Guanylation Of Amines Research Articles

Structural and Mechanistic Insights into s-Block Bimetallic Catalysis: Sodium Magnesiate-Catalyzed Guanylation of Amines.

To advance the catalytic applications of s-block mixed-metal complexes, sodium magnesiate [NaMg(CH2 SiMe3 )3 ] (1) is reported as an efficient precatalyst for the guanylation of a variety of anilines and secondary amines with carbodiimides. First examples of hydrophosphination of carbodiimides by using a Mg catalyst are also described. The catalytic ability of the mixed-metal system is much greater than that of its homometallic components [NaCH2 SiMe3 ] and [Mg(CH2 SiMe3 )2 ]. Stoichiometric studies suggest that magnesiate amido and guanidinate complexes are intermediates in these catalytic routes. Reactivity and kinetic studies imply that these guanylation reactions occur via (tris)amide intermediates that react with carbodiiimides in insertion steps. The rate law for the guanylation of N,N'-diisopropylcarbodiimide with 4-tert-butylaniline catalyzed by 1 is first order with respect to [amine], [carbodiimide], and [catalyst], and the reaction shows a large kinetic isotopic effect, which is consistent with an amine-assisted rate-determining carbodiimide insertion transition state. Studies to assess the effect of sodium in these transformations denote a secondary role with little involvement in the catalytic cycle.

Synthesis of substituted guanidines using Zn–Al hydrotalcite catalyst

Substituted guanidines were synthesized by the guanylation of amines with carbodiimides using Zn–Al hydrotalcite (Zn-Al HT) catalyst. Zn–Al HT was prepared by co-precipitation method and characterized by X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman and Thermogravimetric-Differential Thermal Analysis (TG-DTA). The heterogeneous catalyst afforded moderate to good yields (∼50–60 %) of substituted guanidines in toluene at 110°C in 12 h. The catalyst was recovered quantitatively by simple filtration and reused for three cycles with consistent activity. The XRD and FTIR studies of the used catalyst shows no variation in the structure of the catalyst even after three recycles.

ChemInform Abstract: Lanthanide Amidinates and Guanidinates in Catalysis and Materials Science: A Continuing Success Story

AbstractReview: 72 refs.

Lanthanide amidinates and guanidinates in catalysis and materials science: a continuing success story

Today the rare-earth elements play a critical role in numerous high-tech applications. This is why various areas of rare-earth chemistry are currently thriving. In organolanthanide chemistry the search for new ligand sets which are able to satisfy the coordination requirements of the large lanthanide cations continues to be a hot topic. Among the most successful approaches in this field is the use of amidinate and guanidinate ligands of the general types [RC(NR')(2)](-) (R = H, alkyl, aryl; R' = alkyl, cycloalkyl, aryl, SiMe(3)) and [R(2)NC(NR')(2)](-) (R = alkyl, SiMe(3); R' = alkyl, cycloalkyl, aryl, SiMe(3)), which can both be regarded as steric cyclopentadienyl equivalents. Mono-, di- and trisubstituted lanthanide amidinate and guanidinate complexes are all readily available. Various rare earth amidinates and guanidinates have turned out to be very efficient homogeneous catalysts e.g. for the polymerization of olefins and dienes, the ring-opening polymerization of cyclic esters or the guanylation of amines. Moreover, certain alkyl-substituted lanthanide tris(amidinates) and tris(guanidinates) were found to be highly volatile and are thus promising precursors for ALD (= atomic layer deposition) and MOCVD (= metal-organic chemical vapor deposition) processes in materials science, e.g. for the production of lanthanide nitride thin layers. This tutorial review covers the continuing success story of lanthanide amidinates and guanidinates which have undergone an astonishing transition from mere laboratory curiosities to efficient homogeneous catalysts as well as ALD and MOCVD precursors within the past 10 years.

ChemInform Abstract: Guanylation of Amines with Isonitriles in the Presence of Iodine.

ChemInform Abstract: Guanylation of Amines with Isonitriles in the Presence of Iodine.

ChemInform Abstract: 1H-Pyrazole-1-carboxamidine Hydrochloride: An Attractive Reagent for Guanylation of Amines and Its Application to Peptide Synthesis.

ChemInform Abstract: 1H-Pyrazole-1-carboxamidine Hydrochloride: An Attractive Reagent for Guanylation of Amines and Its Application to Peptide Synthesis.

Rare earth metal bis(trimethylsilyl)amido complexes bearing pyrrolyl-methylamide ligand. Synthesis, structure, and catalytic activity towards guanylation of amines

The N-arylaminomethyl substituted pyrrolyl ligand 2-[(2,4,6-Me(3)C(6)H(2))NHCH(2)](C(4)H(3)NH) (1) was synthesized by reduction of 2-[(2,4,6-Me(3)C(6)H(2))N=CH](C(4)H(3)NH) using NaBH(4). Treatment of [(Me(3)Si)(2)N](3)Ln(μ-Cl)Li(THF)(3) with 1 equiv. of 1 in reflux toluene for 24 h, afforded the corresponding trivalent rare earth metal amides with formula {(μ-η(5):η(1)):η(1)-2-[(2,4,6-Me(3)C(6)H(2))NCH(2)]C(4)H(3)N]LnN(SiMe(3))(2)}(2) (Ln = Y(2), Nd(3), Sm(4), Dy(5), Er(6)). All compounds were fully characterised by spectroscopic methods and elemental analyses. The structures of complexes 2, 4 and 6 were determined by single-crystal X-ray analyses. X-Ray analyses discovered that two rare-earth metal ions were bridged by dianion ligand with the pyrrolyl ring which coordinated to one rare earth metal in an η(5) mode, the tethered nitrogen anion and nitrogen atom of the pyrrolyl ring coordinated to another rare earth metal in η(1) modes forming the centrosymmetric dinuclear structures. The rare earth metal complexes as catalysts for the guanylation of aromatic amines were studied. Results showed all rare earth metal complexes exhibited a high catalytic activity on the guanylation of aromatic amines.

ChemInform Abstract: NIS‐Promoted Guanylation of Amines.

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Synthetic Routes to N‐Pmc‐N′,N′′‐Disubstituted Guanidines via EDCI‐Mediated Guanylation of Amines with N‐Pmc‐N′‐Substituted Thioureas.

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Synthetic Routes to N-Pmc-N′,N′′-Disubstituted Guanidines via EDCI-Mediated­ Guanylation of Amines with N-Pmc-N′-Substituted Thioureas

An overview of the facile and high-yielding EDCI-mediated reaction of amines with N-Pmc-N′-alkyl thioureas to afford guanidines is presented, in which the general scope and limitations of the reaction are probed. It was found that the N-sulfonyl-N′-substituted thioureas cannot possess internal nucleophiles or disubstitution, and that the incoming amine must possess adequate nucleophilicity in order for the reaction to be viable. However, it is noted that the guanidine products can be accessed through two possible synthetic approaches, and that a simple reversal of amine and thiourea substituents allows the reaction to proceed successfully.