General acid catalyzed imidazolidine hydrolysis. Hydrolysis of 2-(tert-butyl)-N,N'-dimethyl-1,3-imidazolidine and 2-(p-methoxyphenyl)-N-isopropyl-N'-phenyl-1,3-imidazolidine

Fife, Thomas H.; Hutchins, J. E. C.; Pellino, August M.

doi:10.1021/ja00488a032

Cited by 16 publications

(10 citation statements)

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“…It was observed that optimum reaction conditions depended strongly on the type of carbonyl compound employed and also on the stability towards hydrolysis of Jul-Aug 2002 655 the resulting cyclic aminals. It is widely accepted that compounds of this type undergo hydrolysis through carbocation-iminium ions (Scheme II) [17]. The stability of such intermediates is enhanced by electron donor substituents on the carbocationic carbon and by N-alkyl groups, whereas N-aryl substituents do not provide stabilization.…”

Section: Synthesismentioning

confidence: 99%

N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

Perillo

García

Bisceglia

et al. 2002

Journal of Heterocyclic Chem

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A series of N-arylhexahydropyrimidines 1a-l were synthesized by condensation of N-aryl-N'-alkyl-(or aryl)-1,3-propanediamines 2a-h with aldehydes. Reactions with formaldehyde proceeded in hydroalcoholic solution, while condensation with aromatic aldehydes required in general the use of activated molecular sieves. 1 H NMR spectra of compounds 1a-l were analyzed and the results correlated with their conformational features. Derivatives devoid of a 2-substituent 1a-g show fast ring reversal and N-inversion. The presence of a 2-aryl group shifts the ring reversal equilibrium towards conformations where the 2-aryl substituent is equatorial. Differential assignment of axial and equatorial hydrogens in these compounds was made on the basis of coupling constants and chemical shift values. In compound 1k spectral data suggest the axial orientation of the N-methyl group. Such findings were confirmed in the corresponding NOESY spectrum.

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Section: Synthesismentioning

confidence: 99%

N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

Perillo

García

Bisceglia

et al. 2002

Journal of Heterocyclic Chem

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“…Several research groups have studied the decomposition of gem-diaminoalkyl moieties. 143,144 However only Loudon and co-workers, following on from their work on carboxy-terminal peptide degradation, studied the mechanism of hydrolysis of monoprotected gem-diaminoalkyl compounds of the variety encountered in PMRI peptides. 103,120 Under basic conditions the mechanism of hydrolysis determined by Loudon and co-workers is as shown in Scheme 22, and the observed rates of hydrolysis were in the order 59d > 59b > 59a, due to imine stabilization in 59d and a better leaving group in 59b than in 59a.…”

Section: Scheme 5 Formation Of Byproducts During the Synthesis Of Bimentioning

confidence: 99%

Partially Modified Retro-Inverso Peptides: Development, Synthesis, and Conformational Behavior

1998

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“…The recovery of 1c from 1c 0 is regarded as hydrolysis under acidic conditions (Fife et al, 1978). Weakly acidic naphthol may catalyze such a reaction.…”

Section: Resultsmentioning

confidence: 99%

Amino-phenol complexes of Fe(III) as promising T1 accelerators

Kuźnik

Wyskocka

Jarosz

et al. 2019

Arabian Journal of Chemistry

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Iron(III) complexes with N,O-ligands are compounds of high interest because they can be applied in catalysis and play an important role in living organisms, e.g., as models of catechol dioxygenase. Several N,O-ligands were studied: their synthesis, iron(III) complexation and the potential of the latter as T 1 -MRI contrast agents. A route to the tetrapodal N 3 O 2 -naphthyl ligand was investigated. The resulting iron complex was obtained in 26% total yield and its relaxivity value was moderate (r 1 = 1.03 in water and 2.54 s À1 mM À1 in serum). Thus, phenyl isomeric salan complexes were obtained. These complexes differed in charge (positive and neutral) and in the presence of polar hydrogen-bonding substituents. The highest relaxivities (r 1 = 2.39 in water and 5.37 s À1 mM À1 in serum) were obtained for the Fe(III) cationic complex with MeO groups in the ligand. EPR studies confirmed a high spin configuration of rhombically distorted Fe(III) complexes. ª 2014 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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General acid catalyzed imidazolidine hydrolysis. Hydrolysis of 2-(tert-butyl)-N,N'-dimethyl-1,3-imidazolidine and 2-(p-methoxyphenyl)-N-isopropyl-N'-phenyl-1,3-imidazolidine

Cited by 16 publications

References 9 publications

N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

Partially Modified Retro-Inverso Peptides: Development, Synthesis, and Conformational Behavior

Amino-phenol complexes of Fe(III) as promising T1 accelerators

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General acid catalyzed imidazolidine hydrolysis. Hydrolysis of 2-(tert-butyl)-N,N'-dimethyl-1,3-imidazolidine and 2-(p-methoxyphenyl)-N-isopropyl-N'-phenyl-1,3-imidazolidine

Cited by 16 publications

References 9 publications

N‐arylhexahydropyrimidines. Part 1. Synthesis and 1H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

N‐arylhexahydropyrimidines. Part 1. Synthesis and 1H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

Partially Modified Retro-Inverso Peptides: Development, Synthesis, and Conformational Behavior

Amino-phenol complexes of Fe(III) as promising T1 accelerators

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N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives

N‐arylhexahydropyrimidines. Part 1. Synthesis and ¹H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives