 84–99% yield. It was found that regio-selectivity of the condensation could be efficiently tuned by changing conditions, such as solvents and acidic additives (HOAc, DMSO or HCl–1,4-dioxane). [ABSTRACT FROM AUTHOR]

A facile and convenient synthesis of ethyl 5-oxohomoadamantane-4-carboxylate is reported, and its chemical properties as a cage analogue of acetoacetic ester are investigated. Various derivatives of homoadamantane were synthesized through the reaction of 5-oxohomoadamantane-4-carboxylate with electrophilic agents, binucleophiles, and hydrazoic acid. Some new unusual products were obtained by the reaction of that β-keto ester with nitric acid and nitrosyl chloride. Cage compounds synthesized could be used as precursors for the diverse condensed heterocyclic compounds with potential viral ion channel abrogating activity that possess conformationally rigid lipophilic moieties. [ABSTRACT FROM AUTHOR]

The synthesis on a gram-scale and the full characterization of naphtho[1,2-b]thiophene and benzo[1,2-b:6,5-b']dithiophene 4-carboxylate esters bearing 2-octyldodecyl side chains, and their stannylated and brominated derivatives, suitable for their insertion into π-conjugated polymers is described. The fully soluble and processable synthons are obtained through a cascade sequence of reactions, namely direct arylation and cross aldol condensation, which create an effective pathway for the annulation and π-extension of suitable, commercially available reagents. The newly reported synthesis are compared, whenever possible, using ‘green chemistry metrics’ with literature synthesis, showing dramatic improvements. [ABSTRACT FROM AUTHOR]

1-(3,3,3-Trifluoro-2,2-dihydroxypropyl)pyridin-1-ium bromide serves as a trifluoromethyl-containing building block for the preparation of trifluoromethyl-substituted aminopyrroles based on the 2H-azirine ring expansion strategy. The primary products, 3-aryl-2-(methoxycarbonyl)-4-(pyridin-1-ium-1-yl)-5-(trifluoromethyl)pyrrol-1-ides, can be hydrogenated by H2/PtO2 to form alkyl 3-aryl-4-(piperidin-1-yl)-5-(trifluoromethyl)-1H-pyrrole-2-carboxylates and transformed into alkyl 4-amino-3-aryl-1-methyl-5-(trifluoromethyl)-1H-pyrrole-2-carboxylates via methylation/hydrazinolysis. [ABSTRACT FROM AUTHOR]

The formation of the key short-lived intermediate nitrilium ion in the Passerini and Ugi reactions was recognized early in the discovery of these two-multicomponent transformations. Surprisingly, the idea of intramolecularly intercepting it, eluding the attack by the carboxylate, and thus interrupting the normal course of the reaction, was missed by chemists for several decades. In this review we describe, in an exhaustive manner, the reported synthetic approaches, which can be categorized as interrupted Passerini/Ugi reactions. Besides, the clear goal of this review is to show the potential of these transformations, whilst highlighting the underexplored combinations of reagents toward the identification of novel interrupted Passerini/Ugi reactions. 1 Introduction 2 The Interrupted Ugi Reaction 2.1 The Interrupting Functional Group is Present on the Amine Reactant 2.2 The Interrupting Functional Group is Present on the Isocyanide Reactant 2.3 The Interrupting Functional Group is Present on the Carbonyl Reactant 3 The Interrupted Passerini Reaction 3.1 The Interrupting Functional Group is Present on the Carbonyl Reactant 3.2 The Interrupting Functional Group is Present on the Isocyanide Reactant 4 Conclusions and Future Outlook. [ABSTRACT FROM AUTHOR]

The iron(II)-catalyzed domino isomerization of 3-alkyl/aryl- 4-arylisoxazoles provides a selective access to a wide range of structurally diverse highly substituted indole-3-carboxylates. The operational simplicity, high atom efficiency, and the use of stable starting materials and an inexpensive and low-toxicity catalyst are some of the attractive features of this tandem double ring-opening-ring-closure strategy. [ABSTRACT FROM AUTHOR]

An easy access to hybrid bioactive molecules, such as the chromenopyrazoles, is described based on the three-component reactions of 3-formylchromones, arylhydrazines, and acetylenedicarboxylates. By manipulating the reaction, four different scaffolds can be derived in an easy, versatile, and robust fashion. To underscore the potential, generality, and diversity that can be generated, representative libraries of each scaffold were synthesized. Moreover, a comprehensive NMR analysis with full assignment of all 1H and 13C NMR chemical shifts has been performed. [ABSTRACT FROM AUTHOR]

S-Benzylisothiouronium halides are used as shelf-stable, odorless thiol equivalents. The method developed is used to access 2-(benzylthio)-4-(trifluoromethyl)thiazole carboxyl building blocks. Using the latent trifluoromethyl substituent the reactions could be monitored using 19F NMR spectroscopy. [ABSTRACT FROM AUTHOR]