The Right Start

The obvious Vfittig disconnection gives stabilised ylid (5fi) and keto-aldehyde (57). We have used many such long-chain dicarbonyl compounds in this Chapter and they are mostly produced from available alkenes by oxidative cleavage (e.g. ozonolysis). In this case, cyclic alkene (58) is the right starting material, and this can be made from alcohol (59) by elimination,... 

This alternative solution is often better. With the right starting material, the tetrahedral intermediate can become stable enough not to collapse to a ketone during the reaction it therefore remains completely unreactive towards nucleophiles. The ketone is formed only when the reaction is finally quenched with acid but the nucleophile is also destroyed by the acid and none is left for further addition. 

A nice synthesis of the bicyclic alkene on the right starts with a pinacol reaction. 

The right start. Suppose that you want to assay reverse transcriptase activity. If polyriboadenylate is the template in the assay, what should you use as the primer Which radioactive nucleotide should you use to follow chain elongation ... 

A daring expedient to obtain the right starting material was the alkaline cleavage of a similarly substituted purine (0.5 N NaOH, room temp, 1 h) to give 6-chloro-5-formamido-4[(2,3-0-isopropylidene-D-ribofuranosyl)-amino]pyrimidine, from which the formyl group was removed by acid hydrolysis, followed by formation of the triazole ring with aqueous nitrous acid (optical purity was retained). ... 

Chemicals and Pregnancy Give Your Baby the Right Start... 

Here are some guidelines to get a metric program off to the right start ... 

As a program transitions from this first phase of getting off to the right start, it is important to reflect on its progress and accomplishments. Box 8.2 summarizes observations of a former program leader of the Mechanical and Materials Engineering Department at Queen s University in Kingston, Ontario (Canada) about this transitional point in the adaptation and implementation of a CDIO approach. 

National Service Framework (2003) Getting the right start national service framework for children, young people and maternity services standard for hospital services. Department of Health, 2003... 

The Right Start-Employee Safety Orientation Booklet NSC... 

The problem of finding the right starting point of the conformational hyperspace before minimization is certainly not yet solved. However, different procedures can reduce the number of possibilities in some cases. 

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