From a Phenol

Tris[bis(trimethylsilyl)amido]lanthanum (3.82 g, 6.16 mmol) in toluene (20 mL) is slowly added during 15 min from a dropping funnel fitted with a pressure equalization attachment to 2,6-di-fcrt-butyl-4-methylphenol (4.18 g, 18.97 mmol) in toluene (50 mL) at 20 °C in a 200-mL Schlenk tube. The dropping funnel is replaced by a reflux condenser, and the mixture is heated under reflux for 48h. Volatiles are removed at 10 torr. Sublimation of the white residue at 250-260 °C and 10 torr aflbrds white crystals of tris(2,6-di-tert-butyl-4-methylphenoxo)lanthanum. Yield 3.30 g (63%). 

Procedures A and B can be employed to prepare a wide range of compounds [Ln(OAr )3]. The lithium aryl oxide procedure has the advantage that [U(/i-OAr )(OEt2)]2 is readily prepared from Ar OH and LiBu (available as a hexane solution) in diethyl ether. The lanthanide metal(III) amide route has the advantage of greatest ease of removal of by-product, in this case of the volatile NH(SiMe3)2 however, because these metal(III) amides are highly hindered, substantial reflux times may be required. Data on some selected aryl oxides are summarized in Table I. 

Compounds 1 are exceedingly sensitive to air or moisture. In an inert atmosphere they are thermally stable, melting without decomposition at high temperatures (Table I), and subliming at 250°C and lO torr. They are soluble in hydrocarbons and are monomers in benzene (cryoscopy). 

The structures of crystalline [Ln(OC6H2t-Bu2 2,6-R-4)3], determined by single crystal X-ray diffraction, confirm their structure, with Ln03 in a 

C Biadley, R. C. Mehrotn, and D. P. Gaur, Metal Alkoxides, Academic Press, New York, 1978. 

Lappert, P. P. Power, A. R. Sanger, and R. C. Srivastava, Metal and Metalloid Amides, Norwood-Wiley, Chichester, 1980. 

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The procedure is not usually applicable to aminosulphonic acids owing to the interaction between the amino group and the phosphorus pentachloride. If, however, the chlorosulphonic acid is prepared by diazotisation and treatment with a solution of cuprous chloride in hydrochloric acid, the crystalline chlorosulphonamide and chlorosulphonanilide may be obtained in the usual way. With some compounds, the amino group may be protected by acetylation. Sulphonic acids derived from a phenol or naphthol cannot be converted into the sulphonyl chlorides by the phosphorus pentachloride method. 

Other modifications of the polyamines include limited addition of alkylene oxide to yield the corresponding hydroxyalkyl derivatives (225) and cyanoethylation of DETA or TETA, usuaHy by reaction with acrylonitrile [107-13-1/, to give derivatives providing longer pot Hfe and better wetting of glass (226). Also included are ketimines, made by the reaction of EDA with acetone for example. These derivatives can also be hydrogenated, as in the case of the equimolar adducts of DETA and methyl isobutyl ketone [108-10-1] or methyl isoamyl ketone [110-12-3] (221 or used as is to provide moisture cure performance. Mannich bases prepared from a phenol, formaldehyde and a polyamine are also used, such as the hardener prepared from cresol, DETA, and formaldehyde (228). Other modifications of polyamines for use as epoxy hardeners include reaction with aldehydes (229), epoxidized fatty nitriles (230), aromatic monoisocyanates (231), or propylene sulfide [1072-43-1] (232). 

Historically, simple Vz-alkyl ethers formed from a phenol and a halide or sulfate were cleaved under rather drastic conditions (e.g., refluxing HBr). New ether protective groups have been developed that are removed under much milder conditions (e.g., via nucleophilic displacement, hydrogenolysis of benzyl ethers, and mild acid hydrolysis of acetal-type ethers) that seldom affect other functional groups in a molecule. 

The tetrahydropyranyl ether, prepared from a phenol and dihydropyran (HCl/ EtOAc, 25°, 24 h), is cleaved by aqueous oxalic acid (MeOH, 50-90°, 1-2 h). ... 

In general, benzyl ethers are prepared from a phenol by treating an alkaline solution of the phenol with a benzyl halide. ... 

The formylbenzenesulfonate prepared from a phenol (2-CHO-QH4SO2CI, Et3N) can be cleaved with NaOH (aq. acetone, rt, 5 min) in the presence of a hindered acetate. ... 

An example of what can happen in a production situation is provided in Fig. 1. This photo shows the devastation resulting from a phenol-formaldehyde reactor explosion that occurred at the Borden Chemical plant in Demopolis, Alabama on June 28, 1974. In this explosion, the stainless steel reactor was blown to bits. The reactor operators control room was obliterated. Two people were killed and several others were injured. All nearby property was demolished and windows were broken in homes for a distance of five miles from the plant. 

From this discussion, the limitations of the force field should have become clear. There is no such thing as a universal force field which describes every system in every condition. The force field is a function with few adjustable parameters and can, therefore, not be expected to reproduce all properties of all chemical species under all circumstances. This means, for example, that an OH group in an aliphatic alcohol will have to be treated differently from a phenolic OH or from the OH of a carboxylic acid group. Similarly, the density and temperature window of a force field is often limited [22]. 

