Five steps

This design procedure is known as the pinch design method and can be summarized in five steps... 

The classification is done in five steps and can be conducted witln for example, ELECTRAS [9] ... 

By the time j ou get to a ten step synthesis, the arithmetic demon ensures that the yield is down to a miserly 35%. And this with 90% yield in eaeh step So clearly a short synthesis is a good one. But we ean cheat the arithmetic demon by making our five steps convergent rather than linear. The convergent version is this ... 

If the yield of each step is again 90%, what is the overall yield of this five step convergent synthesis ... 

The following five step synthesis has been reported in the chemical literature Suggest reagents appropriate for each step... 

Having noted that each field of chemistry brings a unique perspective to the study of chemistry, we now ask a second deceptively simple question. What is the analytical perspective Many analytical chemists describe this perspective as an analytical approach to solving problems. Although there are probably as many descriptions of the analytical approach as there are analytical chemists, it is convenient for our purposes to treat it as a five-step process ... 

Before continuing, take some time to read the article, locating the discussions pertaining to each of the five steps outlined in Figure 1.3. In addition, consider the following questions ... 

Metabolic Functions. Manganese is essential for normal body stmcture, reproduction, normal functioning of the central nervous system, and activation of numerous enzymes (126). Synthesis of the mucopolysaccharide chondroitin sulfate involves a series of reactions where manganese is required in at least five steps (127). These reactions are responsible for formation of polysaccharides and linkage between the polysaccharide and proteins that form... 

The most recent, and probably most elegant, process for the asymmetric synthesis of (+)-estrone appHes a tandem Claisen rearrangement and intramolecular ene-reaction (Eig. 23). StereochemicaHy pure (185) is synthesized from (2R)-l,2-0-isopropyhdene-3-butanone in an overall yield of 86% in four chemical steps. Heating a toluene solution of (185), enol ether (187), and 2,6-dimethylphenol to 180°C in a sealed tube for 60 h produces (190) in 76% yield after purification. Ozonolysis of (190) followed by base-catalyzed epimerization of the C8a-hydrogen to a C8P-hydrogen (again similar to conversion of (175) to (176)) produces (184) in 46% yield from (190). Aldehyde (184) was converted to 9,11-dehydroestrone methyl ether (177) as discussed above. The overall yield of 9,11-dehydroestrone methyl ether (177) was 17% in five steps from 6-methoxy-l-tetralone (186) and (185) (201). 

The synthesis of an anthraquinone dye generally involves a large number of steps. For example. Cl Disperse Red 60 [17418-58-5] (10) (Cl 60756) (a typical disperse red dye) requites five steps starting from anthraquinone, and Cl Disperse Blue 56 [31810-89-6] (11) (Cl 63285) requites six steps. 

Perhaps the greatest utility of (36-39) (and many of their precursors, such as 41, 42 and 48) is as starting points for the synthesis of highly functionalized cyclohexanes. For example, (38) has been converted in five steps (overall yield 70-75%) to streptamine (57) the key step is selective ring-opening with hydrazine to give intermediate (56) (75AG(E)630). 

All of the relations developed here assume that only one step is controlling. A more general case is that of the reaction A B with five steps controlling, namely... 

Motor-driven reciprocating compressors above about 75 kW (100 hp) in size are usually equipped with a step control. This is in reality a variation of constant-speed control in which unloading is accomplished in a series of steps, varying from full load down to no load. Three-step eontrol (full load, one-half load, and no load) is usually accomplished with inlet-valve unloaders. Five-step eontrol (fuU load, three-fourths load, one-half load, one-fourth load, and no load) is accomphshed by means of clearance pockets (see Fig. 10-91). On some machines, inlet-valve and clearance-control unloading are used in combination. 

In this work a novel five-step leaching scheme for HM has been developed addressing exchangeable, acid soluble (carbonate), easily reducible (bound to Mn oxides), easily oxidizable (bound to humic and fulvic acids), and moderately reducible (bound to amorphous Ee oxides) fractions extractable by 0.05 M Ca(N03), 0.43 M CH3COOH, 0.1 M NH,OH-HCl (non-acidified), 0.1 M K/,03 (pH 11), and 0.1 M (NH4),C,04 (pH 3), respectively. The sequence of extractants was chosen according to recent studies on the selectivity of leachants toward dissolved phases of soils. 

