Synthesis of functional derivatives ofN-carboxamidomethyl- andN-phthalimidomethyl-a-amino acids and peptides by reaction of amides and nitriles of α-amino acids with formaldehyde and primary amides or phthalimide

A direct method for the synthesis of functional derivatives ofN-carboxatnidomethyl- and N-phthalimidomethyl-a-amino acids by the reaction of nitriles and amides of -amino acids (including peptides) with formaldehyde and NH-compounds (amides and imides) in DMF in the presence of TsOH was developed. The reactions of the compounds synthesized with acetic anhydride, tosyl chloride, and phcnylalanine benzylamide in the presence of dicyclohexylcarbodiimide affording the corresponding N-acyl and N-sulfonyl derivatives or peptides containing carboxamido- and phthalimidomethyl substituents at the terminal N-atom of the peptide chain, were studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1480–1488, June, 1996.     

Reaction of α-bromocarboxylic acids with hydrazine and dimethylhydrazine

Nucleofilic reaction of a series of α-bromocarboxylic acids with hydrazine and dimethylhydrazine is studied. High reactivity of α-bromocarboxylic acids is revealed and a series of α-hydrazinoarboxylic acids and N-(1-carboxyalkyl)-N,N-dimethylhydrazinium bromides are synthesized.     

Enamines of 3-acyltetramic acids from β-enamino amides and amino acids

A novel approach for the synthesis of enamine derivatives of N-protected 3-acyltetramic acids is described. The synthetic procedure relies on α-C-acylation of β-enamino amides with N-protected α-amino acids and subsequent cyclisation of the obtained intermediates in refluxing TFA. The tetramic derivatives are obtained with very good enantiopurity (e.r. ≥95:5). Ring-enlarged analogues (piperidine-2,4-diones) can also be obtained from β-amino acids.     

Reaction of imidazole and its 2-alkyl derivatives with γ-butyrolactone

Reaction of imidazole with -butyrolactone gives N-alkylation and N-acylation products depending upon the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1491–1493, November, 1992.     

Enzymatic and chiral HPLC resolution of α-azido acids and amides

For the first time, enzymatic resolution of α-azido acid amides has been successfully demonstrated with high yields and enantiomeric excess. In one case dynamic kinetic resolution was achieved leading to more than 50% yield of the enantiomerically pure azido acid. Chiral HPLC was also used to separate racemic α-azido acids and the separation process was automated. Two routes to enantiopure α-azido acid building blocks for solid-phase peptide synthesis have, therefore, been established.     

Synthesis ofN-(amidomethyl)- andN- (imidomethyl)-α-amino acid esters by reactions of α-amino acid esters with formaldehyde and amides or imides

Reactions of hydrochlorides of glycine, alanine, phenylalanine, L-isolcucinc, and L-valine esters with aromatic and heteroaromatic carboxamides afforded hydrochlorides of the correspondingN-(amidomethyl)--amino acid esters.N-(Phthalimidomethyl)--amino acid esters were obtained by reactions of -amino acid esters containing free amino groups with formaldehyde and phthalimide, The¹H NMR studies demonstrated that the chiral centers of -amino acids may be retained in the course of condensation. Reactions of the Mannish bases obtained and their hydrochlorides with acetic anhydride and tosyl chloride afforded the correspondingN-aryl andN-sulfonyl derivatives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp, 1761–1769, July, 1996.     

Acetals of lactams and amides of acids. 72. Investigation of reaction of cyclic β-nitroenamines with p-benzoquinone

The process of condensation of p-benzoquinone with the secondary cyclic enamines 2-(2-nitromethylene)pyrrolidine, -piperidine, and -hexahydroazepine is very much dependent on the size of the saturated ring in these compounds. With increasing ring size, the content of derivatives of 5-hydroxybenzofuran decreases, and the quantity of derivatives of 5-hydroxyindole increases; with the seven-membered enamine, a substituted 6-hydroxyindole is also formed. For enamines of the pyrrolidine and piperidine series, 1,4-bis-2-(2-nitromethylene)pyrrolidono- or piperidinohydroquinones are also recovered.For Communication 71, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 357–362, March, 1992.     

Reaction of 2-aminopyridines with α, β-unsaturated acids

The reaction of 2-amino- and 2-amino-5-halopyridines with acrylic, methacrylic, and crotonic acids forms N-(2-pyridyl)- and N-(5-halo-2-pyridyl)--alanines and the betaines 2-amino-1-(2-carboxylatoethyl)pyridinium or 3,4-dihydropyrido[1,2-a]pyrimidin-2-ones, or their homologs.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–85, January, 1992.     

