Hydrazones N-benzoyl

N-Benzoyl hydrazones 40, derived from aromatic and aliphatic aldehydes, undergo allylation with AllylSiCl3 in DMF at 20 °C [42] or in CH2C12 with excess of DMSO or Ph3PO as activator at —78 °C (Scheme 7.6) [43]. Three equivalents ( ) of... 

Scheme 7.46 NHC-catalyzed asymmetric cross-annulation of enals and N-benzoyl hydrazones reported by Scheldt.

H-benzotriazole 1003 0-benzoyl esters 134 benzoyl hydrazones 440 N-benzoyl hydrazones 394 benzoyl peroxide 72 benzoylmethyl sulfonium ylides 1115 benzyl bromide 545 0-benzyl hydroxyacetone 705 N-benzyl ketimines 958 benzyl protecting groups 558 benzyl thiols 52 a-benzylation 1184 -aldehydes 1184 0-benzylhydroxyamines 1003 benzylideneacetone 591 benzylthiol 257 betaines 257... 

Scheme 6.97 Typical products obtained from the 91-catalyzed asymmetric allylation of N-benzoyl-protected aromatic hydrazones. The product configurations were not determined.

A variety of other monoanionic ligands that contain O and N functional groups have been reported to complex Zr and Hf. For example, hydroxy-pyridionate,707 substituted-thiazolidin-4-ones,708,709 cycloserine,710 V-furfurylidnearylamines711 azopyrazolones,712-714 substituted aroylhydrazone,715 benzoyl hydrazones,716-718 6-amino-penicillinic acid,719 aniline-carboxylate,720 aminoantipyrine,721 and bis-salicyloyl hydrazides722 have been employed in the preparation of various halide and oxide derivatives. The majority of these complexes have been characterized by IR spectroscopy and elemental analysis alone. 

IR data for the dinuclear compound [V0(L)]2(p-0), where H2L = salieyal-dehyde benzoyl hydrazone, show that the hydrazone ligand is tridentate, via two O atoms and one N." Metal (VO +, U02 +, Cd(II), Ni(II), Cu(II), Zn(II) or Hg(II)) complexes with 5-chloro-7-iodo-8-quinohnol, have IR spectra showing ligand coordination via the quinoline ring N and hydroxyl O atoms." ... 

C24H15CI3M0N6S3, (p-Chlorothiobenzoyl-hydrazone-diyl)-(p-chlorothio-benzoyl-hydrazone-triyl)-(N -isopropylidene-p-chlorothiobenzoyl-hydrazone)molybdenum, 45B, 1313 C24H16Cl2Hg02S2, Dichlorobis(phenoxathiin)mercury, 34B, 589 C24H16Cl6PtS2, cis-Dichlorobis(4,4 -dichlorodiphenyl sulfide)platin-um(II), 37B, 635... 

Cyclization of the hydrazone derivatives of 4-benzoyl[ 1,2,3]triazole 695 by reaction with one carbon inserting agent such as an orthoester, an aldehyde, a ketone, or a phosgene afforded triazolotriazine 696 or 697 (88JHC743). The newly created C—N bond displays particular sensitivity due to the electron-attracting effect of the triazole ring (Scheme 147). 

Since Kagan s first report of N-N bond reduction using Sml2,39 the reagent is now routinely used for the transformation. The reaction has been used widely in asymmetric synthesis to reduce the products of asymmetric additions to, or reductions of,47 hydrazone derivatives. For example, Enders reported the nucleophilic addition of alkyllithiums to trifluoroacetaldehyde SAMP and RAMP hydrazones in an asymmetric approach to a-trifluoromethyl-sub-stituted amines.48 After activation of the adducts by benzoylation, Sml2-mediated N-N bond cleavage proceeded in high yield (Scheme 4.41). 

