Hydrazones tosyl

Carbenes of type (113), generated by thermal decomposition of the appropriate tosyl-hydrazone salts, undergo ring opening more readily when the ring heteroatom is oxygen rather than when it is sulfur (78JA7927). 

BAMFORD - STEVENS - CAGUOTI- SHAPIRO Olelinalwn Conversion o( ketones to olelins via tosyl hydrazones with NaOR, LAH, LDA or BuLi... 

The product composition from these reactions is influenced by the location of the functional group in the substrate. Olefin formation is the most common side reaction and in certain cases, especially with reductions of tosyl-hydrazones (section IV-B), it may become dominant so that the reaction can be used for the preparation of mono-labeled olefins. 

Some advantages of this reaction are high yield if the tosylate is in a sterically accessible position excellent isotopic purity of the product (usually higher than-95%) and perhaps most important, access to stereospecifically labeled methylene derivatives. For example, deuteride displacement of 3j -tosylates (183) yields the corresponding Sa-d derivative (185) in 96-98% isotopic purity. Application of this method to the labeled sulfonate (184), obtained. by lithium aluminum deuteride reduction of a 3-ketone precursor (see section HI-A) followed by tosylation, provides an excellent synthesis of 3,3-d2 labeled steroids (186) without isotopic scrambling at the adjacent positions. The only other method which provides products of comparable isotopic purity at this position is the reduction of the tosyl-hydrazone derivative of 3-keto steroids (section IV-B). 

The Hurd-Mori 1,2,3-thiadiazole synthesis is the reaction of thionyl chloride with the N-acylated or tosylated hydrazone derivatives 1 to provide the 1,2,3-thiadiazole 4 in one simple step. ... 

Reaction of tosyl hydrazone 1 with a strong base initially leads to a diazo compound 3, which in some cases can be isolated ... 

Die Tosyl-hydrazone aromatischei Oxo-Verbindungen werden mit Lithiumalanat zu den entsprechenden Kohlenwasserstoffen reduziert18, sterisch gehinderte alicyclische Tosyl-hydrazone liefem in einer Bamford-Stevens-Reaktion19 (Eliminierung von Toluolsulfinsaure ohne Reduktion) als Neben- oder Hauptprodukte die entsprechenden Olefine 18 20 21. 

Alkalimetallhydride reduzieren nicht. Man isoliert ausschlieBlich Olefine22. Bei der Umsetzung von Cyclo-hexanon-N-phenyl-N-tosyl-hydrazon mit Lithiumhydrid erhalt man die Azo-Stufe der Bamford-Stevens-Reaktion unter Bildung von Phenylazo-cyclohexen1. ... 

Die folgenden sterisch behinderten Ketone werden nur in Form der isolierten Tosyl-hydrazone reduziert ... 

Weniger elektrophile Tosyl-hydrazone (auch aromatische) lassen sich besser unter energischen Bedingungen und inverser Zugabe von Natriumboranat-Tabletten reduzie-ren. 

Zucker-(tosyl-hydrazone) werden mit Natrium-cyano-trihydrido-borat in Tetrahydro-furan/Methanol in Desoxyzucker iibergefiihrt5. 

Eine milde Methode stellt die Reduktion mit Benzo-l,3,2-dioxaborol in Chloroform oder Dichlormethan dar. Hierbei werden die Tosyl-hydrazone aliphatischer Ketone zu-nachst hydroboriert und das Addukt mit Natriumacetat zersetzt6 ... 

Konjugierte Tosyl-hydrazone werden unter Verschiebung der C=C-Doppelbindung reduziert7. 

Octan6 Zu ciner Losung von 15,64 g (52,7 mMol) Octanon-(2)-(tosyl-hydrazon) in 105 ml Chloroform werden unter Riihrcn bei —10° und unter Stickstoff 6,31 ml (58 mMol) Benzo-l,3,2-dioxaborol gegcbcn. Man laBt 20 Min. (bei konjugierten p-Tosylhydrazonen 2 Stdn.) bei 20 stehen, versetzt mit 21,1 g (155 mMol) Natrium-acetat-Trihydrat, erhitzt 1 Stdc. am RiickfluB, engt ein und destilliert Ausbeute 4,78 g (81% d.Th.) Kp ... 

Da Tosyl-hydrazone aromatischer Aldehyde und Ketone ohne elektronenschiebende Gruppen nur schwach elektrophil sind, miissen sie entweder vor der Reduktion mit Na-trium-cyano-trihydrido-boranat in Tetrahydrofuran in die Quecksilber-Verbindung I... 

Aliphatische und aromatische Tosyl-hydrazone lassen sich auch mit Pyridin-Boran in salzsaurem Athanol/l,4-Dioxan in Ausbeuten von iiber 90% d.Th. zu den Tosyl-hydrazi-nen reduzieren6. 

