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R Pellegata

Publications and source records attributed to R Pellegata.

8 recordsLinked to original sources
PubMed1993

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) = 395.4 K] and the value determined by differential scanning calorimetry (delta H = 28494 J/mol; TA = 429.6 K; Ts = 394.6 K) are in excellent agreement. The experimental entropy of the mixing of enantiomers is 5.69 J/mol.K. The conglomerate nature of the racemic mixture was confirmed by X-ray and IR spectroscopy. The presence of solvates was also observed.

Calorimetry, Differential Scanning↗
PubMed1990

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. Finally, the quantitative analysis of the cis racemate as an impurity of the trans racemate by means of microcalorimetric determinations is reported.

Calorimetry, Differential Scanning↗
PubMed1986

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). This is in agreement with the chemical reactivity of the compounds.

Animals↗
PubMed1981

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. Results showed that only oxiracetam (III c), and to a lesser extent piracetam, are active both on phospholipid and brain protein synthesis.

Animals↗