ISSN:
0021-8383
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Several model thioacrylamides, Me2N—CH = C(R)—C(S)—NMe2 (R = H, Ph - 2a, b) and (p)MeO—C6H4—NH—CH=C(R)—C(S)—NMe2 (R = H, Ph - 3a, b) have been synthesized. The 1H-n.m.r. spectra have been taken for discussing the E/Z-isomerism of the thioacrylamides and the assignment further strengthened by an added LIS-study. The 2-unsubstituted compounds have been found to exist exclusively in preferred configurations/conformations: 2a - E(s-cis); 3a - Z(s-cis); the 2-phenylsubstituted analogs are of divergent behaviour: in 2b the C(S)—NMe2 moiety is found to be twisted out of the common plane, and 3b prefers the flat s-trans conformations (E(s-trans) ⇌ Z(s-trans)). The compounds show restricted rotations about C1, N- and C3, N-partial double bonds. The corresponding rotational barriers, determined as ΔGc#-values by dynamic n.m.r. spectroscopy, are discussed with respect to (i) the resonance branch at C1, (ii) the influence of substituents, and (iii) the effect of steric hindrance in the thioacrylamide moiety generally.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/prac.19863280115
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