Geometrical isomorism of ethyl N-(pyrimidinyl) aminomethylenceyanoacetates

The geometrical isomers of ethyl N-(Pyrimidinyl)a minomethylenecy anoacetates were isolated and their structures and interconversions are discussed.     

Vibrational spectra and rotational isomerism of bis(N-2-chloroethyl)nitramine

The IR and Raman spectra of bis(N-2-chloroethyl)nitramine (BCENA) in the liquid and crystalline states and in CCl₄ and CH₃CN solutions are studied. The spectra are compared, and it is concluded that BCENA exists as a mixture of conformers of different polarities in the liquid state and as one less polar conformer in the crystalline state. To determine the conformations corresponding to the total electron energy minima and interpret the vibrational spectrum of BCENA, we performed an ab initio quantum chemical calculation of the BCENA molecule in the Hartree-Fock approximation using the 3–21G* and 6–31G* basis sets. Out of twelve possible conformations five are stable; the most stable conformer is C₂(GG). The frequencies and forms of normal vibrations of stable conformers are calculated using scaled quantum chemical force fields. The calculated and experimental frequencies are compared, and the relations between the frequencies of skeletal stretching and bending vibrations are analyzed. It is concluded that the BCENA crystal is formed by the C₂ (GG) conformer. The vibrational spectrum is interpreted, and the frequencies are assigned to vibrations of conformers differing in form. Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 2, pp. 303–317, March–April, 1997.     

Geometrical isomerism of 2′-piperidinomethyl-5-arylidenecreatinines

The aminomethylation of 5-arylidenecreatinines with paraformaldehyde and piperidine in benzene leads to 2-piperidinomethyl-5-arylidenecreatinines, in which the geometrical isomerism in relation to the C(₂) = N(₂) and C(₅) = C bonds was observed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1401–1404, October, 1989.The authors thank A. V. Dogadina for the taking of the PMR spectra.     

Stereospecific substitution of enantiomerically pure 1-(2-pyridinyl)ethyl methanesulfonate with beta-dicarbony compounds

The alkylation of the sodium salt of the malonic acid diester with (R)-1-(2-pyridinyl)ethyl methanesulfonate (2) gave the dimethyl (R)-[1-(2-pyridinyl)ethyl]malonate (3a), stereospecifically. The alkylation reaction of methyl acetoacetate gave the methyl (2'S,2R/2S)-3-oxo-2-[1-(2-pyridinyl)ethyl]butanoate (3d) along with the methyl (S)-3-[1-(2-pyridinyl)ethoxy]-2-butenoate (4d). The acid hydrolysis and decarboxylation of 3d under acidic conditions gave (R)-4-(2-pyridinyl)pentan-2-one (6), and the alkylation of methyl (R)-[1-(2-pyridinyl)ethyl]acetoacetate with benzyl bromide gave a mixture of C-benzylated and O-benzylated products 7 and 8.     

A tandem mass spectrometric investigation of N-(3-ferrocenyl-2-naphthoyl) dipeptide ethyl esters and N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters

N‐(3‐Ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 1–4 and N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 5–8 were prepared by coupling either 3‐ferrocenylnaphthalene‐2‐carboxylic acid or 6‐ferrocenylnaphthalene‐2‐carboxylic acid to the dipeptide ethyl esters GlyGly(OEt) (1, 5), AlaGly(OEt) (2, 6), GlyPhe(OEt) (3, 7) and GlyLeu(OEt) (4, 8), using the standard N‐(3‐dimethylaminopropyl)‐N'‐ethylcarbodiimide hydrochloride, 1‐hydroxybenzotriazole protocol. Electrospray ionization mass spectrometry (ESI‐MS) and laser desorption ionization mass spectrometry (LDI‐MS) were employed in conjunction with tandem mass spectrometry in the analysis of N‐(3‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 1–4 and N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 5–8. Radical cations, [M]^+? and [M + H]⁺ species were both observed in the mass spectra. Intense sodium [M + Na]⁺ and potassium [M + K]⁺ adducts were also present. An important diagnostic ion at m/z [M–65]⁺ was observed in both the MS and MS/MS spectra of the N‐(3‐ferrocenyl‐2‐naphthoyl) dipeptide derivatives. Sequence‐specific ions were generally not observed in the MS/MS spectra of the N‐(3‐ferrocenyl‐2‐naphthoyl) series due to formation of the diagnostic [M–65]⁺ ion. Sequence‐specific ions were observed in the MS/MS spectra of the N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide esters with charge retention on the derivatized N‐terminal of the dipeptide. Both series of compounds could be successfully analyzed by MALDI without the use of a matrix (LDI). Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of N-(2-(Methylamino)ethyl) Derivatives of 2H-Phthalazin-1-ones

A series of new alkyl, tosyl, acetyl, and tert-butoxycarbonyl derivatives of 2-(2-aminoethyl)-phthalazinones were efficiently synthesized by reaction of lactams with N-Boc-, N-acetyl-, or N,O-ditosyl derivatives of N-methylethanolamine in the presence of MeONa or under Mitsunobu reaction conditions. Selected compounds were converted into corresponding 2-[2-(methylamino)ethyl]phthalazinones in good yields.     

2-Aminothiazole derivatives. II. Mass spectra of ethyl N-(2-thiazolyl)-malonamates and ethyl 2-thiazolylaminomethylenemalonates

The fragmentation pattern of the title compounds under electron impact are discussed. During fragmentation in the mass spectrometer, these compounds undergo a rare type of rearrangement involving a long distance transfer of hydrogen.     

Synthesis of N-[2-(1-piperidinyl)ethyl]benzamides

Novel benzamide derivatives, N-[1-(aminocarbonyl)-2-(1-piperidinyl)ethyl]benzamides (4 and 5), were prepared from the reaction of beta-piperidinoalanine (6) as the starting material.     

Investigation of the z,e isomerism of N-(5-pyrimidyl)- and N-(5-pyridyl) acetamidines

The processes of Z,E isomerization about the C=N bond and retardation of rotation about the C-N bond in N-(5-pyrimidyl)- and N-(5-pyridyl)-acetamidines were investigated on the basis of data on the temperature dependence of the PMR spectra. The effect of the type of heteroring, the volume of the ortho substituents, and the character of the solvents on the magnitude of the free energy of activation of Z,E isomerism was analyzed thoroughly. The possible mechanisms for the isomerization process are discussed.     

Synthesis and Fungicidal Activity of Substituted N-(Alkoxy)-1-(3-pyridinyl)methanonimines

Russian Journal of General Chemistry - A number of new substituted N-(alkoxy)-1-phenyl- and N-(alkoxy)-1-cyclohexyl-1-(3-pyridinyl)-methanonymines were prepared by reacting the corresponding...     

"Codimers" of N-(pyrid-2-yl) amides and ethyl cyanoacetate

Potential chelating-forming ligands and reagents for heterocyclization — ethyl esters of 4-[N-(R-pyrid-2-yl)carbamoyl]-3-amino-2-cyanobuten-2-oic acids ["codimers" of cyanoacetic acid ethyl ester (EECA) and the corresponding (pyrid-2-yl) amides of this same acid) — were synthesized in two ways: by condensation of 2-dialkylborylamidopyridines (picolines) with EECA (via chelate compounds of boron) and by the reaction of EECA dimer with 2-aminopyridines (picolines).N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 371–376, February, 1992.