In the present work it has been shown that on-line coupling of flowthrough fractionation in RCC with ICP-EAS detection enables not only the fast and efficient fractionation of trace elements (TE) in environmental solids to be achieved but allows real-time studies on the leaching process be made. A novel five-step sequential extraction scheme was tested in on-line mode. The optimal conditions for the fractionation were chosen. Investigating elution curves provides important information on the efficiency of the reagents used, the leaching time needed for the separation of each fraction, and the potential mobility of HM forms. 

Consider Figure 5.5 with six steps (rotor resistance unit with five steps) and assume the maximum and minimum torques as and between each step, to suit a particular load demand (Figure 5.6(a)). Let the corresponding rotor currents be / ,a and Then by a simple hypothesis using equation (1.7). 

Figure 5.6(a) Torgue curve with a five-step external resistance... 

Maximum inrush occurs when five steps of the PFCR are ON and the sixth is switched ON... 

Hold-on for five steps already ON Inrush for the sixth step ... 

There are many extensive reviews on metric matrix distance geometry [41-44], some of which provide illustrative examples [45,46]. In total, we can distinguish five steps in a distance geometry calculation ... 

HS(Gjl83 Five steps to risk assessment - case studies... 

This cyclization procedure was conveniently applied to the preparation of the key intermediate of a five-step synthesis of ( )-muscone [48]... 

Testosterone, the principal male sex steroid hormone, is synthesized in five steps from cholesterol, as shown below. In the last step, five isozymes catalyze the 17/3-hydroxysteroid dehydrogenase reactions that interconvert 4-androstenedione and testosterone. Defects in the synthesis or action of testosterone can impair the development of the male phenotype during embryogenesis and cause the disorders of human sexuality termed male pseudohermaphroditism. Specifically, mutations in isozyme 3 of the 17/3-hydroxysteroid dehydrogenase in the fetal testis impair the for-... 

The First Five Steps of the TCA Cycle Produce NADH, CO, GTP (ATP), and Succinate... 

A five-step synthesis of ethyl ester of eyelie hydrazonie aeid 314 used in the synthesis of natural produets has been deseribed [94JCA(CC)1867]. The eonden-sation of methoxybutenone with EtCOaCN (t-BuOK, THF, —78°C) is eompleted with the formation of ketoester 310 in 72% yield. The addition of methanol to the latter (Triton B, MeOH, room temperature, 88%) and the reduetion with NaBH4 (EtOH, —78°C) leads to the aleohol 312, yield 90%. The dianion of 312 (EDA, THE, -78°C) reaets with t-butylazodiearboxylate (t-BuOaC—N=N—COaBu-t) to form adduet 313, the treatment of whieh with trifluoroaeetie aeid affords the ester 314 in 55% yield [94JCA(CC)1867]. 

The classic method for controlling stereochemistry is to perform reactions on cyclic substrates. A rather lengthy but nonetheless efficient example in the prostaglandin field uses bicyclic structures for this purpose. Bisacetic acid derivative S is available in five steps from Diels-Alder reaction of trans-piperylene and maleic anhydride followed by side-chain homologation. Bromolactonization locks the molecule as bicyclic intermediate Esterification, reductive dehalogen-... 

Figure 12-29A. Five-step clearance pocket control for compressor unloading. (Used and adapted by permission ingersoii-Rand Company. Aii rights reserved.)...

Depending upon size and type of unit, the mounting may vary from simply bolting to the floor to attaching to a massive foundation designed specifically for the application. A proper foundation must (1) maintain the alignment and level of the compressor and its driver at the proper elevation, and (2) minimize vibration and prevent its transmission to adjacent building structures and machinery. There are five steps to accomplish the first objective ... 

A -order LST The determination of the A -order LST equations proceeds in five steps as a generalization of the 0, and 2" order systems of equations described above ... 

The tree can be constructed in five steps and, correspondingly, the generating function of the structurally isomeric molecules can be built up from five factors (multiplication of the generating function in the case of independence cf. Sec. 17). 

Thus, five steps are needed to synthesize a dipeptide such as Ala-Leu ... 

Problem 26.17 Write all five steps required for the synthesis of Leu-Ala from alanine and leucine. 

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