Synthesis and NMR spectral study of somet(3)-aryl-r(2),c(4)-bisethoxycarbonyl-t(5)-hydroxy-c(5)-methylcyclohexanones

Abstract

Six t(3)-aryl-r(2),c(4)-bisethoxycarbonyl-t(5)-hydroxy-c(5)-methylcyclohexanones (6-11) were synthesized by condensing ArCHO (Ar = Ph, p-O(2)NC(6)H(4), p-CH(3)OC(6)H(4), p-ClC(6)H(4), m-O(2)NC(6)H(4) and m-C(6)H(5)O(6)H(4)) with ethyl acetoacetate in the presence of methylamine and their (1)H and (13)C NMR spectra were recorded. (1)H-(1)H COSY and NOESY spectra were recorded for 6 and 7 and also HSQC and HMBC spectra for 6 and 8. Elemental analysis was carried out for all compounds. The mass spectrum was recorded for 8. All analytical data are consistent with the proposed molecular formulae. Analysis of NMR spectral data suggests that these compounds largely adopt chair conformations with the hydroxyl group occupying an axial orientation and all the other substituents occupying equatorial orientations. Long-range coupling (2-3 Hz) between the OH proton and the axial methylene proton at C-6 is observed in 6, 7, 8 and 11.

Diversification of ortho‐Fused Cycloocta‐2,5‐dien‐1‐one Cores and Eight‐ to Six‐Ring Conversion by σ Bond C−C Cleavage

“…Proton, 13 C and 2D NMR analysis of 15 b are in accord with the major isomer to be the E ‐oxime. Based on the X‐ray structure of the parent carbonyl 1 a and f , we believe that proximity of the OH to the α‐vinylic CH in the E‐ oxime causes characteristic shifts for this signal in 1 H and 13 C NMR spectrums, as has been observed before . In practice, the 1 H NMR E ‐oxime α‐CH signal of 15 b resonates at δ =7.35 ppm versus Z ‐oxime at approximately 6.75 ppm, whereas in the 13 C NMR spectra, the E ‐oxime α‐CH showed δ C ≈118 vs. δ C ≈124 for the Z ‐oxime.…”

Synthesis, Spectral and Antimicrobial Studies of Some N(2)-Substituted Tetrahydroindazoles

“…A series of 4-aryl-5-alkoxycarbonyl-6-hydroxy-6-methyl-4,5,6,7-tetrahydro-3-hydroxy-2-(benzothiazol-2-yl)-indazoles (10)(11)(12)(13)(14)(15)(16)(17)(18) were synthesized by the reaction of 2-hydrazinobenzothiazole with the respective cyclic β keto esters. The optimum reaction medium was found to be toluene/cat.qty of AcOH by performing the reaction at several conditions and also from our previous research experience.…”

A Facile Synthesis of 4-Aryl-5-alkoxycarbonyl- 6-hydroxy-6-methyl-4,5,6,7-tetrahydro- 3-hydroxy-2-(pyridin-2-yl)indazoles and Their NMR Characterizations

“…The 1H-tetrahydroindazoles (25) synthesis has been carried out in EtOH medium by refluxing at 70-80 ˚C for about two hours with good yield (75%). It was helped us that the synthesis of 1H-indazoles from the reaction of cyclic ketoesters with the dinucleophile hydrazine, to find the optimum reaction conditions and also for the structural elucidations of N-pyridylindazoles.…”