Stepwise Methodology

To develop an artificial olfaction system and to build the pattern recognition and the odour regression model for this kind of application, we use a stepwise methodology. 

The first action to be undertaken is a visit in the field in order to investigate the problem. Then the selection come and the development of the method according to the field criteria and limits. First options are taken and a first prototype is developed and tested in the lab. 

A second field campaign is then organised to test the system and to gather some preliminary data to get some proofs before going back a second time in the lab and improving and correcting eventual identified problems. 

A further step in the lab aims at verifying the models in different conditions and with various observation samples. Then a last validation step is carried out in the field. 

Such to-and-fros between field and lab result in a final system able to meet field requirements and to bring an optimum solution to the problem. 

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Very recently, some of us reported novel linear oligo-TB derivatives that exhibit interesting structural features (05OL67). These compounds possess cavitand-shaped binding sites. Effective new stepwise methodology for linear tris-TB 59 was reported (Scheme 11). All three possible diastereoisomers (aa sa ss) were described two of them were isolated and the third was detected after racemization. 

As mentioned in Section 10.2.3, the application of Ga(OTf)3 as an effective and reusable catalyst for the Strecker reaction has been demonstrated [62]. This is a simple and alternative route to the stepwise methodologies for the Strecker reaction of ketones. Moreover, the use of fluorinated ketones is a significant aspect of this procedure due to the increase interest in organofluorated compounds. 

Having developed effective synthetic methodology for the construction of seven-membered cyclic ethers, we were confident that the problem of the frans-fused bis(oxepane) system could now be addressed on a solid foundation. It was our hope that the breve-toxin-type bis(oxepane) system could be assembled by a stepwise strategy utilizing both photochemical dithioester and reductive hydroxy ketone cyclization methods. 

The authors developed two general methodologies for the synthesis of these monodisperse, defined oligomers. They can be built up stepwise, e. g. via additon of organometallic species to cyclohexan-1,4-dione, followed by aromatization to the oligoarylene (e.g. for 21). 

To benchmark our learning methodology with alternative conventional approaches, we used the same 500 (x, y) data records and followed the usual regression analysis steps (including stepwise variable selection, examination of residuals, and variable transformations) to find an approximate empirical model, / (x), with a coefficient of determination = 0.79. This model is given by... 

These disadvantages are overcome by the methodology we will describe in the subsequent paragraph developed by Bakshi and Stephanopoulos. Effects of the curse of dimensionality may be decreased by using the hierarchical representation of process data, described in Section III. Such a multiscale representation of process data permits hierarchical development of the empirical model, by increasing the amount of input information in a stepwise and controlled manner. An explicit model between the features in the process trends, and the process conditions may be learned... 

The total synthesis by Motsumoto et al. is an example of classic organic syntheses using the ring closure methodology to stepwise construct the tricyclic carbon... 

PAMAM dendrimers are synthesized by the divergent approach. This methodology involves the in situ branch cell construction in stepwise, iterative stages (i.e. generation = 1, 2, 3. ..) around a desired core to produce mathemat-... 

Allenylsilanes 159 (Eq. 13.53) and 161 (Eq. 13.54) differ in the axial stereochemistry of the allene function. In each case, formation of the benzyl imine, followed either by treatment with tin(IV) chloride in benzene at room temperature or heating in toluene, leads to diastereomeric products 160 and 162 [63], Significantly, there is no crossover, pointing to a concerted (or fast, stepwise) process. Since the absolute stereochemistry of the allenylsilanes is easily controlled, the methodology is ideal for applications in total synthesis. Weinreb and co-workers have used the reaction for his synthesis of the marine natural product (-)-papuamine. 

In connection with the "logic-centred methodology" we have referred to the elaboration of a "synthesis tree" by a process that involves the stepwise generation... 

In 1962, solid-phase peptide synthesis was introduced, and described in detail in 1963.1171 This new synthetic principle was developed with the hope that it would simplify and accelerate the synthesis of peptides. The idea was to covalently anchor the C-terminal residue of a peptide to an insoluble support and then to assemble the remaining amino acids in a stepwise manner with activated amino acids while the peptide was in the insoluble solid phase, and finally to cleave the peptide from the solid support and liberate it into solution. The general methodology is shown in Scheme 6. 

Coiled-coil polypeptides can also be prepared by stepwise fragment condensations on a solid support. A unique feature of the heptad sequence used in de novo designed coiled coils is that a Gly residue can be incorporated as the C-terminal residue of the heptad sequence without the ability of the polypeptide to form stable two-stranded a-helical coiled coils being affected. Although the fragment condensation methodology can be performed with minimal... 

Peptides were prepared manually by stepwise solid-phase synthesis methodology using conventional N"-Boc chemistry. Briefly, copoly(styrene/l% DVB)-pMeBHA-HCl resin, [100-200 mesh (substitution... 

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