Production repetitive

In a less straightforward way, D-glucose (393) underwent a Maillard-type reaction with an excess of glycine (394) under microwave irradiation to afford 5-hydroxy-l,3-dimethyl-2(l/f)-quinoxahnone (395) as a major product, Repetition with labeled reactants suggested that the product contained six carbon atoms from the sugar and four from the amino acid on this evidence, a detailed mechanism has been postulated. 

The mixture of MoCl4(Ph2PCH2CH2PPh2) (6.80 g, 0.01 mmol) thus formed and diphos (4.78 g, 0.12 mol) dispersed in dry ethanol (150 mL) is stirred at 50 °C for 30 min. To the solution, NaBH4 (3.0 g, 0.08 mol) is added with stirring over a period of 5 min. The solution is heated under reflux for 30 min and then cooled slowly to room temperature. The yellow precipitate thus formed is collected by filtration and dissolved in benzene at 50 °C. Addition of ethanol (200 mL) to the solution crystallizes the product. Repetition of this crystallization procedure yields yellow crystals of MoH4(Ph2PCH2CH2PPh2)2, which are dried in vacuo at 25 for 5 h. Yield 1.5 g. 

Methyl-pyridine iV-oxides react with hot acetic anhydride and produce 2-acetoxymethyl-pyridines trifluoroacetic anhydride reacts at room temperature, with fewer by-products. Repetition of the sequence affords 2-aldehydes after hydrolysis. The course of the rearrangement would seem to be most simply explained by invoking an electrocyclic sequence, as shown below. 

The second reaction produces a more stable tertiary cation from which any of six protons could be lost, but all give the same product. Repetition gives the diene. 

Nature s work is not yet done first, a reduction of the ketone occurs (Fig. 19.111). The reducing agent is NADPH, a molecule closely related to NADH, which we saw in Chapter 16 (p. 814). Next, there is an enzyme-mediated elimination reaction. Finally, NADPH participates again, reducing the newly formed double bond to give the final product. Repetition of the steps in Figures 19.110 and 19.111 eventually leads to the fatty acid. 

Criteria of acceptability are thus quite different from one test to another. Some involve spiking the product repetitively until no growth inhibition is observed. In this case,... 

The adoption of the Taylor system in the late nineteenth century changed the lines of responsibihty for product quahty (4). This management philosophy was based on using incentives, such as pay based on output, to motivate worker productivity. As the workforce became better educated and labor unions gained strength, it became difficult to motivate workers doing simple, repetitive tasks (5). 

Atomic- Vapor Laser Isotope-Separation. Although the technology has been around since the 1970s, laser isotope separation has only recently matured to the point of industrialization. In particular, laser isotope separation for the production of fuel and moderators for nuclear power generation is on the threshold of pilot-plant demonstrations in several countries. In the atomic vapor laser isotope-separation (AVLIS) process, vibrationaHy cooled U metal atoms are selectively ionized by means of a high power (1—2 kW) tunable copper vapor or dye laser operated at high (kHz) repetition rates (51,59,60). 

Repetition of the calculations with N = 7.0 gives R = 2.519, R = 0.9782, and a calculated check value of N = 6.85, which is close enough. The final-product compositions and the (X values used are as follows ... 

Robotics The introduction of robotics has given a new dimension to packaging in that it is now possible to do repetitive tasks with speed and accuracy at notably lower cost than if done by people. The manufacture of robots is well established with corporations of substantial resources providing a quality product with continuity of service, supply, and software support. There is also a specialty industry which is available to supply both accessory hardware and software which are custom designed to handle specific user situations. Economic analysis needs to be done before making the decision as to whether to automate using robots, fixed automation, or the labor of people aided by work aids. 

Certain kinetic aspects of free-radical reactions are unique in comparison with the kinetic characteristics of other reaction types that have been considered to this point. The underlying difference is that many free-radical reactions are chain reactions that is, the reaction mechanism consists of a cycle of repetitive steps which form many product molecules for each initiation event. The hypothetical mechanism below illustrates a chain reaction. 

Nitrogen cannot be eliminated from the latter by further methylation, but (VIII) on catalytic hydrogenation has its vinyl group converted into ethyl and the product, on methylation followed by reduction with sodium amalgam, yields 6-dimethylamino-3 4 3 4 -tetramethoxy-6 -ethyl-a)3-diphenylethane (X), and this, on repetition of the methylation, and reduc-... 

If you are procuring the services of a subcontractor to design and/or manufacture a product or service, you will need specifications which detail all the features and characteristics that the product or service is to exhibit. The reference number and issue status of the specifications need to be specified in the event that they change after placement of the purchase order. This is also a safeguard against the repetition of problems with... 

