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Reduction with NaBH

To investigate this further, we probed the state of Pt before CdS incorporation into the film. After Pt incorporation and reduction with NaBH, the Pt(4f) BE was 71.1 eV, Indicating that Pt2+ complexes were completely reduced to Pt°. Pt in films without CdS can be oxidized by boiling in nitric acid as indicated by the films becoming clear. Thus, the oxidized Pt species present in fresh CdS/Pt/Nafion films is formed at some point during the CdS incorporation process. Thus, while not excluding the process proposed by Aspnes and Heller W, we consider the reduction of partially oxidized Pt as responsible, in part, for the observed induction period (10). [Pg.570]

Methylthiomethyl p-tolyl sulfone 257 was shown to react with various esters in the presence of excess NaH, affording compounds 263 which, upon reduction with NaBH and further treatment with alkali, can be converted to the corresponding aldehydes ". Oxidation of 263 with hydrogen peroxide gives S-methyl a-ketocarbothioates 264. ... [Pg.635]

Anthracene is noncarcinogenic and is structurally incapable of forming a bay region diol epoxide. Anthracene 1,2-dihydrodiol is most conveniently synthesized from 2-anthranol by oxidation with phenylseleninic anhydride to anthracene 1,2-dione (55) followed by reduction with NaBH in ethanol (22) or LiAlH (55). Anthracene 1,2-dihydrodiol has also been synthesized via the Prdvost reaction route... [Pg.51]

Two ciT-dihydroxylation reactions of alkenes formed steps in the synthesis of the antiviral drug (-)-oseltamvir ( tamiflu ) were carried out with RuO /aq. Na(IO )/ EtOAc-CH3CN/4°C [169]. Terminal alkene groups in nucleosides were oxidised to alcohols by RuClj/aq. Na(lO )/EtOAc-CH3CN/0°C thus 3,5-di-0-benzyl-l,2-di-O-isopropylidene-3-C-vinyl-a-D-ribofuranose (1) gave the diol (2) which, on cleavage with Na(lO ) and reduction with NaBH yielded 3,5-di-0-benzyl-l,2-di-O-isopropylidene-3-C-hydroxy-methyl-a-D-ribofuranose (3) (Fig. 3.4) [170]. [Pg.184]

Hydrated nickel(II) salts in the presence of the ligand p3 react with both white phosphorus and yellow arsenic, breaking up the structure of the tetraatomic P4 and As4 molecules to form triatomic cyclo-triphosphorus and cyc/o-triarsenic species. These fragments act as trihapto ligands yielding double sandwich complexes (equation 99).292 The compounds are air-stable both in the solid state and in solution. Upon reduction with NaBH the complexes of equation... [Pg.34]

Microwave-induced imine formation, subsequent reduction with NaBH(OAc)3 and cyclisation of the resulting amino acid with isothiocyanates was used in an efficient one-pot multi-step synthesis of thiohydantoins (Scheme 4.26). The reductive animation was conducted as a two-step procedure to avoid direct reduction of the aldehyde at high temperatures48. [Pg.88]

Prepared by treatment of W-Boc-aspartic acid p-methyl ester with /V-hydroxysuccinimide in the presence of N,N-dicyclohexylcarbodiimide,21 reduction with NaBH, in aqueous THF, and conversion into the iodide using PPh3, l2, and imidazole.22... [Pg.52]

Pyridoxal-5-phosphate (PLP), an analog of 3PGA or phosphorylated sugars that can be covalently bound to the enzyme by reduction with NaBH ... [Pg.52]

Nucleotide binding sites in proteins can be identified by treating the protein-nucleotide complex with periodate, which cleaves ribonucleotides into highly reactive dialdehydes these are able to couple in a Schiff condensation reaction with the c-amino group of any neighbouring lysine residues (Easterbrook-Smith et al. 1976) (Figure 5-7). This coupling is reversible, but it can be made permanent by reduction with NaBH.. ... [Pg.177]

Ester reduction. A method for the conversion of dicarboxylic acids to CD-hydroxycarboxylic acids involves formation and reduction (with NaBH ) of dilactones in which the two carbonyl residues are linked by tm OCH2O chain. Arylpyruvic esters can be reduced to either the a-hydroxy esters or 1,2-diols. ... [Pg.344]

Z,E)-l,3-Dienol ethers. These compounds are available from enynyl ethers by reduction with NaBH,-Ni(OAc)2. [Pg.347]

In an alternative synthesis of ( )-64 by MacLean s group 120), the pyridone 145 was treated with MeLi in tetrahydrofuran at -78°C to afford, after reduction with NaBH, a mixture of ( )-142 and ( )-143. Debenzyl-ation of the mixture by catalytic hydrogenolysis furnished ( )-64 and ( )-144 in 20 and 40% yields, respectively. In yet another synthesis of ( )-64, Reimann and Renz 122) obtained the 8-methylisoquino[2,l-6][2,7]naph-thyridinium salt 149 by alkylation of the Reissert compound 146 with the 4-chloromethylpyridine derivative 147 in N,N-dimethylformamide in the presence of NaH and subsequent treatment of the resulting 1-substituted isoquinoline (148) with hydrochloric acid in EtOH. Reduction of 149 with NaBH, in MeOH gave ( )-142 and ( )-143 in 9 and 34% yields, respectively. Separate debenzylations of ( )-142 and ( )-143 with hydrochloric acid in EtOH furnished ( )-64 and ( )-144, respectively, in good yields. [Pg.295]

