Silver oxide oxidation with

An important mode of oxidation for -phenylenediamines is the formation of ben2oquinonediimines, easily obtained by oxidation with silver oxide in ether solution (17). DHmines undergo 1,4 additions with amines to generate tri- and tetraamines which readily oxidi2e in air to highly conjugated, colored products. An example of this is the formation of Bandrowski s base [20048-27-5] when -phenylenediamine is oxidi2ed with potassium ferricyanide (18). 

Other Methods of Preparation.—The ethyl 2-(D-oro6fno-tetrahydroxybutyl)-5-methyl-4-furoate may also be oxidized with hydrogen peroxide in alkaline medium, to give 5-methyl-2,4-furandicarboxylic acid, but the yield is lower.6 On the other hand, when 2-(4-carboxy-5-methylfuryl-2)-diglycolaldehyde (XXXVI) is oxidized with 6% hydrogen peroxide in alkaline solution at 0°, the acid III is obtained in a yield of 65% of the theoretical.60 The same acid is obtained when ethyl 2-formyl-5-methyl-4-furo-ate (V) is oxidized with silver oxide in alkaline medium.7... 

Transformations of Methyl 5-0-Benzyl-2-0-methyl-/3-I)-glueofuranosidurono-6,3-lae-tone (86) to Dimethyl (Z,E)-2-Methoxy-5-(phenylmethoxy)-2,4-hexadienedioatevl (87). ( Elimination employing DBU b oxidation with silver oxide-sodium hydroxide followed by diazomethane esterification c acidic glycoside cleavage, oxidation by dimethyl sulfoxide-acetic anhydride with formation of 5-0-benzyl-2-0-methyI-D-glucaro-1,4 6,3-dilactone, elimination by using DBU, followed by short treatment with diazomethane d elimination by DBU with subsequent diazomethane esterification e sodium borohydride in hexamethylphosphoric triamide 1 catalytic oxidation followed by short treatment with diazomethane " dimethyl sulfoxide-sulfur trioxide-pyridine-triethylamine.150)... 

Table 1 Comparison of the yields of iso and normal types of oxazolidine ring when alkaloids are oxidized with, silver oxide and with potassium ferricyanide...

The structure of this base (142) was determined by spectral methods and the aldehyde portion was converted to carboxyl by oxidation with silver oxide ISO). 

Fig (25) Catechol (201) on oxidation with silver oxide generates 3-isopropyl-o-benzoquinone (199) which undergoes ultrasound-promoted cycloaddition with 6,6-dimethyl-1 -vinylcyclohexene (200) yielding the synthesis of miltirone (197). 

Periodate oxidation of the ring in LXI led to sirupy n-2-phenyldigly-colaldehyde (LXIV), which in turn was oxidized with silver oxide to sirupy D-2-phenyldiglycolic acid (LXV). The latter was converted through its ester (LXVI), to crystalline D-(+)-2-phenyldiglycolamide (LXVII), m. p. 172-172.5°, [a]KD 102.2° (ethanol). 

The 1-phenyl 3-carboxaldehyde, was found to resist oxidation with silver oxide or selenium dioxide, but was destroyed with permanganate. °9 H as recently converted to l-phenyl-4-methyl-7-azaindole-3-acetic acid and l-phenyl-4-methyl-7-azatryptophan via its azlactone derivative. 9 ... 

Ozonolysis of the phenanthrene alkaloid 206, easily obtained by base treatment followed by acetylation of the aporphine magnoflorine, gives dialdehyde 207 (Scheme 5). Aldehyde oxidation with silver oxide, followed by hydrolysis... 

The lactols 38 obtained were oxidized with silver oxide to optically active 3-alkylphthalides 39 in 80—81% yield without racemization. The absolute configuration of 3-n-butylphthalide 39b was determined by comparison with literature data [53]. 

The domain of oxidations with silver oxide includes the conversion of aldehydes into acids [63, 206, 362, 365, 366, 367 and of hydroxy aromatic compounds into quinones [171, 368, 369]. Less frequently, silver oxide is used for the oxidation of aldehyde and ketone hydrazones to diazo compounds [370, 371], of hydrazo compounds to azo compounds [372], and of hydroxylamines to nitroso compounds [373] or nitroxyls [374] and for the dehydrogenation of CH-NH bonds to -C=N- [375]. Similar results with silver carbonate are obtained in oxidations of alcohols to ketones [376] or acids [377] and of hydroxylamines to nitroso compounds [378]. 

Of aromatic ketone hydrazones, benzophenone hydrazone is oxidized with yellow mercuric oxide [387, 390] or red mercuric oxide [387], fluo-renone hydrazone is oxidized with mercuric oxide [5SS] or nickel peroxide [935], and di-a-thienyl ketone hydrazone and phenyl naphthyl ketone hydrazones are oxidized with silver oxide or manganese dioxide [370] (equations 459-461). 

Diaziridines and diazirines. Hydroxylamine-O-sulfonic acid and ammonia react with cyclohexanone to form 3,3-pentamethylenediaziridine, which can be oxidized with silver oxide to 3,3-pentamethylenediazitidine. The product, a liquid, is distilled... 

Hydroxycyclohexiinone reacts with Ihe reagent and ammonia to give the diuziridine In 4.5% yieldi oxidation with silver oxide gave the diu/.irine in 70% yield. "... 

Phenyllithium adds to the N=N bond of benzo[c]cinnoline giving, on work-up, the air-sensitive, 5,6-dihydro-5-phenylbenzo[c]cinnoline (53). In an attempt to generate the radical corresponding to triphenylhydrazyl from 53, Wittig and Schumacher S found that oxidation with silver oxide or lead tetraacetate produced instead the quinonimine 54, analogous to the product formed by methylating 2-hydroxybenzo[c]cinnoline (Section V,D). On reductive acetylation, the quinonimine is converted into the 5,6-dihydro... 

Diaziridines and diazirines [1,483]. A Lederle group13 investigated the reaction of hydroxylamine-O-sulfonic acid with steroid ketones and found that only noncon-jugated 2(5a)-ketones and 3(5a or 5/3)-ketones react. A4-3-Ketosteroids, 17-keto-steroids, and 20-ketosteroids were found unreactive. A solution of 502 mg. of 17a-methyl-5a-androstane-17/3-ol-3-one (1) in methanol was saturated with ammonia at 2° and treated with 236 mg. of hydroxylamine-O-sulfonic acid, added in small portions. The diaziridine (2) was oxidized with silver oxide in ether in practically quantitative yield to the diazirine (3). 

The lactols 38 obtained were oxidized with silver oxide to optically active... 

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