The tetrahydropyranyl ether, prepared from a phenol and dihydropyran (HCl/EtOAc, 25°, 24 h) is cleaved by aqueous oxalic acid (MeOH, 50-90°, 1-2 h). Tonsil, Mexican Bentonite earth, HSZ Zeolite, and H3[PW,204o] have also been used for the tetrahydropyranylation of phenols. The use of [Ru(ACN)3(triphos)](OTf)2 in acetone selectively removes the THP group from a phenol in the presence of an alkyl THP group. Ketals of acetophenones are also cleaved. ... 

The ethoxyethyl ether is prepared by acid catalysis from a phenol and ethyl vinyl ether and is cleaved by acid-catalyzed methanolysis. ... 

The most common crosslinking agent for novolac resins is HMTA which provides a source of formaldehyde. Novolac resins prepared from a phenol-formaldehyde (F/P) ratio of 1/0.8 can be cured with 8-15 wt % HMTA, although it has been reported that 9-10 wt % results in networks with the best overall performance.3... 

While ESIPT from a phenolic OH to a carbonyl group is a common and efficient process, the highly reversible nature of the reaction often precludes any further reactivity, except in rare cases. For this reason, this reaction is not commonly used to generate or study quinone methides. 

The ability to photogenerate quinone methides via ESIPT from a phenol OH to an aromatic carbon atom was explored for a wider number of substrates by Wan s... 

Scheme SO. Synthesis of the ochotensimine analog 288 from a phenolic protoberberine by base-induced rearrangement. Reagents a, LAH b, Mel c, HBr d, NaOH, aq EtOH e, DMSO.

The CLD methods for HPLC using isoluminol (190) with microperoxidase catalysis, for determination of lipid hydroperoxides in clinical fluids, have been reviewed. Determination of phospholipids hydroperoxides by luminol (124) CL has been reviewed . A fast RP-HPLC method (retention times 1 to 2 min) for determination of hydroperoxides and other peroxide compounds includes UVD, which is not always effective, and CLD, attained on injection of luminol (124), the CL reagent (Scheme 3), hemin (75a), a catalyst, and NaOH to raise the pH of the solution. A FLD cell may act as CLD cell if the excitation source is turned off. The selectivity of CLD is of advantage over UVD in industrial analysis thus, for example, UVD of a sample from a phenol production line based on cumene oxidation (equation 13) shows peaks for cumyl hydroperoxide (27), unreacted cumene, cumyl alcohol and acetophenone, whereas CLD shows only the 27 peak. The... 

A particularly useful chromene synthesis involves the thermal rearrangement in an inert solvent of aryl propargyl ethers (33) (62CPB926,63CPB1042) which are conveniently prepared from a phenol and a chloroalkyne. An indication of the ease of cyclization is apparent from the presence of chromene in the ethers prepared in this manner. 

Hydroxybenzopyrylium salts result when a 1-aryl-1,3-diketone is cyclized with perchloric acid. This route is attractive since a sequence of acylation, Fries rearrangement and a second acylation leads directly to the salt from a phenol (71CHE1587). 

CA 20, 1141(1926)(Description of chlorate expls used in Russia) F)A.C.Scott Mexco, Ltd, BritP 248089(1926) CA 21, 652(1927) (Crysts of O-carrying substs, such as K chlorate are coated with synthetic resin such as may be formed from a phenol, a phenol formaldehyde, or from urea or thiourea. Other ingredients such as MNN, DNT, a perchlorate or woodmeal may be added) G)Dr. Roman, NC 3, l6l-3(1932)(Compn props of some chlorate... 

There is one example in which an ethoxyethyl (EE) protecting group is removed from a phenol during a Mukaiyama oxidation. According to the authors, this deprotection is promoted by a selective complexation of one oxygen with a magnesium atom.80... 

Rearrangement of aryl propargyl ethers.1 Claisen rearrangement of the naphthyl propargyl ether 1 at 215° results in the benzopyran 2 as the only isolable product (40% yield). Addition of 1 equiv. of CsF results in the benzofuran 3 as the major product, presumably formed via an a-allenyl ketone (a). Related salts such as KF, RbF, or BaF2 are completely ineffective. This modified Claisen rearrangement provides a route to o-hydroxy aldehydes such as 4 from a phenol. 

The present method gives better yields and is a simpler procedure than those described previously. The ease of preparation of a-chloro ethers enables one to effectively remove a protecting methyl group from a phenol.2 a-Chloroanisole is used to produce phenoxycarbene, a reactive intermediate in cyclopropane synthesis.5... 

Mechanical Properties and Fracture Behavior. Until recently, little was known about the sequence of fracture behavior that occurs in the 2D composites that are used to fabricate large C-C structures, such as the exit cones of rocket engines. In such composites, the yarns in the cloth are held together by a carbon matrix derived from a phenolic resin filled with carbon particles. 

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