Derivative formation

Urethanes. The reaction with phenylisocyanate should be used for crystalline derivative formation (see below), and not as a general reaction for alcohols. 

Derivative Formation. Hydrogen peroxide is an important reagent in the manufacture of organic peroxides, including tert-huty hydroperoxide, benzoyl peroxide, peroxyacetic acid, esters such as tert-huty peroxyacetate, and ketone derivatives such as methyl ethyl ketone peroxide. These are used as polymerization catalysts, cross-linking agents, and oxidants (see Peroxides and peroxide compounds). 

Isotope labeling by derivative formation with deuterated reagents is useful for the preparation of analogs such as dg-acetonides, da-acetates, da-methyl ethers, dg-methyl esters, etc. The required reagents are either commercially available or can be easily prepared. (The preparation of da-methyl iodide is described in section IX-F. Various procedures are reported in the literature for the preparation of dg-acetone, da-diazometh-ane57.i63.i73 and da-acetyl chloride. ) These reactions can be carried out under the usual conditions and they need no further discussion. A convenient procedure has been reported for the da-methylation of sterically hindered or hydrogen bonded phenolic hydroxyl functions by using da-methyl iodide and sodium hydroxide in dimethyl sulfoxide solution. This procedure should be equally applicable to the preparation of estradiol da-methyl ether derivatives. 

Formation of a quinonoid carboline-type anhydro-base requires loss of resonance stabilization of the indole moiety. In the carboline anhydro-bases this is counterbalanced by the preservation of a 677 system in the hetero ring. No such balancing factor is present in the case of 3,4-dihydro-j3-carboline derivatives. Formation of the exocyclic anhydro-base in the latter case preserves benzenoid resonance. It is noteworthy that in the two cases where formation of a carboUne-type anhydro-base was reported in dihydro derivatives additional aromatic conjugation is present. 

Note The exothermic nitration of phthalic acid or phthalic anhydride by a fuming nitric acid-sulfuric acid mixt may give mixts of the potentially expl phthaloyl nitrates or nitrites or their nitro derivatives. Formation of these compds can be avoided if the nitrating mixt is... 

Several solvent systems dissolve cellulose, a process that may, or may not lead to cellulose derivative formation. Both types of solvent systems will be considered, although the important derivatizing reaction employed in the... 

Chau ASY. 1972. Confirmation of pesticide residue identity V. Alternative procedure for derivative formation in solid matrix for the confirmation of alpha- and beta endosulfan by gas chromatography. J Assoc Off Anal Chem 55 1228-1231. 

The isomerization mechanism is clearly established by labeling experiments. The rearrangement of a to c via a 7i-allyl hydride complex b in the coordination sphere of the metal is a key step in this cayalytic cycle (Scheme 54) [174, 175]. hi case of polyunsaturated derivatives, formation of a stable q" complexes (Scheme 55) is preferred over the rearrangement (a c). 

The nitration of N,N -diethylurea gives nitrated products which are precursors for a new energetic plasticizer N,N -dialkyl-N,N -dinitrourea (DNDA). For macroscopic batch processing, this reaction is characterized by a lack of selectivity owing to mononitro derivative formation and thermal decomposition of the dinitro product due to increasing temperature during the course of reaction [37, 38]. 

De Re Metallica (Agricola), 16 126, 595 Derivative fibers, 11 247 24 616 Derivative formation, from hydrogen peroxide, 14 67 Derivatives, reducing, 12 805 Derivative spectroscopy, 23 139, 144 Derivatization... 

The formation of DNP or dansyl amino acid derivatives followed by chromatography or electrophoresis is a useful technique in certain circumstances. The preparation of DNP derivatives may be indicated when the sample for analysis contains a variety of other substances, removal of which would be complicated, leading possibly to considerable analytical errors. However, the derivative formation and extraction is time consuming and itself can introduce inaccuracies into the analysis and should be used only when it offers an advantage over the separation of untreated amino acids. 

To quantitate and analyze conjugated bile pigments, azo derivative formation is applied most frequently (Fig. 1). Such terms as azobilirubin, or azobilirubin conjugate, erroneously suggest tetrapyrrolic structures. The following trivial names appear to be more appropriate dipyrromethene azo derivative, azodipyrrole, dipyrrolic azo pigment, and the like. The term azodipyrrole will be employed in the present review. 

As might be expected, not every crystal soaked in a solution containing a heavy-atom reagent will be a derivative. Recently, Garman and Murray (2003) have summarized many of the techniques used in evaluating derivative formation these include mass... 

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