Synthesis and structure of complexes of acyl N-aminides with zinc(II) salts

Molina, A.; Heras, Maria A. de las; Martínez, Yolanda Muñoz; Vaquero, Juan J.; Navio, JoséL. García; Alvárez‐Builla, Julio; Gomez-Sal, Pilar; Torres, Rosario

doi:10.1016/s0040-4020(97)00300-1

Cited by 6 publications

(3 citation statements)

References 12 publications

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“…4,5‐Disubstituted oxazoles can also be generated through this method using the N‐ formylpyridinium‐ N ‐aminide 6g (entry 9). π‐Rich and π‐deficient aromatics, where starting materials and products are both potentially viable ligands to transition metals,54,55,56 react smoothly affording 9h–j despite the presence of Lewis basic atoms (Table 2, entries 10–12).…”

Section: Resultsmentioning

confidence: 99%

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

2016

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Oxazolesa re important motifs within bioactive and functional materials.C omplex, fully substituteda nd functionalised 4-aminooxazoles are accessed by an efficienti ntermolecular reactionb etween an ynamide and an N-acylpyridinium N-aminide in the presence of ag old catalyst. Thef ormal [3+ +2] dipolar cycloaddition employs an ucleophilic nitrenoid approach to access the 1,3-N,O-dipole character in ac ontrollable fashion.T he selectivity for ac ycloaddition pathwayp rovides as tark contrast against the indiscriminate reactivity of electrophilic acyl nitrenes.P rotocolsf or the formation of acylfunctionalised aminides are reported from accessible precursors including carboxylic estersa nd acids.T he function of these aminides in the oxazole-forming reaction has been exploreda nd it is shown that substantial elaboration is accommodated despite proximity to the reactivec entre.A saresult functional oxazole-based motifs,s uch as chiral oxazoles with biologically pertinent substitution patterns,a re readily accessible.T he use of ynamide types that are unexplored or little used in gold catalysis has been evaluated. Unusual all-heteroatom substitution patterns around the oxazole are shown to be accessible using thio-ynamides.T he studys hows that ac lose stoichiometry of reactantsi ss uitable alongsider elatively low loadings of the bench-stable precatalysts in practicallys traightforward multi-mmol scale reactions.T he efficiency and flexibility of this regioselective intermolecular preparation is demonstrated in the ready synthesis of oxazoles with substantial structural and functional group variation.

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Section: Resultsmentioning

confidence: 99%

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

2016

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“…The N(1)–Pd(1)–C(1) angle is 80.17(21)°, showing distortion from an idealized square-planar geometry at the palladium center. It appears that no transition metal complexes of acylated 1-aminopyridine ylides have been crystallographically characterized …”

Section: Resultsmentioning

confidence: 99%

1-Aminopyridinium Ylides as Monodentate Directing Groups for sp³ C–H Bond Functionalization

Nguyen

Daugulis

2019

J. Am. Chem. Soc.

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1-Aminopyridinium ylides are efficient directing groups for palladium-catalyzed β-arylation and alkylation of sp3 C–H bonds in carboxylic acid derivatives. The efficiency of these directing groups depends on the substitution at the pyridine moiety. The unsubstituted pyridine-derived ylides allow functionalization of primary C–H bonds, while methylene groups are unreactive in the absence of external ligands. 4-Pyrrolidinopyridine-containing ylides are capable of C–H functionalization in acyclic methylene groups in the absence of external ligands, thus rivaling the efficiency of the aminoquinoline directing group. Preliminary mechanistic studies have been performed. A cyclopalladated intermediate has been isolated and characterized by X-ray crystallography, and its reactivity was studied.

