Quartet signal

Figure 1.2 l5N NMR (INEPT) of intermediate 28. The quartet signal around 51 ppm is protonated 4-chloroaniline. 

If the nuclei interact with each other and give an AB quartet signal, then kc and AG are given by the following equations ... 

Furthermore, this phosphorylation reaction could be applied not only to the glycosyl position but also to other hydroxyl groups. When compound 38 (Figure 11) was treated with butyl-lithium and diphenyl phosphorochloridate as above, a syrupy 4-phosphate 39 was obtained whose structure was unequivocally confirmed by 3oOMHz -NMR. A quartet signal of H-4 (6 4.70ppm,... 

M. L. Walker and J. L. Mills (125) have reported the observation of a quartet signal at -6.63 ppm, 2t/PP = 2.5 Hz, which they assumed to be caused by P409. Reference 82 clearly points out that this attribution is not reliable. 

The spins for the protons Hy can be arranged as shown in (a), leading to four different magnetic environments for proton Hx. This arrangement leads to a "quartet" signal (b) for proton Hx, with areas i 3 3 l reflecting the ways of achieving the various states shown in (a). 

Solution The nmr spectrum shows a quartet signal down-field from a triplet signal, and a singlet as the most downfield signal. The value of 7.0 6 for the singlet strong-... 

Let us now consider the reason for a quartet signal for the—CH group. The three protons of the methyl group couple with the adjacent methylene group in four different ways in relation to the external field as outlined below. 

The resultant DMPO-OH adduct was detected using an electron paramagnetic resonance (EPR) spectrometer. Fig. 4 shows the effect of evening primrose crude extract (EPCE) on the scavenging of the hydroxyl radical. WhUe the characteristic quartet signal for DMPO-OH achiuct was observed in die absence of extracts, crude extracts at 200 ppm as well as most of their fractions conqiletely eliminated the... 

From methyltriphenylphosphonium iodide, prepared by methylation of triphenylphosphine with highly tritiated methyl iodide, the enhanced, coupled % NMR spectrum shows fully resolved and interleaved, doublet, triplet, and quartet signals from the PCT3,... 

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