Natural product simulants

Estimates of service life are usually made either by natural or simulated trials or, most commonly, by accelerated tests with extrapolation to predict performance at longer times under less severe conditions. An alternative approach is to subject the product to environmental exposures which equate to the whole design life, and then to assess performance by real or simulated service tests (the end performance assessment). The exposures usually have to involve accelerated procedures and can be composed of several environmental agents applied simultaneously or sequentially. 

Gillies, M. T. 1974. Dehydration of Natural and Simulated Dairy Products. Food Technology Review No. 15. Noyes Data Corp., Park Ridge, N.J. 

A review cataloging intramolecular Diels-Alder reactions as key steps in the total synthesis of natural products has been published.78 A key step in the total synthesis (g) of (+)-dihydrocompactin (66) is the intramolecular ionic Diels-Alder reaction of the trienone (63) to yield the (+)-compactin core compound (65) via the intermediate cyclic vinyloxocarbenium ion (64) (Scheme 17).79 The intramolecular Diels-Alder reaction of the Asp-Thr tethered compound (67) produced the cycloadduct (68) with high regio- and stereo-selectivity (Scheme 18).80 Mixed quantum and molec- (g) ular mechanics (QM/MM) combined with Monte Carlo simulations and free-energy perturbation (FEP) calculations have been used to show that macrophomate synthase... 

The syntheses of Oikawa et al. (32, 33) are biomimetic in that DDQ was used to simulate the action of the then recently isolated crystalline hemoprotein from Pseudomonas known as tryptophan side chain a,3-oxidase (34). The natural products 70-72 as well as a number of related compounds were prepared by this method. N- Acetyltryptamine 76, on treatment with 2 equiv DDQ under anhydrous conditions, gave pimprinine (70) in only 10% yield (32). Reaction of the... 

Generation III. These compounds often mimic some feature of the insect s natural hormones. These include pheromones, insect growth regulators, and other compounds that simulate these natural products. 

VARICOL A continuous chromatographic process for separating natural products. It generally resembles the Sorbex process, which uses a simulated moving bed, but the column is divided into a larger number of independent sectors. 

I use the verb replicate in reference to the exact reproduction of a natural product—in other words, the re-creation of a natural thing by man. The verb simulate, on the other hand, refers to the making of a copy, an ersatz simulation rather than a product identical to its exemplar. Although this corresponds to the commonsense usage of these terms, the meanings that I attach to them will be more fixed than common parlance dictates. See Webster s Third Neiv International Dictionary (Springfield, MA G. C. Merriam, 1966), s.vv. replicate, simulate. ... 

Simulation of the calicheamicin/esperamicin cascade has been amply demonstrated by Danishefsky and co-workers with a variety of compounds (Scheme 7-49) [219-221]. Furthermore, comparisons of ealicheamicin yj (2) and calicheamicinone (222) in DNA-cleavage experiments pointed to the importance of the carbohydrate fragment of the natural product in the molecular recognition of its target sequence [85]. 

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