Continuous Fermentation of a Prodigiosin-Producing <i>Serratia marcescens </i>Strain Isolated from Soil

A red-pigmented bacterial strain NS-17 was isolated from soil, and physiological and biochemical characteristics and 16S rDNA analysis established this organism as a strain of Serratia marcescens. The red pigment isolated from cells of NS-17 was identified as prodigiosin. By analyzing factors affecting the production of prodigiosin, modified medium and culture conditions were set up, and a continuous fermentation method was carried out to take advantage of the mass production of foam during fermentation. Continuous fermentation was achieved in the following conditions: 32℃, 1:1 ventilation ratio, and medium with a nutrient concentration 5-fold higher than that of the fermentation medium (with half the inorganic salt concentration) supplied as a feed medium at a flow rate of 8 mL/min. For the first time of continuous fermentation of Serratia marcescens coupling with foam flotation, a high yield of prodigiosin was obtained. After 56 h of culturing, the total harvest of cells was enhanced 2.33-fold compared to that of batch fermentation, the total amount of prodigiosin was enhanced 2.70-fold compared to that of batch fermentation, and cells and prodigiosin were concentrated in the efflux broth automatically.

Construction of diaminobenzoquinone imines via ferrocene-initiated radical reaction of benzoquinone with amines

A ferrocene-initiated radical reaction of benzoquinone with amines has been successfully developed for the direct access to diaminobenzoquinone imines in high yields,in which the comme rcially available and cheap ferrocene was employed as a radical initiator and TBHP was used as an oxidant.Moreover,this reaction could be achieved with low loading of ferrocene(0.5 mol%).This protocol is highly efficient with good substrate tolera nce and provides a new approach for the construction of benzoquinone imines with potential pharmaceutical interest.

Palladium-catalyzed oxidative homocoupling of 2-arylquinazolinones

Pd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via C—H bond activation.New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy.The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group.

Ir-catalyzed regiospecific mono-sulfamidation of arylquinazolinones

An Ir-catalyzed selective mono-sulfamidation of 2-arylquinazolinones has been achieved with a low catalyst loading under mild conditions.A series of regioselective mono-sulfamided 2-arylquinazolinones were obtained in up to 90%yields.Compared with our previous work of constructing di-sulfamidated 2-arylquinazolinones,the mono-sulfamided products could be obtained selectively by changing the ratio of substrates,the loading of catalyst,acid additive,and reaction time.