Curvularia falcata

Current Patents Curry and curry powder Curry powder Curtain spin process Curtius degradation Curved laminates Curvilinear regression Curvularia falcata Curvularia lunata var. aeri Curvularia trifolii Curzate... 

Mit Curvularia falcata konnen Oxo- und Dioxo-dekaline ebenfalls zu sterisch einheitli-chen a-Alkoholen reduziert werden7 (weitere Beispiele s.S. 764). Auch 3-Oxo-bicy-clo[4.3.0]nonene unterliegen dieser Reaktion8,9 z.B. ... 

Beim 3,7-Dioxo-6-methyl-bicyclo[4.3.0]nonen-(l) vermag Curvularia falcata (Teflon) Boedijn bei Einhaltung bestimmter Bedingungen zwischen der (6R)- und der (6S)-Form zu unterscheiden3 (nur das 5-Derivat wird reduziert) ... 

Diphenyl-glykol Curvularia falcata(Tehon)Boedijn >... 

HLADH converts a wide range of substrates. For the predicition of the stereoselectivity of reduction reactions, originally Prelog s diamond lattice model was applied, which is based upon the characteristic properties of the ADH of Curvularia falcata [37]. This model describes the stereospecificity of HLADH catalyzed reductions of simple acyclic substrates such as aldehydes. Later on, for more complex acyclic and cyclic substrates, a cubic-space model of the active site was developed [38,121]. Other models are based upon symmetric properties [122-125] or upon a refined diamond lattice model [126-129]. 

The flexibility of this nomenclature may be appreciated from a consideration of the possible results for the reduction of a ketone by a fermentation process. Prelog and his colleagues initiated work in this area by investigating the action of the mold, Curvularia falcata on A4-9-methyloctalin-3,8-dione, as the racemic mixture, 65 plus 66. 

Another aromatic 1,2-diketone, benzil, is reduced to benzoin by yeast254, while Curvularia falcata gives (-)-(.S, .S )-isohydrobenzoin in 57% yield59. 

Decalones are reduced by cultures of the fungus Curvularia falcata. Simple tram-1 -decalone276, 1,4-dioxodecalin, 3,7-dioxooctalin, and methylated derivatives are usually reduced to the (Sb-configurated alcohols. These results led to the development of Prelog s rule58. 

An interesting example is the reduction of 2,7-dioxobicyclo[4.4.0]dcc-l >-ene with resting cells of Curvularia falcata or Rhizopus nigricans in more than 80% yield277 ... 

The / e-face selective alcohol dehydrogenase from Curvularia falcata is not the only system capable of reducing cyclic and bicyclic ketones. The following reduction is observed with the fungus Aureohasidium pullulans28. 

Yeast ADH has a very narrow substrate specificity and, in general, only accepts aldehydes and methyl ketones [770, 771], Therefore, cyclic ketones and those bearing carbon chains larger than a methyl group are not accepted as substrates. Thus, YADH is only of limited use for the preparation of chiral secondary alcohols. Similarly, other ADHs from Curvularia falcata [772], Mucor javanicus and Pseudomonas sp. [773] are of limited use as long as they are not commercially available. The most conunmily used dehydrogenases are shown in Fig. 2.15, with reference to their preferred size of their substrates [774]. 

In order to predict the stereochemical outcome of HLADH-catalyzed reductions, a number of models have been developed, each of which having its own merits. The first rationale emerged from the diamond lattice model of V. Prelog, which was originally developed for Curvularia falcata [798]. A more recently developed... 

Acklin, W., V. Prelog, F. Schenker, B. Serdarevk , and P. Walter Reaktionen mit Mikroorganismen. Reduktion von stereoisomeren Dekalonen-(l) und einigen verwandten bicyclischen und tricyclischen Ketonen durch Curvularia falcata. Helv. Chim. Acta 48, 1725—1746 (1965). 

The cerebrovascular and peripheral vascular active drug pentoxyfylline (53) (Fig. 16) is reduced by S. cerevisiae to the alcohol 54 albeit with only 8% yield within 72 h. The highest conversion rates, however, have been obtained using Rhodotorula mucilagi-nosa, Eryptococcus macerans, or Curvularia falcata [95]. 

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