Alexander Dobrev

Structure o-metallee de lithiocycloalcanecarboxylates de t-butyle

Abstract Lithioesters obtained from (i-Pr)2NLi and cycloalkanecarboxylates at low temperature have been examined by 13C NMR and IR spectroscopy. The chemical shift values suggest an enolate nature of the derivatives even for the most angularly strained lithiocyclopropane carboxylate t-BuO(LiO)C= CCH 2 C H2. Comparison of ν(C=C) values of the metalated compounds and the corresponding methylenecycloalkanes is also in agreement with O-metalated structures in t-BuO(LiO)C= C(CH 2 ) n C H2 (n = 1−5).

Infrared-Spectral investigation of steric effects on hydrogen bond formation in esters of 3-benzoylaminopropionic acids—I. NH stretching region

Abstract The NH stretching frequencies of series of tert. butyl and ethyl esters of 3-benzoylaminopropionic acids and suitably substituted N -benzoyldiphenylmethylamines in various solvents have been studied. The data for the influence of the solvents on the NH stretching vibration were treated according to the Bellamy—Hallam—Williams plot. Steric effects of the substituents and the ester groups on the formation of the intramolecular NH … OC (ester) hydrogen bond were discussed.

α-Amidoalkylation of CH-Acids by Means of N-(1,2,2,2-Tetrachloroethyl)-amides

Abstract The reaction of α-amidoalkylation of malonic and acetoacetic esters as well as tert. butylacetate, arylacetic acids and benzylcyanide with different N-(1,2,2,2-tetrachloroethyl)-amides was investigated and 2-substituted 3-acylamino-3-trichloromethyl propionic acids and esters were synthezised.

Infrared spectral investigation of steric effects on hydrogen-bond formation in esters of 3-benzoylaminopropionic acids: Part II. Empirical energy calculations

Abstract The geometries and energies of the stable conformations of some t-butyl and ethyl esters of 2,3-disubstituted 3-benzoylaminopropionic acids have been obtained by means of empirical energy functions. Irrespective of the α and β substituents, the conformation with gauche NHCOC 6 H 5 and COOR groups is of lowest energy. Substitution in the α position diminishes the torsion angle between these groups but does not adversely affect the orientation of the COOR group necessary for hydrogen-bond formation. The conformational mobility around the C 3 N bond is determined by the steric interactions between the NHCOC 6 H 5 group and the other groups at C 3 . Hence, the β substituents are responsible for the formation of the intramolecular hydrogen bond. The results of the empirical energy calculations are in accord with the IR spectral data for the esters.

α-Hydroxyalkylation of 3-Morpholinones with Aromatic Aldehydes and Chloral

Abstract Lithium derivatives of some 4-substituted 3-morpholinones react with aromatic aldehydes and with chloral to afford 4-alkyl-2-(1-hydroxy-alkyl)-3-morpholinones with good yields.

Preparation des reactifs organolithiens a partir des acides ω-cyanocarboxyliques dans l'ammoniac liquide

Abstract By treating ω-cyanocarboxylic acids with lithium amide in liquid ammonia, salts, of the type [NCCH(CH 2 ) n COOLi]Li are prepared. The formation of these salts is confirmed by their reaction with N -benzolydiphenylketimine and benzophenone to give ω-diarlylate, ω-benzoylamino- and ω-hydroxy-ψ-cyanocarboxylic acids respectively.

A New Synthesis of 2-(2-Hydroxyalkyl)- and 2-(2-Aminoalkyl)-morpholines via 3-Morpholinones

A new pathway for the synthesis of 2-(1-hydroxyalkyl)- and 2-(1-arylaminoalkyl)-morpholines via reaction of α-hydroxy- or α-amino-alkylation of 3-morpholinones followed by reduction with LiAlH4 of the intermediate compounds into the target substituted morpholines is proposed.

Reaction of Lithium Derivatives of 4-Alkyl-3-morpholinones with Azomethine Compounds

Abstract Lithium derivatives of some 4-substituted 3-morpholinones react with azomethine compounds to afford 4-alkyl-2-[aryl(phenylamino)methyl]-3-morpholinones with good yields.

IR-spectral investigation of steric effects on hydrogen bond formation in esters of 3-benzoylaminopropionic acids. III. Correlation between amide-I vibrations and solvent parameters

Abstract The influence of the solvent on the CO (Amide-I) stretching vibration of series of t-butyl and ethyl esters of 2,3-substituted 3-benzoylaminopropionic acids (3-BAPA) is studied. The solvatochromic shift of the Amide-I band is correlated with parameters, characterizing the polarity of the medium. The steric effect of the substituents on the conformational mobility of the compounds is estimated on the basis of the obtained results.

1,4-ADDITION OF Ν,N-DIALKYLPHENYLACETAMIDES TO METHYLENE SUBSTITUTED 1,3-DIHYDRO-3-METHYLENE- 2H-INDOL-2-ONES

Two 3-methylene-2H-indol-2-ones substituted in the methylene group by either a phenyl 6 or two electron withdrawing groups 8 react with the lithium enolates of Ν,Ν-disubstituted phenylacetamides and 2H-indol-2-one giving the corresponding products of conjugate 1,4-addition the l,3-dihydro-indol-2-ones 7 and 9. Introduction The indolin-2-one ring was found in many alkaloids from plant extracts and other natural sources (1,2). The interesting biological activities of the organic molecules with indolin-2-one moiety as nonsteroidal cardiotonics (3), anestetics (4) and antibacterial agents (5) have drown the attention of many research groups for the study of their synthesis and properties. In context of our interest on the 1,4-addition reaction of some ambident nucleophiles we demonstrated recently that the lithium derivatives of some Ν,Ν-disubstituted phenylacetamides 2 add smoothly to 2-arylmethylene-4-butanolides (6). In all cases diastereomeric mixtures of the products 3 were obtained as a result of a typical 1,4-addition reaction with retention of the lacton ring, contrary to some previous reports (7,8): Ar < ^ C H A r L D A / C O N C H 3 + C 6 H 5 C H 2 C O N C H 3 X T ^ O fl THF.r . t .