A luminous quasar at a redshift of z = 7.085.

The intergalactic medium was not completely reionized until approximately a billion years after the Big Bang, as revealed by observations of quasars with redshifts of less than 6.5. It has been difficult to probe to higher redshifts, however, because quasars have historically been identified in optical surveys, which are insensitive to sources at redshifts exceeding 6.

A protecting group free synthesis of (+/-)-neostenine via the [5 + 2] photocycloaddition of maleimides.

A concise, linear synthesis of the Stemona alkaloid (+/-)-neostenine is reported. Key features include an organocopper-mediated bislactone C2-desymmetrization for the stereoselective construction of the cyclohexane-lactone C,D-rings. The assembly of the fused pyrrolo[1,2-a]azepine core was achieved by application of a [5 + 2] maleimide photocycloaddition.

A practical flow reactor for continuous organic photochemistry.

[reaction: see text] Compact flow reactors have been constructed and optimized to perform continuous organic photochemistry on a large scale. The reactors were constructed from commercially available or customized immersion well equipment combined with UV-transparent, solvent-resistant fluoropolymer (FEP) tubing. The reactors were assessed using the [2 + 2] photocycloaddition of malemide 1 and 1-hexyne forming the cyclobutene product 2 and the intramolecular [5 + 2] photocycloaddition of 3,4-dimethyl-1-pent-4-enylpyrrole-2,5-dione 3 to form the bicyclic azepine 4.

Synthesis of brequinar analogue inhibitors of malaria parasite dihydroorotate dehydrogenase.

A series of 2-phenyl quinoline-4-carboxylic acid derivatives related to brequinar, an inhibitor of human dihydroorotate dehydrogenase (DHODH), has been prepared and evaluated as inhibitors of DHODH from the malaria parasite Plasmodium falciparum. Brequinar was essentially inactive against PfDHODH (IC(50) 880 microM) whereas several members of the series inhibited PfDHODH. Unexpectedly, replacement of the carboxylic acid required for brequinar to inhibit hDHODH was not essential in the diisopropylamides that inhibited PfDHODH.