Acyl group, analysis

The distinguishing characteristic of a mutant vd.th a lesion at the fadP locus is a substantial decrease in the amount of both 16 3 and 18 3 fatty acids in extracts of whole leaves and a corresponding increase in the amount of 16 2 and 18 2, respectively (Browse et al., 1986c). Thus, it was inferred that the fadP locus controls the activity of a desaturase which converts both 16- and 18-carbon dienoic to trienoic acyl groups. Analysis of the molecular species of MGP and PGP in the mutant and the wild-type indicated that the mutation specifically affects the desaturation of fatty acids in the prokaryotic pathway of lipid synthesis in the chloroplast and that both the sn-1 and sn-2 position of MGP was affected (Norman and St. John, 1986). 

Although the initial radical formed from the reaction of Ce(rV) ion and acetylanilide (AA) and N-p-tolylacet-amide (PTA) has never been observed in the ESR studies, the presence of AA, PTA moieties in the end group of PAN obtained from initiating the CAN-AA, CAN-PTA system have been detected by the FT-IR spectra analysis method. Similar results were observed in the end group analysis of CAN-phenylcarbamate, CAN-N-acyl-N -tolylurea initiation systems. 

Dipole moments of azolides have been reviewed, with emphasis on the conformation of the acyl group. 441 Unfortunately, structural and conformational studies on azolides by X-ray structure analysis are almost totally lacking, although they would be of great interest with regard to the conformations and to the bond lengths and bond orders in these systems. Only an X-ray analysis of V-acetyl-4-bromopyrazole 451 has been reported. 

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has contributed remarkably to unravelling the termination and initiation steps of the styrene/CO copolymerisation catalysed by the highly active bis-chelated complex [Pd(bipy)2](Pp5)2 in TFE [40]. Chain-end group analysis of the material produced in the absence of BQ showed that the termination by P-H elimination is accompanied by three different initiators two palladium alkyls from Pd-H formed by reaction of the precursor with CO and water (a and b) and a palladium carboalkoxy species formed by reaction of the precursor with the fluorinated alcohol and CO (c) (Chart 7.4). The suppression of the chain-transfer by alcoholysis was proposed to be responsible for the enhanced stability of the palladium acyl intermediates and hence for the high molecular weight of the copolymers produced. 

Amine-imine tautomerism in 3-acyl-substituted aminopyrazines has been examined by H, C, and N spectral analysis as well as X-ray crystallography <2005JST67>. In the same way as the parent aminopyrazine, those aminopyrazines have been shown to exist in the amino form 11 (R = H, Me, Ph) (Scheme 2) in contrast to an expectation that the electron-withdrawing acyl groups adjacent to the amino substituent would stabilize the imino tautomers 12 and 13. Thus, all NMR spectra showed only existence of the amino tautomer 11, and additionally the... 

Although most polysaccharides may be acylated without degradation, acyl derivatives of xylans29 are often unsatisfactory for molecular-weight determinations owing to their poor solubility characteristics. Mixed esters of xylans143 are often superior in this respect, but there are obvious difficulties in the differential analysis of acyl groups. Hemicellulose nitrates have been used for measurements of molecular size,168 but xylan nitrates,29 like xylan acetates, are reported to have poor solubility characteristics. 

The fatty acyl substituents were mainly of three types saturated straight-chain C,6-C,9 acids C21-C25 mycosanoic acids and C24-C28 mycolipanolic acids. Analysis of one of the major 2,3-di-O-acyltrehaloses by two-dimensional H-chemical-shift-correlated and H-detected heteronuclear multiple-bond correlation spectroscopy established that the C18 saturated straight-chain acyl group was located at the 0-2 position and that the C24 mycosanoyl substituent was at the 0-3 position of the same nonglycosylated terminus (structure 8). At least six molecular... 

Determination of the composition of different oils and fats is a very common application of the GC analysis of fatty acids. The samples under analysis are usually hydrolysed first and free fatty acids are esterified. Kleiman et al. [138] used the methanol—BF3 method for determining acyl groups in oils. Barnes and Holaday [139] started directly with ground peanuts when analysing the composition of their fats. After hydrolysis for 8 min by heating at 80°C with a methanolic solution of NaOH they carried out the esterification with 10% of methanol—BF3 at 95°C for 5 min. n-Propyl esters were utilized for the analysis of fatty acids in soaps [140]. After evolving fatty acids with the aid of orthophosphoric acid, the esters were prepared by heating with /7-propanol at 90°C for 2 min. 

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