Physicochemical and crystallographic evidence for polymorphism of the racemic ethyl (2-chloromethyl-2,3-dihydro-5H-oxazolo [3, 2-a]pyrimidin-5-one)-6-carboxylate.
The various crystalline forms of an original bicyclic compound [ethyl (2-chloromethyl-2,3-dihydro-5H-oxazolo[3, 2-a]pyrimidin-5-one)-6-carboxylate); EOC] have been obtained and characterized by powder and single-crystal X-ray diffraction, differential scanning calorimetry (DSC), and infrared (IR) and Raman spectroscopy. At 4 degrees C in methanol, a monoclinic racemate (form II) crystallized from the racemic mixture, whereas at 20 degrees C, an orthorhombic racemate (form I) was isolated in trichloroethylene. By increasing the temperature, a solid-solid transition from the stable form II to the stable form I was observed with a Guinier-Simon camera. A I --> II transformation was observed at ambient temperature by DSC.
Chaimbault
C
C
Laboratoire de Chimie Physique et Minérale, Université Bordeaux II, 146 rue Léo Saignat, 33076 - Bordeaux, France.
Bosc
J J
JJ
Leger
J M
JM
Negrier
P
P
Capelle
F
F
Jarry
C
C
D018360:Crystallography, X-Ray / Q000379:methods; D008314:Malonates / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D019998:Racemases and Epimerases / Q000737:chemistry*; D013237:Stereoisomerism; D013793:Thallium / Q000737:chemistry*
D008314:Malonates; D010080:Oxazoles; C030290:malonic acid; D013793:Thallium; D019998:Racemases and Epimerases