Synthesis Of Amidines Research Articles

Preparation and Utility of Trihaloethyl Imidates: Useful Reagents for the Synthesis of Amidines

2,2,2-Trifluoro- and trichloroethyl imidates, which are easily prepared by reaction of a nitrile and a trihaloethanol in the presence of HCl, have proven to be excellent reagents for the preparation of amidines under mild reaction conditions. Depending on the nature of the amine nucleophile, the imidates can react either as the free-base or the hydrochloride salt in a telescoped process. In several cases, the p-bromobenzoate salt of the desired product was directly isolated from the reaction mixture.

ChemInform Abstract: Syntheses of Amidines from Thioamides, Mediated by the N‐Heterocyclic Carbene Indazol‐3‐ylidene.

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.

Syntheses of Amidines from Thioamides, Mediated by the N-Heterocyclic Carbene Indazol-3-ylidene

On decarboxylation, 1,2-dimethylindazolium-3-carboxylate forms the N-heterocyclic carbene 1,2-dimethylindazol-3-ylidene in situ, which proved to be a suitable reagent for amidinations of the mono-thiolactams of succinimide and phthalimide.

ChemInform Abstract: N‐Heterocyclic Carbenes of Indazole as Reagents: Indazol‐3‐ylidene‐Mediated Syntheses of Amidines from Thiolactams of Pyrrolobenzodiazepines.

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.

Utility of Ammonium Salts for the Synthesis of Amidines

Reported is a copper-catalyzed, three-component coupling reaction of terminal alkynes, sulfonyl or phosphoryl azides and ammonium salts to give N-unprotected amidines. The derived amidines with a 2-bromosulfonyl moiety were efficiently cyclized by a copper-catalyzed ­intramolecular arylation to afford 2H-1,2,4-benzo-thiadiazine-1,1-dioxides. The reaction is carried out under very mild (room temperature), simple (inert atmosphere is not required) conditions using inexpensive ammonium salt or aqueous ammonia reagents. The synthesis of amidines proceeds mostly in good yields, except for using a phosphoryl azide (39% yield). The cyclization also proceeds in good yields as well as a one-pot version of the reaction. The substrate scope was well studied but the one-pot reaction was not well tested (one substrate).

Synthesis of amidines using N-allyl ynamides. A palladium-catalyzed allyl transfer through an ynamido-pi-allyl complex.

A de novo transformation of N-allyl-N-sulfonyl ynamides to amidines is described featuring a palladium-catalyzed N-to-C allyl transfer via ynamido-palladium-pi-allyl complexes.

N-Heterocyclic Carbenes of Indazole as Reagents: Indazol-3-ylidene-Mediated Syntheses of Amidines from Thiolactams of Pyrrolobenzodiazepines

On decarboxylation, 1,2-dimethylindazolium-3-carboxylate forms in situ the N-heterocyclic carbene 1,2-dimethylindazol-3-ylidene, which proved to be a suitable reagent for amidinations of the monothiolactam of benzo[e]pyrrolo[l,2-a][l,4]diazepine. A comparison of this metal-free approach to amidines to HgCl 2 - and Bi(NO 3 ) 3 -mediated reactions is presented.

Functionality of amidines and amidrazones

The review summarizes literature dealing with the synthesis of amidines and amidrazones including some of their physical and chemical properties along with their applications in heterocycles synthesis.

Principais métodos de síntese de amidinas

The amidine functional group is found in a wide range of natural products and is biologically active against several pathogens. In addition, amidines have long been regarded as useful intermediates in the synthesis of heterocyclic compounds. Consequently, a great number of methods have been developed for the preparation of amidines. Pinner's method is the most commonly used. Conventional methods include: - the addition of metal amides or amines to nitriles, the addition of amines to imido esters and the condensation of amides with amines in the presence of halogenating reagents. In this report, the main methods for synthesis of amidines will be described.

Solid-phase synthesis of amidines by the reduction of amidoximes

Amidines can be prepared on a solid support by reducing polymer-bound amidoximes with SnCl2·2H2O. The method has proved to be straightforward and highly efficient. Amidoximes attached to the solid support are readily available by treating resin-bound nitriles with hydroxylamine.

