Smith analog

At Smith Kline French a general approach to cephalosporin and penicillin nuclear analogs was developed that utilizes a monocyclic /3-lactam (59) with the correct cis stereochemistry as a key intermediate. This is prepared by reaction of the mixed anhydride of azidoacetic acid and trifluoroacetic acid with imine (58) followed by oxidative removal of the dimethoxybenzyl group. This product could be further elaborated to intermediate (60) which, on reaction with a -bromoketones, provides isocephalosporins (61). These nuclear analogs displayed antibacterial properties similar to cephalosporins (b-79MI51000). 

Where specialized fluctuation data are not available, estimates of horizontal spreading can be approximated from convential wind direction traces. A method suggested by Smith (2) and Singer and Smith (10) uses classificahon of the wind direction trace to determine the turbulence characteristics of the atmosphere, which are then used to infer the dispersion. Five turbulence classes are determined from inspection of the analog record of wind direction over a period of 1 h. These classes are defined in Table 19-1. The atmosphere is classified as A, B2, Bj, C, or D. At Brookhaven National Laboratory, where the system was devised, the most unstable category. A, occurs infrequently enough that insufficient information is available to estimate its dispersion parameters. For the other four classes, the equations, coefficients, and exponents for the dispersion parameters are given in Table 19-2, where the source to receptor distance x is in meters. 

By using basicity data, Ridd and Smith- showed that 5-nitro- and 5-chloro-benzimidazole and their 2-methyl analogs exist essentially as mixtures of equivalent amounts of 29 and 30, and, in agreement with this ratio, 5-substituted benzimidazoles form comparable amounts of 1- and 3-derivatives on alkylation,- showing earlier alkylation ratios- to be erroneous. There are, however, other factors which can lead to the predominance of one tautomeric form. Basicity measurements indicate that 31 is preferred to the alternative non-hydro-... 

Simmons-Smith reaction of cyclohexene with diiodomethane gives a single cyclopropane product, but the analogous reaction of cyclohexene with 1,1-diiodoethane gives (in low yield) a mixture of two isomeric methyl-cyclopropane products. What are the two products, and how do they differ ... 

Collman JP, Boulatov R, Sunderland CJ. 2003a. Functional and structural analogs of the dioxygen reduction site in terminal oxidases. In Kadish KM, Smith KM, Guilard R, editors. The Porphyrin Handbook. Boston Academic Press, p. 1. 

VHL Lee, DJ Schanzlin, RE Smith. (1986). Interaction of rabbit conjunctival mucin with tear protein and peptide analogs. In FJ Holly, ed. The Preocular Tear Film in Health, Disease, and Contact Lens Wear. Lubbock, TX Dry Eye Institute, pp 341-355. 

Lenhert and Hodgkin (15) revealed with X-ray diffraction techniques that 5 -deoxyadenosylcobalamin (Bi2-coenzyme) contained a cobalt-carbon o-bond (Fig. 3). The discovery of this stable Co—C-tr-bond interested coordination chemists, and the search for methods of synthesizing coen-zyme-Bi2 together with analogous alkyl-cobalt corrinoids from Vitamin B12 was started. In short order the partial chemical synthesis of 5 -de-oxyadenosylcobalamin was worked out in Smith s laboratory (22), and the chemical synthesis of methylcobalamin provided a second B 12-coenzyme which was found to be active in methyl-transfer enzymes (23). A general reaction for the synthesis of alkylcorrinoids is shown in Fig. 4. 

The chemistry and utility of zinc-based Lewis acids are similar to those of their magnesium analogs. Their mild Lewis acidity promotes several synthetic reactions, such as Diels-Alder reactions, hetero Diels-Alder reactions,229 radical-mediated reactions,230 ene-type cyclization, and Simmons-Smith reactions. 

The reaction of D-glucosone and other osones with cyanide, as a first stage in the synthesis of ascorbic acid and its analogs, has been reviewed by Smith.136... 

H Gausepohl, U Pieles, RW Frank. Schiff base analog formation during in situ activation by HBTU and TBTU, in JA Smith, JR Rivier, eds. Peptides Chemistry and Biology. Proceedings of the 12th American Peptide Symposium, Escom, Leiden, 1992, pp 523-524. 

Polymers of 4(5)-vinylimidazole and copolymers containing this monomer are usually studied with ethanol-buffer mixtures as solvent because of their insolubility in water. Overberger and Smith (82) found that poly(l-Me-5-vinylimidazole) was soluble in water. Negatively charged substrates with long apolar side chains were bound very strongly to this polymer. A rate enhancement of 106 over the monomeric analog, 1,5-dimethylimidazole, was observed. 

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