Other Preparations

Other Preparations.—A mild method for converting a nitro-group into a carbonyl function involves the oxidative cleavage of nitronate anions using t-butyl hydroperoxide and VO(acac)2 as catalyst. Nitronate anions are also implicated as intermediates in the simple procedure for the same conversion employing basic silica gel (i.e. chromatographic grade silica gel previously treated with sodium methoxide in methanol and dried at 400 °C).  

Alkyl phenyl thioethers RCH2SPh are available by radical-initiated addition of benzenethiol to a terminal olefin or by reaction of an alkyl bromide with thio-phenoxide ion. N -Chlorosuccinimide effects halogenation at the a-site, and the a-chloroalkyl thioether gives the corresponding aldehyde RCHO on treatment with mercury(ll) chloride and cadmium(ll) carbonate in aqueous carbon tetra- 

Vinyl chlorides of different chemical structures can be smoothly converted into carbonyl compounds in formic acid in the presence of a stoicheiometric amount of mercury(ii) acetate. The high yields of aldehydes obtained from 1-chloroalk-l-enes are notable.  

The introduction of a carbonyl group into a molecule through the use of sulphur-containing reagents that are equivalent to acyl anions has been reviewed.  

Other Preparations.—Carboxylic acids have been converted into aldehydes through di-isobutylaluminium hydride reduction of 3-acylthiazolidine or 2-thiazoline-2-thiol ester intermediates. Bis(triphenylphosphine)copper(l) tetrahydroborate, (Ph3P)2CuBH4, shows promise as a new reagent for the reduction of acid chlorides to aldehydes. The same conversion can be accomplished using sodium borohydride in a mixture of acetonitrile and hexamethyl-phosphoramide containing a cadmium(il) chloride-dimethylformamide complex.  

Organotin compounds readily undergo palladium-catalysed coupling with acid chlorides [equation (6)] this process has distinct advantages over similar traditional methods e.g. an aldehyde moiety is unaffected in the new method.  

The transformation of acid chlorides into hydroxymethyl ketones can be achieved in good yield under mild conditions using tris(trimethylsilyloxy)ethylene. a-Hydroxy-carboxylic acids, readily available from carboxylic acids, are decar-bonylated at room temperature on treatment with a benzoxazolium salt and triethylamine to give ketones in good yields [equation (7)].  

Polymer-supported tetracarbonylhydridoferrate converts an alkyl bromide or iodide into the corresponding aldehyde in excellent yield.  

Cainelli, F. Manescalchi, A. Umani-Ronchi, and M. Panunzio, J. Org. Chem., 1978, 43,1598. R. Couffignal and J.-L. Moreau, Tetrahedron Letters, 1978, 3713. 

Acyl chlorides have been converted into unsymmetrical ketones by reaction with alkyl halide at a cadmium anode- - and by reaction with alkyl manganese iodide.Cyclopropylalkyl (or vinyl) ketones are formed in moderate yields by reaction of an acyl halide with cyclopropyltrimethylsilane.  

The partial reduction of lactones and esters to aldehydes has been explored using reagents obtained by modification of sodium bis-(2-methoxyethoxy) aluminium hydride. 

Baldwin has outlined two methods whereby a ketone function can be modified to a dihydroxyacetone moiety both involve initial reaction of the ketone with methoxyvinyl-lithium.  

The Pummerer rearrangement of sulphoxides to a-acetoxy-sulphides (known aldehyde synthons) proceeds to the exclusion of competitive elimination processes 

Cahiez, A. Masuda, D. Bernard, and J. P. Normant, Tetrahedron Letters, 1976, 3155. M. Grignon-Dubois, J. Dunogues, and R. Galas, Synthesis, 1976, 737. 

The reaction of 3,4,5,6-tetrachloro-2-pyrone with Grignard reagents results in substitution of the chlorine atom at C6 (77CB1000). Nucleophilic 

Trimerization of ketenes [77HCA3007 89IJC(B)285] and treatment of acetyl chloride with aluminum trichloride (73USP3743658) produce 4-hydroxy-2-pyrones. 

Formation of N-substituted 4-amino-2-pyrones has been observed in reactions of ketene with some of its derivatives (64JOC2513). 

Many natural 4-hydroxy- and 4-methoxy-2-pyrones have been isolated from natural sources. Some of them bear biogenetically plausible substituents at C3 or C5 or at both, and significant examples were presented in Section I. 

Triacetic acid lactone (1) is one of the simplest polyketides, and its formation from acetyl-CoA and malonyl-CoA has been proved (68JBC5471). Biogenetic formation of triacetic acid lactone has been considered a derailment from fatty acid biosynthesis promoted by the absence of the reductant NADPH (69MII). Pyrone 1 has been isolated from microorganisms (67JA676) and is transformed into tropolone derivatives by Penicillium stipitatum (67JA681). 

