O-Benzoyl hydroxylamine

Recently, a new method for synthesis of tertiary amines 326 from iV,iV-dialkyl O-benzoyl hydroxylamines 325 was proposed.425 The protocol is based on the copper-catalyzed reaction of hydroxylamines 325 with dialkyl- and diarylzinc reagents (Scheme 166). It is noteworthy that alkyl- and phenylzinc halides also reacted with compounds 325, however, yields were significantly lower than those for ZnR2 (18-29% vs. 69-98%). 

An alternative strategy preventing fnrther oxidation of hydroxylamines is based on concomitant O-protection of the hydroxyamino gronp. Reaction of primary amines with benzoyl peroxide affords O-benzoyl hydroxylamines of type 139 (equation 92) that can be deprotected under mildly basic conditions. The oxidation is compatible with a number of functionalities and does not interfere with other functionalities snch as an isolated double bond in the molecule of amine. This reaction is versatile and a number of hydroxylamines has been prepared in this way, although yields are only moderate in most cases . Oxidation of secondary amines with benzoyl peroxide is also possible and usually proceeds in better yields. 

Berman and Johnson observed that amination of phenylzinc halide and n-butylzinc chloride with A-benzoyloxymorphoUne 2a and A,A-dibenzyl O-benzoyl hydroxylamine 2f, respectively, under Cu catalysis was not effective (equation 7) . 

Enehydroxylamine 0-derivatives 149 and 151, prepared from the reactions of A-alkyl-3-(hydroxyamino)cyclohex-2-enone (148, R = H) and iV-alkyl-3-(hydroxyamino)-5,5-dimethylcyclohex-2-enone (148, R = Me) with MsCl (equation 41) and Mc2NC(S)Cl (equation 42), respectively, in the presence of base rearrange spontaneously providing the corresponding [3,3]-sigmatropic rearranged products 150 and 152 in moderate to excellent yield . However, the diethyl phosphate 153 (equation 43) and the O-benzoyl hydroxylamine 154 rearrange under reflux in toluene (equation 44). 

Milewska and Chimiak utilized oxidation of the co-amine group of amino acid derivatives with benzoyl peroxide in a new synthesis of useful derivatives of N -hydroxyornithine and N -hydroxylysine (223). The desired O-benzoyl hydroxylamine derivatives were the main products formed on oxidation. The O-benzoyl group and other protective groups may be removed easily after acetylation. It should be added that oxidation of a-amino acid esters under the same conditions leads to N-benzoylamino acid esters only (224). 

Related Reagents. O-Mesitylsulfonylhydroxylamine Hy-droxylamine C -Sulfonic Acid O-Tiimethylsilylhydroxylamine O-Benzoyl Hydroxylamine. 

Umpolung Cross-Coupling Johnson and coworkers reported electrophilic amination of organozinc nsing o-benzoyl hydroxylamine as electrophilic nitrogen (Scheme 20.26) [56]. This process allows the facile synthesis of sterically hindered amines via ort/io-metalation/frans-metalation/catalytic amination. 

N-Diphenylmethylen- 374 N-Diphenylmethylen-O-aminocarbonyl- 612 N-[l,3-Diphenyl-propyl-(2) - 374 N-[l,3-Diphenyl-propyliden-(2)]- 374, 377, 380 N-(4-Halogen-phenyI)- 683 N-Heptyl- 375 N-Heptyl-N-acetyl- 376 N-Heptyliden- 375 N-Hcptyliden-O-acetyl- 376 0-(2-Hydroxy-athyl)-N-athoxycarbonyl- 133 N-(4-Hydroxy-phenyl)- 683 0-(2-Hydroxy-l-phenyl-athyI)-N-athoxycarbonyI-aus 0-(ci-AthoxycarbonyI-benzyl)-N-athoxycar-bonyl-hydroxylamin und Lithiumalanat 133 N-Isopropyl- 682 N-Isopropylidcn- 613 N-Methyl- 133, 682 O-Methyl-N-bcnzyliden- 377 O-Methyl-N-benzyliden- 375 0-Methyl-N-(4-chlor-benzyl)- 375 0-Methyl-N-(4-chlor-benzyliden)- 375 N-Methy -N,0-diacetyI- 682 N-(4-Methyl-phenyl)- 683 0-McthyI-N-( 1 -phenyl-athyliden)- 375 N-(4-Methylthio-phenyl)- 684 N-(4-Nitro-benzyl)- 374 N-[4-Nitro-benzyliden - 374, 377 N-(2-Nitro-phenyl)- 562 N-(4-Nitro-phenyl)- 682 N-Nitroso-N-cyclohexyl- 697 N-Octyl- 374 N-Octyl-(2)-N-acetyl- 376 N-Octyliden- 374 N-0ctyliden-(2)-0-acctyl- 376 N-(Pentafluor-phenyl)-0,N-diacetyl- 697 N-Phenyl- 474, 481, 682, 783 N-Phenylacetyl-O-benzoyl- 265 N-(l-Phenyl-athyl)- 374 N-(l-Phenyl-athyl)-N-acetyl- 376 N-(l-Phenyl-athyliden)-374, 613 N-( l-Phenyl-athyliden)-0-acetyl- 376 N-[ 1 -Phenyl-buten-( 1 )-yl-(3)-iden]- 582 N-f4-Phenyl-butyl-(2)-iden]- 581 N-Phcnyl-N,0-diacetyl- 682 N-(4-Phenylthio-phenyl)- 684 N-Propyl-N-cyclohexyl- 376 N-Propyl-N-isopropyl- 376 O-Sulfonyl- 481 N-(4-Sulfonyl-phenyI)- 683 N-(2-Vinyl-phenyl)- 698... 

