S hindered

Wall, D. B. Kachman, M. T. Gong, S. Hinderer, R. Paras, S. Misek, D. E. Hanash, S. M. Lubman, D. M. Isoelectric focusing nonporous RP HPLC A two-dimensional liquid-phase separation method for mapping of cellular proteins with identification using MALDI-TOF mass spectrometry. Anal. Chem. 2000, 72, 1099-1111. 

Introduce additional halogen(s) to the terminal carbon to decrease the alkylating activity. Alkylating activity is reduced as the increased electron-withdrawing power of additional halogen(s) hinders the departure of the first halogen. 

Lorenz M, Stamm S, Hinder M, et al. Inhibition of thrombin generation by Otamixaban (XRP0673), a direct and selective factor Xa inhibitor. J Thromb Haemost 2005 3(suppl I ) P0716. 

CLEMENS, S., HINDERER, W WITTKAMPF, U BARZ, W Characterization of cytochrome P450-dependent isoflavone hydroxylases from chickpea. Phytochemistry, 1993,32,653-657. 

The spectrum obtained from a magenta sample removed from the binding of the same manuscript indicates a protein substance and additional unidentified component(s). The additional component(s) hinder identification of the protein. Although the protein present could be hide glue, it could also originate from pigments extracted from insect sources. 

Goodwin, P.S., Hinder, T.M.T., Wisbey, A., and Ward-Close, C.M., Recent progress in the clean mechanical alloying of advanced materials. Mater. Sci. Forum, 269-272, 53-62, 1998. 

Ha, T, Glass, J, Enderle, T, Chemla, DS, and Weiss, S, Hindered rotational diffusion and rotational jumps of single molecules. Physical Review Letters 80 (1998) 2093-2096. 

The axial H s hinder H attack from the axial direction. As a result, this mode of attack is more difficult with larger reducing agents. In this case the product is trans. This product is not formed to any appreciable extent. 

Goldstein, S., Hindered Amines and Their Interactions with Pigments , SPE Colorants and Appearance Division RETEC, September 1995. 

Wagner A F, Kiefer J H and Kumaran S S 1992 The importance of hindered rotation and other... 

Gutowsky H S and Holm C H 1956 Rate processes and nuclear magnetic resonance spectra. II. Hindered internal rotation of amides J. Chem. Phys. 25 1228-34... 

Kiefer J H, Mudipalli P S, Wagner A F and Harding L 1996 Importance of hindered rotations in the thermal dissociation of small unsaturated molecules classical formulation and application to hen and hcch J. Chem. Phys. 105 1-22... 

Ha T, Glass J, Enderle T, Chemla D S and Weiss S 1998 Hindered rotational diffusion and rotational ]umps of single molecules Phys. Rev. Lett. 80 2093-7... 

In the case of hindered enolates, the equillibrium favors reactants. Mg2+ and Zn2+ counterions will stabilize the intermediate p-alkoxycarbonyl and push the equillibrium towards products. (jAC.S 1973, 9.5,3310)... 

The final condensation could haye gone the other way too, but it doesn t, presumably because attack on, the other carbonyl group is hindered. TM 120 is in fact piperitone, one of the flayouring principles of mint, and has been synthesised essentially by this route g.C.S... 1935, 1583 Rec. Tray. Ctum.. 1964, 464 Zhur. Obshchei Khim.. 1964, 34=... 

Synthetically useful stereoselective reductions have been possible with cyclic carbonyl compounds of rigid conformation. Reduction of substituted cyclohexanone and cyclopentan-one rings by hydrides of moderate activity, e.g. NaBH (J.-L. Luche, 1978), leads to alcohols via hydride addition to the less hindered side of the carbonyl group. Hydrides with bulky substituents 3IQ especially useful for such regio- and stereoselective reductions, e.g. lithium hydrotri-t-butoxyaluminate (C.H. Kuo, 1968) and lithium or potassium tri-sec-butylhydro-borates or hydrotri-sec-isoamylborates (=L-, K-, LS- and KS-Selectrides ) (H.C. Brown, 1972 B C.A. Brown, 1973 S. Krishnamurthy, 1976). 

The hydrogenolyaia of cyclopropane rings (C—C bond cleavage) has been described on p, 105. In syntheses of complex molecules reductive cleavage of alcohols, epoxides, and enol ethers of 5-keto esters are the most important examples, and some selectivity rules will be given. Primary alcohols are converted into tosylates much faster than secondary alcohols. The tosylate group is substituted by hydrogen upon treatment with LiAlH (W. Zorbach, 1961). Epoxides are also easily opened by LiAlH. The hydride ion attacks the less hindered carbon atom of the epoxide (H.B. Henhest, 1956). The reduction of sterically hindered enol ethers of 9-keto esters with lithium in ammonia leads to the a,/S-unsaturated ester and subsequently to the saturated ester in reasonable yields (R.M. Coates, 1970). Tributyltin hydride reduces halides to hydrocarbons stereoselectively in a free-radical chain reaction (L.W. Menapace, 1964) and reacts only slowly with C 0 and C—C double bonds (W.T. Brady, 1970 H.G. Kuivila, 1968). 

The benzylidene derivative above is used, if both hydroxyl groups on C-2 and C-3 are needed in synthesis. This r/vzns-2,3-diol can be converted to the sterically more hindered a-cpoxide by tosylation of both hydroxy groups and subsequent treatment with base (N.R. Williams, 1970 J.G. Buchanan, 1976). An oxide anion is formed and displaces the sulfonyloxy group by a rearside attack. The oxirane may then be re-opened with nucleophiles, e.g. methyl lithium, and the less hindered carbon atom will react selectively. In the following sequence starting with an a-glucoside only the 2-methyl-2-deoxyaltrose is obtained (S. Hanessian, 1977). 

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