Regarding service reports, these should be collected from the servicing or maintenance personnel and analyzed for repetitive problems. The data can also be used to compute the actual reliability, maintainability, and many other characteristics of the products. 

Difficulty was experienced when repetition of this preparation was attempted, but conditions were soon found that enabled the pyrido-pyrimidine to be obtained in good yield. This product, however,... 

The original objective of the synthetic work was the preparation of basic derivatives of the 3,1,4-benzoxadiazepine system (2) for animal testing. The basic ring system had been reported previously in the literature as the dehydration products of 2-acylaminobenzophenone oximes (1). Repetition of the work quickly cast doubt on the earlier structural assignment. Both the chemistry of the products and their spectral data suggested that the products were in fact quinazoline-3-oxides (3). ... 

The original scientific account of the preparation of this body stated that mcfa-isohutyl toluene was heated on a water-bath for twenty-four hours, with five times its weight of a mixture of sulphuric and nitric acids. The product was subjected to a repetition of the same treatment, so as to convert it into trinitro-butyl toluene, which crystallises from alcohol in white needles melting at 96° to 97°. It is insoluble in water, but soluble in organic solvents. Even in very dilute solutions this compound has a. 

During the exhaust stroke (see Figure 3d) the ascending piston expels most of the reniaiiiing products through the open exhaust valve, in preparation for a repetition of the cycle. 

The horizontal line at the bottom of the pressure-volume diagram of Figure 4 traces the other tv o strokes of the four-stroke cycle. On the exhaust stroke, from 5 to 6, the rising piston expels most of the remaining combustion products from the cylinder. On the intake stroke, from 6 to 7 (= 1), the descending piston inducts a fresh charge for repetition of the cycle. The net thermodynamic work developed in this cycle is proportional to the area enclosed by the pressure-volume diagram. In the ideal case, both the exhaust and intake strokes occur at atmospheric pressure, so they have no effect on the net output work. That justifies their exclusion from the thermodynamic representation of the ideal Otto... 

The general idea of peptide sequencing by Edman degradation is to cleave one amino acid at a time from an end of the peptide chain. That terminal amino acid is then separated and identified, and the cleavage reactions are repeated on the chain-shortened peptide until the entire peptide sequence is known. Automated protein sequencers are available that allow as many as 50 repetitive sequencing cycles to be carried out before a buildup of unwanted by products interferes with the results. So efficient are these instruments that sequence information can be obtained from as little as 1 to 5 picomoles of sample—less than 0.1 /xg. 

The outcomes of intramolecular cyclizations of hydroxy vinylepoxides in more complicated systems can be difficult to predict. In a study of the synthesis of the JKLM ring fragment of dguatoxin, epoxide 44 was prepared and subjected to acid-mediated cydization conditions (Scheme 9.24) [114]. Somewhat surprisingly, the expected oxepane 45 was not formed, but instead a mixture of tetrahydropyran 46 and tetrahydrofuran 47 was obtained, both compounds products of attack of the C6 and C5 benzyl ether oxygens, respectively, on the allylic oxirane position (C3). Repetition of the reaction with dimsylpotassium gave a low yield of the desired 45 along with considerable amounts of tetrahydropyran 48. 

Luminescence reaction (Viviani et al., 2002a) The luciferin-luciferase luminescence reaction was carried out in 0.1 M Tris-HCl, pH 8.0, containing 2mM ATP and 4mM Mg2+. Mixing luciferase with luciferin and ATP resulted in an emission of light with rapid onset and a kinetically complex decay. Further additions of fresh luciferase, after the luminescence has decayed to about 10% of its maximum value, resulted in additional luminescence responses similar to the initial one (Fig. 1.15). According to the authors, the repetitive light emission occurred in consequence of the inhibition of luciferase by a reaction product, as seen in the case of the firefly system (McElroy et al., 1953). The luminescence spectrum showed a peak at 487nm (Fig. 1.16). 

Complex ( + )-(FeS)-3 is obtained by extraction of the diastereomeric mixture with 50 mL of pentane in portions at r.t. The specific rotation of the solid product obtained from the first fraction is [a]jJ6 +50 (o = 0.001. benzene). The rotation of the remaining mixture becomes more negative as the (+)-isomer is removed. After concentration of the combined fractions, the resulting material, enriched in the ( + )-isomcr, is further purified by extraction with 10 mL of pentane in portions. Repetition of the pentane extraction procedure affords ( + )-(FeS)-3 yield-. 750 mg (30%) mp 120"C (dee) [a] +72 (c = 0.001, benzene). The residue, enriched in (—)-(FeR)-3 is extracted for 1 h with boiling pentane. After separation from the extraction liquor, a yellow-orange solid is obtained yield I -35 g (50%) mp 120°C (dec) — 120... 

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