Efficient synthesis of N-carboxyalkyl-substituted dithiaza- and dioxadithiazacycloalkanes by cyclocondensation of amino acids with formaldehyde and α,ω-dithiols

Russian Journal of Organic Chemistry - A method of synthesis of N-carboxyalkyl-substituted dithiaza- and dioxadithiazacycloalkanes was developed consisting in a tricomponent...     

Reaction of N,N′-Methylenebis(trifluoromethanesulfonamide) with Styrene under Oxidative Conditions

Russian Journal of Organic Chemistry - The reaction of N,N′-methylenebis(trifluoromethanesulfonamide) with styrene in the oxidative system t-BuOCl/NaI affords triflamide,...     

Reaction products and kinetics of the reaction of NO2 with γ-Fe2O3

The reaction of NO(2) with Fe(2)O(3) has relevance for both atmospheric chemistry and catalysis. Most studies have focused on hematite, α-Fe(2)O(3), as it is the thermodynamic stable state of iron oxide; however, other forms of Fe(2)O(3) naturally occur and may have different chemistries. In this study, we have investigated the reaction products and kinetics for NO(2) reacting with γ-Fe(2)O(3) powder using diffuse reflectance infrared Fourier transform spectroscopy and compared the results to those of previous studies of NO(2) reacting with α-Fe(2)O(3). Both α- and γ-Fe(2)O(3) produce surface-bound nitrate at the pressures examined in this study (24-212 mTorr); surface-bound nitrite products are observed at all pressures for γ-Fe(2)O(3) whereas nitrite was only observed on α-Fe(2)O(3) at lower pressures. Surface-bound NO(+) and Fe-NO products are observed on γ-Fe(2)O(3), which have not been observed with α-Fe(2)O(3). The reaction kinetics show a first-order dependence on NO(2) pressure and this is used to support the hypothesis of unimolecular reaction of adsorbed NO(2) with the γ-Fe(2)O(3) surface as the slow step in the reaction mechanism. The difference in product formation between NO(2) reacting with γ-Fe(2)O(3) and previous studies of α-Fe(2)O(3) illustrate the fact that care must be taken in generalizing reactivity of different polymorphs.     

Reactions of aminobenzoic acids with α,β-acetylenic γ-hydroxy nitriles: synthesis of functionalized amino acids and unusually facile esterification and acetylene hydration

2-Aminobenzoic acid 1 reacts with α,β-acetylenic γ-hydroxy nitriles 4 and 5 to afford 2-[(5-iminio-2,2-dialkyl-2,5-dihydro-3-furanyl)amino]benzenecarboxylates 7 and 8 (yield 73-74%), a new class of unnatural amino acids in a peculiar zwitterionic form, having the positive charge transferred to the remote imino group of the dihydrofuranyl substituent. 3- and 4-Aminobenzoic acids 2 and 3 with α,β-acetylenic γ-hydroxy nitriles 4-6 undergo entirely different transformations to deliver the esters of cyanomethylhydroxyalkyl ketones 9-12, which result from the unusually facile esterification of the hydroxyl function and simultaneous hydration of the triple bond. 4-Aminobenzoic acid 3 is found to be an active organic catalyst for the one-pot conversion of α,β-acetylenic γ-hydroxy nitrile 4 to 5-amino-2,2-dimethyl-3(2H)-furanone 13, in 80% yield.     

Theoretical am1 studies of inclusion complexes of α- and β-cyclodextrins with methylated benzoic acids and phenol,and γ-cyclodextrin with buckminsterfullerene

Semiempirical AM1 calculations have been performed on the inclusion complexes of - and -cyclodextrin with benzoic acid and phenol and -cyclodextrin with methylated benzoic acids in the head first and tail first positions. The results show that -cyclodextrin complexes with phenol and benzoic acid guests in the head first position are more stable than in the tail first position, while -cyclodextrin complexes with the same guests prefer the tail first position. The preferred orientation for -cyclodextrin with methylated benzoic acids is determined by the position of the methyl substituent(s). In general, para-methyl benzoic acid derivatives prefer the tail first position. -cyclodextrin forms a slightly unstable 1:1 complex with C₆₀ (3.4 kcal/mol), but two -cyclodextrins provide enough stabilization by about 10 kcal/mol to cage-in the C₆₀.