927-80-0Relevant articles and documents
Structural, spectroscopic, and photochemical study of ethyl propiolate isolated in cryogenic argon and nitrogen matrices
Fausto, Rui,Lopes, S.,Nikitin, T.
, (2020/07/15)
Ethyl propiolate (HC ≡ CCOOCH2CH3, EP) was studied experimentally by infrared spectroscopy in argon and nitrogen cryomatrices (15 K) and by quantum chemical calculations (at the DFT(B3LYP) and MP2 levels of theory). Calculations predict the existence of four conformers: two low-energy conformers (I and II) possessing the carboxylic moiety in the cis configuration (O=C–O–C dihedral equal to ~0°) and two higher-energy trans forms (O=C–O–C dihedral equal to ~180°; III and IV). The conformation of the ethyl ester group within each pair of conformers is either anti (C–O–C–C equal to 180°; in conformers I and III) or gauche (C–O–C–C equal to ±86.6° in II, and ± 92.5° in IV). The two low-energy cis conformers (I and II) were predicted to differ in energy by less than 2.5 kJ mol?1 and were shown to be present in the studied cryogenic matrices. Characteristic bands for each one of these conformers were identified in the infrared spectra of the matrix-isolated compound and assigned taking into account the results of normal coordinate analysis, which used the geometries and harmonic force constants obtained in the DFT calculations. The two trans conformers (III and IV) were estimated to be 17.5 kJ mol?1 higher in energy than the conformational ground state (form I) and were not observed experimentally. The unimolecular photochemistry of matrix-isolated EP (in N2 matrix) was also investigated. In situ irradiation with UV light (λ > 235 nm) leads mainly to decarbonylation of the compound, with generation of ethoxyethyne, which in a subsequent photoreaction generates ketene (plus ethene).
Combined epimerisation and acylation: Meerwein-ponndorf-verley-oppenauer catalysts in action
Klomp, Dirk,Djanashvili, Kristina,Svennum, Nina Cianfanelli,Chantapariyavat, Nuttanun,Wong, Chung-Sing,Vilela, Filipe,Maschmeyer, Thomas,Peters, Joop A.,Hanefeld, Ulf
, p. 483 - 489 (2007/10/03)
A practical racemisation-epimerisation method for chiral secondary alcohols has been developed. Meerwein-Ponndorf-Verley-Oppenauer catalysts such as neodymium(III) isopropoxide are able to racemise these alcohols with retention of other stereocentres in the molecule. This is particularly useful for the recycling of the undesired products of kinetic resolutions of alcohols. By combination of such a racemisation with an acylation using isopropenyl or ethoxyvinyl esters as acyl donors, a fast straightforward recycling of starting materials may be achieved. The combined epimerisation and acylation process is demonstrated for the steroid estradiol methyl ether.
Synthesis and phosphorylation of 1-ethoxy-1-trimethylsiloxy-2-trimethylsilylthioethene
Burilov, A. R.,Cherepashkin, D. V.,Pudovik, M. A.
, p. 20 - 21 (2007/10/03)
A new organosilicon reagent, 1-ethoxy-1-trimethylsiloxy-2-trimethylsilylthioethene, was prepared by silylation of ethyl (trimethylsilylthio)acetate. its thermal isomerization and phosphorylation with bis(diethylamino)chlorophosphine and diphenylchlorophosphine were studied.