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“…[1][2][3][4] Furthermore, these products may be important as bidentate ligands of metal ions of different radii in view of the possibility to vary at will the methylene spacing groups. 7,8 …”

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Efficient Simultaneous Closure of Polysubstituted 1-Aminopyrrole Rings Spaced by a Variable Number of Methylene Groups

Attanasi¹,

Crescentini²,

Fïlippone³

et al. 1999

Synlett

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The treatment of alkyl 2-chloroacetoacetate with carbohydrazide, succinic or adipic dihydrazide produces the relevant a,a'-dichlorobishydrazones. In the presence of sodium carbonate, these compounds react at room temperature with b-diketones, b-ketoesters or b-ketoamides to give rise to functionalized 1-carbonylaminopyrrole rings spaced by a variable number of methylene groups.The pyrrole ring represents a very important skeleton in organic, polymeric, natural, biological, medicinal and agricultural products. 1 In particular, 1-aminopyrrole derivatives seem to be quite difficult to prepare by Knorr and its modified procedures, mainly due to the severe reaction conditions and/or the formation of dihydropyridazine byproducts. The limited presence of 1-aminopyrroles in the literature can be ascribed to a few procedures existing for their preparation. 2,3 In previous papers, we reported the mild and convenient one-pot synthesis of polysubstituted monocyclic 1-aminopyrrole derivatives by reaction of conjugated azoalkenes with various compounds containing activated methylene or methine groups. 4 We now report an efficient simultaneous closure of polysubstituted 1-aminopyrrole rings spaced by a variable number of methylene groups by preliminary reaction of alkyl 2-chloroacetoacetate with different dihydrazides to give the corresponding a,a'-dichlorobishydrazones and subsequent treatment with bdiketones, b-ketoesters or b-ketoamides through the corresponding conjugated azoalkene intermediates.Initially, we treated methyl 2-chloroacetoacetate 1a with carbohydrazide 2a obtaining dimethyl (a,a'-dichloroacetoacetate)carbobishydrazone 3a (see Scheme 1 and Table). In the presence of sodium carbonate, this last compound reacts in THF at room temperature with two equivalents of benzoylacetone 5a or acetoacetanilide 5b affording directly the corresponding N,N'-di(1H-pyrrol-1-yl)ureas 6a-b (see Scheme 1 and Table). 5 The regiochemistry of 6a is clearly shown by 1 H-and 13 C-NMR analysis in accordance with our previous findings. 6 Likely, this latter reaction passes through the conjugated azoalkene intermediate 4 generated in situ, as manifested by the appearance of the red colour typical of these compounds when the base-promoted dehydrohalogenation occurs and then by the turning to colourlessness when the same compounds lose the conjugated double bonds by addition of the b-dicarbonyl derivative. This hypothesis is also supported by the isolation of a similar entity in the reaction reported in Scheme 2. 5 We then tried successfully analogous reactions between methyl 1a or ethyl 2-chloroacetoacetate 1b and succinic 2b or adipic dihydrazide 2c producing dialkyl (a,a'- Scheme 1Downloaded by: York University libraries. Copyrighted material.

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Synthesis and structure of complexes of acyl N-aminides with zinc(II) salts

Abstract: The structures of complexes obtained by reacting acyl N-aminides and ZnCI: were ascertained by Xray analysis and were show to incorporate one Zn atom and two molecules of the N-aminide in a distorted tetrahedral geometry. Bis-aminides act as bidentate tigands forming ZnI,C12 complexes.

Cited by 6 publications

References 12 publications

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

1-Aminopyridinium Ylides as Monodentate Directing Groups for sp³ C–H Bond Functionalization

Efficient Simultaneous Closure of Polysubstituted 1-Aminopyrrole Rings Spaced by a Variable Number of Methylene Groups

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Synthesis and structure of complexes of acyl N-aminides with zinc(II) salts

Abstract: The structures of complexes obtained by reacting acyl N-aminides and ZnCI: were ascertained by Xray analysis and were show to incorporate one Zn atom and two molecules of the N-aminide in a distorted tetrahedral geometry. Bis-aminides act as bidentate tigands forming ZnI,C12 complexes.

Cited by 6 publications

References 12 publications

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

Efficient and Flexible Synthesis of Highly Functionalised 4‐Aminooxazoles by a Gold‐Catalysed Intermolecular Formal [3+2] Dipolar Cycloaddition

1-Aminopyridinium Ylides as Monodentate Directing Groups for sp3 C–H Bond Functionalization

Efficient Simultaneous Closure of Polysubstituted 1-Aminopyrrole Rings Spaced by a Variable Number of Methylene Groups

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1-Aminopyridinium Ylides as Monodentate Directing Groups for sp³ C–H Bond Functionalization