A- propionic acid

The Stobbe condensation thus provides a method for introducing a propionic acid residue at the site of a carbonyl group. 

The tetramerization of suitable monopyrroles is one of the simplest and most effective approaches to prepare porphyrins (see Section 1.1.1.1.). This approach, which is best carried out with a-(hydroxymethyl)- or ot-(aminomethyl)pyrroles, can be designated as a biomimetic synthesis because nature also uses the x-(aminomethyl)pyrrole porphobilinogen to produce uroporphyrinogen III. the key intermediate in the biosynthesis of all kinds of naturally occurring porphyrins, hydroporphyrins and corrins. The only restriction of this tetramerization method is the fact that tnonopyrroles with different -substituents form a mixture of four constitutionally isomeric porphyrins named as porphyrins I, II, III, and IV. In the porphyrin biosynthesis starting from porphobilinogen, which has an acetic acid and a propionic acid side chain in the y6-positions, this tetramerization is enzymatically controlled so that only the type III constitutional isomer is formed. 

Phenyl(3-a -"ethylpropionate ), 4-carboxamide] -tetrazanetll. Note a-ethylpropionate (or more correctly, in the opinion of the editor, a-ethylpropionatyl) is the proper name for the radical —CH(CH3).CCfe-C2H5, derived from a-propionic acid ethyl ester. (C6H5).N N.N[CH(CH3).C02.C2H5].NH(C0.NH2), mw 279.34, N 25.08%, crysts from aq ale, mp (melts with expln ca 125°)... 

FIGURE 17.23 2D contour plot of a propionic acid modified polyamide 6.6 (assignments according to Table 17.1), first dimension LCCC, second dimension MALDI-TOF. (See color plate.)... 

BODIPY 530/550 C 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 that contains two phenyl rings off the No. 5 and 7 carbon atoms and a propionic acid hydrazide group on the No. 3 carbon... 

Indometacin is an indole acetic acid derivative, while naproxen is a propionic acid derivative. Both are non-steroidal anti-inflammatory drugs (NSAIDs). Indometacin is associated with a higher incidence of side-effects, particularly gastrointestinal as well as headache and dizziness. 

Naproxen is a non-steroidal anti-inflammatory agent classified as a propionic acid derivative. 

Horse radish peroxidase on the other hand, is a hemoprotein which is inhibited by alkylation of the porphyrin ring 48 by a -propionic acid radical resulting from the ring cleavage of the cyclopropanone hydrate 21, providing the car-boxylate 49,Eq. (17). 

Estrone, or l,17p-Dihydroxy-4-methylestra-1,3,5(10)triene 3-(l-Oxo-8p-methyl-5p-carboxy-trans-perhydroindanyl-4 a)propionic acid C [248]... 

NSAIDS and a Statin . Benzene rings provide the aromatic nucleus for the majority of the NSAIDs. A propionic acid attached at its 2 position provides the side chain for most of these compounds, as noted in Chapter 2. Inhibition of the cyclooxygenase enzyme and consequently NSAID activity is retained when the role of an aromatic ring is filled by a pyrrole. The side chain for all but one of those compounds, it should be noted, consists of an otherwise unsubstituted acetic acid. 

Flurbiprofen is a propionic acid derivative with a possibly more complex mechanism of action than other NSAIDs. Its (S)( ) enantiomer inhibits COX nonselectively, but it has been shown in rat tissue to also affect tumor necrosis factor- (TNF- ) and nitric oxide synthesis. Flepatic metabolism is extensive its (R) +) and (S) ) enantiomers are metabolized differently, and it does not undergo chiral conversion. It does demonstrate enterohepatic circulation. 

Ketoprofen is a propionic acid derivative that inhibits both COX (nonselectively) and lipoxygenase. Its pharmacokinetic characteristics are given in Table 36-1. Concurrent administration of probenecid elevates ketoprofen levels and prolongs its plasma half-life. 

Fenoprofen, a propionic acid derivative, is the NSAID most closely associated with the toxic effect of interstitial nephritis. This rare toxicity may be associated with a local T cell response in renal tissue. 

