Propionic acid, labelled with

This reaction provides a wide variety of products since decomposition of the deuterated alkylborane intermediate (164) can be achieved with hydrogen peroxide to yield labeled alcohols (165), with hydroxylamine-O-sulfonic acid leading to deuterated amines (166), as well as with boiling propionic acid or propionic acid-OD, to form mono- (167) or dideuterio (168) hydrocarbons, respectively. Furthermore, if a monodeuterium label at the sterically more accessible position (170) is sufficient, the use of expensive metal deute-... 

The successful labeling of the elusive 14a-position in cholestane represents a very important application of this reaction.It is known that hydroboration of the double bond in 5of-cholest-14-ene (174) occurs on the a-side. Consequently, by using deuteriodiborane (generated by the reaction of boron trifluoride etherate with lithium aluminum deuteride) and then propionic acid for hydrolysis of the alkylborane intermediate, 14a-d,-5a-cholestane (175) is obtained in 90% isotopic purity. This method also provides a facile route to the C-15 labeled analog (176) when the alkylborane derived from 5a-cholest-14-ene is hydrolyzed with propionic acid-OD. ... 

Mesobilirubin-XIIIa labelled with 13C in two propionic acid 13COOH groups, 90, has been synthesized75 in 11% overall yield from K13CN in 10 steps shown in equation 34. 90, a model compound not found in nature, is to be used to study the conformation of bilirubin in solution76 or when bound to proteins or in membranes to understand its ability to cross several selective physiological barriers such as placenta and blood-brain barrier... 

Slepnev et al. [313] presented a simple method for protein radio-labeling with Bolten-Hunter reagent (iV-hydroxy succinimide ester of 3-(p-hydroxy di-iodophenyl)) propionic acid) in AOT/octane-RMs using mouse IgG, human transferrin, protein A, and a2-interferon as labeling examples. The yield of radio-labeling in RMs was found to be higher than that achieved in homogeneous aqueous solution. 

BODIPY 530/550 C3 hydrazide is 4,4-difluoro-5,7-diphenyl-4-bora-3a,4a-diaza-s-indacene-3-propionyl hydrazide, a derivative of the basic BODIPY structure, which contains two phenyl rings off the No. 5 and 7 carbon atoms and a propionic acid hydrazide group on the No. 3 carbon atom (Molecular Probes). The hydrazide functional group reacts with aldehyde- or ketone-containing molecules to form hydrazone linkages (Fig. 229). The compound may be used to label glycoproteins or other carbohydrate-containing molecules after oxidation of their polysaccharide portions with sodium periodate to yield aldehyde residues. 

Fig. 33. Outline of the biosynthesis of uroporphyrinogen III (abbreviated urogen III), Starting with glycine labelled at position 2. The label is distributed as indicated with filled circles. The carboxyl group of glycine is lost as carbon dioxide. A = acetic acid side chain P = propionic acid side chain.

Disposition in the Body. Absorbed after oral administration accumulates in the body during chronic daily dosing. The main metabolic reactions are iV-demethylation and deamination. About 50% of a " C-labelled dose is excreted in the urine in 5 days, with 10% of the dose as unchanged brompheniramine, 11% as monodesmethylbrompheniramine, 10% as didesmethyl-brompheniramine, 4% as 3-(4-bromophenyl)-3-(2-pyridyl)-propionic acid, and 2% as its glycine conjugate other unidentified polar metabolites are also present. Less than 3% of the dose is eliminated in the faeces. Under steady-state conditions the daily excretion rate appears to be dependent on urinary pH and volume. 

DOT CLASSIFICATION 3 Label Flammable Liquid SAFETY PROFILE Mildly toxic by ingestion. Flammable when exposed to heat or flame, can react vigorously with oxidizing materials. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS, PROPIONIC ACID, and ISOBUTYL ALCOHOL. 

Tracer experiments with C-labeled carbon dioxide or propionic acid indicate that approximately 1 mol of carbon dioxide is formed per mole of propionic acid consumed and that carbon dioxide is the precursor of most of the methane. Tracer experiments were also conducted with propionic acid using enrichment... 

Tracer studies have confirmed the kind of bond cleavage indic ited by the stereochemical evidence. When ethyl propionate labeled with was hydrolyzed by base in ordinary water, the ethanol produced was found to be enriched in the propionic acid contained only the ordinary amount of... 

It has been shown that it is the vinyl group that is transferred in this reaction, not an alcoholic one as in acid- or alkali-catalyzed transesterification of esters with saturated alcoholic components. With 0-labeled acetic acid in the transvinylation of vinyl-propionate, the labeled oxygen remained completely in the acetate group [68]. 

Fig. 3.1 The optimized ground-state structures of SiQDs. The silicon, carbon, hydrogen, and oxygen atoms are cyan, gray, white, and red, respectively. The three different adsorption positions are labeled by number 1, 2, or 3 in (a) and (b) [22]. Reprinted with permission from (Li QS, Zhang RQ, Niehaus TA, Frauenheim T, Lee ST (2007) Theoretical studies on optical and electronic properties of propionic-acid-terminated sdicon quantum dots, J Chem Theory Comput 3 1518-1526). Copyright (2007), American Chemical Society...

Compounds labeled with 20-min half-lived carbon-11 were first intro- duced into biomedical research over 40 years ago (1-6). Before the discovery of carbon-14, compounds such as propionic acid (3) and lactic acid (2) labeled with carbon-11 were synthesized and utilized in biochemical research. After the introduction of carbon-14 as a biomedical tracer, interest in the shorter-lived carbon-11 decreased, and only in the past decade has there been renewed interest in labeling compounds with carbon-11 as well as with other short-lived positron-emitters such as oxygen-15, nitrogen-13, and fluorine-18. 

C-labeled porphobilinogen, requir for biosynthetic studies, has been prepared via reductive C-methylation using C-formaldehyde (derived from C-methanol). Further syntheses of 2-aminomethyl pyrroles and related lactams have been described, utilizing the azaindole route, and this method has also been adapted to the preparation of porphobilinogen labeled with C in the propionic acid side chain. °... 

Propane-l,2- C, specific activity of about 110 mCi mmol" has been synthesized from doubly labelled acetylene in reaction series shown in equation 12. This synthesis included preparation of doubly labelled acetylene from barium carbonate-according to Cox and Warne, nearly quantitative hydrogenation of acetylene to ethylene, addition of hydroiodic acid to the latter to form iodoethane, preparation of ethylmagnesium iodide followed by carbonation to yield propionic acid and reduction o n-propanol with 70-75% yield. The latter yielded a tosylate which was finally reduced to doubly labelled propane 2 with sodium borohydride, and purified by gas chromatography on alumina or silica. Its specific activity was close to the maximal possible specific activity of acetylene (i.e. 124.9 mCi mmol " ). 

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