Acetyl Propionyl

Exceptions formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, oxalyl, malonyl, succinyl, glutaryl, furoyl, and thenoyl. 

Figure 7.1 The overall pathway of haem biosynthesis. 5-AminolaevuIinate (ALA) is synthesized in the mitochondrion, and is transferred to the cytosol where it is converted to porphobilinogen, four molecules of which condense to form a porphyrin ring. The next three steps involve oxidation of the pyrrole ring substituents to give protoporphyrinogen fX, whose formation is accompanied by its transport back into the mitochondrion. After oxidation to protoporphyrin IX, ferrochelatase inserts Fe2+ to yield haem. A, P, M and V represent, respectively acetyl, propionyl, methyl and vinyl (—CH2=CH2) groups. From Voet and Voet, 1995. Reproduced by permission of John Wiley Sons, Inc.

Scheme 4 6 -0-Acyl-lactose (acetyl, propionyl, butyryl) derivatives prepared via the selective enzymatic acylation of lactose by the protease subtilisin were used as acceptors for enzymatic transglycosylations catalyzed by a-D-galactosidase from Talaromyces flavus, forming iso-globotriose a-Gal(l -> 3)-p-Gal-(l -> 4).92 (/) Protease N, pyridine, 37 °C (ii) a-galactosidase from Talaromyces flavus.

Sodium salts of fluoroacids react with chlorine fluoride at —112 to —78°C to give explosively unstable fluoroacyl hypochlorites. Trifluoroacetyl hypochlorite and its pentafluoropropionyl, heptafluorobutyryl, difluoroacetyl and chlorodifluo-roacetyl analogues explode without fail if the partial pressure exceeds 27-67 mbar. Hexafluoroglutaiyl dihypochlorite explodes above — 10°C [1]. Of the 4 compounds prepared, acetyl, propionyl, isobutyryl and pivaloyl hypobromites, the 2 latter appeared stable indefinitely at —41°C in the dark, while the 2 former exploded unpredictably as isolated solids [2],... 

The reactions of 0-naphthol and 4-methoxyphenol with acetyl, propionyl, butyryl, 0-chloropropionyl and chloracetyl chlorides in acetonitrile produce some striking kinetic results109. The behaviour of acetyl, propionyl and n-butyryl chlorides fit reasonably well into the pattern for acetyl chloride in nitromethane and acetyl bromide in acetonitrile. However, with chloracetyl chloride the mechanism is essentially a synchronous displacement of covalently bound chlorine by the phenol and this process is powerfully catalysed by added salt with bond breaking being kinetically dominant. When no added salt is present the rate of hydrolysis of chloracetyl chloride is ca. 8000 times slower than that of acetyl chloride. Although, normally, in second-order acylation reactions, substituents with the greatest electron demand have been found to have the fastest rates, the reverse is true in this system. Satchell proposes that a route such as... 

Thne-of-flight (TOF) mass spectrometric analysis of the pyrolysis fragments of di-t-butyl peroxide suggests t-BuCO as the primary product, followed by decomposition of this radical into CHj.253 Elsewhere, the kinetics of the pyrolysis of dimethyl, diethyl, and di-t-butyl peroxides in a modified adiabatic bomb calorimeter have been investigated.254 The lifetime of acyloxy radicals, generated by the photolysis or thermolysis of acetyl propionyl peroxide, have been studied. Chemical nuclear polarization has been used to determine the rate constant for the decarboxylation of these radical intermediates.255... 

The biosynthesis of polyketides is analogous to the formation of long-chain fatty acids catalyzed by the enzyme fatty acid synthase (FAS). These FASs are multi-enzyme complexes that contain numerous enzyme activities. The complexes condense coenzyme A (CoA) thioesters (usually acetyl, propionyl, or malonyl) followed by a ketoreduction, dehydration, and enoylreduction of the [3-keto moiety of the elongated carbon chain to form specific fatty acid products. These subsequent enzyme activities may or may not be present in the biosynthesis of polyketides. 

Figure 12. Thermomechanical behavior of an acetylated-propionylated wood sample and the acetylated-propionylated wood-polystyrene composites prepared by the y-ray induced graft copolymerization in a pyridine medium. Numerical values on the curves represent the total dose of the irradiated y-ray. Key (total irradiation, resultant weight increase based on the weight of wood) A, 0.1 Mrad, 4.2% , 0.5 Mrad, 12.2% , 1.9 Mrad, 49.1% A, 2.4 Mrad, 66.0% and ,...

N-Acetyl glucosaminidase, V, 61 Acetyl phosphate, III, 237 Acetyl propionyl. See 2,3-Propanedione. Acetyl value, determination of, for starch acetates, I, 290 Acetylation, of cellulose, I, 311 rates for various cellulosic fibers, V, 122, 123... 

Pentanedione FEMA No. 2841 Acetyl Propionyl 100.12/C5H802/ o o II II ch3ch2c-cch3 yel to yel-green liq/ penetrating, buttery on dilution m—ale, prop glycol, most fixed oils ins—gly, water/ 108° 1 mL in 3 mL 50% ale... 

R—C—N-C-R II II II OHO Imide CH3CO—NH—OCCH2CH3 Acetyl propionyl imide -ic or -oic acid to -imide... 

Numerous undesirable reactions that result in organoleptic, nutritional and functional deterioration may occur in food proteins during processing and storage. These include the non-enzymatic or Maillard reactions, transamidation condensation reactions with dehydroalanine forming crosslinks, and carbonyl amine interactions, all of which may involve the free e-amino group of lysine (11,23). To minimize these reactions a significant volume of work has been done on the protective modification of the e-NH2 of lysine by formylation, acetylation, propionylation (26) or reductive dimethylation (10,11). 

Further considerations should include the following analytical method(s) (e.g., denaturation of antibodies in lA by the digest must be avoided), the possible necessity of derivatization (e.g., methylation, acetylation, propionylation), pharmacokinetic and chemical reflections on formation of metabolites or degradation products, and/or the disposition pattern of parent drug or metabolite(s) to be detected. 

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