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Basic Iodine

Dieckmann reaction, 4, 471 Indolizidine alkaloids mass spectra, 4, 444 Indolizidine immonium salts reactions, 4, 462 Indolizi dines basicity, 4, 461 circular dichroism, 4, 450 dipole moments, 4, 450 IR spectra, 4, 449 reactivity, 4, 461 reviews, 4, 444 stereochemistry, 4, 444 synthesis, 4, 471-476 Indolizine, 1-acetoxy-synthesis, 4, 466 Indolizine, 8-acetoxy-hydrolysis, 4, 452 synthesis, 4, 466 Indolizine, I-acetyl-2-methyI-iodination, 4, 457 Indolizine, 3-acyloxy-cyclazine synthesis from, 4, 460 Indolizine, alkyl-UV spectra, 4, 449 Indolizine, amino-instability, 4, 455 synthesis, 4, 121 tautomerism, 4, 200, 452 Indolizine, 1-amino-tautomerism, 4, 38 Indolizine, 3-amino-synthesis, 4, 461, 470... [Pg.672]

Replacement of iodine in (perfluoroalkyl)ethyl iodides predominates over the usual conversion to olefins when the reagent is very nucleophilic and weakly basic Soft nucleophiles like sodium thiocyanate and sodium thiolates react well in displacements [46, 47] (equation 42)... [Pg.456]

These workers also prepared the thio analog of 17 (R = H) by treating 16 (R = H) with aqueous ammonia to provide the P-oxoamide, which was converted into the corresponding enolized P-thioxoamide 18 by treatment with hydrogen sulfide and hydrogen chloride in ethanol. Compound 19 was synthesized by oxidation of 18 with iodine in ethanol under basic conditions. [Pg.222]

Treatment of commercially available and symmetrical 3,4,5-tri-methoxytoluene (37) with iodine, periodic acid, and acetic acid under the conditions of Suzuki19 results in the formation of symmetrical diiodide 38 in 93 % yield. Although only one of these newly introduced iodine atoms is present in intermediate 13, both play an important role in this synthesis. Selective monodemethylation of 38 with boron trichloride furnishes phenol 39 in 53% yield together with 13 % of a regioisomer. Evidently, one of the Lewis-basic iodine substituents coordinates with the Lewis-acidic boron trichloride and directs the cleavage of the adjacent methyl ether... [Pg.535]

A similar procedure may also be used for the determination of antimony(V), whilst antimony (III) may be determined like arsenic(III) by direct titration with standard iodine solution (Section 10.113), but in the antimony titration it is necessary to include some tartaric acid in the solution this acts as complexing agent and prevents precipitation of antimony as hydroxide or as basic salt in alkaline solution. On the whole, however, the most satisfactory method for determining antimony is by titration with potassium bromate (Section 10.133). [Pg.398]

X-ray Contrast Agents and Molecular Imaging. Figure 1 Basic chemical structure of water-soluble iodinated X-ray contrast agents. [Pg.1324]

The first step, as we have already seen (12-3), actually consists of two steps. The second step is very similar to the first step in electrophilic addition to double bonds (p. 970). There is a great deal of evidence for this mechanism (1) the rate is first order in substrate (2) bromine does not appear in the rate expression at all, ° a fact consistent with a rate-determining first step (3) the reaction rate is the same for bromination, chlorination, and iodination under the same conditions (4) the reaction shows an isotope effect and (5) the rate of the step 2-step 3 sequence has been independently measured (by starting with the enol) and found to be very fast. With basic catalysts the mechanism may be the same as that given above (since bases also catalyze formation of the enol), or the reaction may go directly through the enolate ion without formation of the enol ... [Pg.776]

In the haloform reaction, methyl ketones (and the only methyl aldehyde, acetaldehyde) are cleaved with halogen and a base. The halogen can be bromine, chlorine, or iodine. What takes place is actually a combination of two reactions. The first is an example of 12-4, in which, under the basic conditions employed, the methyl group is trihalogenated. Then the resulting trihalo ketone is attacked by hydroxide ion ... [Pg.813]

Iodine is a very good electrophile for effecting intramolecular nucleophilic addition to alkenes, as exemplified by the iodolactonization reaction71 Reaction of iodine with carboxylic acids having carbon-carbon double bonds placed to permit intramolecular reaction results in formation of iodolactones. The reaction shows a preference for formation of five- over six-membered72 rings and is a stereospecific anti addition when carried out under basic conditions. [Pg.312]

It has long been known that iodine dissolves in solvents possessing electron lone pairs and that the colors of these solutions are related to the solvent s basicity. Explaining this simple observation has required decades of work and has consistently required the application of the most sophisticated experimental tools available. The observation has also continually challenged theories of bonding, and even today taxes the capabilities of the fastest computers in efforts to provide accurate descriptions of its origin. [Pg.76]

Chemical plants are a series of operations that take raw materials and convert them into desired products, salable by-products, and unwanted wastes. Fats and oils obtained from animals and plants are hydrolyzed (reacted with water) and then reacted with soda ash or sodium hydroxide to make soaps and glycerine. Bromine and iodine are recovered from sea water and salt brines. Nitrogen and hydrogen are reacted together under pressure in the presence of a catalyst to produce ammonia, the basic ingredient used in the production of synthetic fertilizers. [Pg.6]


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See also in sourсe #XX -- [ Pg.225 ]




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