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Besides pH, other preparative variables that can affect the microstructure of a gel, and consequendy, the properties of the dried and heat-treated product iaclude water content, solvent, precursor type and concentration, and temperature (9). Of these, water content has been studied most extensively because of its large effect on gelation and its relative ease of use as a preparative variable. In general, too Httie water (less than one mole per mole of metal alkoxide) prevents gelation and too much (more than the stoichiometric amount) leads to precipitation (3,9). Other than the amount of water used, the rate at which it is added offers another level of control over gel characteristics. 

In 1973 D-homo corticosteroids (109—112), eg, D-homo-9a- uoroprednisolone acetate (111) were reported to have antiinflammatory activity (107). Compounds such as 21-acetoxy-liP- uoto-9a-chloto-17aa-hydtoxy-D-homo-ptegn-4-en-3,20-dione (110) had especially strong topical activity with weak systemic activity (108). Other preparations of D-homocorticoids included... 

In the eadiest known paintings, the primitive cave paintings, paint was appHed directly onto the cave wall, with tittle or no preparation. As early as the Old Kingdom in ancient Egypt, however, wall surfaces were specially prepared using a coating of plaster. In time, the refinement and complexity of the preparation layers increased until in the Renaissance several layers of different composition and fineness were superimposed. Other preparations used, especially in the Far East, consisted of a clay layer. 

Other preparations of trifluoromethanesulfonic acid kiclude oxidation of methyltrifluoromethyl sulfide under a variety of conditions (10,11). Perfluorosulfonyl fluorides have also been prepared by reaction of fluoroolefkis with sulfuryl fluoride (12,13). Chinese chemists have pubflshed numerous papers on the conversion of telomer-based alkyl iodides to sulfonyl fluorides (14,15) (eqs. 8 and 9) ... 

Iron(II) bromide [7789-46-0] FeBr2, can be prepared by reaction of iron and bromine ia a flow system at 200°C and purified by sublimation ia oitrogea or uader vacuum. Other preparative routes iaclude the reactioa of Fe202 with HBr ia a flow system at 200—350°C, reactioa of iroa with HBr ia methanol, and dehydration of hydrated forms. FeBr2 crystallizes ia a layered lattice of the Cdfy type and has a magnetic moment of... 

Methyl Amyl Ketone. Methyl amyl ketone [110-43-0] (MAK) (2-heptanone) is a colorless Hquid with a faint fmity (banana) odor. It is found in oil of cloves and cinnamon-bark oil, and is manufactured by the condensation of acetone and butyraldehyde (158). Other preparations are known (159-162). 

Other Preparative Reactions. Polyamidation has been an active area of research for many years, and numerous methods have been developed for polyamide formation. The synthesis of polyamides has been extensively reviewed (54). In addition, many of the methods used to prepare simple amides are appHcable to polyamides (55,56). Polyamides of aromatic diamines and aUphatic diacids can also be made by the reaction of the corresponding aromatic diisocyanate and diacids (57). 

Other preparative routes iaclude hydrogenation of succinonitdle in the presence of methylamine and hydrogenation of solutions of maleic or succinic acid and methylamine (82,83). Properties are Hsted in Table 3. l-Meth5i-2-pyrrohdinone is completely miscible with water, lower alcohols, lower ketones, ether, ethyl acetate, chloroform, and benzene. It is moderately soluble in aUphatic hydrocarbons and dissolves many organic and inorganic compounds. 

The existing ground mbber producers have expanded their capacity to meet anticipated demands. Potential new entrants have been forced to decide whether to go ahead with investment plans, or await a final Congressional verdict. State transportation department groups that lead the anti-Section 1038 faction are also deciding whether to proceed with test sections and other preparations for implementing the requirement. 

Other preparative methods for alkoxysilanes, in approximate order of declining utOity, are given by the following equations (34—40) ... 

Other preparations of succinic acid mentioned in the Hterature are electrochemical reduction of maleic or fumaric acid (153,154), ultrasound-promoted Zn—acetic acid reduction of maleic or fumaric acid (155), reduction of maleic acid with H2PO2 at room temperature (156),... 

Other preparative methods include direct synthesis from the elements, reaction between gaseous hydrogen fluoride and titanium tetrachloride, and decomposition of barium hexafluorotitanate [31252-69-6] BaTiF, or ammonium, (NH 2TiFg. 

Titanium Silicides. The titanium—silicon system includes Ti Si, Ti Si, TiSi, and TiSi (154). Physical properties are summarized in Table 18. Direct synthesis by heating the elements in vacuo or in a protective atmosphere is possible. In the latter case, it is convenient to use titanium hydride instead of titanium metal. Other preparative methods include high temperature electrolysis of molten salt baths containing titanium dioxide and alkalifluorosiUcate (155) reaction of TiCl, SiCl, and H2 at ca 1150°C, using appropriate reactant quantities for both TiSi and TiSi2 (156) and, for Ti Si, reaction between titanium dioxide and calcium siUcide at ca 1200°C, followed by dissolution of excess lime and calcium siUcate in acetic acid. 

