Hydrazones sodium salts

Most tosylhydrazone sodium salts could be usually Isolated from the reaction of the corresponding tosylhydrazones with sodium methoxide. However, a number of more functionalized hydrazone sodium salts, such as those derived from alkenyl aryl (25) sulfonyUiydrazones, ketone sulfonylhydrazones, and trimethylsi-lylacrolein sulfonylhydrazones, could not be isolated and an in situ salt generation procedure using NaHMDS was developed. A mixture of the desired hydrazones and NaHMDS was stirred at —78 °C then concentrated down before the addition of rhodium... 

Other approaches to alkylidenecycloproparenes have been attempted without success. Aromatization of appropriate alkylidenecyclopropanes or their precursors could not be realized, and flash vacuum pyrolysis of methylene phthalide and 3-methylene-2-coumaranone afforded rearrangement products rather than alkylidenecycloproparenes via extrusion of 002. The photochemical or thermal decomposition of the sodium salt of benzocyclobutenone p-toluenesulfonyl hydrazone led to products derived from dimerization of the intermediate benzocy-clobutenylidene, or from its reaction with the solvent, but no ring-contracted products were observed. When the adduct of methylene-l,6-methano[10]annulene to dicyanoacetylene (249) was subjected to Alder-Rickert cleavage, phenylacety-lene (250) was formed, which derives reasonably from the parent 234. ... 

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... 

Rather than yielding sulfonylhydrazide, the action of hydrazine on o-esters of benzenesulfonyl chloride 10 effects cyclization to benzothia-diazine 11 (62JOC1703). The action of the phosphorus pentachloride on the sodium salt of hydrazone 12 gives up to an 80% yield of benzothia-diazine 13 (R = H) (69CC33), which can also be made from the reaction of hydrazine with o-formylbenzenesulfonyl chloride (79MI1). 

Separation of a number of keto acid hydrazones may be accomplished as their free hydrazones [37], as sodium salts [38] or as ammonium salts [39]. For TLC separation of the sodium salts a plate (20 X 20 cm) is coated with a 0.25-mm layer of a mixture of silica gel and 0.1 N sodium bicarbonate (1 2 w/v). The plate is activated by heating at 110 °C for 40 min and is then cooled and kept in a desiccator until required. The solvent systems are ethyl acetate (saturated with 0.1 N sodium bicarbonate)-methanol (5 1) and butanol-ethanol-0.1 N sodium bicarbonate (10 3 10) (upper layer). The plates are developed for 2.5 h at room temperature. For quantitation, the spots may be removed from the plate and dissolved in 2.07V sodium hydroxide for color development and determination in solution. Treatment of the plate directly with base (as a spray) should also be possible for quantitation in situ. The wavelengths of the absorption maxima of a number of DNPH-keto acids in aqueous base are listed in Table 4.6... 

Metal-Complex (Formazan) Dyes. The hydrazone from 2-carboxyphenylhydra-zine-4-sulfonic acid and benzaldehyde is suspended in water and then dissolved by adding aqueous sodium hydroxide to obtain pH 6.5 -7.0. This solution is added to the aqueous diazonium salt solution obtained from a typical aqueous diazotiza-tion of 4-(2-sulfooxyethylsulfonyl)-2-aminophenyl-6-sulfonic acid. The mixture is then dripped into an aqueous solution of copper sulfate, while the pH is maintained with soda at 5.5 - 6.5. After complete coupling the pH is adjusted to 1 with concentrated hydrochloric acid. The strongly acidic solution is then neutralized with alkali to pH 5.5. The copper - formazan complex is salted out along with sodium chloride, filtered, washed with dilute aqueous sodium chloride solution, and dried. A dark powder results which gives a dark blue solution in water. It consists of an electrolyte-containing powdered sodium salt of the acid 25 ... 