Polymer-bound chiral hydrazines have been synthesized to furnish a-branched amides (Scheme 12.17) [13, 23], Enantiopure (i-methoxyamines 37 and 38, derived from readily available hydroxyproline and N,N-dibenzylleucinol, respectively, have been attached to solid support and transformed into the corresponding hydrazine auxiliaries 39 and 40 via several steps. The synthesis of a series of enantiomerically enriched a-branched amides required the coupling of aliphatic and aromatic aldehydes to form hydrazones 41 and 42 followed by the addition of different nucleophiles. Cleavage of the N-N bond of the resulting hydrazines 43 and 44 led to a-branched amines 45. Further conversion with benzoyl chloride or acetyl chloride furnished amides 46 in yields of 24—51% and 50-83% ee. 

In attempts to prepare the 2-benzyl-2-phenylhydrazone (29) of 3,5-di-O-benzoyl-2-deoxy-n-eryribose derivative), the unsaturated hydrazone (30) was obtained. ... 

The infrared spectra of phenylosazones have also been studied in detail, and have been suggested as a means of identification of the different saccharide osazones. Saccharide osazones show the characteristic hydroxyl bands at 3 n, the C=N band of the hydrazone residues at 6.3 n, and three bands attributed to the phenyl ring. In the case of acetylated osazones, the 0-acetyl band appears at 1735 cm. and JV-acetylated derivatives show the A-acetyl band at " about 1640 cm.. These characteristics have greatly simplified the differentiation of 0-acetyl from iV-acetyl groups in acetylated osazones. Also, for benzoylated osazones, the differentiation offers no difficulty the 0-benzoyl band appears at 1725 cm. and the A-benzoyl band at 1685 cm.. ... 

Stoichiometrically, one equivalent of HgO is necessary for the dehydrogenation of a hydrazone. Examples have been published in Organic Syntheses Smith and Howard (1955) described the procedure for diphenyldiazomethane, obtained from benzophenone hydrazone in petroleum ether in 89-96% yield. The necessity for the absence of moisture is emphasized, but no activation of the mercury(n) oxide seems to be required. Andrews et al. (1988) have reported on the dehydrogenation of acetone hydrazone to 2-diazopropane (70-90% yield) in ether in the presence of catalytic amounts of KOH in ethanol. There are also cases where two equivalents are used, e.g., the procedure for (benzoyl)(phenyl) diazomethane (2.62, yield 87-94%) published in Organic Syntheses by Nenitzescu and Solomonica (1943). Neither these nor other authors have explained, however, why two equivalents would be necessary. 

Oxadiazoles.—1,2,3-Oxadiazoles. 3-Phenylsydnone (594 R = H) is anodically chlorinated at position 4, while anodic oxidation yields mainly phenol and benzaldehyde. The foregoing sydnone reacts with tetracyanoethylene to give the ene-hydrazone (596), presumably via the cyclo-adduct (595), by loss of carbon dioxide and cleavage of the strained carbon-carbon single bond. Irradiation of diphenylsydnone (594 R = Ph) in the presence of methyl pro-piolate affords the pyrazole (597) by way of the nitrile imine PhC=N—NPh with benzonitrile, a mixture of the 1,2,3- and 1,2,4-triazoles (598) and (599), together with the 1,3,4-oxadiazolinone (600) and 7s/ -benzoyl-iV -phenylhydrazine, is formed. ATV -Dibenzoylphenylhydrazine is produced by photo-oxygenation of diphenylsydnone. 

Verbindung CuHijClNjO aus S-Phanyl-[pyridino-2. 3 3.4-pyrazol] 27, 77. C,4H42CIN302 [N-(4-Chlor-benzoyl)-anthTanib saursl-hydrazid 14 II 222. cu-Chlor-acetophenon-[2.nitro-phenyb hydrazon] 15 I1179. 

The group ofTsogoeva discovered that BINOL-phosphate catalyst 93 can promote the enantioselective addition of TMSCN to aliphatic hydrazones 92 (Table 30.12) [50]. The so-formed a-hydrazino nitriles 95 can be readily transformed via acidic hydrolysis into biologically and synthetically important a-hydrazino acids. In general, N-p-N02-benzoyl-protected ahphatic hydrazones 92 could be converted in good enantioselectivities (71-93% ee). The yields showed inconsistency, but... 

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