Chemical correlation between

When pyridinium salt 187 was transformed to an indolo[2,3-a]quinolizidine compound in a similar way and the unsaturated lactone 188 was hydrogenated over platina catalyst, a mixture of vallesiachotamine-type compounds (189 di-astereomers) epimeric at C-20 was formed (134). These compounds have also been prepared in optically active form from vallesiachotamine (9), thus producing the first chemical correlation between synthetic and natural vallesiachotamine derivatives (134). 

In eq. [20] the chemical correlation between (S)-( — )-phenyllactic acid (known absolute configuration) and (- )-epoxychalcone is shown. 

Spiradine D was also isolated from S.japonica by Goto and Hirata (140) in 1968. The structure of spiradine D (160) was elucidated by chemical correlation between spiradines A and D. 

Two secodaphnane-type alkaloids (Figure 18.2), secodaphniphylline (8) [19,21,22] and methyl homosecodaphniphyllate (11) [19,21,22], were isolated by Yamamura and Hirata, and their structures were elucidated by X-ray analysis of methyl N-bromoa-cetyl homosecodaphniphyllate and chemical correlations between 8 and 11. The structures of the two related alkaloids, daphniteijsmine (9) [23] and daphniteijsma-nine (10) [24], were elucidated by spectroscopic analysis coupled with an exhaustive comparison of the NMR data of secodaphniphylline and methyl homosecodaphniphyllate (11). 

There are two especially relevant cases where Cp2TiCl-promoted epoxide deoxygenations have been demonstrated to conform to the requirements of selectivity, mildness, and wide functional group tolerance desirable in natural product synthesis the chemical correlation between cryptophycin-23 and cryptophycin-45 and the synthesis of anhydrovinblastine, the key intermediate in the synthesis of the anticancer drug Navelbine, from leurosine (Scheme 14) [91-93]. 

Figure 11 CD and UV spectra of (6R,15R)-(+)-6,15-dihydro-6,15-ethanonaphtho[2,3-c]pentaphene 3 in dioxane/EtOH and chemical correlation between compound 3 and related compounds, where the most ideal chiral cage compound 3 with two anthracene chromophores shows intense exciton-coupled CD Cotton effects, establishing the consistency between X-ray Bijvoet and CD exciton chirality methods. Redrawn from N. Harada K. Nakanishi, Circular Dichroic Spectroscopy - Exciton Coupling in Organic Stereochemistry, University Science Books Mill Valley, CA, and Oxford University Press Oxford, 1983.

S. aallium contains two glycoalkaloids which on hydrolysis afford 25-isosolafloridine (50) and solacallinidine (51), respectively. These have been investigated spectrally and the hydrochloride of the former subjected to an X-ray diffraction analysis (Bird et al.. Tetrahedron Letters, 1976, 3653 Acta Cryst., 1977, 33B, 3782). A chemical correlation between the pair has been established idem. Austral. 

Careful examination of these stereochemical assignments revealed that in many instances a simple chemical transformation could have provided a more secure correlation. Over the last few years we have pursued several chemical correlations between marine sesquiterpene/quinones with interesting and useful consequences. Some of these results are highlighted below. 

Scheme 11. Chemical correlation between pantherine and muscimol.

Scheme 66. Chemical correlations between active principles of jack-o -lantem.

There are many examples of chemical correlations between lactarane sequiterpenes of the different classes. These experiments have often been... 

Both tests measure alcohol in the breath.The legal definition of being under the influence of alcohol is based on blood alcohol content, not breath alcohol content. The chemical correlation between these two measurements is that air deep within the lungs is in equilibrium with blood passing through the pulmonary arteries, and an equilibrium is established between blood alcohol and breath alcohol. It has been determined by tests in persons drinking alcohol that 2100 mL of breath contains the same amount of ethanol as 1.00 mL of blood. 

Inouye H, Yoshida T, Tobita S, Okigawa M (1970) Studies on monoterpene glucosides-IX chemical correlation between asperuloside and loganin. Tetrahedron 26 3905-3915... 

The correlations given in the Atlas are in general the most recent and rehable available. Where a chemical correlation between substances has been carried out, this is given preference over correlation by chiroptical methods, asymmetric synthesis, quasi-racemate formation, etc., and these in turn are given precedence over any older work involving comparison of monochromatic rotations. The latter is included only in a few cases where no more recent information is available and where the correlation is of considerable interest. 

Subsequent studies revealed similar morphological and chemical correlations between various kerogens and the resistant biopolymers... 

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