A new synthetic approach to D-ribose has recently been made by Sowden.43 In this procedure 4,6-benzylidene-D-glucose (X) was reduced catalytically to 4,6-benzylidene-D-glucitol (XI) which was then oxidized with sodium metaperiodate to 2,4-benzylidene-D-erythrose (XII). Condensation of this latter compound with nitromethane gave a mixture of epimeric, crystalline, substituted C-nitro alcohols, 3,5-benzylidene-1-desoxy-l-nitro-D-arabitol and 3,5-benzylidene-l-desoxy-l-nitro-D-ribitol (XIII). After separation, the appropriate isomer was hydrolyzed to 1-nitro-l-desoxy-D-ribitol (XIV) which, in the form of its sodium salt was decomposed directly to D-ribose (XV), isolated as its benzylphenyl-hydrazone. This synthesis is of interest in that it may be used to obtain D-ribose labeled at carbon 1 with C.14... 

The sodium salts of the hydrazones of 2-hydroxybenzaldehydes or of 2-hydroxyphenyl methyl ketones, prepared from the phenols and sodium methoxide in methanol, condensed... 

The hydrazone 364 of 3-thietanone reacts with hydrogen sulfide to give the dispiro derivative 384. Thermolysis of the sodium salts of p-toluenesulfonyl-hydrazones of 3-thietanone,2,2,4,4-tetramethyl-3-thietanone and 2-isopropylidene-4,4-dimethyl-3-thietanone yields allene or cumulene epi-sulfides, for example, 385. The reactions of some tris-iminothietanes are discussed in Section XV.3.B. ... 

Reactions of this type were first studied by Curtius and co-workers . For example, diethyl malonate and /(-toluenesulphonyl azide reacted in the presence of cold sodium ethoxide to give the sodium salt of the 5-hydroxytrizizole (296) . Acidification gave the 5-triazolone (297) which isomerized to the diazo compound (298) (overall yield 90%). (The same product could be obtained in 85% yield without base by heating the azide and malonate at 100° and a pressure of 20 mm) . This reaction provided the basis for the so-called diazo-transfer reaction, an extremely useful method of synthesizing diazo compounds, which has been reviewed. The reaction has been formulated as shown in equation (134), and has been extended to the synthesis of azides by a diazo transfer to amine anions/i-Toluenesulphonyl azide reacts with hydrazone... 

Diazo-compounds can in turn be generated photochemically from sodium salts of toluenesulphonyl hydrazones. Irradiation of the cyclobutane tosylhydrazone (44) gave trans-tricyclo[5.1.0.0 ]-octane (45 R=Me) by the pathway shown in Scheme 4 44 the tricycle (45 R=H) can also be obtained by photoelimination of nitrogen from the diazatricyclo[ 5.2.1.0 4]decene (46). The unexpected conversion of the anthracenocycloheptatriene derivative (47) into triptycene with loss of one carbon atom was observed on irradiation in tetrahydrofuran 4 the mechanism of this unusual reaction remains obscure and merits further investigation, but neither 1-triptycenyl nor 2-triptycenyl carbene appears to be an intermediate in this transformation. 

The cyclization of 2-carboxynicotinaldehyde hydrazones, obtained by mixing an aqueous solution of the sodium salt of the acid with hydrazine hydrochloride at room temperature, gives pyrido[2,3-d]pyridazin-8(7//)-ones. The 7-phenyl derivative 4a is obtained by boiling an ethanolic solution of 2-carboxynicotinaldehyde phenylhydrazone in the presence of catalytic amounts of hydrochloric acid.37... 

The sodium salt of the JV-methoxycarbonyl hydrazone rearranges faster than the hydrazone itself or the parent ketone. This method has been used for the construction of vicinal quaternary centers, since the accelerating functionality can simply be removed by Wolff Kischner reduction. For charge-accelerated Claisen rearrangements of related systems see refs 85 and 113— 118. 

Carbenes are best produced by thermal decomposition of diazo compounds that are formed in situ for example, the sodium salt of a / -toluenesulfonyl-hydrazone is decomposed at 130-150° it is best to effect this decomposition in a proton-free solvent, usually Diethylcarbitol, which avoids a competing reaction that involves carbonium ions ... 

Photodecomposition of sodium salts of toluene-p-sulphonylhydrazones is a well-established route for the generation of carbenes. Irradiation of the lithium salt of the hydrazone (150) or the diazoalkenyl ether (151) derived from it afforded... 

