An Alternative Strategy

So far, this approach recalls the strategy of the experiment on an ensemble of Be+ ions mentioned above [19,20]. However, the present approach is characterised by essential and distinctive features  

The effective pulse of driving is split up in n fractional pulses of area it In. During the intermittent intervals, the ion s coherent evolution is supposed to halt. 

There is no spurious decoherence effect expected to impair the overall coherent evolution, since perturbations that affect the ion s internal state are minimised by its solitary positioning in the trap centre, within ultra-high vacuum. 

The probe pulses are applied within the intermissions of the coherent driving, not during the driving pulses. Thus, nonlinear interaction of the ion with simultaneously present drive and probe fields is avoided. 

The photon counter is activated during all the probe-light irradiations such that actual detections of the scattered light form sequences of n results each. This recording provides control of the ion state whenever probe light examines the ion. 

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An alternative strategy is to put a 3-(-2-dioxolanyl)ethanoyl substituent in place first and then add the C7-substituent by a Grignard addition. This approach was applied to the synthesis of 8.2C but in this case it was found necessary to remove the tosyl protecting group prior to cyclization[l]. 

The above treatment is predicated on the assumption that the kinetic energies of the photoelectrons from atoms A and B are close in energy. In the event that this assumption does not hold, then all of the instmmental parameters do not cancel for these equations, and the situation is more complex. An alternative strategy in this case is to compare the spectmm of the unknown matedal with a spectmm acquired under identical conditions of a pure standard reference matedal containing A and B that is close in suspected composition to the unknown. In this case. 

An alternative strategy for producing new derivatives by directed biosynthesis is to produce mutants in which particular pathways may be blocked or a new pathway created. Again, we will use a specific example to illustrate this approach. 

Earlier we indicated that an alternative strategy to prevent ring cleavage is to use selective inhibition of the enzymes which catabolise the ring structure. 

An alternative strategy to inhibit a protein kinase relies on different conformations that active and inactive protein kinase can acquire. Antagonists for a protein kinase can be selected that exclusively bind to the inactive form of the kinase, so as to sequester the molecule in a state that cannot participate in signal transduction. 

Phosphate should ideally be added continuously, direct to the boiler shell or steam drum, and in proportion to FW consumption. Where this is not possible and the phosphate is added to the feedline, several program options exist to minimize the potential for feedline blockage. The use of an alternate strategy is particularly important where an economizer is present. Options include ... 

An illustrative example of an alternative strategy (cf Fig. 11c) involving the use of a novel traceless linker is found in the multistep synthesis of 6-epi-dysidiolide (363) and several dysidiolide-derived phosphatase inhibitors by Waldmann and coworkers [153], outlined in Scheme 70. During the synthesis, the growing skeleton of 363 remained attached to a robust dienic linker. After completion of intermediate 362, the terminal olefin in 363 was liberated from the solid support by the final metathesis process with concomitant formation of a polymer-bound cyclopentene 364. Notably, during the synthesis it turned out that polymer-bound intermediate 365a, in contrast to soluble benzoate 365b, produced diene 367 only in low yield. After introduction of an additional linker (cf intermediate 366), diene 367 was released in distinctly improved yield by RCM. 

An alternative strategy for promoting Diels-Alder reaction by proton involves the activation of dienophile by hydrogen bonding [93]. Biphenylene diol 143 (Scheme 4.26) forms doubly hydrogen-bonded complexes with a,j]-unsaturated carbonyl compounds, which strongly accelerate the Diels-Alder... 

Phosphine-borane 63a (75% ee) was obtained by reduction of compound (Sp)-62a using LDBB at -60°C and nucleophilic substitution with iodomethane in 72 % yield. The observed loss of optical purity may be ascribed to stereomutation of the generated tricoordinated phosphorus species. Recrystallization afforded (S)-63a in > 99% ee. On the other hand, severe racemization was observed using the same method with (Rp)-62b. An alternative strategy consisted of deborana-tion of (Rp)-62b using ZSl-methylpyrrolidine, methylation with methyl triflate. 

Example Ester (59) was needed for a photochemical synthesis of chrysanthemate ester (60), a component of the pyrethrin insecticides. The a,B disconnection (59a) gives synthon (61) and aldehyde (62). This 8,y-unsaturated compound could be made by dehydration of (63) as the double bond can appear in only the required position. On page T 149 we discussed the synthesis of (62) by the aldol dimerisation of (64), An alternative strategy is to work at the ester oxidation level (65) which means synthon (66) is needed to combine with (64). 

An alternative strategy, avoiding the danger of over-reaction with diax.omethane, is to make the diazonium salt, by diazotisation of a hydroxy amine (14), available from the original ketone (12) via epoxide (13),... 

An alternative strategy for (1) would have been to reconnect both substituents into a ring to ensure their ais arrangement. This strategy was used in syntheses of the antibiotic methylenomycin (4) and the trail pheromone of pharaoh s ant, faranal (5). 

An alternative strategy is for the microorganism to kill the phagocyte. This can be achieved by the production of leucocidins (e.g. staphylococci, streptococci) which promote the discharge of lysosomal substances into the cytoplasm of the phagocyte rather than into the vacuole, thus directing the phagocyte s lethal activity towards itself. 

Direct evidence for the biodegradation of benzene and toluene in a contaminated aquifer was lacking, and an alternative strategy was examined. Bio-Sep beads were maintained in tubes and [ C] benzene or [ C]toluene were sorbed on to the surface. Analysis of 8 C in fatty acids extracted from lipids showed enrichments up to 13,500 ppm for benzene and... 

AOS responsiveness to hormonal influences is shown in the action of sodefrin on the lateral nasal sinus of newts (Cynops). The receptors in the accessory pocket are differentially affected by pituitary and ovarian hormones (Toyoda et al., 2000). The local EOG response to the pheromone (Fig. 5.1) was enhanced by the presence of prolactin or of estrogen alone. Receptor sensitivity increase is perhaps an alternate strategy to AOS receptor density increase several alternate routes of signal receptor adaptation (Fig. 7.1) have been hypothesised (Sorenson and Stacey, 1998). 

The limitations of allometric scaling led us to investigate the method of effect scaling as an alternative strategy for matching equivalent doses of MDMA in rats and humans. In this approach,... 

An alternative strategy for the synthesis of these tricyclic compounds involves the reaction of the azidoalkenyl-functionalized furo[3,2-A]pyrrole 30, which reacts with triphenylphosphine to give the corresponding iminophos-phoranes 31 these upon reaction with aryl isocyanates give the pyrrolo[2, 3 4,5]furo[3,2-r-]pyridines 32, via the corresponding carbodiimides which are not isolated < 1994H(37) 1695, 1992M807> (Scheme 9). 

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