Snider studies

Snider S., McClung R. E. D. Raman studies of molecular reorientation in liquid sulfur hexafluoride, Can. J. Phys. 52, 1209-14 (1974). 

Some older examples of this type of process include the studies of Marko on the synthesis of pseudomonic acid C analogues [118], the preparation ofindanones by Snider [119], and synthesis of the skeleton of the sesquiterpenes khusiman and zi-zaen by Wenkert and Giguere and their coworkers [120, 121]. 

In the early thirties of the last century Baade and Zwicky conjectured in their studies of supernova explosions that supemovae represent a transition from ordinary stars to compact objects, whose size is an order of magnitude smaller than the size of a white dwarf. At that time it was already known that the atomic nucleus consists of neutrons and it was clear that the density of the remnant objects must be of the same order as the nuclear density. Baade and Zwicky predicted that a supernova explosions will result in objects composed of closely packed neutrons (neutron stars). Prior to the beginning of the second World War (1939) a number of theoretical works by Landau, Oppenheimer, Volkoff and Snider showed, that indeed objects could exist with sizes about 10 km and masses about a solar mass. The density in these objects is about the nuclear saturation density and they basically consist of neutrons with a small amount of protons and electrons. The studies of neutron stars were subsequently stopped most likely due to the engagement of the nuclear scientists in the development of the nuclear bomb both in the West and the East. 

Although cyclizations from the direct anodic oxidation of acyclic 1,3-dicarbonyl compounds have not been reported, the analogous mediated reactions have been studied [24]. Snider and McCarthy compared oxidative cyclization reactions using a stoichiometric amount of Mn(OAc)3 with oxidations using a catalytic amount of Mn(OAc)3 that was recycled at an anode surface (Scheme 11). In the best case, the anodic oxidation procedure led to a 59% yield of the desired bridged bicyclic product with the use of only 0.2 equivalents (10% of the theoretical amount needed) of Mn(OAc)3- Evidence that the reaction was initiated by the presence of the mediator was obtained by examining the electrolysis reaction without the added Mn(OAc)3. In this case, none of the cyclized product was obtained. For comparison, the oxidation using... 

Ene and 2 + 2 cycloaddition reactions of acetylenic esters (7, 7 8 8, 13). In the early studies on the reaction of acetylenic esters with alkenes, Snider used A1C1( as the Lewis acid catalyst. The presently preferred catalyst is C2H5A1C12, which is a Lewis acid and also serves as a proton scavenger by reaction with HC1 to give ethane and AIC13. It is generally used in amounts close to 1 equivalent for a neutral Hlkene. 

An intensive study of R2AlCl-induced cyclization of unsaturated carbonyl substrates was made by Snider and co-workers. Their results show the advantage of alkyl-aluminum chloride over AICI3 in Lewis acid-catalyzed reactions, because these reagents can act as proton scavengers and Lewis acids. The reaction is interpreted as a Me2AlCl-promoted cyclization of the y,(5-unsaturated ketone then sequential hydride and methyl shift, as depicted in Sch. 25 [49],... 

Sabourin, C.L., Hayes T.L., and Snider T.H., 2001. A medical research and evaluation facility study on Canadian reactive skin decontamination lotion. Final report, USAMRICD, Edgewood Area, Aberdeen Proving Ground, MD. 

A confusing picture emerges when cannabinoids are evaluated in animal models of epilepsy (Karler and Turkanis 1981 Consroe and Snider 1986). CBD has anticonvulsant properties with a spectrum distinct from standard anticonvulsants, apparently not hampered by the development of tolerance but with a varying profile according to the species tested. THC can produce seizures in some circumstances but is anticonvulsant in others. In a recent study, THC (10 mg/kg) completely abolished spontaneous seizures in the rat pilocarpine model of epilepsy (Wallace et al. 2003). The results also indicated that endogenous cannabinoid tone may modulate seizure termination and duration via the CBi receptor. 

