Camphor structure

The first reported chiral catalysts allowing the enantioselective addition of diethylzinc to aryl aldehydes in up to 60% cc were the palladium and cobalt complexes of 1,7,7-trimethylbicy-clo[2.2.1. ]heptane-2,3-dione dioxime (A,B)3. A number of other, even more effective catalysts, based on the camphor structure (C K, Table 26) have been developed. 

Figure 16. Carbonyl C PECD from enantiomers of camphor. The experimentally derived data (Ref. [56]) for the (iS)-enantiomer have been negated prior to plotting on expectation that they will then fall on the same trend line as the (/ )-enantiomer data. The CMS-Xa and B-spline calculations (Ref. [57]) for the (R)-camphor enantiomer are included for comparison. The inset shows the (R)-camphor structure.

Predominant attack of the reagent from the equatorial direction is observed even in the case of a simple cyclohexanone containing a single substituent in the 3- or 4-position. Thus, 3-t-butylcyclo-hexanone gives 72% of the trans isomer as compared to only 15% with LiAlH4. From 3,3,5-trimethylcyclohexanone, trans alcohol (99%) is obtained. In all cases, even in the reduction of the highly hindered camphor structure, the reaction is 100% complete within 0.5 h at 0°C <70JA709>. 

Preparation of 1,7,7-trimethyl-3-hydroxybicyclo[2.2.1]heptan-2-one (Structure 14). Hydroxylation of camphor (Structure 13) by [Mo05(py) OP(Nme3)3)] (MoOPH) (Scheme 1.5)... 

The structure of the bicychc monoterpene borneol is shown in Figure 26 7 Isoborneol a stereoisomer of borneol can be prepared in the labora tory by a two step sequence In the first step borneol is oxidized to camphor by treatment with chromic acid In the second step camphor is reduced with sodium borohydride to a mixture of 85% isoborneol and 15% borneol On the basis of these transformations deduce structural formulas for isoborneol and camphor... 

Camphor was originally obtained from the camphor tree Lauras eamphora in which it appeared in the optically active dextro-rotary form. Since about 1920 the racemic ( ) mixture derived from oil of turpentine has been more generally used. By fractional distillation of oil of turpentine the product pinene is obtained. By treating this with hydrochloric acid, pinene hydrochloride (also known as bomyl chloride) may be produced. This is then boiled with acetic acid to hydrolyse the material to the racemic bomeol, which on oxidation yields camphor. Camphor is a white crystalline solid (m.p. 175°C) with the structure shown in Figure 22.3. 

In a study of the nitrosation of camphor-3-glyoxylic acid (89), Chorley and Lapworth isolated a compound whose structure (90) has recently been clarified by Hatfield and Huntsman. Decarboxylation and ring expansion occur and the reaction is rationalized in the sequence 89 90. The buttressing effect of a methyl group on... 

Substituted norbomanes, such as camphor, aTe found widely in nature, and many have been important historically in developing organic structural theories. 

Camphor, molecular model of, 129 specific rotation of, 296 Cannizzaro, Stanislao, 724 Cannizzaro reaction. 724 mechanism of, 724 Caprolactam, nylon 6 from, 1213 Capsaicin, structure of. 78 -curbahlehyde, aldehyde name ending, 696... 

Loss of ketene from bicyclic structures (e.g., for camphor)... 

In bridged bicyclic ring systems, two rings share more than two atoms. In these cases, there may be fewer than 2" isomers because of the structure of the system. For example, there are only two isomers of camphor (a pair of enantiomers), although it has two chiral carbons. In both isomers, the methyl and hydrogen are cis. The trans pair of enantiomers is impossible in this case, since the bridge must be cis. The... 

As is the case with many members of Lamiaceae, Satureja douglasii produces abundant essential oil from glandular trichomes on the leaves. Gas chromatographic analysis of the leaf oils from specimens collected throughout the species range revealed the presence of some dozen and a half well-known compounds. The major compounds identified were camphene [215], camphor [216], which, taken together, were considered to comprise the bicyclic type, carvone [217], pulegone [218], menthone [219], and isomenthone [220] (see Fig. 2.68 for structures 215-220). The predominance of each of these major components defined a terpene type. (All compounds were observed in each of the terpene types, most in comparatively small amounts, some only as traces.)... 

