Hydro xylamine

Although the yields of 38 were high, the oxindole (39) was also formed as a by-product. This exemplifies the problem of reducing the nitro group specifically to a hydro xylamine. 

Nitroso compounds and hydroxylamines can be reduced to amines by the same reagents that reduce nitro compounds (19-41). One example reduces a hydro-xylamine to the amine with CS2 in acetonitrile. N-Nitroso compounds are similarly reduced to hydrazines ... 

Treatment of the anthraquinone-based a,/3-unsaturated ketone 277 with hydrazine, phenylhydrazine, and hydro-xylamine is reported to give the corresponding pyrazolo- and isoxazolo-fused ring systems <2002JCCS387> (Scheme 75). 

Following a similar approach, the first bis(triorganosilyl) diazene 402 that is stable at room temperature could be obtained.410 Thus, the reaction of (/-Bu2MeSi)HNNH(SiMe/-Bu2) 403, an analog of 399, with 2 equiv. of BuLi has provided (/-Bu2MeSi)LiNNLi(SiMe/-Bu2) 404, whose oxidation with bromine has led to the formation of the diazene /-Bu2MeSiNNSiMe/-Bu2 402 (Scheme 58). Recently, the stepwise synthesis of cyclic and open-chain silyl hydro-xylamines has been reported by Klingebiel < / /.411 14 For hypervalent silyl hydroxylamines, see Section 6.8. 

The migration of a C=C bond to form a C=N bond was also observed with hydro-xylamine [78, 79], hydrazine [80, 81] and primary amines [82]. The /f iminylphos-phine oxide formed in the reaction may serve as a Wittig reagent in the presence of a base to react with a ketone or an aldehyde leading to ,/fun saturated alkenyl-imines 153 (Scheme 10.74). The phosphorus group can be a phosphonium salt as well as a phosphonate. 

The photolysis (366 nm) of nitrobenzene in 2-propanol leads to phenyl hydro-xylamine as the first stable and identifiable product The initial stages of the reaction are conveniently depicted as follows ... 

The synthesis of isoxazolines and pyrazolines via the Michael addition of hydro-xylamine and phenyl hydrazine to chalcones and related enones was also reported with activated Ba(OH)2 as a basic catalyst (293) (Scheme 45). In both cases, reactions were performed at reflux of ethanol, and excellent yields (65-80%) with 100% selectivity to the heterocyclic compounds were observed. Steric hindrance associated with the carbonyl compound as well as the electronic character of the substituents in the aromatic ring slightly affected the yields of the heterocyclic compounds. 

Preparation of nitrile acetates from oximes with sodium acetate and acetic anhydride. Pentaacetyl-v-glucononitrile. If only the nitrile is needed, isolation of the oxime can be avoided. One hundred grams of anhydijous n-glucose was dissolved in 50 ml. of warm water, and maintaining the temperature at 60°, a solution of 28 g. of hydro-xylamine in 700 ml. of ethanol was added sufficiently slowly that no precipitation took place. After one hour at 65°, the reaction mixture was concentrated under reduced pressure to a thick sirup. The residue was mixed with absolute ethanol, the ethanol evaporated and the operation repeated in order to eliminate all water. One hundred and twenty grams of anhydrous sodium acetate and 700 ml. of acetic anhydride were added to the sirup, and the mixture was slowly and cautiously warmed in a water bath to 95°. It was advisable to agitate the flask continuously and to watch the... 

Benzyl -o-xylopyranoside was converted into the alcohol 54 (a somewhat capricious isopropylidenation) [39] and a Mitsunobu inversion with N-hydroxyphthalimide, followed by protecting group removal, gave the hydro-xylamine 55. Transfer-hydrogenation (ammonium formate and palladium-on-charcoal in refluxing methanol) [40] then gave, on a small scale and in almost a quantitative yield, the enantiomer of the desired tetrahydro-l,2-oxazine 52. We have never been able to repeat this result since Figure 4 shows the NMR spectra acquired at the time [41]. 

Filter off the precipitated crystals, collect them (carefully, hydro-xylamine is poisonous ), weigh them, and calculate the yield in per cent. Examine the shape of the crystals under a microscope. Write the equations of the reactions. 

The structure of these compounds remained obscure for a long time. Traube originally assigned the structure —N—N—OH to the isonitramino group, but in further researches he found that isonitramines and the derivatives of nitrosohydro-xylamine which he prepared by the action of nitrous acid on -derivatives of hydro-xylamine were identical. He did not, however, draw from this any definite conclusions as to the structure of isonitramines in spite of the fact that by the synthesis of isonitraminoisobutyric acid, Gomberg [63] had confirmed the nitrosohydro-xylamine structure of the isonitramino group. 

