About nitrile‐formamide‐chloride‐adducts. IX. Synthesis of 1,3‐ or 1,5‐disubstituted 1,2,4‐triazoles by the reaction of nitrile‐formamide chloride‐adducts and their products of hydrolysis with hydrazines

Liebscher, Jürgen; Rumler, Andrea

doi:10.1002/prac.19843260216

Cited by 9 publications

(2 citation statements)

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“…nucleophilen Angriff an der Carbonylgruppe und Bildung eines Heterocyclus, beispiclsweise eines 1,2,4-Triazols, eingehen [4,8]. Kurzlich konnten wir zeigen, daB auf diese Weise aus entsprechend o-funktionalisierten Smidderivaten 1 und 2 (n = 1, 2; X = C1, Phthalimido) und Hydrazinen auch vorteilhaft entsprechende o-funktionalisierte 5-Alkyl-l,2,4-triazole zuganglich sind 111 -141.…”

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Functionalised N‐Acylformamidinium Salts and Formamides as Acylating or Iminoformylating Reagents for Semicyclic Amidines and Special Amines

Bechstein

Liebscher

1989

J. Prakt. Chem.

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Functionalised N‐Acylformamidinium Salts and Formamides as Acylating or Iminoformylating Reagents for Semicyclic Amidines and Special Amines

Bechstein

Liebscher

1989

J. Prakt. Chem.

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“…1-Phenyl-1 H -1,2,4-triazole ( 1c ), 20 1-methyl-5-phenyl-1 H -1,2,4-triazole ( 2b ), 10c 1-phenyl-5-phenyl-1 H -1,2,4-triazole ( 2c ), 21 and 4-methyl-3-phenyl-4 H -1,2,4-triazole ( 7 ) 22 are known compounds.…”

Section: Methodsmentioning

confidence: 99%

C–H Bonds as Ubiquitous Functionality: Preparation of Multiple Regioisomers of Arylated 1,2,4-Triazoles via C–H Arylation

2012

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We describe a general approach for the synthesis of complex aryl 1,2,4-triazoles. The electronic character of the C–H bonds and the triazole ring allows for the regioselective C–H arylation of 1-alkyl and 4-alkyl triazoles under catalytic conditions. We have also developed the SEM- and THP-switch as well as trans-N-alkylation, which enable sequential arylation of the triazole ring to prepare 3,5-diaryltriazoles. This straightforward strategy provides rapid access to a variety of arylated 1,2,4-triazoles and well complements existing cyclization methods.

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Efficient Syntheses of ω‐Chloro‐, ω‐Imido‐ and ω‐Aminoalkyl‐1,2,4‐triazoles from N‐Acyl‐formamidinium Salts or N‐Acylformamides and Hydrazines

Bechstein

Rumler

Liebscher

1992

Archiv der Pharmazie

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@Halo and wamidoalkylcyanides 1 are transformed to ofunctionalized N-acylfonnamidinium salts 4 or fonnamide 6a by HCI catalyzed addition of chloromethylene iminium salts, derived from formamides 2 and POCl3. Advantageously, p-halo-propionyl-formamidinium salts 4 can also be obtained from acrylonitrile. Regiospecific and chemoselective cyclization of N-acylfonnamidinium salts 4 or fonnamide 6a to wfunctionalized 5-alkyl-1.2.4- These syntheses have only a limited range of application. Therefore, we tied to synthesize mchloro, mphthalimido and maminoalkyl-1,2,4-triazoles 9 by reaction of N-acylfomamidines or N-acylformamides as C-N-C-synthons with hydrazines as N-N-building block. This method was very useful in the' synthesis of 5-aryl and 1,5-diaryl-I ,2,4-triazoles6).The o-functionalized N-acyl-formamidinium salts 4 and -formamide 6a (Table 1) necessary as educts for the preparation of the o-functionalized 5-&yl-l,2,Ctriazoles 9 can be conveniently obtained') by addition of adducts of N,Ndisubstituted formamides 2 and POCl3 (chloromethylene iminium salts) to corresponding o-functionalized nitriles 1 (chloroacetonitrile, phthalimidoacetonitrile or phthalimidopropionitrile) via intermediate 2-aza-3-cNoro-2-propniminium salts 3*O). This addition requires mild conditions and catalysis by gaseous HC1. Otherwise no reaction takes place or other products, e.g. azapentamethinium salts') by bisiminoformylation, are obtained. In some cases the success of the reaction also depends on the substituents R' at the N atom of 2 that is on its electron density in the chloromethylene iminium salts'). E.g. the adducts of DMF or Nformyl-pyrrolidine 1 ( N R ' 2 = pyrrolidino) with POC13 in reaction with chloroacetonitrile give the corresponding Nchloroacetyl-formamidinium salts 4 while the stronger electrophilic N-fomylmorpholine gives 2-aza-3,4-dichloro-pentamethinium salts by bisiminoformylation even in the presence of HCl and at low temp. (OOC).6-Phthalimido-propionitrile 1 (X = phthalimido, n = 2) smoothly reacts in the same way. But during working up mixtures of N-(P-phthalimido-propiony1)-amidinium salts 4 and formamide 6a are obtained. Therefore, these reaction mixtures are further hydrolyzed by ice water in order to obtain N-(P-phthalimido-propiony1)formamide 6a (X = phthalimido, n = 2) solely in high yield, N-(P-Halopropiony1)formamidinium salts 4 (X = C1, Br; n = 2) can be prepared starting from NJV-disubstituted formamide 2/POCl3 adducts in two different ways (Method A), i.e. using P-halopropionitrile 1 (X = halo, n = 2) or, more conveniently, acrylonitrile as substrate. In the latter procedure two additions take place, that is addition of hydrohalide to the C=C double bond and addition of the 2/POC13 adduct to the CkN triple bond. Again 2-aza-3-chloro-propeniminium salts 3 (n = 2, X = C1, Br) are assumed as intermediates. With the exception of not well described NJV-dimethyl-N'-(P-chloropropiony1)-formamidinium salts 4 (X = C1, n = 2, R' = CH3) which were claimed") as intermediates in the synthesis of phosphorus containing ...

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About nitrile‐formamide‐chloride‐adducts. IX. Synthesis of 1,3‐ or 1,5‐disubstituted 1,2,4‐triazoles by the reaction of nitrile‐formamide chloride‐adducts and their products of hydrolysis with hydrazines

Cited by 9 publications

References 20 publications

Functionalised N‐Acylformamidinium Salts and Formamides as Acylating or Iminoformylating Reagents for Semicyclic Amidines and Special Amines

Functionalised N‐Acylformamidinium Salts and Formamides as Acylating or Iminoformylating Reagents for Semicyclic Amidines and Special Amines

C–H Bonds as Ubiquitous Functionality: Preparation of Multiple Regioisomers of Arylated 1,2,4-Triazoles via C–H Arylation

Efficient Syntheses of ω‐Chloro‐, ω‐Imido‐ and ω‐Aminoalkyl‐1,2,4‐triazoles from N‐Acyl‐formamidinium Salts or N‐Acylformamides and Hydrazines

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