Hydroxy double salts

Zinc hydroxy double salts are layered materials similar to layered double hydroxides which show intercrystalline reactivity and incorporate organic compounds between layers.337 Hydroxy double salts of high crystallinity can be obtained by reacting ZnO with organic metal salts in water. Zinc oxide crystals could then be prepared by thermal treatment of hydroxy zinc acetate.338... 

A) Layered double hydroxide (LDH), (B) hydroxy double salt (HDS) and (C) hydrocalumite. 

Nanosized ZnO particles are prepared by hydrolysis-condensation at moderate temperature (from 20 to 70°C) [27-29] of zinc-acetate precursors [30] in ethanolic medium. Besides the determination of local order around Zn and of the particle sizes during the nanosized ZnO preparation, the motivation of the combined investigation was also to clarify the occurrence of a Zn-based hydroxy double salt phase, Zn5(0H)8(0C0CH3)2.2H20 (labeled hereafter Zn-HDS) observed as final solid mixed with ZnO and zinc acetate phases [29]. In particular, we were interested in determining whether the formation of the Zn-HDS phase was concomitant to the ZnO formation or arose from the reaction of ZnO with zinc acetate precursors during ageing of the colloidal suspension before extraction of solids. 

Effects of Hydroxy Double Salts and Related Nanodimensional-Layered Metal Hydroxides on Polymer Thermal Stability... 

Hara, T., Ishikawa, M., Sawada, J., et al. (2009). Creation of Highly Stable Monomeric Pd(ll) Species in an Anion-Exchangeable Hydroxy Double Salt Interlayer Application to Aerobic Alcohol Oxidation under an Air Atmosphere, Green Chem., 11, pp. 2034—2040. 

LDHs are the most investigated anion-exchangeable layered materials, but other examples of crystals belonging to this family are layered hydroxide (or basic) salts and layered hydroxy double salts. Layered phosphate and phosp-honate ° can also be nsed for the preparation of layered organo-modified derivatives through topotactic exchange reactions with anionic moieties. 

Choy, J.H. Kwon, Y.M. Song, S.W. Chang, S.H. Structural phase transformation of layered hydroxy double salts depending on hydration degree. Bull. Korean Chem. Soc. 1997, 18, 450-453. 

Calcium D-galactonate, I, 70 Calcium D-gluconate, III, 141, 142, 149, 152, 155, 156, 161 IV, 331 Calcium hypochlorite, III, 165 Calcium 2-keto-D-gIuconate, III, 148, 155 Calcium 5-keto-D-gluconate, III, 156 Calcium lactobionate, calcium bromide double salt, III, 155 Calcium Ievulinate, IV, 311 Calcium maltobionate, III, 161 Calcium D-mannonate, III, 152 Calcium pectate, I, 334 Calcium D-rhamnonate, III, 144 Calcium salts, in preparation of aldonic acids with NaCN, I, 23 Calcium vicianobionate, III, 154 Calcium D-xylonate, III, 155 Camphor, optically active, formed from inactive (racemic) camphor carboxylic acid in the presence of quinine, quinidine or nicotine, V, 53 Camphor carboxylic acid. See Camphor. Camphor, 3-hydroxy-, IV, 89 Camphorquinone, phytochemical reduction of, IV, 89... 

Folkers and coworkers - found that when sufliciently pure concentrates of streptomycin were treated with methyl orange (the sodium salt of helianthine) a crystalline salt was formed with the sulfonic acid group of this dye. On recrystallization from aqueous methanol, pure streptomycin helianthate was obtained. The helianthate could be converted to streptomycin hydrochloride, sulfate or any other suitable salt for chemical or therapeutic purposes. All of these salts with the common inorganic acids are amorphous. They - also obtained a crystalline salt of streptomycin and p-(2-hydroxy-l-napthylazo)-benzenesulfonic acid from streptomycin hydrochloride and the azo dye Orange II. Streptomycin helianthate was converted directly into a crystalline streptomycin trihydrochloride-calcium chloride double salt. The chemistry of streptomycin was thus put on a crystalline basis. 

Pyrones, which are the ring-oxygen equivalents of pyridones, are simply a- and y-hydroxy-pyrylium salts from which an 0-proton has been removed. There is little to recommend that 2- and 4-pyrones be viewed as aromatic they are perhaps best seen as cyclic unsaturated lactones and cyclic p-oxy-a,P-unsaturated-ketones, respectively, for example 2-pyrones are hydrolysed by alkali, just like simpler esters (lactones). It is instructive that, whereas the pyrones are converted into pyridones by reaction with amines or ammonia, the reverse is not the case - pyridones are not transformed into pyrones by water or hydroxide. Some electrophilic C-substitutions are known for pyrones and benzopyrenes, the oxygen guiding the electrophile ortho or para, however there is a tendency for electrophihe addition to the C-C double bond of the heterocyclic ring, again reflecting their non-aromatic nature. Easy Diels-Alder additions to 2-pyrones are further evidence for diene, rather than aromatic, character. 

