Norcamphor

A range of polysulphones has been prepared with a variety of bis-phenols other than bis-phenol A. As might be expected from the discussion in Chapter 4 and from experience with the range of polycarbonates (Chapter 20), replacement of the isopropylidene link with a methylene, sulphide or oxygen link depresses the Tg whilst —C(CgH5)2— and sulphone links raise it. The bis-phenol derived from norcamphor leads to a polysulphone with a Tg of 250°C (195°C for a Udel-type polymer). 

Norcamphor (28) and hexamethylenimine (29) in xylene containing a catalytic amount of p-toluenesulfonic acid gave not only the enamine (30) but also the saturated amine (31) (50). Hexamethylenimine was believed... 

Nor-guajakharzsaure, /. norguaiaretic acid, -homokamphersfture, /. norhomocamphoric acid, -kampher, m. norcamphor. -kampher-sSure,/. norcamphoric acid. 

Whereas exo-norbornene oxide rearranges to nortricyclanol on treatment with strong base through transannular C-H insertion (Scheme 5.11), endo-norbornene oxide 64 gives norcamphor 65 as the major product (Scheme 5.14) [15, 22]. This product arises from 1,2-hydrogen migration very little transannular rearrangement is observed. These two reaction pathways are often found to be in competition with one another, and subtle differences in substrate structure, and even in the base employed, can have a profound influence on product distribution. 

In contrast to the extraordinarily high preference for endo attack observed with camphor (1), nucleophilic additions of organolithium and Grignard reagents to norcamphor (3) proceed with exclusive attack of the nucleophile from the exo face of the carbonyl group. 

Addition of trimethylaluminum to norcamphor (3), regardless of the stoichiometry of the reactants, leads to a mixture of the diastereomeric alcohols in a ratio of 95 5 also in favor of the erafo-alcohol6. Examination of the norcamphor model indicates that endo attack is sterical-ly more hindered than exo attack. However, steric interaction may not fully account for the exceptionally high exo selectivity. On the other hand, no severe torsional strain is involved if the nucleophile approaches the carbonyl group from the exo side, however, a nucleophile approaching from the endo side encounters torsional strain between the incipient bond and the C-l to C-6 carbon-carbon bond. Thus, in the case of norcamphor, steric and stereoelectronic factors reinforce each other, resulting in a strong directional influence for exo attack. 

Notbornyl alcohol, 58, 78 2-Norbornyl fluoride, 58, 78 Norcamphor, 59, 85 Nucleophilic acylation, 59, 56 Nucleophilic acylation with disodium... 

A. 2,2-Dichloronorbornane. A 1-1., round-bottomed flask equipped with a mechanical stirrer and a calcium sulfate drying tube is charged with 91.3 g. (0.665 mole) of phosphorous trichloride and 90.0 g. (0.817 mole) of norcamphor (Note 2). The solution is stirred and cooled to 0° in an ice-salt bath, then 193 g. (0.927 mole) of phosphorous pentachloride is added in portions... 

The submitters purehased norcamphor from Aldrich Chemical Company, Inc. The checkers prepared this compound according to a literature procedure. ... 

Norbomen-2-carbaldehyde, bl36 Norbomene, bl35 Norbomylene, bl35 Norcamphor, al04 Norleucine, al82 Norvaline, a248 NT A, n20... 

Similarly to 8-lactone 260, y-lactone 263, prepared also from ( )-norcamphor (228), proved to be another useful intermediate for the synthesis of all four corynantheidol stereoisomers as well as of the corresponding 18,19-didehydro derivatives. Cleavage of the a-diketone monothioketal moiety in 263 and the formation of amide 265 by its reaction with tryptamine, followed by Bischler-Napieralski cyclization and sodium borohydride reduction, resulted in a mixture... 

Figure 5. Top Tetraurea calixarene monomers 37 and 38 bearing chiral amino acid ester residues (isoleucine and valine methyl esters, respectively) attached to the urea functions. Norcamphor 39 was the chiral guest used to detect the chirality transfer from the outside to the inner cavity.

Atkins, W.M. and Sligar, S.G. (1988) Deuterium isotope effects in norcamphor metabolism by cytochrome P-450cam kinetic evidence for the two-electron reduction of a high-valent iron-oxo intermediate. Biochemistry, 27 (5), 1610-1616. 

Synonyms AI3-18783 Alphanon 2-Bornanone DL-Bornan-2-one BRN 1907611 BRN 3196099 2-Camphanone DL-Camphor Camphor-natural Camphor-synthetic Caswell No. 155 EINECS 200-945-0 EINECS 207-355-2 EINECS 244-350-4 EPA pesticide chemical code 015602 Formosa camphor Gum camphor Iphanon Japan camphor 2-Keto-l,7,7-trimethyl-norcamphane Laurel camphor Matricaria camphor Norcamphor 2-Oxobornane Root bark oil Sarna Spirit of camphor Synthetic camphor l,7,7-Trimethylbicyclo[2.2.1]heptan-2-one 1,7,7-Trimethylnorcamphor UN 2717. 

The effect of steric hindrance can be nicely demonstrated in the reduction of two bicyclic ketones, norcamphor and camphor. The relatively accessible norcamphor yielded on reduction with complex hydrides predominantly (the less stable) endo norborneol while sterically crowded camphor was reduced by the same reagents predominantly to the less stable exo compound, isobor-neol [837], From the numerous examples shown it can be deduced that the stereoselectivity increases with increasing bulkiness (with some exceptions), and that it is affected by the nucleophilicity of the reagent and by the solvent. 

Similar stereoselectivity was noticed in reductions of ketones by alkali metals in liquid ammonia and alcohols. 4-rerr-Butylcyclohexanone gave almost exclusively the more stable equatorial alcohol, norcamphor 68-91% of the less stable e cfo-norborneol, and camphor a mixture of bomeol and isoborneol [860],... 

Krow and colleagues investigated the migratory preferences of the Schmidt and Beckmann rearrangements in norcamphors. Two isomeric lactams are usually formed in the Schmidt reaction but one lactam is obtained almost exclusively in a Beckmann reaction (equation 178). 

Electrochemical reductions of camphor oxime (R = Me) and norcamphor oxime (R = H) at a mercury cathode proceed with a high degree of diastereoselectivity (equation 3) . The products are in fact of opposite stereochemistry to those formed in dissolving metal (sodium-ethanol) reductions of the oximes. 

Ashby and coworkers reported in 1974 stereochemical studies on addition of lithium trimethyhnagnesate to several ketones . The reactions of 4-ferf-butylcyclohexanone with methyllithium, with dimethylmagnesium and with lithium trimethyhnagnesate in ether afforded mixtures of the corresponding axial and equatorial alcohols in ratios of 65 35, 70 30 and 69 31, respectively (equation 11). Reaction of 3,3,5-trimethylcyclohexanone with lithium trimethylmagnesate yielded exclusively the axial alcohol (equation 12). Reaction of norcamphor provided 95% of the endo alcohol and 5% of the exo alcohol (equation 13). In contrast, reaction of camphor yielded the exo alcohol with high stereoselectivity (equation 14). Among the methylmetals examined, no difference in the stereoselectivity was virtually observed. 

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