Smith conjugation

Thallium(III) acetate reacts with alkenes to give 1,2-diol derivatives (see p. 128) while thallium(III) nitrate leads mostly to rearranged carbonyl compounds via organothallium compounds (E.C. Taylor, 1970, 1976 R.J. Ouelette, 1973 W. Rotermund, 1975 R. Criegee, 1979). Very useful reactions in complex syntheses have been those with olefins and ketones (see p. 136) containing conjugated aromatic substituents, e.g. porphyrins (G. W. Kenner, 1973 K.M. Smith, 1975). 

Lithium-ammonia reductions of most steroidal enones of interest create one or two new asymmetric centers. Such reductions are found to be highly stereoselective and this stereoselectivity constitutes the great utility of the reaction. For conjugated enones of the normal steroid series, the thermodynamically most stable products are formed predominantly and perhaps exclusively. Thus the following configurations are favored 5a, 8/ , 9a, and in certain cases 14a (see page 35). Starr has listed numerous examples illustrating these facts and Smith " and Barton have tabulated similar data. 

Stults, N. L., Rivera, H. N., Burke-Payne, J., and Smith, D. F. (1997). Preparation of stable covalent conjugates of recombinant aequorin with proteins and nucleic acids. In Hastings, J. W., et al. (eds.), Biolumin. Chemilumin., Proc. Int. Symp., 9th, 1996, pp. 423-426. Wiley, Chichester, UK. 

The stereoselectivity of conjugate addition and cyclopropanation of the chiral nitrovinyldioxolanes 17 can be effectively controlled <96TL6307>, and good selectivity is observed in the ultrasound-promoted cycloaddition of nitrile oxides to alkenyldioxolanes 18 <95MI877,95JOC7701 >. Asymmetric Simmons-Smith cyclopropanation of 19 proceeds with... 

Muratovska a., Lightowlers R. N., Taylor R.W., Turnbull D.M., Smith R.A. J., WiLCE J.A., Martin S.W., Murphy M.P. Targeting peptide nucleic acid (PNA) oligomers to mitochondria within cells by conjugation to lipophilic cations implications for mitochondrial DNA replication, expression and disease. Nucleic Acids Res. 2001 29 1852-1863. 

Chemo- and stereoselective reduction of (56) to (55) is achieved In highest yield by sodium borohydride in ethanol. The isolated ketone is reduced more rapidly than the enone and (55) is the equatorial alcohol. Protection moves the double bond out of conjugation and even the distant OH group in (54) successfully controls the stereochemistry of the Simmons-Smith reaction. No cyclopropanation occurred unless the OH group was there. Synthesis ... 

NADH, which enters the Krebs cycle. However, during cerebral ischaemia, metabolism becomes anaerobic, which results in a precipitous decrease in tissue pH to below 6.2 (Smith etal., 1986 Vonhanweh etal., 1986). Tissue acidosis can now promote iron-catalysed free-radical reactions via the decompartmentalization of protein-bound iron (Rehncrona etal., 1989). Superoxide anion radical also has the ability to increase the low molecular weight iron pool by releasing iron from ferritin reductively (Thomas etal., 1985). Low molecular weight iron species have been detected in the brain in response to cardiac arrest. The increase in iron coincided with an increase in malondialdehyde (MDA) and conjugated dienes during the recirculation period (Krause et al., 1985 Nayini et al., 1985). 

Thompson, S. and Smith, M.T. (1985). Measurement of the diene conjugated from of linoleic acid in plasma by high performance liquid chromatography. A questionable non-invasive assay of free radical activity. Chem. Biol. Interactions 55, 357-366. 

Mayor, T., Lipford, J.R., Graumann, J., Smith, G.T., Deshaies, R.J. (2005). Analysis of polyubiquitin conjugates reveals that the rpnlO substrate receptor contributes to the turnover of multiple proteasome targets. Mol. Cell. Proteomics 4, 741-751. 

As a result of the excellent precedent from the Takeda and Smith groups, we targeted vinylsilane 136 as a key intermediate in a Brook rearrangement/conjugate... 

Smith, S. N. and Steer, R. P. (2001). The photophysics of Lissamine rhodamine-B sulphonyl chloride in aqueous solution implications for fluorescent protein-dye conjugates. J. Photochem. Photobiol. A Chem. 139, 151-156. 

Thompson, A., Prescott, M., Chelebi, N., Smith, J., Brown, T., and Schmidt, G. (2007) Electrospray ionisation-cleavable tandem nucleic acid mass tag-peptide nucleic acid conjugates Synthesis and applications to quantitative genomic analysis using electrospray ionisation-MS/MS. Nucleic Acids Res. 35(4), e28. 

The concept of microbial models of mammalian metabolism was elaborated by Smith and Rosazza for just such a purpose (27-32). In principle, this concept recognizes the fact that microorganisms catalyze the same types of metabolic reactions as do mammals (32), and they accomplish these by using essentially the same type of enzymes (29). Useful biotransformation reactions common to microbial and mammalian systems include all of the known Phase I and Phase II metabolic reactions implied, including aromatic hydroxylation (accompanied by the NIH shift), N- and O-dealkylations, and glucuronide and sulfate conjugations of phenol to name but a few (27-34). All of these reactions have value in studies with the alkaloids. 

J.D. Stenger-Smith, P. Zarras, L.H. Merwin, S.E. Shaheen, B. Kippelen, and N. Peyghambarian, Synthesis and characterization of poly(2,5-bis(A -methyl-/V-hexylamino)phcnylcnc vinylene), a conjugated polymer for light-emitting diodes, Macromolecules, 31 7566-7569, 1998. 

C Weder, C Sarwa, C Bastiaansen, and P Smith, Highly polarized luminescence from oriented conjugated polymer/polyethylene blend films, Adv. Mater., 9 1035-1039, 1997. 

Smith, G., Watkins, J., Thompson, T., Rozman, K. and Klassen, C. (1984). Oxidative and conjugative metabolism of xenobiotics by livers of cattle, sheep, swine and rats. J. Anim. Sci. 58 386-395. 

Smith RC, Tennyson AG, Lim MH, Lippard SJ (2005) Conjugated polymer-based fluorescence tum-on sensor for nitric oxide. Org Lett 7 3573-3575... 

The conversion experience is found in Ingold s response to a paper presented by Robinson at the Chemical Society in the summer of 1925 and sent to Ingold before its publication in 1926. Robinson s paper, written with J. Allen, A. E. Oxford, and John C. Smith, classified conjugated systems into nine categories of reactants, two of them "anionoid" and the rest "cationoid." "Crotonoid" and "crotenoid" were two of the nine types. This was a detailed and cumbersome classification, based on studies of crotonic acid, amino acids, and their salts, in which crotenoid was an instance of anionoid (electron donor) reaction and crotonoid of cationoid (or electron acceptor) reaction. 

Cycloalkenones are ubiquitous as reactive intermediates and bioactive materials. Modification of a simple cycloalkenone by addition of a carbon substituent at the o-position should be a useful transformation, but one that is not readily accomplished by conventional enone chemistry. a-Substituted cycloalkenones could of themselves be of interest, but perhaps, of more general importance would be their use as intermediates for the production of substituted cycloalkanones or a, 5-disubstituted cycloalkanones by a subsequent conjugate addition procedure.2 These strategies avoid many of the limitations attendant to the trapping of enolates with carbon electrophiles. The method of Kim involving treatment of enones with the combination of a dimethyl acetal, pyridine and trimethylsilyl triflates results in a-(1-methoxyalkyljenones.3 The metallation of a-bromoenones masked as ketals for [Pg.184]

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