Preparation of a Series

To 3500 g. of a cerium-free rare earth oxide mixture in a 16-in. porcelain dish is added sufficient water to wet all portions of the mass. The thick paste so obtained is treated with 4.2 1. of concentrated nitric acid in small portionsf and heated until solution is complete. The magnesium nitrate may now be added in the form of Mg(N03)2-6H20 crystals (810 g.) dissolved in 1.51. of water. If, however, many large series are to be set up, it is more 

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The preparation of a series of transition metal complexes (Co. Ni. Pd. Pt, Ir. Au. Cu. Ag) with ambident anion (70) and phosphines as ligands has been reported recently (885). According to the infrared and NMR spectra the thiazoline-2-thione anion is bounded through the exocyclic sulfur atom to the metal. The copper and silver complexes have been found to be dimeric. 

The perfluoroalkane sulfonic acids were fkst reported ki 1954. Trifluoromethanesulfonic acid was obtained by the oxidation of bis(ttifluoromethyl thio) mercury with aqueous hydrogen peroxide (1). The preparation of a series of perfluoroalkanesulfonic acids derived from electrochemical fluotination (ECF) of alkane sulfonyl haUdes was also disclosed ki the same year (2). The synthetic operations employed when the perfluoroalkanesulfonic acid is derived from electrochemical fluotination, which is the best method of preparation, are shown ki equations 1—3. 

From these and other experimental results Pinner and Schwarz suggested that pilocarpine could be represented by formula (V), and subsequently Jowett confirmed this by the preparation of a series of disubstituted glyoxalines from wopilocarpine by distillation with soda-lime, 1 although he pointed out that the reactions of the alkaloid were... 

A Scheme for the preparation of a series of eyelie urea HIV protease inhibitors eontaining alkynyl-tethered heteroeyeles in the P2 region ineludes hydrogenation with LiAlH4 in THF in 60-80% yields (96BMCL797) (Sehemes 83 and 84). 

First, they compared CSPs 1 and 3 prepared by the two-step solid-phase methodology with their commercially available counterparts (CSPs 2 and 4) obtained by direct reaction of the preformed selector with a silica support. Although no exact data characterizing the surface coverage density for these phases were reported, all of the CSPs separated all four racemates tested equally. These results shown in Table 3-3 subsequently led to the preparation of a series of dipeptide and tripeptide CSPs 5-10 using a similar synthetic approach. Although the majority of these phases exhibited selectivities lower or similar to those of selectors built around a single amino acid (Table 3-3), this study demonstrated that the solid-phase synthesis was a... 

Our strategy consisted of the following steps A mixture of potential chiral selectors is immobilized on a solid support and packed to afford a complete-library column , which is tested in the resolution of targeted racemic compounds. If some separation is achieved, the column should be deconvoluted to identify the selector possessing the highest selectivity. The deconvolution consisted in the stepwise preparation of a series of sublibrary columns of lower diversity, each of which constitute a CSP with a reduced number of library members. 

The body of chemistry described above for amphotericin B (1) allowed, for the first time, the preparation of a series of novel derivatives of this polyene macrolide antibiotic and set the stage for a total synthesis of this target molecule. Below we unfold the adventure that led to the accomplishment of this goal.910... 

The cyclization of o-substituted amides 206 was used for the preparation of a series of purine derivatives 207. In this case, the amine behaved as a nucleophile toward the amide function followed by ring closure to the imidazole ring (Scheme 75) [133]. 

Recent examples of these reactions are the preparation of a series of norbornyl-, norbornenyl-, and norbornadienyl-tin compounds (87) 1-AdSnMes, (l-Ad)4Sn and 2-AdSnMes (Ad = adamantyl) (81, 83) Pr8SnCH=CHCH=CHj (83) and (Me3Sn)4C (82). 

The classic route to halogenomethyltin compounds is the methylena-tion of tin halides with diazomethane, and this reaction has been used as the basis for the preparation of a series of thiomethyltin compounds (286). 

