PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 12509155

Barbituric and thiobarbituric acids: a conformational and spectroscopic study.

Felice Zuccarello·Giuseppe Buemi·Concetta Gandolfo·Annalinda Contino
View original source ↗Export metadata ↓

Abstract

A conformational study on Barbituric (BA) and Thiobarbituric (TBA) acids was performed at ab initio MP2/6-31G** level on the neutral, protonated, mono- and di-anionic forms. Acid-base equilibria were studied by comparing the electronic transitions evaluated for the most stable conformations and the experimental spectra at different pH values. The electronic transitions were obtained through the ZINDO approach.

Explore related subjects

BarbituratesHydrogen-Ion ConcentrationModels, ChemicalSpectrophotometryThiobarbituratesUltraviolet RaysJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Felice Zuccarello, Giuseppe Buemi, Concetta Gandolfo, Annalinda Contino. 2003-01-01. Barbituric and thiobarbituric acids: a conformational and spectroscopic study.. https://doi.org/10.1016/s1386-1425(02)00146-4

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Occurrence and fate of barbiturates in the aquatic environment.

Barbiturates have been widely used as sedative hypnotics in the mid-1960s and since then mainly as veterinary drugs. To monitor their presence and fate in the aquatic environment, a method based on gas chromatography-mass spectrometry (GC-MS) has been developed to quantify butalbital, secobarbital, hexobarbital, aprobarbital, phenobarbital, and pentobarbital, all with a limit of detection (LOD) down to 1 ng/L. From the various investigated waste and surface water samples, barbiturates were only, but regularly detected in the Mulde, a tributary of the river Elbe in Germany at relevant concentrations up to several microg/L. Investigations of groundwater being affected with wastewater infiltration several decades ago also revealed a barbiturate pattern, indicating a strong recalcitrance of these drugs. To confirm this hypothesis, studies were carried out on biotic and abiotic degradation. Both, the biodegradability under aerobic conditions and hydrolysis did not show any degradation, implementing, that the investigated barbiturates, once released into the aquatic environment, show high stability over a long period of time.

Barbiturates↗
PubMed2006

True and false reversal of the elution order of barbiturates on a bonded cellulose-based chiral stationary phase.

A set of racemic N-alkylated barbiturates were investigated for their direct enantioselective HPLC separation on a new chiral stationary phase (CSP) containing cellulose tris(3,5-dimethylphenylcarabamate) immobilized onto silica gel (Chiralpak IB) and its coated version (Chiralcel OD). They were online detected by UV and optical rotation detectors to trace the elution order of their enantiomers. Surprisingly, examples of false and true reversal of the elution order of enantiomers of barbiturates were observed and reported.

Barbiturates↗