Position shift carboxyl

Position shift of carboxyl Disproportionation of arylcarboxylic acids Henkel reaction or Raecke process... 

Furthermore, Bauerle and Emge prepared uracil-substimted end-capped terthiophene 2.188 and bithiophene 2.189 (Scheme 1.24) [283, 284]. Compound 2.188 was prepared by reaction of 5-bromopentyl-substituted terthiophene with orotic acid in 38% yield. Bithiophene derivative 2.189 was synthesized by conversion of 3-(5-bromopentyl)-2,2 -bithiophene to the nitrile and carboxylic acid followed by reaction with 6-(chloromethyl)uracil in 36% yield. Molecular recognition properties of 2.188 and 2.189 with complementary acetyl-9-octyladenine and 2,4-diacetamido-6-pentoxypyrimidine were smdied by cyclic voltammetry in CH2CI2 solutions. A positive shift of the oxidation potential (AE = 20-130 mV) was observed upon addition of complementary nucleobases to the electrolyte. 

Alkoxyformic acid anhydrides, mixed s. Carboxylic alkoxyformic anhydrides Alkoxy groups, position shift 18, 338 suppl. 26 Alkoxyhalides, ring closure 27, 279... 

In the case of substances whose structures are pH-dependent (e.g. phenols, carboxylic and sulfonic acids, amines etc.) it is possible to produce fluorescences or make them disappear by the deliberate manipulation of the pH [213] (Table 20). Shifts of the positions of the absorption and emission bands have also been reported. This is particularly to be observed in the case of modified silica gels, some of which are markedly acidic or basic in reaction (Table 25). 

An acetyl group in the 2-position favors the monocyclic structure presumably because of the resonance stabilization.12 The same observation was made with oxepin-2,7-dicarbaldehyde, oxepin-2,7-dicarboxylic acid, and oxepin-2,7-dicarbonitrile.23 Substituents in the 4- and 5-positions of the oxepin such as methyl or methoxycarbonyl groups shift the equilibrium towards the epoxide.12 24 Low temperature 1H NMR studies on 7-ethyloxepin-2-carbonitrile and ethyl 7-ethyloxepin-2-carboxylate established a nonplanar boat geometry with a ring-inversion harrier of 6.5 kcal mol-1.25... 

---