Tosylhydrazine, reactions

Hexafluoroacetone azine accepts nucleophiles (ROH, RSH, R NH) in positions 1 and 2 to yield hydrazones [27] Phosphites give open-chain products via a skeletal rearrangement [22] Radical addition reactions are also reported [22] Treatment of tnfluoropyruvates with tosylhydrazine and phosphorus oxychlo-ride-pyndme yields tnfluoromethyl-substituted diazo compounds [24] (equation 3)... 

To seek further evidence for a bromonium ion-mediated dioxabicyclization and to investigate the regioselectivity of ring closure, we studied reactions with 3,4-dibromocyclohexyl hydroperoxides411. We developed a synthesis of 3-cyclohexenyl hydroperoxide based on oxidation of the corresponding N-tosylhydrazine by the procedure of Caglioti et al.42). Anisole was the starting material and the full reaction sequence is shown in Eq. 29. 

A disadvantage of the traditional synthesis of A -alkyl-A -tosylhydrazones, particularly in the reaction of the tosylhydrazine with weakly electrophilic carbonyl compounds, is the instability of the hydrazine under the reaction conditions. However, A -alkylation of the tosylhydrazone (Table 5.23) under weakly basic condi-... 

The Shapiro reaction occurs when a tosylhydrazone 86, easily prepared from a ketone and tosylhydrazine, is treated with 2 equivalents of an ethereal solution of n-butyllithium 87, resulting first in the removal of the N—H proton to give the anion 88 and then of a one proton from the less-substituted a position to give the dianion 89. Elimination of lithium p-toluenesulfinate in the rate-limiting step gives the lithium aUtenyldiazenide 90, which suffers loss of nitrogen to afford the alkenyllithium 91 (equation 31) ° . ... 

Esckenmoser fragmentation (2, 419 422). This hydrazine can be more effective than tosylhydrazine for this fragmentation.2 Thus reaction of 1 with the a-keto epoxide 2 results in formation of l-cyclononyn-5-one (3) in about 43% yield. Another example is the preparation of 2,2-dimcthyl-5-hexynal (5) from 4. These relictions proceed in about 15- 20% yield with tosylhydrazine. 

Flavone reacts with hydroxylamine in anhydrous pyridine to give two products, the oxime (432) and isoxazole (433). The structure of the latter was confirmed by mass spectrometry. It appears from this work that 3-(2-hydroxyaryl)isoxazoles of type (430a) are not produced in the reaction of flavones with hydroxylamine (B-77MI22304). On the other hand, flavone and tosylhydrazine in hot ethanolic hydrochloric acid yield only the tosylhydrazone (434) (65TL2269). 

A 2-cyclohexenone derivative can be transformed into the corresponding epoxy tosyl-hydrazone by sequential treatment with peracid and tosylhydrazine. The elimination of nitrogen and p-toluenesulfinate and fragmentation after rearrangement to the 3-tosylazo allylic alcohol may occur under mild conditions. Carbonyl compounds with 5,6-triple bonds are formed in high yields (J. Schreiber, 1967 M. Tanabe, 1967). If one applies this reaction to a 9,10-epoxy-1-decalone, a ten-membered 5-cyclodecyn-l-one ring is formed (D. Felix, 1971). This product is an important intermediate in the perfume industry and has been used on a large scale. For this purpose Eschenmoser developed a synthesis in which the readily removed styrene was split off instead of a sulfmic acid. Thus a l-amino-2-phenylaziridine hydrazone was used instead of a tosylhydrazone (D. Felix, 1968). ... 

A paste of a mixture of aromatic aldehyde (5 mmol) and hydroxylamine (5 mmol), semicarbazide (5 mmol), or tosylhydrazine (5 mmol) in methanol (few drops) was exposed to microwaves (heating and cooling at intervals of 15 s and 1 min for the specific time). After completion of the reaction (TLC) the product was extracted with 3x5 mL CH2CI2. Removal of the solvent under reduced pressure gave pure product in excellent yields. 