Until recently, the reaction of a,/3-unsaturated esters with electron-rich olefins has been reported to afford cyclobutane [2 + 2] cycloaddition products. Amice and Conia first proposed the intermediacy of [4 + 2] cycloadducts in the reaction of ketene acetals with methyl acrylate,108 and the first documented example of the 4v participation of an a,/3-unsatu-rated ester in a Diels-Alder reaction appears to be the report of Snider and co-workers of the reversible, intramolecular cycloaddition of 1-allylic-2,2-dimethyl ethylenetricarboxylates.142 Subsequent efforts have recognized that substitution of the a,/3-unsaturated ester with a C-3 electron withdrawing substituent permits the 4w participation of such oxabutadiene systems in inverse electron demand Diels-Alder reactions with electron-rich olefins. In the instances studied, the rate of the [4 + 2] cycloaddition showed little dependence on solvent polarity [ aeetomtnie/ cycio-hexane — 3, Eq. (15) j acctomtnic toiuene 10, Eq. (20)], and reactions generally... 

In studies which represent the first carefully documented example of the 4-n participation of an a,/3-unsaturated ester in a [4 + 2] cycloaddition,142 Snider and co-workers systematically investigated the competing thermal, intramolecular Diels-Alder and ene reactions of l-allylic-2,2-dimethyl ethylenetricarboxylates [Eq. (39)].142... 

Several studies have focussed on the use of chiral esters as auxiliary groups in radical transformations. Perhaps the most comprehensive survey of auxiliary groups was reported by Snider and collaborators in their pioneering examination of Mn(llI)-promoted radical cyclization reactions of fi keto amides and esters [34]. The selectivities obtained in cyclization generally mirror those observed in inter-molecular addition reactions. These examples again illustrate that the models developed for intermolecular radical reactions can apparently be applied successfully to intramolecular additions (cyclizations). Selectivity for the conversion of 34 to 35... 

The development, by Snider, of intramolecular cyclizations of unsaturated p-keio esters with Mn(III) and Cu(II) has been the souree of numerous and speetacular cascades [27]. Intrigued by the potential of this chemistry as a biomimetic approach to polycyclic systems, Zoretic [28] reported the tetracyclization of precursor 46 to provide tetracyclohexyl derivative 47, in which seven asymmetric centers have been established with complete stereocontrol (Scheme 16). This remarkable sequence deserves several comments. The regioselectivity 6-endo-tng) and diastereoselectivity of the initial cyelization is consistent with Snider s seminal studies notably the ester group adopts an axial position to minimize unfavorable dipole/dipole interactions with the ketone. The two subsequent 6-endo-lng cyclizations that can be rationalized by a slower 5-exo mode of cyelization involving a bond formation sandwiched... 

Four total syntheses of FR901483 have been reported so far the enantiocontrolled approaches of Snider [2], Sorensen [5], and Ciufolini [6], and Funk s synthesis in the racemic series [7]. Furthermore, Brummond has communicated a partial total synthesis [8] and Wardrop reported a formal synthesis of the desmethylamino analog, which had been described by Snider [9,10]. Additionally, Kibayashi and Bonjoch and co-workers have reported other synthetic entries to the azatricyclic core of FR901483, which has also been reported by Brummond in her initial studies [11-14], An overview of FR901483 synthetic studies is outlined in Table 1. 

Snider and Vali (1994) reported studies of S02 oxidation in winter orographic clouds in which S02 was released and the increased concentrations of sulfate in cloudwater relative to the unperturbed cloud were compared to decreased concentrations of H2O2. Despite considerable scatter, the data fell fairly close to the one-to-one line, indicative of the expected stoichiometry of the reaction. 

R. Allison, G. Hewson, W. Snider, R. Moskowitz (1998). A phase II/III clinical study of tin ethyl etiopurpurin (Purlytin)-induced photodynamic therapy for the treatment of recurrent cutaneous metastatic breast cancer. Cancer J. Scl Am., 4, 378-384. 

Snider GL, Celli BR, Goldstein RH, O Brien JJ, Lucey EC. Chronic interstitial pulmonary fibrosis produced in hamsters by endotracheal bleomycin. Lung volumes, volume-pressure relations, carbon monoxide uptake, and arterial blood gas studied. Am Rev Respir Dis 1978 117 289-297. 

E. H. Snider and F. C. Alley [Environ. Sci. Technol., 13,1244 (1979)] studied the kinetics of the chlorination of biphenyl in dilute aqueous solution. The conditions employed were representative of those employed in waste treatment facilities. The reactions of interest may be written as... 

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