Cellulose III. Cellulose III results from treatment of cellulose with Hquid ammonia (ammonia mercerization) or amines. Cellulose III can be made from either Cellulose I or II. When treated with water. Cellulose III can revert to its parent stmcture. Some cellulose III preparations are much more stable than other preparations. The intensities on diffraction patterns from Cellulose III differ slightly depending on whether the Cellulose III was made from Cellulose I or II, and thus these allomorphs are called IIIj or IHjj- Workers studying III concluded, based partiy on the results of I and II, that the packings of IIIj and IIIjj are parallel and antiparallel, respectively (67). IIIjj also is thought to have hydrogen bonds between the corner and center chains. 

Pad-batch dyeing shows its primary benefits over other methods where it is possible to apply the dye on grey (unbleached) minimally prepared fabric, eg, T-shirts, followed by washing on the same perforated beam used to batch the fabric after dyeing. Where a bleached fabric base is needed, the bleaching is best carried out using peroxide by pad-batch technique in order to ensure an even effect and pick up when padding the dye Hquor. Similarly all other preparation is best carried out in open-width. 

Other preparative methods will be considered in Chapter 7 of Part B. 

Names of compounds m small capital Utters indicate substances for which directions are given the numbers m bold face type refer to volumes of Organic Syntheses, numbers in italics refer to pages in those volumes on which preparative directions are given and num bers in Arabic refer to pages on which the compounds or subjects are mentioned in connection with other preparations For example Acetoacetic Ester 4 45 6, 36 indicates... 

The lithium enolate of the oc-silyl-substituted iron-acyl complex 19 reacts with aldehydes, however, products of the Peterson elimination process (E)- and (Z)-22 are usually isolat-ed22- 23,36.37 for t[1js anc other preparations of a,/t-unsaturated iron-acyl complexes see Section I.3.4.2.5.I.3.). 

Other preparations and isolations. If damp methylenedi(nitroformamide) is allowed to stand for several days, the odor of formic acid is noticed, and MEDINA can be isolated from the residue (Ref 11, p 14). The details of scale-up to 150 lb batches, including exp details and flow sheets, and further scale-up with the aim of prodn of 1000 lbs are given. The report describes a fume-off and fire which occurred during the S3rd run. The cause was attributed to a stuck valve which allowed nitric acid to build up in the reactor (Ref 13, p 57). In Ref 16, p 73 there are cost analysis data for pilot plant and large scale prodn, flow sheet for a proposed coml plant, and material balances. The action of acet anhydr on N,Nf-bis(hydroxy-methyl)MEDlNA regenerates MEDINA (Ref 6) the diNa salt of N. N trinitrotrimethylene-diamine, on warming with me ale, ppts the Na salt of MEDINA... 

Several routes to such derivatives have been covered already by primary synthesis (Chapter 1), from quinoxalinecarboxylic acids (Section 7.1.2), from quinoxalinecarboxylic esters (Section 7.2.2), and from quinoxalinecarbonyl halides (Section 7.3). Other preparative routes are illustrated in the following classified examples. 

The compounds AlYX are best prepared by direct reaction between the respective aluminum halide and chalcogenide in a sealed ampoule at 350°C. The reaction is complete after 2 weeks. In the case of the iodides, a mixture of A1 and I2 (molar ratio 3 10) is used instead of AII3. Other preparative methods, such as the reaction of an aluminum halide with Zn or Cd chalcogenide, or with the chalcogen itself, are applicable to the bromide and chloride only, and give poor yields (15-20%) (158, 159, 266, 327, 328). 

Adtveoitages. The antibody technology is remarkably convenient. It requires only that a significant fraction of FLPEP be receptor bound ( 10%). The assay can be set up in a few minutes and is applicable to membranes, permeabilized cells, cells, or any other preparation in which the receptor concentration is in the range of 1 niV or greater. We use this assay routinely to analyze ligand dissociation kinetics. 

The rate of oxidation with Ce(IV) perchlorate depends on the method of preparation . The material from certain preparations gives a deep red complex, containing two equivalents of Ce(IV) to one molecule of H2O2, which decomposes in second order fashion-presumably by means of two concerted one-equivalent oxidations of the substrate. Other preparations give no complex and decompose peroxide much faster. The difference is thought to lie in the degree of association of the oxidant cf. the Ce(IV) oxidation of iodide ion, p. 359). 

The extruded fibres can also gel in these conditions and must be considered as ingredients and not additives. Gelled products enriched in dietary fibres can be obtained. The extruded fibres can be used in jams, or other preparations requiring HM pectins as gelling agents.. 

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