A systematic study of this class of compounds did not start until twenty years later and led to the preparation of a series of M3Q7X4 (M = Mo, W Q = S, Se and X = C1, Br) inorganic polymers by high-temperature reactions (ca. 350 °C) of the elements in a sealed tube [10-14]. The interest on these cluster phases was mainly motivated by their excellent role as synthons for the preparation of molecular M3Q7 and M3Q4 cluster complexes, as will be presented in this section. 

The in situ deprotection/alkynylation protocol has proven to be exceedingly useful. In addition to graphdiyne models, an array of PAM/PDM hybrids have been prepared (76 (R=H), 81, 97-99) [66]. Extension of the simple, one-pot procedure to various iodoarenes has allowed preparation of a series of bis(tri-isopropylsilyl)-protected a,m-polyynes in very good yields. Subsequent depro-... 

D. O., Warrington, B. H., Wong, S. Y. F., The preparation of a series cf nitrostilbene ester compounds using micro-reactor technology. Analyst 126 (2001) 7-10. 

The same authors have previously reported the preparation of a series of various sulfoximine ligands, which were further investigated in the test reaction.In almost all the ligands, moderate enantioselectivities were observed for the product of the test reaction, except for a ligand bearing a hydroxyl group on the aryl substituent of the sulfur atom, which gave a 73% ee (Scheme 1.52). 

In preparation for scale-up of the strigol synthesis described by Sih (8), efforts were made to improve the yield of some of the seven steps involved in the scheme. Of these steps, nine are satisfactory from the standpoint of yield and experimental conditions. For three of the steps, we have improved the yield and/or experimental conditions such that the yield of (+ )-strigol would be raised to 2.85% overall from citral rather than 1.53% based on Sih s procedure and reported yields. Improvements were developed preparation of a-cyclocitral (III), the oxidation of the hydroxyaldehyde (V) to the ketoacid (VII), and for the preparation of the hydroxybutenolide (XVII). For the remaining five steps, our attempts to change experimental conditions have failed to improve, and in most cases to even obtain, the yields reported in the literature (8). We have considered the preparation of strigol analogs and determined the conditions and limitations for the preparation of a series of alkoxybutenolides (XVI) and a butenolide dimer (XVIII). Modification of the literature procedure (11) to eliminate the use of the mesylate (XX) and the use of polar aprotic solvents gave better yields of the 2-RAS (XXI). 

Thiadiazoles have proven of some utility as aromatic nuclei for medicinal agents. For example, the previous volume detailed the preparation of a series of "azolamide" diuretic agents based on this class of heterocycle. It is thus of note that the 1,2,5-thiadiazole ring provides the nucleus for a clinically useful agent for treatment of hypertension which operates by an entirely different mechanism, p-adrenergic blockade. In its preparation, reaction of the amide-nitrile 211 with sulfur monochloride leads directly to the substituted thiadiazole 212. ... 

In the preparation of a series of substituted phenylethylenediamines, it is essential to add the reagents to an aromatic solvent at 30-80°C in the order aniline, then aluminium chloride, then ethylenimine to prevent uncontrollable exothermic reaction. 

Many versatile approaches to the construction of fused heterocyclic systems (6 5 6) with ring junction heteroatoms have been reported. More general reactions which can be used for synthesis of derivatives of several tricyclic systems, and transformations which have potential for use in the preparation of a series of substituted compounds, are discussed in this section. Formation of the five-membered ring is presented first because it is a conceptually simple approach. It should be noted, however, that the addition of a fused six-membered ring to a bicyclic component offers much more versatility in the construction of a (6 5 6) system. Each subsection below starts with intramolecular cyclization of an isolated intermediate product. Reactions which follow are one-pot intermolecular cyclizations. 

Preparation of a series of phycobiliprotein tandem dyes allows multiplexed analysis of different targets in a sample. In addition, since RPE can be excited by the argon-ion laser at 488 nm, a fluorescein-labeled probe can be used concurrently with RPE alone and RPE-tandem conjugates to create a multiplexed system of different fluorescent probes that can be used simultaneously. Table 9.3 shows the different combinations of dyes that can be used in this type of assay with RPE and APC. 

