Benzothiophenes design

A new stabilized phosphorus ylide 357 designed to undergo thermal tandem cyclization has been prepared. Upon flash vacuum pyrolysis at 850 °C, loss of PhsPO and Me radical results in tandem cyclization to give [l]ben-zothieno[3,2- ][l]benzothiophene 356 (Equation 7) <1998J(P1)3937>. 

Whitehurst, Isoda, and Mochida write about catalytic hydrodesulfurization of fossil fuels, one of the important applications of catalysis for environmental protection. They focus on the relatively unreactive substituted di-benzothiophenes, the most difficult to convert organosulfur compounds, which now must be removed if fuels are to meet the stringent emerging standards for sulfur content. On the basis of an in-depth examination of the reaction networks, kinetics, and mechanisms of hydrodesulfurization of these compounds, the authors draw conclusions that are important for catalyst and process design. 

To realize the above-mentioned systems, we carefully chose suitable switching units and radical moieties. As an initial attempt, we employed l,2-bis(2-methyl-l-benzothiophen-3-yl)perfluorocyclopentene (9a) as a photochromic spin coupler (Scheme 9.2). Compound 9a is one of the most fatigue-resistant diarylethenes [21]. Nitronyl nitroxide was chosen for the spin source, because this radical is jr-conjugative. Thus, we designed molecule 10a, which is an embodiment of the simplified model 8a [37, 62]. 

A series of a-aminophosponates bearing a benzothiophene moiety was designed and synthesized and their antiviral activity assayed (14PS530).The results of the bioassays showed that aU compounds exhibit certain anti-TMV activity at 500 pg/mL. 

A variety of novel benzothiophene-substituted oxime ester strobilurins were designed and synthesized and their fungicidal activities investigated (14BMCL2173). 

The main sulphur-bearing impurities of fuel oils are generally mercap-tans, sulphides, disulphides, thiophenes and benzothiophenes. Because of differences between petrol and diesel oil compositions, they will have different optimal desulphurization RTILs. In both cases, the central task in designing an RTIL-based separation system is to find an RTIL that dissolves the sulphurbearing compounds without dissolving the hydrocarbons. Because of the great solvent power of most RTILs, this task is not easy. For example, [Omim][BF4] dissolves thiophene very weU, and is practically immiscible with cyclohexane... 

Example 2.7.2.2.A Sequential Design for Optimal Parameter Estimation in Benzothiophene Hydrogenolysis... 

Van Parijs et al. [1986] applied sequential discrimination in their experimental study of benzothiophene hydrogenolysis. The final rate equations were already given in Example 2.6.4.A. The efficiency of the sequential discrimination was remarkable. At 533 K, a total of seven experiments (four preliminary, three designed) were sufficient to reject 14 out of 16 rivals. Only one of the two remaining models was consistently the best at 513, 553, and 573 K also, after four, five and nine designed experiments, respectively. A total of 41 experiments sufficed to select the best among the postulated rate equations. The location of the settings of these experiments is shown in Fig. 2.7.2.2.A-1 of Example 2.7.2.2.A. 

When the models are nonlinear in the parameters, Xis replaced by J. An example of application of sequential design for optimal estimation is given by Van Parijs et al. [1986] in their study of benzothiophene hydrogenolysis. At 533 K the desired accuracy of the parameters of the equations given in Example 2.6.4.A was reached after four more experiments beyond the seven required for discriminating between the 16 rival models. In total, no more than 16 experiments were required for the four temperature levels that were investigated. 

SEQUENTIAL DESIGN FOR OPTIMAL PARAMETER ESTIMATION IN BENZOTHIOPHENE HYDROGENOLYSIS... 

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