Phase diagram of (R)- and (S)-4-hydroxy-2-pyrrolidone mixtures: a new case of a conglomerate-forming system.

The phase diagram of (R)- and (S)-4-hydroxy-2-pyrrolidone presents a conglomerate in the racemic mixture. The enthalpy of melting extrapolated by the Schröder-van Laar-Le Chatelier equation [change in enthalpy (delta H) = 28410 J/mol; melting temperature (TA) = 429.9 K; solidus temperature (Ts) = 395.

Sobrerol enantiomers and racemates: solid-state spectroscopy, thermal behavior, and phase diagrams.

The characterization of the solid state of sobrerol enantiomers and racemates has been accomplished by a number of techniques on solid phase such as thermal analysis (DSC) and spectroscopy (IR, 13C NMR, and X-ray diffraction both on powders and on single crystal). Experimental and theoretical binary phase diagrams of cis- and trans-sobrerol enantiomers and their mixtures have been drawn and are discussed. Thermal analysis allowed, moreover, the detection of cis racemate polymorphism.

Biotransformation of trans-sobrerol. III. Metabolites of 8-hydroxycarvotanacetone in the rat.

The metabolism of 8-hydroxycarvotanacetone (HCA), a major metabolite of trans-sobrerol, was studied in female rats after a single oral dose. The metabolic pathways include hydroxylation, reduction to cis- and trans-sobrerol, glucuronylation and Michael addition with glutathione giving rise to mercapturic acids which then undergo reduction. Biological reduction appears to occur more readily for the alicyclic-saturated ketones (Michael adducts) than for the alpha, beta unsaturated ketones (HCA and hydroxylated metabolites).

Cyclic GABA-GABOB analogues. III - Synthesis and biochemical activity of new alkyl and acyl derivatives of 4-hydroxy-2-pyrrolidinone.

The synthesis of new N-substituted 4-hydroxy (III) and 4-acyloxy- or 4-alkoxy-2-pyrrolidinones (IV), as analogues of oxiracetam (III c), is reported. For this purpose, a convenient procedure for N-alkylation of the base-labile 4-hydroxy-2-pyrrolidinones (II a, c, d) was developed. Compounds (III) and (IV) were examined on phospholipid synthesis in brain microsomal membranes of rats, both in vivo and in vivo-in vitro, and on protein synthesis in brain slices.