The quantitative test, known as the hydro-xylamine hydrochloride test (Refs 8 16) or as the oximation method (Refs 15 20) is based on the following equation ... 

In addition to primary or secondary amines, attachment of hydro-xylamine, hydrazines, sulfoximines, or phenols proceeds equally well (Scheme 10). Secondary amines can be cleaved directly from the resin, while primary amines give rise to a different reaction pathway (see below). 

The butadiene (80%)-acrylonitrile(17%)-aerylamidoxime(3%) terpolymer was prepared by reacting 2.5g butadiene 80%)-acrylo-nitrile(20%) copolymer (Aldrich) in 150 ml xylene with 1.61g hydro-xylamine hydrochloride in 12 ml n-butanol (freed of HC1 immediately before addition by method of Hurd (4) by dropwise addition under nitrogen. Reaction time and temperature were 23 hr. and 90-95°C. The polymer product was worked up by slowly adding the reaction mixture to 500 ml ether with rapid stirring. The precipitated polymer was allowed to settle, the supernate decanted and the polymer resuspended and washed with two 100 ml portions of ether followed by vacuum drying. Yield 2.04g (81%). Conversion of nitrile functional groups to amidoxime groups was 15% by infrared absorption. 

The butadiene 55%)-acrylonitrile 38%)-acylamidoxime(7%) terpolymer was prepared by reacting 2.00g butadiene 55%)-acrylni-trile(45%) copolymer in 50 ml tetrahydrofuran with 1.46g hydro-xylamine hydrogen chloride (freed of HC1 (5)) in 12 ml n-butanol at 70°C for 18 hrs. under nitrogen. The product was worked up analogously to the 3% amidoxime terpolymer. Yield and conversion to amidoxime were 2.02g (91%) and 15%, respectively. 

AminoFA (659) was prepared directly from FA by amination with hydro-xylamine O-sulphonic acid in dilute sodium hydroxide. Rearrangement of (659) to the hydrazino analogue (660) was then smoothly effected under acidic conditions (a base-induced Dimroth rearrangement was not successful) (Scheme 3.145) [265],... 

Hydro xylamin-O-sulfinsaure und etwa 10% zum Betain der Amido-sulfonsaure umsetzen lassen (9) ... 

Hydro xylamin N,N-Bis-[trifluorme-thyl]-0-(4-chlor-benzyI)- E16a, 300 (O-Benzylier.)... 

SYNS BIS(HYDROXYLAMINE) SULFATE HYDRO-XYLAMINE NEUTRAL SULFATE HYDROXYLAMINE SULFATE HYDROXYLAMINE SULFATE (2 1) HYDROXYLAMMONIUM SULFATE... 

The same methodology was employed by Tiecco to effect the cyclizations of 0-allyl oximes 164 indicated in Scheme 25. Treatment of the intermediate iminium salt 165 with sodium borohydride affords M-alkyl isoxazolidines 166 [95]. Alternatively, 165 can be treated with water to produce M-unsubstituted isoxazolidines 167 [96]. This synthesis of M-alkyl isoxazolidines represents a valid alternative to that described in Scheme 23. Moreover, the present cyclization reaction is much more stereoselective than the cyclization of 0-allyl hydro-xylamines. In fact, when the methyl derivative 168 was employed, the two isomeric isoxazolidines 153 and 154 were obtained in a ratio of 95 5. The same two products were, in contrast, formed in a 1 1 ratio when the reaction was carried out starting from the corresponding 0-allyl hydroxylamines. Clearly, the steric requirements for the selenium-induced cyclization of the 0-allyl oximes are much greater than those for the corresponding 0-allyl hydroxylamines. 

In light of your answ cr to Problem 19.56, propose a mechanism for the formation of 3,5-dimethyliso.xazole from hydro.xylamine and 2,4-pentanedione. 

The intermediate X, present in low concentration, is probably an aryl hydro-xylamine-O-sulphonate. The further oxidation products consistmainlyof polymeric humic acid. The stationary-state approximation applied to [X] shows that the ratio of the rate of formation of o-amino aryl sulphate to the rate of formation of other products is k3/k2[S20g ]", in qualitative agreement with the dependence of the yield of o-amino aryl sulphate on peroxodisulphate concentration, and the deviation from first-order kinetics with respect to peroxodisulphate towards the end of a run. 

---