Novel α‐Amino Amidine Synthesis via Scandium(III) Triflate Mediated 3CC Ugi Condensation Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Facile One-pot Syntheses of Amidines and Enamines from Oximes via Beckmann Rearrangement Using Trifluoromethansulfonic Anhydride

Abstract Facile one-pot syntheses of amidines and enamines were achieved by trapping carbocation intermediates that were formed by Beckmann rearrangement of oximes with amines and carbon nucleophiles, respectively, under mild conditions.

Novel α-amino amidine synthesis via scandium(III) triflate mediated 3CC Ugi condensation reaction

α-Amino amidines are made via a novel scandium(III) triflate catalyzed multi-component reaction involving aldehydes, amines, and isonitrile. The reaction can be automated and is amenable to library production. The chemistry of α-amino amidine described herein can be elaborated further for the synthesis of hydantoin imides and imidopyrazine derivatives.

Synthesis of Amidines Derived from Phosphonates and Phosphane Oxides — Amidine‐Mediated Preparation of Phosphorylated Oxazolines.

Alkylation of N-(phosphorylalkyl)phosphazenes 2 with methyl iodide and allyl bromide and acylation with ethyl chloroformate leads to the formation of aminophosphonium salts 4 derived from (aminoalkyl)phosphonates. N-(Phosphorylalkyl)amidines 8 were obtained by reaction of phosphazenes derived from aminophosphonates with benzoyl chloride and subsequent addition of amines. These functionalized amidines were used as key intermediates in the synthesis of oxazolin-4-ylphosphonates 9 and 10. In a similar manner, oxazolin-4-ylphosphane oxides 17 and 18 were prepared from N-(phosphanylalkyl)amidines 16, which were obtained by reaction of phosphazenes derived from phosphane oxides 15 with benzoyl chloride and amines. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis of Amidines Derived from Phosphonates and Phosphane Oxides − Amidine‐Mediated Preparation of Phosphorylated Oxazolines

AbstractAlkylation of N‐(phosphorylalkyl)phosphazenes 2 with methyl iodide and allyl bromide and acylation with ethyl chloroformate leads to the formation of aminophosphonium salts 4 derived from (aminoalkyl)phosphonates. N‐(Phosphorylalkyl)amidines 8 were obtained by reaction of phosphazenes derived from aminophosphonates with benzoyl chloride and subsequent addition of amines. These functionalized amidines were used as key intermediates in the synthesis of oxazolin‐4‐ylphosphonates 9 and 10. In a similar manner, oxazolin‐4‐ylphosphane oxides 17 and 18 were prepared from N‐(phosphanylalkyl)amidines 16, which were obtained by reaction of phosphazenes derived from phosphane oxides 15 with benzoyl chloride and amines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Readily Prepared Resin-Bound Thioimidates as Reagents for the Synthesis of Amidines

The use of commercially available resins to prepare novel and stable polymer supported thioimidates was investigated. Polymer supported thioimidates were found to enable acetamidine formation in a convenient manner, with a significantly easier work-up than solution-phase reactions.

A Palladium-Catalyzed Synthesis of Amidines from Aryl Halides

Tin-free three-component coupling: Palladium-catalyzed coupling between aryl or heteroaryl bromides, primary or secondary amines, and tert-butyl isocyanide gives high yields of pharmaceutically interesting arylamidines [Eq. (1)]. dppf=1,1′-bis(diphenylphosphanyl)ferrocene; R1/R2=Bu/H, Ph/H, −(CH2)4−.

A Palladium-Catalyzed Synthesis of Amidines from Aryl Halides

A Palladium-Catalyzed Synthesis of Amidines from Aryl Halides

Mild method for the synthesis of amidines by the electrophilic activation of amides

The synthesis of amidines was achieved by the addition of amines to amides that were previously activated with trifluoromethanesulfonic anhydride (triflic anhydride) and pyridine. Various disubstituted and trisubstituted amidines were prepared in yields up to 84%.

A new mild method for the synthesis of amidines

A new method for the synthesis of amidines is presented using N-acetylcysteine as a catalyst. The key advantage of this new method is that it is compatible with a large number of functional groups. It allows the synthesis of amidines in complex molecules containing acid-labile groups, base-labile centers of asymmetry or functional groups sensitive to hydrogenation.