Orthophosphates crystallise not only as tribasic, monohydrogen or dihydrogen add salts, but also as oxide, hydroxide or halide double salts. Calcium salts, for example, include oxyapatite, hydroxy-... 

P-Hydroxy-a-naphthaldehyde, Equip a 1 litre three-necked flask with a separatory funnel, a mercury-sealed mechanical stirrer, and a long (double surface) reflux condenser. Place 50 g. of p-naphthol and 150 ml. of rectified spirit in the flask, start the stirrer, and rapidly add a solution of 100 g. of sodium hydroxide in 210 ml. of water. Heat the resulting solution to 70-80° on a water bath, and place 62 g. (42 ml.) of pure chloroform in the separatory funnel. Introduce the chloroform dropwise until reaction commences (indicated by the formation of a deep blue colour), remove the water bath, and continue the addition of the chloroform at such a rate that the mixture refluxes gently (about 1 5 hours). The sodium salt of the phenolic aldehyde separates near the end of the addition. Continue the stirring for a further 1 hour. Distil off the excess of chloroform and alcohol on a water bath use the apparatus shown in Fig. II, 41, 1, but retain the stirrer in the central aperture. Treat the residue, with stirring, dropwise with concentrated hydrochloric acid until... 

In order to avoid as far as possible double bond positional isomers, a problem quite common in drugs with indene moieties, N-trityl-2-hydroxymethylmorpholine (23) was reacted with the potassium. salt of 4-hydroxy-1-indanone (24) in DMSO solvent to give condensation product 25 in good yield. Reduction of 25 with LLAIH produced the hydroxyindane which was dehydrated and deprotected with HCl to give indeloxazine (26) [8]. 

Comparison of results for the first and last entries in Table 7 (AOS 2024 and IOS 2024) was for samples for which the hydrophobe linearity, hydrophobe carbon number, and relative disulfonate content were held nearly constant. The major differences in these surfactants were possible differences in the relative locations of the double bond and the sulfonate group in the alkenesulfonate and in the relative locations of the hydroxy group and the sulfonate group in the hydroxyalkanesulfonate. Analyses to determine these are quite difficult. At calcium ion concentrations below 100-250 ppm, AOS 2024 appeared to be more salt-tolerant than linear IOS 2024. At higher calcium concentrations, the calcium ion tolerance of the two surfactants was similar. 

N-AryInitrones (XIII) formed by oxidation of N-hydroxy-N-methyl arylamines, show high reactivity toward carbon-carbon and carbon-nitrogen double bonds in non-aqueous media (21,203) (Figure 10). Under physiological conditions, however, it appears that N-arylnitrones exist as protonated salts that readily hydrolyze to formaldehyde and a primary N-hydroxy arylamine and efforts to detect N-arylnitrone addition products in cellular lipid, protein or nucleic acids have not been successful (204). Nitroxide radicals derived from N-hydroxy-MAB have also been suggested as reactive intermediates (150), but their direct covalent reaction with nucleic acids has been excluded (21). 

Shackelford and co-workers studied the 1,2-addition of 2,2-dinitropropanol, 2,2,2-trinitroethanol, and 2-fluoro-2,2-dinitroethanol across the double bonds of vinyl ethers. These reactions are Lewis acid catalyzed because of the weak nucleophilic character of alcohols which contain two or three electron-withdrawing groups on the carbon p to the hydroxy functionality. Base catalysis is precluded since alkaline conditions lead to deformylation with the formation of formaldehyde and the nitronate salt. 

The adrenal glands secrete over 50 different steroids, the most important of which are aldosterone and hydrocortisone. Aldosterone causes salt retention in the body. It is not commercially available. Hydrocortisone is useful for its anti-inflammatory and antiallergic activity. Cortisone and its derivatives have similar activity and it is reduced in vivo to hydrocortisone. The two substances are used to treat rheumatoid arthritis. The 11-P-hydroxyl of hydrocortisone is believed to be of major importance in binding to the receptors of enzymes. Anti-inflammatory activity is significantly Increased by various substituents 6a-fluoro, 9a-fluoro, 21-hydroxy, 2a-methyl, 9a-chloro, and a double bond at C-1. 

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