The fragmentation of 2-heterosubstituted 4,7-dihydro-1,3-dithiepins (232)-(234) viacarbene (235) gave 1,3-butadiene and carbon disulfide. The tosylhydrazone (232) was synthesized by cyclization of l,4-dichlorobut-2-ene with the 5,5 -sodium-potassium salt of dithiocarbonic acid-tosyl-hydrazone, the diazo compound (233) was synthesized by careful pyrolyzation of the dry Na salt of (232), and the trithiocarbonate (234) was synthesized from l,4-dichlorobut-2-ene and potassium trithiocarbonate in DMSO. Similarly, pyrolysis of the sodium salt of benzoannelated dithiepin (236), obtained in a one-pot synthesis from a,a -dichloro-o-xylene, carbon disulfide, potassium hydroxide, and tosylhydrazide gave o-quinodimethane, which could be trapped by dienophiles, such as acrylonitrile, to give Diels-Alder product (238) (Scheme 40) <92SCi7ii>. 

Deprotonation of Tosylhydrazones. The deprotonation of tosylhydrazones with NaHMDS provides the corresponding sodium salts very efficiently. The formation of aUyUc alcohols from sugar hydrazones was accompUshed when NaHMDS was combined with LiAlH4 (eq 27). ... 

Semi-empirical INDO calculations have been carried out on cycloheptatrienyli-dene, cycloheptatetraene, and related systems. The most stable structure for cyclo-heptatetraene was found to be non-planar with a C2 axis of symmetry, and should be more stable than the carbene form. Even though most of the chemistry of cyclo-heptatrienylidene is consistent with carbene behaviour, the allene and carbene forms may be in equilibrium, and the position of equilibrium solvent-dependent. In fact decomposition of the sodium salt of the toluene-p-sulphonyl-hydrazone (163) gives dimeric products formed from allene (164), and addition of cycloheptatrienylidene to tetracyclones gives products derived from the adduct (165). ... 

The generation of carbenes by the thermolysis of lithium or sodium salts of tosyl-hydrazones continues to provide interesting chemistry. The selectivity exhibited by 7-bicyclo[2,2,l]hept-2-enylidene (generated from the corresponding tosylhydrazone) is quite the opposite to that expected from theoretical predictions and earlier studies. Addition to 3,3-dimethylbut-l-ene affords the syn-isomer (118) as the major adduct and consequently any carbene-7i interaction resulting in bridge bending cannot of itself dominate the stereoselectivity of addition. Furthermore, the intramolecular insertion products of 2-methylbicyclo[2,2,l]hept-2-en-7-ylidene have been characterized and, from the product ratios, the species behaves as a true carbene. A 3-furyl-... 

Reaction of 2,6-dimethyl-l,4-benzoquinone with the quinomethyl carbanion derived from 2,3-dimethyl-1,4-naphthoquinone is reported to give the tricyclo-[6,3,l,0 ]dodecane derivative (749). Pyrolysis of the sodium salt of the tosyl-hydrazone of 7-cycloheptatrienylmethyl methyl ketone in diglyme at 150 C afforded (750 7%) similar pyrolysis of the tosylhydrazone salt from l-(7-cycloheptatrienyl)-ethyl methyl ketone gave (751 9 %). Both compounds are examples of the previously... 

Cyclo-octa-l,2,4,6-tetraene has been generated by photolysis and thermolysis of the sodium salt of 2,3-homotropone p-toluenesulphonyl hydrazone. When generated photolytically, it could be trapped by cyclopentadiene but not by furan, and in the... 

C-Labelling showed that the thermal conversion of the phenyl trimethylsilyl diazo-compound (168) into (169) involved isomerization of a phenyl carbene into a cycloheptatrienylidene, silacyclopropanes were not involved. It was shown that the P-naphthyl carbene obtained by rearrangement of 4,5-benzocycloheptatrienylidene enters the singlet-triplet manifold as a singlet. Evidence has been reported that aryl carbenes can show both electrophilic and nucleophilic properties in their intramolecular ring expansion. Low-temperature photolysis of the sodium salt of the toluene-p-sulphonyl hydrazone (170) gave, by intramolecular carbene addition, the dibenzobicyclo[4,l,0]heptatriene (171) which was trapped by buta-l,3-diene. ... 

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