Nitrogen selectivity calculation

Af-methylation of the 3-amino-substituted THD 66 has been reported <2005JOC6230, 2005JMC2266>. Due to the calculated p-ATa s of the two nitrogens, selective methylation of the nitrogen attached to the THD nucleus is only possible for the synthesis of compound 214 via intermediate 213 in a two-step protocol (Scheme 13). 

Figure 8.13 Calculated permeate vapor concentration for a vapor-permeable membrane with a vapor/nitrogen selectivity of 30 as a function of pressure ratio. The feed vapor concentration is 1 %. Below pressure ratios of about 10, separation is limited by the pressure ratio across the membrane. At pressure ratios above about 100, separation is limited by the membrane selectivity [36]...

Figure 8.16 A one-stage vapor separation operation. The performance of this system was calculated from a crossflow model using a vapor/nitrogen selectivity of 20 and a pressure ratio of 20...

TMPhen/Pd = 2, substrate/Pd = 20, [substrate] = S IO" M, in toluene (10 ml). ) TMBH/Pd = 24 was used in this experiment. ) 10 % of the dimeric form derived from C-C coupling of the 3-carbon atom of Uie indole nucleus has been also observed. " ) 7 % of tlie compoimd having a CO inserted between carbon and nitrogen has also been observed. ) 40 % of tlie derivative in which both the nitro groups have given the indole nucleus has also been obtained. ) Isolated by flash-chromatography, selectivity calculated with respect to the converted substrate. 

For X=p Figure 12.1 shows for nitrogen selected experimental data as deviations from the values calculated with the equation of state of Span et al ... 

Use Figure 9.2 (equal to Figure 6.19 from Section 6.3.3) to select the appropriate calculation method. The only information needed for selection of a method is the phase of the fluid. Nitrogen at ambient temperature can be regarded as an ideal gas at these pressures. Therefore, the basic method (Section 6.3.3) is used. 

To test whether we could accurately calculate the fold-difference of ADA inhibitory potency between purine riboside (8) and analogues of purine riboside, we selected 8-azapurine riboside (9) for our studies. Compound 9 was reported to be a 400-fold more potent ADA inhibitor relative to 8 despite differing from 8 only by the replacement of C8 with a nitrogen (Figure 8).19 The molecular reason for this enhancement in potency was not determined, but could be due either to enhanced hydration or enhanced ADA binding affinity of the hydrated species or both. To determine the reason,... 

Tab. 6.1 Calculated and experimental solid-state principle values of the chemical shifts of selected nitrogen atoms in nucleic acid bases...

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