Using batch reactor results to calculate optimal flow rates for the scale-up of UV photochemical reactions

The perceived difficulty of the scale-up of photochemistry is one of the main obstacles preventing its widespread use. Herein, we take three different challenging reactions and show that they can be reliably scaled, from immersion well batch reactors to higher power FEP flow reactors. Key to the success has been the development of a powerful calculation methodology which enables the accurate calculation of reactor flow rates from these and previously optimised batch reactions. Despite the challenging nature of these systems, in all cases tens of grams of material was obtained

Iron (III)-mediated free radical transformations of cyclopropanone acetals

Treatment of the cyclopropanone acetals 7 or 11 with three different FeIII species gives the lactone 9 and the ester 13 respectively via an oxidative cyclopropane cleavage followed by a 5-exo radical cyclisation–abstraction sequence

Chemical characterisation of disruptants of the Streptomyces coelicolor A3(2) actVI genes involved in actinorhodin biosynthesis

The actVI genetic region of Streptomyces coelicolor A3(2) is part of the biosynthetic gene cluster of actinorhodin (ACT), the act cluster, consisting of six ORFs: ORFB, ORFA, ORF1, ORF2, ORF3, ORF4. A newly devised method of ACT detection with a combination of HPLC and LC/MS was applied to the analysis of the disruptants of each ORE ACT was produced by those of ORFB, ORFA, ORF3, and ORF4. Instead of ACT, the ORF1 disruptant produced 3,8dihydroxy-1-methylanthraquinone-2-carboxylic acid (DMAC) and aloesaponarin II as shunt products. The ORF2 disruptant gave 4-dihydro-9-hydrsxy-1-methyl-10-oxo-3-H-naphtho-[2,3-c]-pyran-3-(S)-acet ic acid, (S)-DNPA. These results support our previous proposal for stereospecific pyran ring formation in the biosynthesis of ACT, most importantly suggesting that the actVI-ORF2 product would recognize (S)-DNPA as a substrate for stereospecific reduction at C-15. The disruptant of ORFA produced (S)-DNPA together with ACT, suggesting that actVI-ORFA might play a role such as stabilising the multicomponent, type II PKS complex