Camphor hydrazone

Well-dried camphor hydrazone (lOg) is heated with a solution of sodium (0.8 g) in alcohol (10 ml) for 18 h in a bomb tube at 190°. Crude crystalline camphane is then obtained on addition of water (750 ml) and is purified by distillation in steam. The camphane melts at 156-157° and boils at 161°/757 mm. The yield amounts to 7 g, i.e., 84%. 

Tricyclanes and Quadricyclanes.—Oxidation of camphor hydrazone with silver carbonate on celite gave the tricyclane (565) and a trace of bomylene, whereas other hydrazones are found to rearrange to azines. Diazocamphor (566) in THF is decomposed by catalytic silver perfluorobutyrate and affords the tricyclanone (567) in nearly quantitative yield the a-ketocarbene is the presumed intermediate. The carbomethoxylation of a-bonded organomercurials in the presence of stoicheio-metric amounts of lithium tetrachloropalladate and CO occurs with predominant retention of configuration at carbon. Thus (568) gave (569 38 %) and various minor components. 

Camphor Quinone Monotosylhydrazone To 22 g (0.133 mole of camphor quinone in 150 ml of chloroform is added 26.1 g (0.14 mole) of p-toluenesulfonylhydrazide in one batch. The reaction vessel is protected with a drying tube and fitted with a magnetic stirrer, and the mixture is stirred at room temperature for 24 hours. The monotosyl-hydrazone is not isolated. 

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. ... 

An indirect vanadometric method of assay for camphor was developed. The method involves the formation of 2, -dinitrophenylhydrazone of camphor. The nitro groups in the hydrazone are then reduced to amines by treatment with vanadium sulfate (VSOl ) and the excess of the reagent is back titrated with sodium dichromate (NapCrpO-y). The entire procedure is carried out in a modified separatory funnel into which standard vanadate, 6tJ and zinc amalgam... 

A stereoselective synthesis of 3-( 1,2,4-triazolo[4,3-A ]azin-3-yl)-bicyclo[2.2.1 ]heptanones 58 starting from (l/ )-(+)camphor 56 has been described. The reaction comprises oxidative cyclization of the intermediate hydrazones 57 with methanolic bromine <02TA821>. 

As mentioned previously, DMSO as the reaction medium provides significant enhancement of Wolff-Kishner reaction rates and this allows the use of much lower temperatures to effect reductions. In 1962 Cram et al. introduced the use of r-butoxide in dry DMSO for the successful reduction of preformed hydrazones at room temperature. Using this process, benzophenone hydrazone (15) afforded an 88% yield of diphenylmethane (16), along with 11% of benzophenone azine (17) as side product (equation 5). However, maximum success requires very slow addition (i.e. over 8 h) of the hydrazone to the reaction solution, otherwise yields of reduced products are decreased and azine formation augmented. Thus, addition of (15) over 0.5 h in the above reaction lowered the yield of (16) to 72%, while the yield of (17) was increased to 22%. - Other successful reductions reported - include hydrazones of benzaldehyde (67%), camphor (64%) and cyclohexanone (80%). 

The reaction of (1S,4S)- and racemic camphor thiosemicarbazone [(1S,4S)- and rac-CTSC] leads to the formation of trans- and c/.v-isomers of (1S,4S)- or racemic camphor 5,-fluoro-4 -hydroxy-4, 5 -di(perfluoroalkyl)-l,3,-thiazolinyl-2/-hydrazones 211a-c and 213b,c (Scheme 189). The molecular structure of the two diastereomers (1S,4S,4 R,5 R)- and (1S,4S,4 S,5 S)- of 211a has been established by X-ray crystallography (03JFC(120)41). This result can be explained by a considerable contribution of the SN2 type of nucleophilic substitution both to the epoxide ring... 

A new hydroxycamphene (566) has been found in two species of chrysanthemum. [2- H J-2-bornene can be made by the action of BuLi on camphor tosylhydrazone in hexane followed by DjO quench. In ether proton abstraction from solvent occurs before work-up. However, with less hindered hydrazones, deuterium incorporation is much reduced since the vinyl anion can apparently act as the base (B) in (567) and so capture a proton. ... 

Formation of Hydrazones. Much of the rich chemistry exhibited by TPSH comes from its condensation products with ketones and aldehydes. Such trisyl hydrazones are typically prepared in excellent yield by mixing equimolar amounts of reagents in methanol or ethanol at room temperature with a catalytic amount of acid such as HCl and storing the reaction in the cold. The product precipitates and is filtered off. Very hindered ketones such as camphor and diisopropyl ketone require stoichiometric amounts of acid and extraordinarily hindered ketones may not condense at aU.i ... 

Alkylation Alkylation of ACC hydrazones proceeds with both excellent stereo- and regiochemical control and in excellent yield. As mentioned, camphor-derived auxiliary 54 and phenyl alanine-derived auxiliary 55 have proven to be the most versatile. Although the initial report on ACCs gave an er of 96 4 for ACC 54 and of 76 24 for ACC 55 in the allylation of 3-pentanone, subsequent work has revealed that in fact ACC 54 produces an er of >99 land 55 an er of 95 5 (Table 7.1). ... 

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