Purchasing substitution

When specified or approved by the purchaser, substitute seals may be used during the performance test if needed to prevent damage to the contract seals or if the contract seals are not compatible with the test flrrid. 

Out first example is 2-hydroxy-2-methyl-3-octanone. 3-Octanone can be purchased, but it would be difficult to differentiate the two activated methylene groups in alkylation and oxidation reactions. Usual syntheses of acyloins are based upon addition of terminal alkynes to ketones (disconnection 1 see p. 52). For syntheses of unsymmetrical 1,2-difunctional compounds it is often advisable to look also for reactive starting materials, which do already contain the right substitution pattern. In the present case it turns out that 3-hydroxy-3-methyl-2-butanone is an inexpensive commercial product. This molecule dictates disconnection 3. Another practical synthesis starts with acetone cyanohydrin and pentylmagnesium bromide (disconnection 2). Many 1,2-difunctional compounds are accessible via oxidation of C—C multiple bonds. In this case the target molecule may be obtained by simple permanganate oxidation of 2-methyl-2-octene, which may be synthesized by Wittig reaction (disconnection 1). 

Neither benzenepentacarboxylic acid nor mellitic acid are manufactured commercially, but synthetic mellitic acid can be purchased as a laboratory chemical (99). Both can be synthesized by oxidizing the corresponding methylbenzenes or other substituted benzenes, and both are present in trace amounts after oxidation of coal or coal-like substances. 

Salt Substitutes. As a result of concern about the relationship between dietary sodium and hypertension, some salt producers and food companies have developed salt substitutes or low sodium products. Mixtures of sodium chloride and potassium chloride, herbs and spices, as well as modified salt crystals of lower density are marketed in response to a limited consumer demand for reduced-sodium products. This amounts to about 2% of user salt purchases. 

In the Philippines, the sale of filled milk had become 85% of the dairy products market by the early 1970s, reflecting convenience as a purchase incentive rather than price. Filled condensed and evaporated milk has a market share of 10, 27, 54, 69, and 77% in the Netherlands, Mexico, Malaysia, Phillipines, and Thailand respectively (30). Imitation cream has an 8% market share in the United States, 11% in Spain, and 33% in Canada (30). Areas in the world expected to show the greatest growth in the sale of substitute and imitation dairy products are Canada, Ireland, and Mexico (30). 

An optional tight cap shall be substituted when specified by the purchaser. 

More than 60 percent of natural gas physically consumed in the course of a year is nevertheless attributable to purchases at lower, interruptible prices by industrial boilcr-fucl users and electrical generators that are capable of substituting natural gas in off-peak months, when gas is available at prices competitive with those of black fuels (coal and heavy fuel oil). In addition to these relatively low-value, pricc-scnsitivc industrial gas uses is a wide range of intermediate-value demand categories for natural gas, such as in process and feedstock use. 

By contrast, a given synthetic preparation of a major phospholipid possesses fatty acid constituents all of identical chain length and unsaturation. A synthetic PC derivative can be purchased that contains only, for instance, 1,2-dimyristoyl (C14) fatty acid substitutions on its glyceryl... 

ArgoGel MB-CHO resin was purchased from Argonaut Technologies, substitution = 0.42 mmol/g, lot 104—20. 

Rink amide MBHA resin was purchased from Novabiochem, substitution = 0.54 mmol/g, lot A20678. 

Wang resin was purchased from Advanced ChemTech (1% DVB, 0.70mmol/g substitution, 100-200 mash, Cat. SA5009). Anhydrous tetrahydrofuran (THF), A/A-dimcthyl-formamide (DMF), methanol, dichloromethane, pyridine, 1,1 -carbonyldiimidazole (CDI), piperazine, homopiperazine, trans-1,4-diaminocyclohexane, 4-(dimethylamino)pyridine (DMAP), succinic anhydride, diglycolic anhydride, 3-methyl-glutaric anhydride, 2-aminophenol, 2-amino-p-cresol, 2-amino-4-tert-butyl phenol, /V-methylmorpholine (NMM), triphenylphosphine, diethyl azodicarboxylate (DEAD), and trifluoroacetic acid (TFA) were purchased from Aldrich Chemical Company, Inc. and used without further purification. PyBOP was purchased from Novabiochem. 

Although the company officials and plant personnel cooperated fully in acquiring wastewater samples for analysis, they provided little information concerning identities of reactants of company products. Specific ring substitution patterns are not easily derived from mass spectrometrlc data and are included here only for cases where the literature specifies the Isomer or in cases where we have purchased standards and observed identical mass spectra and gas chromatographic retention times. 

In urban areas there is also less time for fishing, and often more cash available to purchase canned substitutes. Not uncommonly there is a paucity of fresh locally caught fish in the market place, e.g. Suva, Fiji, and Rarotonga, Cook Islands. These factors of course also have implications for nutrition and economic development and they underline the fact that ciguatera can not be studied in isolation but must be viewed as one factor in island dwellers complex adaptation to the ever changing reality of the contemporary Pacific. 

Ethyl ether was purchased from Mallinckrodt Inc. (analytical grade) methylene chloride may be substituted, but the monomethyl ester is more soluble in ether. At least two other extractions will be necessary to optimize the yield when methylene chloride is used. 

In principle, the Advanced Purchase Commitment proposal can also use this approach, since if the subsidy paid by the sponsors is very large, it will attract more firms to compete to develop an eligible vaccine, thus dissipating the available profits. However, to the extent that vaccines are substitutes for each other, there may be a substantial increase in costs without an accompanying increase in therapeutic impact. 

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