Tosylhydrazones hydrolysis

This reagent was obtained either from Aldrich Chemical Company, Inc., or Lithium Corporation of America, Bessemer City, NC. A technical data sheet is available from the suppliers. Solutions of ca. 2 M were titrimetrically analyzed for active alkyllithium by the tosylhydrazone method. It is advisable to make certain that the organolithium reagent to be used was prepared in pentane solution. This evaluation can be easily accomplished by the gas chromatographic analysis of the organic layer obtained from the hydrolysis, under a nitrogen atmosphere, of the tert-butyllithium solution to be used. Isobutane and pentane should comprise essentially all of the... 

Hydrolysis of tosylhydrazones has been achieved by treatment with alkaline hypochlorite [61]. This allylic activation ensures the sp1 hybridized carbon behave as an avid acceptor. 

V-acylaziridine-2-imides to oxazoline-4-imides, followed by hydrolysis of these latter compounds, has been used586 to afford chiral / -hydroxy-a-amino acid precursors. It has been suggested587 that the observed thermal rearrangement of c/.s-aziridinyl ketone tosylhydrazones (449) to 5-alkylamino-3,5-diphenyl-l-tosyl-2-pyrazolines (450) is... 

A new selective and very mild method for the reduction of ketone tosylhydrazones to hydrocarbons offers promise for steroid chemistry reduction with catechol-borane and buffered hydrolysis gives the hydrocarbon in good yield.193 2,4-Dinitrobenzenesulphonylhydrazine is superior to toluene-p-sulphonylhydrazine for... 

Some 2-deoxy-analogues of rubrosterone have been reported.73 The synthesis commenced with a Bamford-Stevens reaction upon 3/3,17/3-diacetoxyandrost-5-en-7-one tosylhydrazone to yield the corresponding 5,7-diene. Successive chromic acid and selenium dioxide oxidation of this diene furnished the 2-deoxyrubrosterones (177 R1 = OAc, R2 = H, R3 = OH, X= 17/3-0Ac,H 5a-H) and (177 R = OAc, R2 = R3 = H, X = 17/3-OAc,H 5a-H) respectively. Alkaline hydrolysis of the latter derivative afforded an A-homo-B-nor-steroid (178). The rubrosterone (177 R1 = R2 = R3 = OH, X = O 5/3-H), which possesses antidiabetic activity, has been prepared by oxidative degradation of the cholestene (179), itself obtained from ecdy-sterone.74... 

Molybdenum hexafluoride, MoFj (mp 17 °C, bp 35 °C) [528], and molybdenum oxychloride, M0OCI3, which is prepared by the partial hydrolysis of molybdenum pentachloride [528], are suitable for the recovery of ketones from their dimethylhydrazones and tosylhydrazones under very mild conditions [525]. 

Regeneration of carbonyl compounds from tosylhydrazones. The rapid hydrolysis is carried out in methanol at room temperature (9 examples, 75-93%). 

P-Hydroxy tosylhydrazones, which are the products of a conventional aldol reaction between a dilithi-ated tosylhydrazone reagent and an aldehyde, can also be prepared by alternative routes. For example, Stork and Ponaras have described a procedure whereby an epoxy ketone is converted into an epoxy hydrazone. Subsequent addition of an alkyl- or aryl-magnesium bromide followed by hydrolysis yields either an a-alkyiated- or a-arylated-p-hydroxy ketone or an a,p-unsaturated ketone. Since the attack of the Grignard reagent on the epoxide occurs with inversion at the a-carbon, this reaction can be used to... 

The diazonium ion (141) made by protonation of diazonorcamphor in alcohol decomposes to (143), (144), and (145), via (142). The ratio of (143) and (144) to (145) varies with the nucleophilicity of the solvent alcohol. The diazonium ions (146) and (147) were made by photolysis of dimethoxynorbornanone tosylhydrazone. The former gives the same products as (141) whereas (147) gives mainly (148). Details have appeared of the hydrolysis of 4-diazoacetylcyclopentene which gives products identical to those from solvolysis of 5-oxonorbornyl-2-cndo-brosylate and different from those from the exo-isomer. The cation (149) is thought to be a common intermediate. ... 

The bicyclo[2,2,l]heptane system also continues to find employment for the assessment of new synthetic procedures, or for testing the efficacy of new reagents. Isolated yields of 50—65 % of ap-unsaturated aldehydes have been obtained by reaction of alkyl tosylhydrazones with butyl-lithium, addition of DMF, and hydrolysis however, reaction of camphor tosylhydrazone (381 X = NNHTs) according to this procedure only gave 10 % of the aldehyde (382 X = CHO), presumably because of unfavourable steric effects. " Trimethylsilyl trifluoromethanesulphonate is a mild reagent for converting carbonyl compounds into trimethylsilyl enol ethers, for example the production of (382 X = OSiMcj) from camphor (381 X = Experimental details... 

Scheme 9.14. In the top half (Part a), the formation of a toluenesnlfonylhydrazone (tosylhydrazone) derivative of ethyl phenyl ketone and p-toluenesulfonylhydrazine is shown. In the lower half (Part b), a potential path for the redaction of the tosylhydrazone with lithium aluminnm hydride (LiAUHLi) in ether solvent is presented (and the products shown are obtained after hydrolysis).

Similarly, when an aldehyde or ketone is treated with p-toluenesulfonylhydrazine (P-CH3C6H4NHNH2), a p-toluenesulfonylhydrazone (tosylhydrazone) (Scheme 9.69) is formed. Now, when this stable, easily purified carbonyl derivative is treated with at least two equivalents of a strong base (such as methyllithium, CH3Li),proton loss on the carbon adjacent to the xp -hybridized center (i.e., the a-carbon) occurs and an organolithiated alkene results. Hydrolysis of the latter results in alkene formation and the consummation of the Shapiro reaction. ... 

Dinitrophenylhydrazones of ketones including cycloheptanone are cleaved by aqueous solutions of TiCla." Only cis-cycloheptene was obtained by alkyl-lithium induced decomposition of cycloheptanone tosylbydrazone. Tosylhydrazones of a-halogenoketones react with phenyl copper at — 60 °C to give a-phenyl ketones after hydrolysis, thus a-chlorocycloheptanone was converted into a-phenylcyclohept-anone. ... 

Reaction of the dianions of cyclic ketone tosylhydrazones with dimethyl disulphide, followed by elimination and hydrolysis, constitutes a 1,2-carbonyl transposition (Scheme 72). ... 

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