947-05-7Relevant articles and documents
Alkyne amide-mediated one-pot method for preparing macrolide
-
Paragraph 0014, (2018/10/24)
The invention discloses a method for preparing macrolide by using alkyne amide as a condensation reagent and hydroxy carboxylic acid as a raw material at 10-50 DEG C; the method comprises a method formildly and efficiently preparing an alpha-acyloxy alkenyl amide compound through addition of carboxylic acid and alkyne amide at room temperature under the catalysis of cuprous salt and a method forobtaining macrocyclic lactonization through enabling the intramolecular hydroxyl of the alpha-acyloxy alkenyl amide compound to react under the catalysis of p-toluenesulfonic acid; the two reactions can be performed through a one-pot method as well, i.e., an intermediate alpha-acyloxy alkenyl amide obtained after complete reaction of carboxylic acid and the alkyne amide does not need to be separated, the p-toluenesulfonic acid is directly added to perform intramolecular condensation reaction in the next step, thereby realizing the formation of the alkyne amide-mediated macrocyclic lactonization at room temperature. The method disclosed by the invention has the characteristics of mild reaction condition, simplicity and easy operation.
Novel photolactonisation from xanthenoic esters
Plessis, Caroline,Derrer, Sam
, p. 6519 - 6522 (2007/10/03)
In the context of our work on photocleavable fragrance precursors, we have discovered a new photo-fragmentation of xanthenoic esters into xanthene- and formyl radicals. This homolytic cleavage has not been reported previously. Thus, unsaturated formyl radicals cyclise to lactones of various ring size.
Lactones. 3. A comparison of the basicities of lactones and esters
Wiberg, Kenneth B.,Waldron, Boy F.
, p. 7705 - 7709 (2007/10/02)
The basicity of lactones and esters toward triethyloxonium ion was studied via NMR spectroscopy. The equilibrium constants were and the order of decreasing basicity was found to be δ-valerolactone > γ-butyrelactone > diethyl carbonate > ethyl acetate > ethyl propionate. The rates of reaction were parallel to the equilibrium constants. The origin of the differences in basicity was via ab initio calculations of structures and energies of ions formed by adding H+ or CH3+ to methyl acetate. The calculated proton affinity of the Z ester rotamer agreed with the experimental data and was found to be considerably smaller than that for the E rotamer. The relative energies of the four ions that could be formed by adding a proton to methyl acetate were related to the orientation of the dipole components at oxygen. The methyl cation affinities of the methyl acetate conformers were found to parallel the proton affinities and gave the same preferred direction of addition. The proton affinity of valerolactone was calculated to be greater than that for butyrolactone in good accord with the experimental results.
