New methods based on photolithography and surface fluorescence were used to determine photodeprotection rates and stepwise yields for light-directed oligonucleotide synthesis using photolabile 5‘-(((α-methyl-2-nitropiperonyl)oxy)carbonyl)(MeNPOC)-2‘-deoxynucleoside phosphoramidites on planar glass substrates. Under near-UV illumination (primarily 365 nm) from a mercury light source, the rate of photoremoval of the MeNPOC protecting group was found to be independent of both the nucleotide and length of the growing oligomer (t 1/2 = 12 s at 27.5 mW/cm2). A moderate dependence on solvent polarity was observed, with photolysis proceeding most rapidly in the presence of nonpolar solvents or in the absence of solvent (e.g., t 1/2 = 10−13 s at 27.5 mW/cm2). In solution, the photolysis rate was linearly dependent on light intensity over the range 5−50 mW/cm2. Average stepwise yields for the synthesis of dodecamer oligonucleotides were in the range of 92−94%, using monomers based on N 6-(phenoxyacetyl)-2‘-deoxyadenosine, N 2-isobutyryl-2‘-deoxyguanosine, N 4-isobutyryl-2‘-deoxycytidine, and thymidine. By comparison, an efficiency of 98%/step was obtained using a conventional 5‘-dimethoxytrityl monomer with acid deprotection on the same support. The lower yields associated with the photochemical process appears to be due to incomplete recovery of free 5‘-hydroxyl groups after photolysis on the support, although high yields of 5‘-OH nucleosides (≥96%) are consistently observed when 5‘-MeNPOC monomers are photolyzed in solution.

The parallel carbonylation of aryl halides with 6-25 bar of CO in 1-mL vials in a standard autoclave was investigated. 4-Bromoacetophenone and 2-chloropyridine were used as model substrates with 102 different O-nucleophiles (primary and secondary alcohols, phenols). No inertization during the loading was necessary. Fifty esters (43 new, yield up to 60%) were isolated and characterized. Ether, ester, ketone, and sometimes even olefin functions were usually tolerated. The new method is suitable for screening and small scale products synthesis.

Soil health-based agricultural management practices are widely promoted to reduce erosion, increase nutrient use efficiency, improve soil structure, and sustain or increase yields. Pest and disease management are less frequently considered as components of a soil health management system. We present a framework for how the crop protection industry can advance soil health by developing systems of crop protection innovation that simultaneously target soil health outcomes, either through direct impact on soil or by enabling practices that promote soil health outcomes. Such an approach could lead to cross-sectoral, integrated agricultural solutions that achieve agronomic, environmental, and economic goals.

An efficient synthesis of a difluorosulfone-containing herbicide has been achieved by selective reductive silylation of a symmetrical bis(trifluoromethyl)-1,2,3-triazole. Subsequently, a fluoride-induced reaction led to a difluoromethyl anion equivalent, which was reacted with a sulfur electrophile leading ultimately to the key difluorosulfide moiety.

The problems associated with the use of combinatorial chemistry in lead generation and optimization are discussed. A post‐synthesis data evaluation process is described which can cope with large data sets from parallel synthesis effects. It relies on analysis of purity as well as on identification, and can efficiently limit compounds screened to manageable numbers. © 1999 Society of Chemical Industry