Structural and theoretical evidence of the reaction products of ethyl(ethoxymethylene)cyanoacetate with 5-phenoxymethyl-2-amino-2-oxazoline

An easy route to 2‐substituted‐2,3‐dihydro‐5(7)H‐oxazolo[3,2‐a]pyrimidin‐5‐ones and 7‐ones starting from the corresponding 2‐amino‐2‐oxazolines

“…This conformation could explain the relative stability of 5a-b,6a towards an ulterior intramolecular cyclization involving the second nucleophilic nitrogen atom [14]. A comparable behavior of related amidines towards other biselectrophiles was previously described [15][16][17].…”

“…Both structures were determined by direct methods using MULTAN 80 [18]. The Jul-Aug 2001 825 (14) 1093 (2) 1561 (1) 10380 (2) 41(1) N (15) 1383 (1) -848 (1) 11284 (2) 40(1) C (16) 1336 (1) -901 (1) 13121 (2) 40 (1) C(17) 1222 (2) -157 (1) 14154 (2) 45(1) C (18) 1131 (2) 752 (1) 13413 (2) 43(1) C (19) 1432 (2) -1853 (2) 13885 (3) 60 (1) O(20) 1014 (2) 1481 (1) 14186 (2) 66(1) Table 3 Bond lengths (Å) and Angles (°) for Compound 3a (13) scattering factors were taken from [19]. C, N and O Atoms were refined anisotropically.…”

Synthesis and Preliminary Pharmacological Evaluation of New 6-cyano-2,3-dihydro-5<I>H</I>-oxazolo[3,2-<I>a</I>]pyrimidin-5-ones and 2-ethyl(methylenecyanoacetate)-2-iminooxazolidines

“…The structures of all the synthesized compounds were assigned by means of spectral data. For the bicyclic heterocycles 4 and 5, the spectroscopic data were compared with those of a related cyclocondensation compound, the structure of which was established by X-ray crystallography (Chaimbault et al 1999).…”

Recent Developments and Biological Activities of 2-Aminothiazole Derivatives

“…38 The amino-imino tautomeric equilibrium of the isolated, mono-, di-and trihydrate configurations and dimer of 2-aminothiazole and the effects of hydration or self-assistance on the transition state structures corresponding to proton transfer from the amino to imino tautomers, were theoretically and experimentally explored in the gas phase as well as in the solution, which directly affected the orientation of substitution and the product assignments when they reacted with the other compounds. [39][40][41][42][43] Several spectroscopic investigations, e.g. infrared (IR), ultraviolet (UV), density functional theoretical calculations (DFT), Raman spectra (RS), Khalifa M. E.: Recent Developments and Biological Activities ... surface-enhanced Raman spectra (SERS) and nuclear magnetic resonance spectra (NMR), indicated that the 2-aminothiazole derivatives are existing in solution preferentially in the amino tautomer, based on the analysis of their reactivity data.…”