Examples procedure formats

The enolates of ketones can be acylated by esters and other acylating agents. The products of these reactions are [Tdicarbonyl compounds, which are rather acidic and can be alkylated by the procedures described in Section 1.2. Reaction of ketone enolates with formate esters gives a P-ketoaldehyde. As these compounds exist in the enol form, they are referred to as hydroxymethylene derivatives. Entries 1 and 2 in Scheme 2.16 are examples. Product formation is under thermodynamic control so the structure of the product can be predicted on the basis of the stability of the various possible product anions. 

Entries 7 and 8 illustrate conversion of diazonium salts to phenols. Entries 9 and 10 use the traditional conditions for the Sandmeyer reaction. Entry 11 is a Sandmeyer reaction under in situ diazotization conditions, whereas Entry 12 involves halogen atom transfer from solvent. Entry 13 is an example of formation of an aryl iodide. Entries 14 and 15 are Schiemann reactions. The reaction in Entry 16 was used to introduce a chlorine substituent on vancomycin. Of several procedures investigated, the CuCl-CuCl2 catalysis of chlorine atom transfer form CC14 proved to be the best. The diazonium salt was isolated as the tetrafluoroborate after in situ diazotization. Entries 17 and 18 show procedures for introducing cyano and azido groups, respectively. 

For example, the formation constants of 1 1 complexes of alkali metal ions with crown ethers or cryptands have been determined by Procedures 1 or 2 below [24] ... 

Figure 4-4 shows the Pmpose, References, Precautions, Special Tools/ Equipment, Prerequisites, and procedure steps as they may appear in a procedure. Refer to Appendix F, Sample Procedure Formats (page 130), for more examples. 

PURPOSE This example demonstrates a sample procedure format. 

For thin-film metallization, a thin metallic film is first deposited onto the surface of the substrate. The deposition can be accomplished by thermal evaporation, electronic-beam- or plasma-assisted sputtering, or ion-beam coating techniques, all standard microelectronic processes. A silicon wafer is the most commonly used substrate for thin-film sensor fabrication. Other substrate materials such as glass, quartz, and alumina can also be used. The adhesion of the thin metallic film to the substrate can be enhanced by using a selected metallic film. For example, the formation of gold film on silicon can be enhanced by first depositing a thin layer of chromium onto the substrate. This procedure is also a common practice in microelectronic processing. However, as noted above, this thin chromium layer may unintentionally participate in the electrode reaction. 

This method has been developed largely by Klemm et al. and is discussed in a recent review,7 which gives details on catalysts, procedure, and possible mechanisms Examples include formation of the peri-condensed compounds 35 (29-39%), from bridging at positions 4 and 5 of the phenanthrene molecule 149 at ca. 630°C in the presence of various sulfided mixed metallic oxide catalysts,6,36 and 80 (18%), from similar bridging in the triphenylene molecule 150 at 500°C.37 Since the sulfur bridge forms by substitution at the sterically most hindered positions of these hydrocarbon substrates, method... 

Two examples serve to show the relative usefulness of the Michaelis-Becker and Michaelis-Arbuzov procedures. In the first, 540 (Z = Br) suffers debromination when heated with triethyl phosphite, and 541 was prepared only from 540 (Z = Cl) and sodium or potassium diethyl phosphite . In the second example, the formation, from 542, of the enol phosphate 543 in the Michaelis-Arbuzov case, is obviated by the use of sodium diethyl phosphite when the desired phosphonate 544 was obtained l... 

Another example is formation of graft copolymers of formaldehyde with starch, dextrin, and poly(vinyl alcohol)This procedure is also carried out in two steps. Potassium naphthalene is first reacted with the backbone polymer in dimethylsulfoxide. The formaldehyde is then introduced in gaseous form to the alkoxide solution. 

Iodine forms the most extensive group of polyhalide anions, with triiodide, I3, being the best-known example. The formation of this anion is responsible for the increased solubility of I2 in water on addition of potassium iodide (KI). Triiodide is used extensively in analytical chem-isfly, many analytical procedures being based on the release or uptake of iodine and its subsequent titration with sodium thiosulfate (iodometry). The largest polyhalide anion known, Ijg, consists of an alternate arrangement of triiodide anions and neutral iodine molecules. 

Experiments at atmospheric pressure of carbon monoxide have shown that complex 24 converts rapidly first into 23 and diethyl malonate and in a much slower reaction, complex 23 converts further into octacarbonyl dicobalt and an other mole of diethyl malonate. In both reactions, the formation of highly reactive ethoxycarbo-nylketene was assumed by coupling of the ethoxycarbonyl carbene ligand with carbon monoxide, whose intermediate is scavenged by ethanol [76]. Reactions of complex 24 with in the presence of excess ethanol result in diethyl malonate with natural isotopic distribution of[77]. The combination of these steps led to an effective one-pot procedure for the preparation of various malonic acid derivatives by catalytic carbonylation of ethyl diazoacetate in the presence of a few mol% octacarbonyl dicobalt catalyst precursor [76]. Two new example procedures illustrate the usefulness of the method. 

Procedure. Cany out the STO-3G single point calculations on H2 in a way similar to that of Exercise 10-9 at interatomic distances of 0.4 to 1.2 A at intervals of 0.1 A. This is best done in the z-mahix format, for example. 

You learned in Section 17 8 of the relationship among hemiacetals ketones and alcohols the for mation of phenol and acetone is simply an example of hemiacetal hydrolysis The formation of the hemiacetal intermediate is a key step in the synthetic procedure it is the step in which the aryl—oxygen bond is generated Can you suggest a reasonable mechanism for this step" ... 

Representative Method Although each volatilization gravimetric procedure has its own unique characteristics, the following indirect method for the determination of Si in ores and alloys by formation of volatile SiF4 provides an instructive example of a typical procedure. 

Aldol Addition and Related Reactions. Procedures that involve the formation and subsequent reaction of anions derived from active methylene compounds constitute a very important and synthetically useful class of organic reactions. Perhaps the most common are those reactions in which the anion, usually called an enolate, is formed by removal of a proton from the carbon atom alpha to the carbonyl group. Addition of this enolate to another carbonyl of an aldehyde or ketone, followed by protonation, constitutes aldol addition, for example... 

However, simplification of the refining procedure is not always the end result. IncompatibiUty of different cmde oils, which can occur if, for example, a paraffinic cmde oil is blended with a heavy asphaltic oil, can cause sediment formation ia the unrefined feedstock or ia the products, thereby complicating the refinery process (5). 

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