The major structural difference between monocyclic and bicyclic compounds should be obvious camphene and camphor exhibit bridged structures. It should be noted, however, that the monocyclic compounds can be further distinguished from each other based on the position of the oxygen atom, located at C-2 in carvone, and at C-3 in pulegone, and in the menthones. Work by others had shown that the... 

Whittingham JL, JP Turkenburg, CS Verma, MA Walsh, G Grogan (2003) The 2-A crystal structure of 6-oxo-camphor hydrolase. J Biol Chem 278 1744-1750. 

The zinc complex of 1,1,1,5,5,5-hexafluoroacetylacetonate forms coordination polymers in reaction with either 2,5-bis(4-ethynylpyridyl)furan or l,2-bis(4-ethynylpyridyl)benzene. The X-ray crystal structures demonstrate an isotactic helical structure for the former and a syndio-tactic structure for the latter in the solid state. Low-temperature 1H and 19F NMR studies gave information on the solution structures of oligomers. Chiral polymers were prepared from L2Zn where L = 3-((trifluoromethyl)hydroxymethylene)-(+)-camphorate. Reaction with 2,5-bis(4-ethy-nylpyridyl)furan gave a linear zigzag structure and reaction with tris(4-pyridyl)methanol a homo-chiral helical polymer.479... 

There are two types of electron transport those involving flavoproteins and iron-sulfur proteins, and those requiring only flavoproteins. The X-ray crystal structure of the soluble cytochrome P450 from Pseudomonas putida grown on camphor (P-450-CAM) has been determined (Poulos et ah, 1985), as have several others. The haem group is deeply embedded in the hydrophobic interior of the protein, and the identity of the proximal haem iron ligand, based on earlier spectroscopic studies (Mason et ah, 1965) is confirmed as a specific cysteine residue. 

A quarter of a century later complex (97), structurally related to CoII(salen), was prepared from camphor and used as the catalyst for cyclopropanation. Although diastereselectivity was modest, good enantioselectivity was achieved in the reaction of 1-octene (Scheme 70).266... 

Figure I. Crystal structure of lTa.ns-4 -hydroxy- N-methyl-4-stilbazoIium (+)-camphor-...

Asymmetric cyclopropanol formation has been achieved with olefmic acylsulfonamides, which act like olefmic esters. Thus, their reaction with 1 provides a method for synthesizing cyclopropanols in an optically active form. As represented by Eq. 9.41, alkylation of Oppolzer s camphor sultam and reaction of the resulting unsaturated acylsulfonamides with 1 provides optically active bicyclic cyclopropanols having exclusively the structure shown in the equation [76],... 

Perhaps the most interesting arthropodan defensive compounds from the point of view of structural diversity are the alkaloids. While alkaloids had long been believed to arise only as a consequence of plant secondary metabolism, it has become apparent over the last few decades that arthropods are both prolific and innovative alkaloid chemists. The millipede Polyzonium rosalbum, once thought to secrete camphor (20), in fact gives off a camphoraceous/earthy aroma produced by the spirocyclic isoprenoid imine polyzonimine (21). 

Synthetic camphor, 24 540 Synthetic compounds, as plant growth regulators, 13 39-56 Synthetic crude oil, 13 640 Synthetic cyclic molecules, 24 35 Synthetic diamond, 3 530-543 catalyzed synthesis, 3 531-535 crystal growth, 3 535 crystal morphology, 3 534-535 crystal structure, 3 537-538 direct graphite-to-diamond process, 3 535-538... 

Electrocapiilary phenomena on Hg-electrode in presence and absence of an adsorbate (camphor). From a measurement of interfacial tension (a) (e.g., from droptime of a Hg-electrode) or of differential capacity (d) (e.g., by an a.c-method) as a function of the electrode potential (established by applying a fixed potential across tine Hg-electrolyte interface) one can calculate the extent of adsorption (b) (from (a) by the Gibbs Equation) and of the structure of the interface as a function of the surface potential. Figs, a, c and d are interconnected through the Lippmann Equations. 

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