engleski

Convenient synthesis, H-1, C-13 NMR study and X-ray crystal structure determination of some new disubstituted thiophenes

2, 5-, 3, 4-, and 2, 3-Thienylenediacrylic acids(1, 4 and 7 respectively) were synthesized in one step reaction by catalytic vinylation of corresponding dibromothiophenes in the presence of cyclohexylamine salt of acrylic acid. 2, 4-Thienylenediacrylic acid 10 was prepared by catalytic vinylation of 3-(4-bromo-2-thienyl)acrylic acid. From 1, 4, 7 and 10, the acid dichlorides 2, 5, 8, 11 and dianilides 3, 6, 9, and 12, respectively, were prepared in good yields. One- and two-dimensional H-1 and C-13 n.m.r. spectra of prepared compounds have been studied. Chemical shifts of protons could be assigned on the basis of the two-dimensional nuclear Overhauser (NOESY) spectroscopy and homonuclear correlation (COSY) spectra. Chemical shifts of substituted carbons were assigned using two-dimensional H-1/C-13 heteronuclear correlation (HETCOR) spectra. The substitution effects on the chemical shifts of thiophene analogues are reported, and the coupling constants (3)J(H, H) are determined. The crystal structure of compound 12 was determined by X-ray analysis.

acids ; H-1 and C-13 NMR spectra ; synthesis ; crystal structure

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