The selective reduction of the D-ring olefin in 106 using a partially poisoned catalyst (Pd/C, 0.25 % pyridine) provided intermediate 107 (83 %), which was epimerized at -78 °C with sodium methoxide (HOAc quench at -78 °C, 89 %) (Scheme 10.9). Deoxygenation by means of tosyl hydrazone 108 and subsequent treatment with catechol borane and tetrabutylammonium acetate gave pentacyclic... 

Although the symmetrical olefin is the main product, Scheme 21, 8 is obtained from fenchone p-toluenesulfonyl hydrazone220 (tosyl hydrazone) with t-BuOK and elemental selenium. 

The tosyl hydrazones are reduced to R2CH2. Since the reduction proceeds smoothly, it constitutes a valuable method of removing carbonyl groups in organic synthesis. 

Vollhardt s investigations100 into electrocyclic transformations on a CpCo template produced the following unusual result. After photolysis of CpCo(CO)2 in the presence of the tosyl hydrazone of trans-4-pheny -3-buten-2-one, the only isolated product was the vinylketene complex 123. Note that the tricarbonyliron analogue of this complex has also been isolated.3,87 The mechanism of formation was not discussed, but it seems likely that the ketene carbonyl originated as a carbonyl ligand that replaced the hydrazone moiety, perhaps via a vinylcarbene intermediate. 

The unconventional 3-diazoindoles were prepared by oxidative conversion of hydrazones and oximes. Thus, l-methyl-3-diazo-2-oxindole (21d) was prepared by mercuric oxide oxidation of l-methylisatin-3-hydrazone 297 (X = NNH2) in benzene at room temperature (1891JPR551) (Scheme 91). It can also be prepared by decomposition of l-methylisatin-3-tosyl-hydrazone 297 (X = NNHTs) with aqueous sodium hydroxide in a two-... 

The 1-isopropoxymethyl derivative of pyrrolo-benzothiazepine 376 can be obtained from aldehyde 375 through the tosyl hydrazone followed by reduction with sodium borohydride in 2-propanol. 1-Methyl substituted 378 is available from aldehyde 375 and hydrazine monohydrate followed by potassium tert-butoxide (Scheme 76, Section 5.1.1 (2004JMC143)). 

In search of a convenient procedure for preparing diazo substrates for the cycloaddition to Cgg, Wudl introduced the base-induced decomposition of tosyl-hydrazones [116]. This procedure allows the in situ generation of the diazo compoimd without the requirement of its purification prior to addition to Cgg. Since they are rapidly trapped by the fullerene, even unstable diazo compounds can be successfully used in the 1,3-dipolar cycloaddition. In a one-pot reaction the tosyUiydrazone is converted into its anion with bases such as sodium methoxide or butylHfhium, which after decomposition readily adds to Cgg (at about 70 °C). This method was first proven to be successful with substrate 142. Some more reactions that indicate the versatility of this procedure are shown in Table 4.4. Reaction of 142 with CgQ under the previously described conditions and subsequent deprotection of the tert-butyl ester leads to [6,6]-phenyl-C5j-butyric acid (PCBA) that can easily be functionalized by esterification or amide-formation [116]. PCBA was used to obtain the already described binaphthyl-dimer (obtained from 149 by twofold addition) in a DCC-coupling reaction [122]. 

Other papers of interest in this section report transamination of camphor-3-carbothioamides with secondary cyclic amines, reaction of camphorquinone with dimethyl /S-ketoglutarate, the use of fenchone (212 X=0) in alkene formation from Grignard reagents, bromination of 2-e/itfo-6-endo-dibromobornane to yield 2,3,6-endo-tribromoborn-2-ene, and camphor-enol trimethylsilyl ether formation by quenching the reaction mixture of butyl-lithium and camphor tosyl-hydrazone with trimethylsilyl chloride. ... 

Tertiary amines are oxidized to the corresponding nitrogen oxides. Tosyl hydrazones of ketones and aldehydes and imines are oxidized to the corresponding carbonyl compounds. Reactions have been carried out with small molecules and also with molecules that would not diffuse into the pore structure of the titanium silicates. As in the case of C—C bond cleavage, it is possible that these reactions take place on the outer surface of the catalyst crystals. 

Toluene p-sulfonyl hydrazones (tosyl hydrazones) undergo C=N oxidative bond cleavage with H202 in the presence of TS-1, to give high yields of the corresponding carbonyl compounds very likely, the reaction proceeds through... 

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). ... 

On photolysis or thermolysis of the peri-methylmercapto-substituted sodium salt of a-naphthaldehyde tosyl hydrazone 77 or diazomethyl-naphthalene 78, 2//-2-methylnaphtho[frc]thiophene 80 (83JA6096) is formed in 20% yield. Ylid 79 may be a predecessor of thiophene 80. In... 

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