These drugs are available in many other countries but are not sold in the USA. Azapropazone (apazone), a pyrazolone derivative, is structurally related to phenylbutazone but appears less likely to cause agranulocytosis. Its half-life of 12-16 hours may be doubled in patients with decreased renal function. Carprofen is a propionic acid derivative with a half-life of 10-16 hours. The indications and adverse effects of azapropazone and carprofen are similar to those of other NSAIDs. 

Acrylic acid esters can polymerize readily this must be taken into account during their preparation. Thus, attempts to prepare pentafluorophenyl acrylate from acrylo-yl chloride in the presence of pyridine led to extensive polymerization of the product [24], This polymerization can be prevented by using the less nucleophilic 2,6-dimethylpyridine as base and diethyl ether or pentane instead of THF as solvent (Scheme 7.5). Esterifications of acrylic acid under acidic conditions should be conducted in the presence of small amounts of hydroquinone as radical scavenger. Acrylic acid derivatives can also be prepared by acylation with a propionic acid with a leaving group at C-3 followed by/3-elimination. 

Figure 9.37 Chemical structures of chlorophylls-a and b which contain a propionic acid esterified to a C20 phytol chlorophylls-cj and C2 have an acrylic acid that replaces the propionic acid. Also included are the pheopigments, the four dominant tetrapyrrole derivatives of chloropigments (pheopigments) found in marine and fresh-water/estuarine systems (chlorophyllide, pheophorbide, pheophytin, pyropheophorbide.) More specifically, chlorophyllase-mediated de-esterification reactions (loss of the phytol) of chlorophyll yield chlorophyllides. Pheophytins can be formed when the Mg is lost from the chlorophyll center. Pheophorbides are formed from removal of the Mg from chlorophyllide or removal of the phytol chain from pheophytin, and pyrolyzed pheopigments, such as pyropheophorbide and pyropheophytin, are formed by removal of the methylcarboxylate group (-COOCH3) on the isocylic ring from the C-13 propionic acid group.

Side Note 13.4 presents the diastereoselective alkylation of a very special ester enolate in which one can easily understand what the stereocontrol observed is based upon. However, only very specific carboxylic acid derivatives are made accessible by those alkylations. Much more broadly applicable diastereoselective alkylations of chiral ester or amide enolates will be introduced in Figures 13.42 and 13.43. Figure 13.42 shows alkylations of a propionic acid ester—derived from an enantiomerically pure chiral alcohol—via the and Z -enolate. 

Disposition in the Body. Rapidly and almost completely absorbed after oral administration. It is extensively metabolised by hydroxylation and oxidation. About 75% of a dose is excreted in the urine as metabolites and 15% is eliminated in the faeces, in 72 hours. Less than 1% of a dose is excreted in the urine as unchanged drug. The major urinary metabolites are a propionic acid derivative (3-oxo-l,2,4-triazolo[4,3- ]pyridine-2-propionic acid), /7-hydroxytrazodone, and a dihydrodiol derivative and its glucuronide and sulphate conjugates, which account for about 35%, 20%, and 15% of the urinary material respectively an N-oxide has also been identified. In plasma, the major metabolite is l-(3-chlorophenyl)piperazine (active), but this accounts for less than 1% of a dose in the urine. 

MCPP MCPP 2,4-D MCPP-D-4 MCPP-K-4 MECOMEC MECOPEOP MECOPER xMECOPEX MECOPROP MECOTURF MECPROP MEPRO METHOXONE a-(2-METHYL-4-CHLOROPHENOXY)-PROPIONIC ACID 2-(2-METHYL-4-CHLOROPHENO-XY)PROPIONIC ACID 2-METHYL-4-CHLOROPHENO-XY-a-PROPIONIC ACID 2-(2-METHYL-4-CHLOR-PHENOXY)-PROPIONSAEURE (GERMAN) 2M 4KHP... 

TRICHLOOR-FENOXY)-PROPIONZUUR -(DUTCH) 2-(2,4,5-TRICHLOROPHENOXY)PROPIONIC ACID 2,4,5-TRICHLOROPHENOXY-a-PROPIONIC ACID 2-(2,4,5-TRICHLOR-PHENOXY)-PROPION-SAEURE (GERMAN) WEED-B-GON... 

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