Geometrical stereoselectivity can often be achieved in the condensation of unsymmetrical ketones 8 with tosylhydrazine l,2 and this feature means Shapiro reactions direct from an unsymmetrical ketone 8 via E-9 lead to the less substituted vinyllithium 11. On the other hand, a sequential alkylation-Shapiro sequence from a starting symmetrical hydrazone 12 will reliably form the more substituted vinyllithium 14 via Z-9 Retention of Z stereochemistry in Z-9 is dependent on its re-use almost immediately on standing, for example, Z-9 (R = vinyl) equilibrates to an 85 15 ratio E Z-9J ... 

Benzodiazocine 264 was prepared through a 4-component Ugi reaction including a primary amine tethered to a BOC-protected internal amino nucleophile, followed by a postcondensation base-catalyzed cyclization. Thus, 2 equiv of aldehyde 262 were employed to promote Schiff base formation and a one-pot, double scavenging protocol with immobilized tosylhydrazine and di-isopropylethylamine removed both the excess aldehyde and any unreacted acid 261. The intermediate 263 was then subjected to treatment with TFA, followed by proton scavenging with resin bound morpholine, to promote cyclization to afford the eight-membered ring (Scheme 47) <2001TL4963>. 

Amines and hydroxylamine and hydrazine derivatives react with 36 at the lactim ether group and not at the keto group76 88 [Eq. (2)]. By contrast, in the reaction between the imidochloride of isatin and tosylhydrazine (or aniline) the keto group at position 3 was found to be attacked and at the same time the imidochloride was transformed into the lactam89 [Eq. (3)]. Thus it may be argued that, at least in the case of the isatin derivatives, the lactim ether function is more reactive than the imidochloride. 

Oxidative cleavage of hydrazones. Carbonyl compounds can be regenerated from 2,4-dinitrophenylhydrazones, tosylhydrazones, or N-methyl-N-tosylhydra-zones in 80-95% yield by oxidation with sodium nitrite in TFA or HOAc (0-5°, 1-2 hours). In the case of tosylhydrazones, the other product of cleavage has been identified as tosyl azide, the product of reaction of tosylhydrazine with nitrous acid. 

N,N-Methyltosylhydrazones. Ketones react only slowly with N,N-methyl-tosylhydrazine (1) but hydrazones of this type can be prepared by N-alkylation of tosylhydrazones with phase-transfer catalysis. The more reactive thioketones also react sluggishly with 1, but in this case, the reaction can be catalyzed by soft Lewis acids. Thus the reaction of 2 with 1 proceeds in high yield at room temperature in the presence of 1 equiv. of silver nitrate. Mercuric acetate also promotes this reaction, but the yield of 3 is only 50% because of formation also of 4 in 44% yield. 

The carbonyl group of 3-thietanone reacts typically with nucleophiles such as hydrazine (to give 364), 2,4-dinitrophenylhydrazine, ° tosylhydrazine, semicarbazide, and phenylmagnesium bromide.It undergoes the Wittig reaction (e.g., the formation of 365) yields vary from 14 to 74%. Sodium hydroxide cleaves the presumed 2,2-bis-trifluoromethyl-4,4-diphenyl-3-thietanone to diphenylacetic acid. ... 

Tosylhydrazine (3.53g, 18.9 mmol) was added to 60% aqueous MeOH (46 mL) and then heated to 60 °C. The heptanone (2.33 g, 18.8 nunol) was then added dropwise to the clear solution. The reaction was then immediately stored at 5 °C for 15 h. The resultant white crystals were filtered, washed with 60% aqueous methanol, and air dried for 10 min. The hydrazone was obtained as white crystals (4.91 g, 89%). 

Hydrazine hydrate reacts with 1,3-butadiyne moieties in competition with the carbonyl groups. Therefore, tosylhydrazine is employed for the selective reaction with the latter. The sodium salts of the resulting tosylhydrazones are heated to give the diazo compounds 16,18, and 20 [8, 10]. As some of the 1,3-butadiyne derivatives in Table 11-2 undergo spontaneous polymerization in the solid state (see Section 11.4.1), they have to be kept in solution. 1,3-butadiyne units are also known to react with diazo groups [11] and therefore the diazo compounds such as 16, 18, and 20 must be kept refrigerated. 

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