L- barbituric

Clayton, L. Barbiturates and Other Depressants. Rosen Publishing Group. Inc., New York. NY, 1998. 

A. Specific levels of phenobarbital are usually readily available from hospital clinical laboratories concentrations greater an 60-80 mg/L are usually associated with coma and those greater than 150-200 mg/L with severe hypotension. For short- and intermediate-acting barbiturates, coma is likely when the semm concentration exceeds 20-30 mg/L. Barbiturates are easily detected in routine urine toxicologic screening. 

Derivatization with p-nitrobenzaldehyde followed by reaction with o-dinitrobenzene to yield a purple color LOD = 10 pg/L Barbituric or N,N-dimethylbarbituric acid derivative... 

There is an admirable summary of the stereochemistry of barbiturates and di- to hexahydropyrimidines Further information on reduced pyrimidines is collected <70HC 16-81)322) and some examples of the use of proton NMR spectra in elucidating the conformations of hydropyrimidines is given elsewhere (Section 2.13.1.3.1), based on the general principles of such work <65QR426). 

As mentioned above (Section 2.13.2.1.3), bipyrimidine photoproducts can arise, probably by reaction between two radicals. Thus, irradiation of an aqueous solution of 5-bromouracil (ill R=Br) in the absence of oxygen produces a variety of products including uracil, barbituric acid, 5-carboxyuracil (111 R = CO2H), several non-pyrimidine compounds and, as a stable end-product, the biuracil (114 R = H). A similar product (114 R = Me) is formed from 5-bromo-l,3-dimethyluracil (ilS). When two such related uracil derivatives are irradiated together, a mixed bipyrimidine product is formed, inter alia (B-76MI21302). 

Ethyl-5-(l-methylbutyl) barbituric acid (pentobarbital Nembutal)... 

As expected, heterocyclic enols and potential enols (i.e, compounds existing mainly in the CH form) behave toward diazomethane similarly to the open chain and isocyclic enols, i.e. they form enol methyl ethers by reactions of the SnI type (cf. footnote 29). Examples of this behavior are barbituric acid, picrolonic acid, dchydroacetic acid (64), 3-methyl-l-phenylpyrazolin-5-one, 1-phenylpyrazoli-dine-3,5-dione, 1,2-diphenylpyrazolidine-3,5-dionc, 3-hydroxy-... 

Ibrahim RB, Wilson JG, Thorsby ME, et al Effect of buprenorphine on CYP3Aactivity in rat and human liver microsomes. Life Sci 66 1293—1298, 2000 Iguchi MY, Handelsman L, Bickel WK, et al Benzodiazepine and sedative use/abuse by methadone maintenance clients. Drug Alcohol Depend 32 257—266, 1993 Isbell H Manifestations and treatment of addiction to narcotic drugs and barbiturates. Med Clin North Am 34 423 38, 1950... 

Blakey GE, Nestorov lA, Arundel PA, Aarons LJ, Rowland M. Quantitative structure-pharmacokinetics relationships I. Development of a whole-body physiologically based model to characterize changes in pharmacokinetics across a homologous series of barbiturates in the rat. J Pharmacokinet Biopharm 1997 Jun 25(3) 277-312. Erratum in J Pharmacokinet Biopharm 1998 Feb 26(l) 131. 

GABAc receptors are defined by their insensitivity to bicuculline and their activation by conformationally restricted analogues of GABA such as CACA and (+)-CAMP (15, 2i -2-(aminomethyl)cyclopropanecarboxylic acid). They are blocked by picrotoxin but can be selectively antagonised by TPMPA (l,2,5,6-tetrahydropyridin4-ylphosphinic acid). Unlike GABAa receptors, they are not affected by benzodiazepines, barbiturates or anaesthetics (Barnard et al. 1998 Bormann 2000 Chebib and Johnston 2000). 

In the Diels-Alder reaction with inverse electron demand, the overlap of the LUMO of the 1-oxa-l,3-butadiene with the HOMO of the dienophile is dominant. Since the electron-withdrawing group at the oxabutadiene at the 3-position lowers its LUMO dramatically, the cycloaddition as well as the condensation usually take place at room or slightly elevated temperature. There is actually no restriction for the aldehydes. Thus, aromatic, heteroaromatic, saturated aliphatic and unsaturated aliphatic aldehydes may be used. For example, a-oxocarbocylic esters or 1,2-dike-tones for instance have been employed as ketones. Furthermore, 1,3-dicarbonyl compounds cyclic and acyclic substances such as Meldmm s acid, barbituric acid and derivates, coumarins, any type of cycloalkane-1,3-dione, (1-ketoesters, and 1,3-diones as well as their phosphorus, nitrogen and sulfur analogues, can also be ap-... 

Fusion of a barbituric acid motif and a pyrone ring afforded compounds containing a novel pyranopyrimidine core (L) that were discovered as GPR109A agonists [92,93]. This core appears to be distinct from other fused bicyclic cores such as xanthine and anthranilide based on their poor overlap. Furthermore, several compounds, exemplified by 39 and 40, provided remarkable potency in the cAMP assay. The critical acidic functional group is present as the N-PI of barbituric acid motif which has a calculated pKa of 8 [82]. 

Likewise, suitable starting materials are iminoisoindolines, especially diimino-isoindoline (l-amino-3-iminoisoindolenine), which reacts with a cyanoacetamide NCCH2CONHR5 to afford a mono-condensation product 49. Further reaction with a compound containing an activated methylene group (such as cyanoacetamide derivatives, barbituric acid) yields the desired pigment 47 ... 

Waste or leachate (EPA Method 901OA) Reflux-distillation of acidified sample absorption of released HCN in NaOH treatment with AgNOs and an indicator (titrimetric) or chloramine-T/pyridine-barbituric acid (colorimetric) Titrimetric or colorimetric detection (total and amenable cyanide) 0.1-0.2 mg/L titrimetric) 0.02 mg/L (colorimetric) (Titrimetric) 94-99 (total cyanide), 87-97 (amenable cyanide) EPA1992d... 

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