Schemes footnotes

For the vibrational numbering scheme, see Chapter 4, footnote 4 (page 93). 

The fact that the experimentally determined exponent of h0 in Scheme 3-25 is not an integer ( — 2), as expected for the mechanism discussed here, is due to the complexity of concentrations and activities in highly acidic solutions. In 66-74% H2S04 the rate is propotional to ho2A. Concerning the subscript 6, see the footnote explaining this point for Schemes 3-12 to 3-14. 

Important mechanistic information can be obtained from the reaction rates of the two diazoates with acid. The older literature, e. g., publications by Grachev (1947 a, 1947 b, 1948), by Porai-Koshits (1960), and by Porai-Koshits et al. (1946, 1960), will not be reviewed here because it is outdated and in some cases the results were not reproducible (see Lewis and Suhr 1958 b, footnote 5). On the basis of the above discussion of the formation of the (Z)-diazoate from the diazonium ion by reactions 1 and 2 of Scheme 5-14, one might assume that the reverse process should be easy to follow experimentally. This is not the case, however, as was first shown simultaneously by Lewis and Suhr (1958 b) and by Passet and Porai-Koshits (1958). The investigation of the acidification of (2i)-4-nitrobenzenediazoate is difficult due to irreversible decomposition, particularly at pH >5. Lewis and Suhr (1958b) observed,... 

The data from Beckwith s work given in Table 10-9 look very confusing but, as discussed in the four papers by Beckwith s group (see footnote a) in Table 10-9) and in additional comments in Galli s review (1988), they can all be explained on the basis of our present knowledge of aryl radical chemistry, with the exception of the endo cyclization of the 2-(7V-2,-propenylsulfamoyl)-benzenediazonium ion in Scheme 10-81. 

Figure 5.13 Solvent demands during the development of a process for the synthesis route in Scheme 5.7. For percentage changes see Table 5.2 (footnote b recycling considered). Due to the introduction of a second solvent in the pilot and operation scale solvent demand is higher than in the laboratory scale (laboratory scale 6.1 kgkg versus pilot scale 10.6 kgkg and operation scale 7.9 kgkg, see also Figure 5.1 0).

Fic. 6.—Proposed Distribution of Disaccharide Units Along an Average Heparin Chain.151 [For simplicity, possible linkage regions and antithrombin-binding sequences are not considered. For notations, see legend and footnote to Scheme 1. Arrows indicate possible insertion of units G-Ana.]... 

In his first paper3 , Stokes called the observed phenomenon dispersive reflexion, but in a footnote, he wrote I confess I do not like this term. I am almost inclined to coin a word, and call the appearance fluorescence, from fluorspar, as the analogous term opalescence is derived from the name of a mineral. Most of the varieties of fluorspar or fluorspath (minerals containing calcium fluoride (fluorite)) indeed exhibit the property described above. In his second paper7, Stokes definitely resolved to use the word fluorescence (Scheme 1.2). 

It should be remarked, at this juncture, that Bamford s experiments utilising 3-methyl hydantoin as a co-catalyst do not shed light on the problem of propagation. They have shown, merely, that a proton is required for the simple amine-piropagated polymerisation and, according to his scheme, any proton donor may suffice to produce this result (see however the footnote on p. 44). For example, if his mechanism is correct, sarcosine NCA should not be polymerised by sodium methoxide in a rigorously aprotie medium1, but polymerisation should ensue on... 

Scheme 2. Schematic relationships between C2 hydrocarbon adsorbates and the surface species that could be derived from them. Possible relationships are indicated between surface species that involve not more than one addition/subtraction of H and/or M atoms. Strong bonding of these species to metal atoms could give rise to structures approximating to metallocyclopropanes or metallocyclopropenes, respectively. These structures with C=C or C = C groupings frequently occur on surfaces with additional n bonds to further metal atoms, M in other cases, two additional CM bonds may replace a CC double bond. JOn surfaces the metal atoms are usually bonded to each other so that the analogous molecular cluster compounds would be metallocyclopropanes or metallocyclobutanes, etc. 1 See footnote to Scheme I. The dashed rectangles indicate surface species that involve no CH bond breaking on adsorption of the parent hydrocarbon. These are most likely to be present under low-temperature adsorption conditions.

A recent summary of the history and dynamics of the theoretical models of benzene39 cites a view that even though the current molecular orbital (MO) view of benzene seems complete and ultimate while the valence bond (VB) view seems obsolete, the recent findings about zr-distortivity in benzene indicate that the benzene story is likely to take additional twists and turns that will revive the VB viewpoint (see footnote 96 in ref 39). What the present review will show is that the notion of delocalized zr-systems in Scheme 1 is an outcome of both VB and MO theories, and the chemical manifestations are reproduced at all levels. The use of VB theory leads, however, to a more natural appreciation of the zr-distortivity, while the manifestations of this ground state s zr-distortivity in the excited state of delocalized species provides for the first time a physical probe of a Kekule structure .3... 

Developing a theory of coset geometries (as mentioned in the previous footnote), one obtains from our recognition theorem of Coxeter schemes Jacques Tits main result on buildings of spherical type . This theorem asserts that each such building is associated with a group if it is thick and of rank at least 3. 

In practical terms, the purification of aqueous solutions of XX on Rohm and Haas macroreticular resin XAD-16 proved to be very efficient (95-98% recovery of material with a purity of approximately 95%) and economical to carry out. This chromatographic purification step removes salts (especially phosphates) introduced at earlier processing steps in Antibioticos plant (Schemes 1 and 2), thereby enabling us to minimize the amount of DDM needed to fully esterify both carboxyl groups of XX 2.3 to 2.5 moles DDM per mole of XX generally proved sufficient.31 Although DDM is a relatively stable molecule (see footnote 20), its separate preparation does introduce some safety concerns. In practical terms, it should be possible to prepare... 

We went on to show that the electrochemical reduction process afforded an elegant route to a key cefaclor intermediate diphenylmethyl 7-amino-3-chloroceph-4-carboxylate (Scheme 12). (see footnote 31). 

SCHEME 6. Outline of Smith and Hughes (Wyeth s) synthesis of Norgestrel (see footnote 53). 

Scheme S. Preparation of both triphenylcyclopentadiene isomers through the reduction of 1,5-diones followed by dehydration (31,50). Note that in the reaction at top dehydration does not yield the straightforward 2,3,5 but the thermodynamically favored 1,2,4 isomer, which possesses both a stabilizing stilbene and a 1,4-diphenylbutadiene conjugated system (See footnote 13 in Ref. 26).

Figure 3.1 The composition of reaction mixture as a function of reaction time in the hydrogenation of 1,5-cyclooctadiene over unpoisoned (a), phenylacetaldehyde-poisoned (b), and carbon monoxide-poisoned (c) palladium catalysts. The points are experimental values, and the curves show the simulations using the values given in Table 3.4. For the reaction conditions, see footnote b in Table 3.4. (Key 1,5-COD 1,4-COD O COE 9 COA. (For abbreviations, see Scheme 3.9.) (FromHigashijima, M. Ho, S.-M. Nishimura, S. Bull. Chem. Soc. Jpn. 1992, 65, 2960. Reproduced with permission of Chemical Society of Japan.)...

Schemes are numbered consecutively as Scheme 1, Scheme 2, and so on, with either arabic or roman numerals. Schemes should be labeled with Scheme and a number they also may have brief titles and footnotes. 

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