The reaction of quinazolones with POCl3 to form the corresponding chloroquinazolines occurs in two distinct stages, which can be separated through appropriate temperature control. An initial phosphorylation reaction occurs readily under basic conditions (R3N, aq pKa > 9) at t < 25 °C to give a variety of phosphorylated intermediates. Pseudodimer formation, arising from reaction between phosphorylated intermediates and unreacted quinazolone, is completely suppressed at these temperatures, provided the system remains basic throughout the POCl3addition. Clean turnover of phosphorylated quinazolones to the corresponding chloroquinazoline is then achieved by heating to 70−90 °C. (N)- and (O)-phosphorylated intermediates, involving multiple substitution at phosphorus, have been identified and their reactions monitored using a combination of 1H, 31P, and 19F NMR. Kinetic analysis of the reaction profiles suggest that the various intermediates react with both Cl− and Cl2P(O)O−, but product formation arises exclus...
Euan A. Arnott; Lai C. Chan; Brian G. Cox; Brian Meyrick; Andy Phillips
In this article we have investigated intermolecular excited-state proton transfer (ESPT) of firefly’s chromophore D-luciferin in DMSO–water binary mixtures using steady-state and time-resolved fluorescence spectroscopy. The unusual behavior of DMSO–water binary mixture as reported by Bagchi ... more
Resonantly driven quantum emitters offer a very promising route to obtain highly coherent sources of single photons required for applications in quantum information processing (QIP). Realizing this for on-chip scalable devices would be important for scientific advances and practical applica ... more
The aryl hydrocarbon receptor (AhR) is a nuclear receptor regulating a wide range of biological and toxicological effects. Metabolites of l-tryptophan are able to bind and activate AhR, providing a link between tryptophan catabolism and a novel mechanism of protective tolerance, referred to ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more