The preparation of 1,3-dialkylimidazolium halides by conventional heating in solvent under reflux requires several hours to afford reasonable yields and also uses a large excess of alkyl halides and/or organic solvents as the reaction medium. To circumvent these problems Varma and coworkers [106] investigated the preparation of a series of ionic liquids 72 (Scheme 8.74), using microwave irradiation as the energy source, by simple exposure of neat reactants, in open containers, to microwaves by use of an unmodified household MW oven (240 W). 

The scope of the reaction has been demonstrated by the preparation of a series of isoxazolo[60]fullerenes 198 (Scheme 9.61) [109]. The nitrile oxides were prepared from the corresponding oximes by reaction with NBS or NCS and subsequent treatment of the mixture with triethylamine under microwave irradiation. 

Pizzano and Suarez described a convenient preparation of a series of new chiral phosphine-phosphites based on the easy demethylation of o-anisyl phosphines [124]. Rh-156a complex was found to be the most effective catalyst for the hydrogenation of dimethyl itaconate (99.6% ee), whereas 155b and 156a induced >99% ee in the hydrogenation of methyl N-2-acetamidocinnamate. Reetz... 

K. Dedeian, P.I. Djurovich, F.O. Garces, G. Carlson, and R.J. Watts, A new synthetic route to the preparation of a series of strong photoreducing agents fac tris-ortho-metalated complexes of Iridium (III) with substituted 2-phenylpyridines, Inorg. Chem., 30 1685-1687 (1991). 

Table 9.2 shows the results of a preparation of a series of copoly(carbonate)s having a wide range of hexafluoroisopropylidene unit content. Reduced viscosity of copoly(carbonate)s (5) decreases gradually with increasing feed ratio of Bisphenol AF (1) to Bisphenol A (4). This is attributed to the lower nucleophi-licity of Bisphenol AF induced by strongly electron-withdrawing trifluoromethyl groups as described above. 

Very recently we8 reported on a class of processable heavily fluorinated acrylic resins that exhibit dielectric constants as low as 2.10, very close to the minimum known values. In this chapter we report on the preparation of a series of processable heavily fluorinated acrylic and methacrylic homo- and copolymers that exhibit dielectric constants as low as 2.06, and the factors that affect the reduction of dielectric constant from structure-property relationships is elucidated.9... 

Although not within the general coverage of this review, it is of interest to note the preparation of a series of trinuclear metal compounds which are chiral. Vahrenkamp, using an elimination reaction, has been able to prepare a series of tetrahedral molecules containing three different metal centers ... 

Preparation of Copolymers Containing Both Electrophilic and Nucleophilic Groups. Our first implementation of this reaction scheme involved the preparation of a series of copolymers incorporating both a latent electrophile and an electron-rich aromatic moiety which, being phenolic, also provides access to swelling-free development in aqueous medium. The copolymers are prepared as shown in Figure 1 by copolymerization of 4-t-butyloxycarbonyloxy-styrene with 4-acetyloxymethyl-styrene. Although the reactivity ratios of these two monomers are different [11], our study of this system has confirmed that they copolymerize essentially in random fashion. 

Another interesting example of the application of sugars in the synthesis of bioactive compounds was presented by Nicotra s group.61 In this approach fructose was used as the starting material for the preparation of a series of GABA ligands, having a considerable therapeutic potential (Fig. 45). 

Finally, it would be pertinent here to demonstrate that the present methodology of cation stabilization can be successfully applied to the preparation of a series of radical-cation salts and dication salts of oligothiophenes (2T, 3T, 4T, and 6T), fully annelated with BCO units, 24, 25, 26, and 27 (Figure 18) (31,32). 

Serial dilution is the preparation of a series of solutions by always diluting the solution just prepared to make the next one. For example, to make solutions with concentrations 10, 20, 30, 40, and 50 ppm, serial dilution would mean to prepare the 50 ppm first, then to prepare the 40 ppm from the 50 ppm, the 30 ppm from the 40 pmm, the 20 ppm from the 30 ppm, etc. 

In most manual methods of analysis this relationship is most easily expressed in the form of a calibration graph, although in many automated analysis systems, the equation for the relationship is determined by the instrument. One very common and important step in determining this relationship is the preparation of a series of standard solutions. 

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