An O-labelling investigation of the oxygen to sulfur transposition in the base-catalysed rearrangement of o-benzoyl-A-(diphenylphosphinothioyl)hydroxylamine (200) to (201) has been undertaken. The labelling results are outlined in Scheme 70 although further evidence is required to substantiate the mechanism... 

Harger has studied the rearrangement of A-substituted N-phosphinoylhydroxylamines in the presence of base . He proposed a concerted mechanism based on the observed retention of the configuration at the phosphorous center during the transposition , and on studies with 0-labelled compounds . Similar cyclic transition states 572 were proposed in the base-induced rearrangement of A,0-bis(diphenylphosphinoyl)hydroxylamines (571) (equation 254). However, in the rearrangement of O-benzoyl-A-(diphenylphosphino-thiol)hydroxylamine where a transposition of O and S atoms occurs, the proposed cyclic transition state has sulfur participation . 

Benzoyl-l-(4-brom-phenyl)-4,5-dimethyl-l. 2,3,6-tetrahydro-pyridin (52% bez. auf die Gesamtreaktion)2 2- Benzoyl-4,5-dimethyl-1-( 4-methyl-phenyl)-l, 2,3,6-telrahydro-pyridin (36% bez. auf die Gesamtreaktion)2 2-Benzoyl-4,5-dimethyl-l-phenyl-l,2,3,6-tetrahydro-pyridin (52% bez. auf das intermediate O-Silyl-hydroxylamin-Derivat)2... 

Hydroxylamin O-Benzoyl-N-tert.-butyl- X/l, 1232f. (N-Benzoy-loxylier.) E5. 775 (O-Acylier.) Isoquinolin (4aR, 8a5 )-l-Ethoxy-... 

Preparation. The reagent is obtained by a general method developed by Carpino for the synthesis of 0-aroylhydroxylamines as illustrated for O-benzoylhydroxyl-amine (5). f-Butylazidoformate (I) on treatment with hydroxylamine hydrochloride and alkali affords f-butyl N-hydroxycarbamate (2). Benzoylation in the presence of triethylamine gives the O-benzoyl derivative (3). Cleavage with hydrogen chloride... 

The O-carboxyhydroxamic acid, prepared by treatment of pyrazine 2,3-dicarboxylic acid anhydride with hydroxylamine, gives an O-benzoyl derivative. This forms a sodium salt which is isolated as a methanolate and which on heating in boiling toluene gives a mixture of 24% 3-aminopyrazine 2-carboxylic acid and 55% of the corresponding methyl ester (Scheme 20a).253a... 

Besides BPHA, many other hydroxylamine derivatives have been proposed for determining vanadium, including A-cinnamoyl-A-phenylhydroxylamine (CHCI3, e = 6.3-10 ) [34], A-benzoyl-A-(o-tolyl)hydroxylamine [35], and A-(/n-tolyl)-A-phenylhydroxylamine [36]. 

Other methods, among which thermolysis or photolysis of tetrazene [59], photolysis of nitrosoamines in acidic solution [60], photolysis of nitrosoamides in neutral medium [61], anodic oxidation of lithium amides [62], tributylstannane-mediated homolysis of O-benzoyl hydroxamic derivatives [63, 64], and spontaneous homolysis of a transient hydroxamic acid sulfinate ester [65] could have specific advantages. The redox reaction of hydroxylamine with titanium trichloride in aqueous acidic solution results in the formation of the simplest protonated aminyl radical [66] similarly, oxaziridines react with various metals, notably iron and copper, to generate a nitrogen-centered radical/oxygen-centered anion pair [67, 68]. The development of thiocarbazone derivatives by Zard [5, 69] has provided complementary useful method able to sustain, under favorable conditions, a chain reaction where stannyl radicals act simply as initiators and allow transfer of a sulfur-containing... 

O-Acetyl-N-methyl-hydroxylamin N-Methyl-O- (phenylacetyl )-hydroxy Iambi O-Benzoyl-N-methyl-hydroxylamin... 

Anthrapoyl-phenylanthranila pie 14, 360, N-Hiepyl-N-apilinoiormyl-O-benzoyl-hydroxylanun 1 10. N-Phepyl-O-anilinoiannyl-N-baizoyl-hydroxylamin 16,10. 

On this basis the extent to which an enzyme-catalyzed transamidation will occur will depend on the relative concentration of water and the replacement reagent, and the relative affinity of the replacement agent for the ES-complex. Durell and Fruton (51) have studied papain-catalyzed hydroxamic acid formation from o-benzoyl-L-argininamide. Their calculations show that hydroxylamine is about 420 times more efficient in its reaction with the enzyme-substrate complex than is water. Preliminary observations suggest that when amino acid amides or peptides are the attacking molecule the efficiency is even greater. Moreover, papain is a much more effective catalyst for transamidation than trypsin. 

Hydroxylamine, O-acetyl-A -benzoyl-.V-phenyl-hydroxamic acids from, 2, 506... 

O -Benzoyloximcs are nicely reduced to <9-benzoyl hydroxy lamincs with EtsSiH/TFA (Eq. 328) 550,551 <9-Acetyl oximes arc reduced with Et3SiH/TMSOTf in moderate to high yields.552 The diethylphosphatoimine 88 is reduced to the hydroxylamine derivative.553... 

The best way to prepare 3-amino-5-phenyloxadiazole is the action of hydroxylamine on N-benzoyl-O-ethylisourea 25f). 

Hydroxylamine, O-acetyl-N-benzoyl-N-phenyl-hydroxamic acids from, 506 Hydroxylamine ligands, 101 Hydrozirconation, 342 Hypoxanthines metal complexes, 93... 

Hydroxylamin N-(Cyan-ethoxy-carbonyl-methylen)-0-(4-nitro-benzoyl)- E5, 780 (OH - O-CO-Ar)... 

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