Benzy loxy

Example 63 Meier in his studies on potential prodrugs derived from biologically active nucleoside monophosphates used the cyclic chlorophosphites 2-chloro-4-ff-l,3,2,-benzodioxa-phosphinines for the synthesis of the cyclic phosphotriesters having two ligands of different hydrolytic stability benzy-loxy and aryloxy [102]. 

These features provide evidence for a reaction path, common to the four methyl-aromatics under study, that involves the following steps i) activation of the methyl-aromatic in the form of a benzyl species ii) reaction of this species with the catalyst surface giving the corresponding aldehyde, probably with the intermediacy of benzy-loxy- species, as discussed previously (13) iii) oxidation of the aldehyde by the catalyst surface to give the carboxylate species iv) decarboxylation of the carboxylate species giving COj, and, likely, a demethylated hydrocarbon (toluene from xylenes and benzene from toluene). All these successive processes occur both with and without gas phase oxygen, that, consequently, is not active in them. 

Aldol reactions1 (15, 314-315). In the presence of a complex (1) obtained from a chiral diamine such as (S)-l-ethyl-2-[(piperidinyl)methyl]pyrrolidine (13, 302), and Sn(OTf)2 and Bu2Sn(OAc)2, aldehydes react with silyl enol ethers of a-benzy-loxy thioesters to form anti-a,P-dihydroxy thioesters in high diastereoselectivity. 

Aporphines having various oxygenation patterns in ring D were also synthesized by a similar methodology (29). Starting from ( )-l-(4-benzyloxy-3-methoxybenzyl)- and ( )-1 -(3-benzy loxy-4-methoxyben-zyl)-l,2,3,4-tetrahydro-6-methoxy-2-methylisoquinolin-7-ols (30 and 31),... 

Lin and co-workers also investigated a related ligand system derived from 4-benzoyl-3-methyl-l-phenyl-2-pyrazolin-5-one (Figure 12). The related magnesium and zinc benzy-loxy-bridged complexes are all active for the controlled polymerization of lactide, with... 

In a recent investigation, Kibayashi et al. have used a nitroso Diels-Alder strategy in the synthesis of tropane alkaloids (Scheme 3-VIII).27 The initial cycloaddition of a-chloronitrosocyclohexane with 6-benzy-loxy-l,3-cycloheptadiene showed a 4 1 facial selectivity. The major isomer of this cycloaddition could be converted to pseudotropane and tropa-cocaine by a straightforward sequence of steps. 

A class of Protox inhibitors that redefined the accepted SARs and QSARs of the aromatic 4 position was the substituted benzyloxyphenyl heteroaryl area. As discussed earlier, SAR and QSAR studies of the phenyl ring of Protox herbicides demonstrated the need for halogens in the 2- and 4 positions of the phenyl ring, with the exception of the 4-chlorobenzyloxy group such as that of 4-chlorobenzyloxyphenyl tetrahydrophthalimide outlier 55 (Fig. 3.15) and reported by Ohta and coworkers in 1980 [79]. Chlorine at the para position of the benzy-loxy was reported to provide optimum biological activity. 

Benzylidenamino-benzi loxy ]-benzoe> B ure-methyleiter 14 II 26i2. 

Preparation by reaction of benzyl chloride 2-(benzy loxy)-3,6-dihydroxyacetophenone with potassium carbonate in refluxing acetone (10%) [2358]. 

Obtained by alkaline degradation of 2 -benzoyloxy-7-benzy loxy-4, 5-di-methoxy-2-me thoxycarbonylisoflavone (m.p. 183-184°) with potassium hydroxide in reflnxing dilute ethanol for 2 h... 

Obtained by reaction of pyridinium hydrobromide perbromide with 3-benzy-loxy-4-methoxy-acetophenone in THF at r.t. for 3 h [5971]. 

Preparation by treatment of the tetralone 24—two diastereoisomeric l-acetoxy-5-benzy-loxy-3,4-dihydro-6-methoxy-3-methyl-l-pro-pionyInaphthalen-2( lH)-ones—in methylene chloride with silica gel for 16 h (81%) [78 ]. 

Percec V, Heck J (1990) Liquid crystalline polymers containing mesogenic units based on half-disc and rod-Uke moieties. 2. Synthesis and characterization of poly 2-[3,4,5-tri p-(n-dodecan-1 -y loxy)benzy loxy ]benzoate]-7 - p-11 -undecan-1 -y loxy )benzoate]naphtha-lenejmethyl siloxane. Polym Bull 24(3) 255—262. doi 10.1007/BF00306572... 

The nucleophilic addition of bisaldehyde 274 by p-benzy-loxy-phenylmagnesium provided all the necessary carbons for the target molecule. Hydrogenation over catalytic Pd/C then excised the benzyl ethers, and stereoselective formation of trawi-disposed dihydrofuran rings within the resulting polyphenol gave this sophisticated resveratrol tetramer, ampelopsin H (247). 

Scheme 33.16a shows the preparation of a key intermediate for the synthesis of terpenoids by a baker s yeast-catalyzed reduction of a cr-cyclohexanedione. DMSO (10%) was used to solubilize the substrate. Scheme 33.16b shows reduction of 3,5-dioxo-6-(benzy-loxy)hexanoic acid ethyl ester by Acinetobacter sp. SC13874 to the corresponding iyn-(3R,55)-diol, which are potential intermediates for the synthesis of HMG-CoA reductase inhibitors, in 99.4% ee with 52-74% de... 

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