Hydrogen peroxide 2-hydroxy

Ethers of benzenepentol have been obtained by Dakin oxidation of the appropriately substituted acetophenone. Thus, the oxidation of 2-hydroxy-3,4,6-ttimethoxyacetophenone and 2-hydroxy-3,4,5-ttimethoxyacetophenone with hydrogen peroxide ia the presence of alkali gives l,2-dihydroxy-3,4,6-ttimethoxybenzene and l,2-dihydroxy-3,4,5-ttimethoxybenzene, respectively further methylation of these ethers yields the pentamethyl ether of benzenepentol (mp 58—59 degC) (253). The one-step aromatization of myoinositol to produce esters of pentahydroxybenzene is achieved by treatment with carboxylic acid anhydrides ia DMSO and ia the presence of pyridine (254) (see Vitamins). 6-Alkyl- or... 

In the flask are placed 60.8 g. (0.4 mole) of 2-hydroxy-3-methoxybenzaldehyde (Note 2) and 200 ml. of 2N sodium hydroxide (0.4 mole). The mixture is stirred until almost all the solid has dissolved. The stirrer is replaced by a dropping funnel which contains 284 ml. (0.5 mole) of 6% hydrogen peroxide (Note 3). With occasional shaking, the hydrogen peroxide is added in portions of 20-25 ml. About 1 hour is required for the addition the temperature is kept between 40 and 50°. After the addition of the first portion of hydrogen peroxide, the temperature rises to about 45° and a dark solution results. The temperature is allowed to fall to 40° before the next portion of the peroxide is added. 

A solution of testosterone (54 10 g) in 300 ml methanol is cooled to 0° and treated successively with 60 ml of cold 30 % hydrogen peroxide and 20 ml of cold aqueous 10% sodium hydroxide. The reaction mixture is stored for 48 hr at 0° and then poured into ice water. The resultant oil is extracted with methylene dichloride (or ether) and the extract is dried (MgS04). Removal of the solvent affords the crude product, a mixture of 4a,5a- and 4, 5 -isomers, which is purified by chromatography. A sample of pure 17j5-hydroxy-4/3,5 -oxidoandrostan-3-one, mp 157-158°, crystallizes after trituration of the crude product with ether. 

P-Hydroxy-A-norpregn-3(5)-en-2-one (7) A solution of the hydroxy-methylene steroid (5) (24.8 g) dissolved in 240 ml of acetic acid and 240 ml of ethyl acetate is ozonized at — 10° with one molar equivalent of ozone. The resulting solution is diluted with 240 ml. of water and 60 ml of 30 % hydrogen peroxide and allowed to stand overnight. The solution is diluted with 1.5 liters of water and extracted with 3 x 700 ml portions of ethyl acetate. The combined extracts are washed with water, saturated sodium chloride solution, dried over sodium sulfate and concentrated to dryness under vacuum, leaving 23.4 g of a colorless amorphous residue of crude diacid. This material shows a maximum in the ultraviolet spectrum at 224 mp (s 6,400) indicating a 53 % yield of unsaturated acid (6). It is used without further purification. 

Acetylenedimagnesium bromide, 66, 84, 137 Acyl-alkyl diradical disproportionations, 299 Acyl-alkyl diradical recombination, 296 Alkaline hydrogen peroxide, 10, 12, 20 Alkylation of formyl ketones, 93 Alkylation via enolate anions, 86 17a-Alkynyl steroids from 17-ketones, 67 2a-Al]yl-17jS-hydroxy-5a-androstan-3 -one, 9 5 Allylic acetoxylation, 242 Allylmagnesium bromide, 64 17 -Aminoandrost-5-en-3 -ol, 145 17 a-Aminomethy 1-5 a-androstane-3, 1718-diol, 387... 

D-homosteroids, 382 Hydrazoic acid, 27, 145 Hydriodic acid, 172 Hydroboration, 165, 166 Hydrogen peroxide, 221 Hydrogen transfer, 239 17 i3-Hydroxy-2-acety l-5a-androstan-3 -one acetate, 342... 

The presence of 9a-fluorme in the molecule of a 1 iP-hydroxy-8 -3-keto steroid causes completely stereospeafic alkalme epoxidation with hydrogen peroxide m a much slower reacuon (4 days vs 4 h) compared with the nonfluonnated analogue [21]... 

Ruormated benzaldehydes are easily oxidized to peroxy compounds with 30% hydrogen peroxide, oxidahon with concentrated hydrogen peroxide leads to geminal hydroxy hydroperoxides [69] (equation 61)... 

AMcycUc perfluoroketones undergo similar oxidation reactions as aromaUc fluoroaldehydes (equation 61). a lower concentration of hydrogen peroride oxidizes the ketones to a-hydroxy hydroperoxides [72], whereas concentrated hydrogen peroxide converts them to I,l -dihydroxydi(petfluorocycloalkyl) peroxides [16, 73] (equation 64). 

The conversion of 2 -hydroxychalcones to 2-aryl-3-hydroxy-4f/-lbenzopyran-4-ones (flavonols) by alkaline hydrogen peroxide oxidation is known as the Algar-Flynn-Oyamada (AFO) reaction or AFO oxidation. ... 

The AFO reaction has seen very few variations since it was first reported in 1934. However, the most significant modification was reported in 1958 by Ozawa and further elaborated by Smith and others. Prior to this modification the intermediate chalcones were purified and then subjected to hydrogen peroxide in a basic medium. With the modification, the chalcone was generated in situ, from an aldehyde and a hydroxyacetophenone, and then allowed to react with aqueous hydrogen peroxide in the presence of sodium hydroxide to deliver the flavonol. Smith and coworkers conducted a limited study to examine the scope and limitations of this modification.Flavonols were delivered in 51-67% however, no flavonols were isolated with highly reactive aldehydes such as p-nitrobenzaldehyde and when 2-hydroxy-4-methoxyacetophenone was used. 

Tamaoku and colleagues presented an efficient enzymatic photometric determination of hydrogen peroxide ffiat is essentially a color reaction resulting from the oxidative condensation of A/-ethyl-A/-(2-hydroxy-3-sulfopropyl)aniline derivatives wiffi 4-aminoantipyrine in the presence of hydrogen peroxide and peroxidase (82CPB2492). A similar calorimetric detection of hydrogen peroxide has been patented (83GEP3301470). 

The Dakin reaction proceeds by a mechanism analogous to that of the Baeyer-Villiger reaction. An aromatic aldehyde or ketone that is activated by a hydroxy group in the ortho or para position, e.g. salicylic aldehyde 12 (2-hydroxybenzaldehyde), reacts with hydroperoxides or alkaline hydrogen peroxide. Upon hydrolysis of the rearrangement product 13 a dihydroxybenzene, e.g. catechol 14, is obtained ... 

As in the case of the steroids, introduction of additional nuclear substituents yields morphine analogs of increased potency. The more important of these are derived from one of the minor alkaloids that occur in opium. Thebaine (14), present in crude opium in about one-tenth the amount of morphine, exhibits a reactive internal diene system that is well known to undergo various addition reactions in a 1,4 manner (e.g., bromination). Thus, reaction with hydrogen peroxide in acid may be visualized to afford first the 14-hydroxy-6-hemiketal (15). Hydrolysis yields the isolated unsaturated ketone (16). Catalytic reduction... 

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