The mercurio ketone 4 upon reduction with NaBH yields a radical which is trapped in situ by reactive acceptors such as vinyl ketones [37]. Treatment of a 1 3 mixture of mercurio ketone 4 and electron deficient terminal alkenes (or fumarate) in CH2CI2 with a concentrated solution of NaBH in water gives conjugate adducts, Eq. (36). [Pg.18]

The diastereoselectivity of the reduction with NaBH was very high as no trace of epr-lupinine (with tram H-1 and H-9a) was detected. [Pg.964]

Table 3 Experimental selectivities of trajw-2-heterobicyclo[4.4.0]decan-5-ones in reductions with NaBH, and Na(CN)BH3... Table 3 Experimental selectivities of trajw-2-heterobicyclo[4.4.0]decan-5-ones in reductions with NaBH, and Na(CN)BH3...
C12H24O Mr 184.32, is a mixture of isomers where one of the dashed lines represents a carbon-carbon double bond, the others a single bond. None of the compounds occur in nature. It is a colorless to slightly yellow liquid, df1 0.864-0.872, rej3° 1.454-1.460, with a fine woody, ambra, dry odor with a clean vetivert character. Synthesis starts from 2-methyl-2-butene (isoamylene) which is dimerized and the product acetylated to give the corresponding hepten-2-ones (see p. 18). The hepten-2-ols are obtained by reduction with NaBH [13]. The mixture is used in perfume compositions, for example, for detergents. [Pg.11]

C14H24O, Mx 208.34, is a mixture of isomers and not reported as being found in nature. It is a pale yellow liquid with a powerful woody, sandalwood odor with musk aspect. The mixture is obtained by condensation of campholenaldehyde with 2-bu-tanone and isomerization of the reaction mixture with potassium ferr-butylate in dimethyl formamide. Subsequent reduction with NaBH yields a mixture of chiefly four diastereomeric title alcohols [108]. [Pg.83]

Stmosflfetlve reduction of ketones, Ttie germine Uicstcr 2 is reduced by 1 in HOAc to the 7 -akohol (3) in yield. In contrast, reduction with NaBH, gives the 7amajor product. The difference in stereoselectivity is attributed to the o-C,fhydroxy group. [Pg.287]

The major product is observed to be the endo alcohol (endo/exo 9 1) for reduction with NaBH or LiAlH. The stereoselectivity observed in this reaction is due to decreased steric hindrance to attack of the hydride reagent from the exo face of the molecule, giving rise to the endo alcohol. [Pg.1692]

Reduction. The differentiation of two aldehyde groups is important while (-F)-digitoxigenin is being synthesized. During reduction with NaBH(OAc), in benzene, the neopentyl aldehyde can be retained. [Pg.315]

Polonoeski reaction (2, 7 5, 3). The first synthesis of the dimeric indole alkaloid vinblastine (4), used in the treatment of lymphomas, involved coupling of two indole units using a Polonovski reaction. Thus reaction of the N-oxide (1) and vindoline (2) with trichloroacetic anhydride afforded the quaternary im-monium compound (3), which was converted into (4) by standard methods (reduction with NaBH, rcacclylalion). ... [Pg.194]

Figure 6.4 Photoluminescence spectra of allylamine-grafted Si NPs in water solution synthesized by reduction with NaBH and LiAlH4. Figure 6.4 Photoluminescence spectra of allylamine-grafted Si NPs in water solution synthesized by reduction with NaBH and LiAlH4.
Recent studies have demonstrated (ref. 10) the potential synthetic utility of C-N bond formation via heteromercuration of carbamate derivatives of unsaturated amines. This prompted us to utilize the dehydration products 19a and 20a in the tropane synthesis via intramolecular heteromercuration. Thus the 1 1 mixture of 19a and 20a was treated with mercuric acetate followed by reduction with NaBH to furnish N-carbobenzoxynortropane (26) in 45% yield (based on reacted starting material). The product 26 must result from reductive demercuration of both organomer-curials 24 and 25 initially formed from the asymmetrical and symmetrical olefins 19a and 20a, respectively, via cationic intermediates 22 and 23 as depicted in Fig. 3. Thus separation of the olefin mixture is not necessary since both the olefins can equally be utilized as the reaction substrates in this cycliza-tion. [Pg.160]

The group also applied the former protocol to synthesize hydroxylated a-amino acid 16. The procedure involved addition of ketone 14 to ethyl glyoxylate 21 in wet DMSO, followed by in situ reduction with NaBH. The amino alcohol 16 was formed in 30% yield, excellent ee (>99%) and a dr of 8 1 in favor of the 5yn-adduct (Scheme 5.9). [Pg.348]

Another interesting application involved the formation of allylic amines 33a-e in enantiomerically pure form as published by the Jprgensen group (Scheme 5.18) [25]. This Mannich reaction was conducted between the benzothiazolesulfonyl-derived aldehydes 31a-e and the Boc-protected aldimine 23a. After the initial Mannich reaction, a subsequent reduction with NaBH was carried out to give rise to the allylic amines 33a-e in moderate yields, but high E/Z-ratios and enantioselectivity. [Pg.352]


See other pages where Reduction with NaBH is mentioned: [Pg.150]    [Pg.33]    [Pg.233]    [Pg.283]    [Pg.134]    [Pg.51]    [Pg.52]    [Pg.56]    [Pg.569]    [Pg.284]    [Pg.629]    [Pg.195]    [Pg.2118]    [Pg.450]    [Pg.342]    [Pg.352]    [Pg.1923]    [Pg.320]    [Pg.210]    [Pg.283]    [Pg.47]    [Pg.367]    [Pg.342]    [Pg.182]    [Pg.274]    [Pg.299]   
See also in sourсe #XX -- [ Pg.3 , Pg.4 , Pg.4 , Pg.237 ]




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