Synthesis of some 2-alkyl-4-quinolone and 2-alkyl-4-methoxyquinoline alkaloids

Acid-catalyzed condensation of a series of 3-oxoalkanoic acid esters with aniline affords the corresponding 2-alkyl-4-quinolones in good yield. Treatment of these compounds with methyl iodide affords 2-alkyl-4-methoxyquinolines and 2-alkyl-N-methylquinolones. Three of the compounds are naturally-occurring alkaloids which are synthesized here for the first time.     

[4+2] Cycloaddition reactions of 1-alkyl-2,3,4,5-tetraphenylphosphole derivatives

Russian Chemical Bulletin - The [4+2] cycloaddition reactions of 1-alkyl-2,3,4,5-tetraphenylphosphole derivatives with N-phenylmaleimide were studied for the first time. The reactions of...     

Synthesis,Crystal Structure and Bioactivity of N-Phenethyl-4-hydroxy-4-phenyl Piperidine Hydrochloride

A novel compound N-phenethyl-4-hydroxy-4-phenyl piperidine hydrochloride （C19H24ClNO·H2O） has been synthesized and structurally characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group P212121 with a = 8.6306（8）, b = 11.0464（10）, c = 19.3221（18）A^°, V = 1842.1（3）A^°^3, Z = 4, Dc =1.211 g/cm^3,μ = 0.217 mm^-1, Mr= 335.86, F（000） = 720, S = 0.973, R = 0.0420 and wR = 0.1009 for 3627 unique reflections with 3157 observed ones （I 〉 2σ（I））. In the crystal, the dihedral angles made by piperidine ring with two benzene rings are 84.8（6） and 62.5（7）°, respectively. Intermolecular O-H…O and O-H…Cl hydrogen bonds involving water molecules form chains along the b axis, which stabilizes the crystal structure. The preliminary bioactivity tests indicated that the title compound has good effect of cellular growth inhibition to K562 cells and potential bioactivity of anti-leukemia.     

Synthetic Study of 4‐Substituted Piperidine Ring in Elarofiban,RWJ‐50042, Tirofiban and Paroxetine

A new strategy for synthesizing a 4‐substituted piperidine ring uses the formal [3+3] cycloaddition reaction as the key protocol. This method provides a convenient formal synthesis of elarofiban, RWJ‐50042, tirofiban and paroxetine.     

Chemoselective synthesis and spectral studies of N-thiocyanatoacetyl derivatives of 3-alkyl-2,6-diarylpiperidin-4-ones

A series of N–thiocyanatoacetyl derivatives of 3–alkyl–2,6–diarylpiperidin–4–ones has been synthesized by the reaction between the N–chloroacetyl derivatives of the respective piperidin–4–ones and the ambident thiocyanate nucleophile. The synthesized compounds have been characterized through FT–IR, ¹H, ¹³C, ¹H–¹H COSY, ¹H–¹³C COSY and NOESY spectra. The spectral data reveal the conformational priority of the six-membered heterocyclic ring.     

Comparative evaluation of antioxidant activity of 2-alkyl-4-methylphenols and their 6-n-octylaminomethyl derivatives

Russian Chemical Bulletin - A series of 2-alkyl-4-methyl-6-n-octylaminomethylphenols (where alkyl is methyl or tert-butyl group, or terpene substituent) was synthesized. A comparative evaluation of...     

1H, 13C NMR, X-ray and conformational studies of new 1-alkyl-3-benzoyl-pyrazole and 1-alkyl-3-benzoyl-pyrazoline derivatives

The (1)H and (13)C NMR resonances of 22 1-alkyl-pyrazole and 25 1-alkyl-pyrazoline derivatives were assigned completely using the concerted application of one- and two-dimensional experiments (DEPT, gs-HMQC and gs-HMBC). Nuclear Overhauser enhancement (NOE) effects, conformational analysis and X-ray crystallography confirm the preferred conformation of those compounds.     

Synthesis of 2-cycloalkyl-4-phenylindenes and the derived <Emphasis Type="Italic">ansa</Emphasis>-zirconocenes

An efficient route to 2-cycloalkyl-4-phenylindenes and the corresponding ansa-zirconocenes with the -SiMe₂- bridge was proposed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1630–1633, August, 2008.     

Synthesis of 4-alkyl-3-cyano-5,6,7,8-tetrahydroquinoline-2(1H)-thiones and their derivatives

4-Alkyl-3-cyano-5,6,7,8-tetrahydroquinoline-2(1H)-thiones, used in synthesis of substituted 2-alkylthioquinolines and thieno[2,3-b]pyridines, were obtained by condensation of cyanothioacetamide, aliphatic aldehydes, and morpholinocyclohexene.T. G. Shevchenko Lugansk State Pedagogical Institute, Lugansk 348011 Ukraine. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913 Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 81–85, January, 1998.     

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3h-cycloheptimidazol-4-ones and 2-alkyl-3h-cycloheptimidazol-4-ones

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (1) and 2-alkyl-3H-cycloheptimidazol-4-one (2) was investigated. 3-[2'-(1-tert-Butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-1H-cycloheptimidazol-4-one (6) was preferentially obtained under the conditions by using NaH in DMF or THF. On the other hand, 3-[2'-(1-tert-butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (5), the synthetic intermediate compound of Pratosartan, was obtained selectively in the presence of n-Bu(4)NBr in toluene by using aqueous sodium hydroxide as a base. In this reaction, it was found that the concentration of the alkaline solution influences its regioselectivity. This selectivity was observed even for aldehyde and ester derivatives.     

Circular dichroism of N-2,4-dinitrophenyl derivatives of chiral 1-alkyl-2-propynylamines and 1-alkyl-2-propenylamines

The sign of the Cotton effects near 320 and 400 nm in the CD spectra of the N-2,4-dinitrophenyl derivatives of chiral 1-alkyl-2-propynylamines and 1-alkyl-2-propenylamines correlates with their absolute configurations. The Cotton effects are generated by the coupled oscillator methanism and their sign is the same as the chirality (right-handed screw for positive chirality) of the interaction of the dominant oscillators of the 2,4-dinitrophenylamino chromophore with that of the amine moiety, the chirality of the interaction being deduced by conformational analysis.     

General synthesis for chiral 4-alkyl-4-hydroxycyclohexenones

[reaction: see text] Some selective transformations of resorcinol-derived cyclohexadienone are reported. Efforts led to a structure reported to display anticancer properties. On the basis of the results, the structures for natural products reported to contain a 4,6-dihydroxy-4-alkyl-cyclohexenone nucleus are corrected.     

A practical, two-step synthesis of 1-alkyl-4-aminopyrazoles

A novel synthesis of N1 alkyl-substituted pyrazoles with a free amino group at the C4 position is described. Commercially available 4-nitropyrazole was found to readily undergo Mitsunobu reactions with primary and secondary alcohols. Subsequent reduction of the nitro group via hydrogenation affords 1-alkyl-4-aminopyrazoles, which are valuable intermediates in the synthesis of pharmaceutically active compounds.     

A convenient synthesis of 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-, 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo-, and 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines

The reactions of 1-alkylamino-1-alkylthio-3-phenylpropene-3-thiones 3 with thiophosgene and phosgene in toluene, followed by treatment of the reaction mixture with triethylamine gave 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo- 4 , 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-4H-1,3-thiazines 5 , respectively in good to excellent yields. Similarly treatment of compounds 3 with N-arylimidoyl dichloride in benzene at room temperature gave 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines 6 in excellent yields. The reactions of compounds 3 with oxalyl chloride in toluene gave also 5 in good yields.