Synthesis of 5-phenylpyrrolo[1,2-b][1,2,5]-triazepin-2(3H)-ones

The synthesis of a series of 5-phenylpyrrolo[1,2-b][1,2,5]triazepin-2(3H)-ones 1 as potential anxiolytic agents is described. Benzoylation of 1-phthalimidopyrrole, followed by hydrolysis, gave the 1-amino-2-benzoylpyrroles 3 . These were further functionalized to give the penultimate 1-aminoacetamido-2-benzoylpyrroles 8 and 9 , which were cyclized to the target pyrrolotriazepines 1.     

The lexicographic sum of Cohen-Macaulay and shellable ordered sets

We study the problem of determining when the lexicographic sum ∑ _q∈Q P _q of a family of posets {P _q/qεQ} over a posetQ is Cohen-Macaulay or shellable. Our main result, a characterization of when the lexicographic sum is Cohen-Macaulay, is proven using combinatorial methods introduced by Garsia. A similar characterization for when the lexicographic sum is CL (chainwise-lexicographically)-shellable, is derived using the recursive atom ordering method due to Björner and Wachs.     

Ab initio theoretical studies of a novel tungsten dihydrogen complex

Theoretical studies of H₂ bound to W(CO)₃(PH₃)₂ predict a stable η² complex with equal WH bonds (2.15 A) and a slightly lengthened (0.79 A) HH bond. The results are compared with recent experimental studies of the related W(CO)₃(P-i-Pr₃)₂(H₂) complex, and the nature of the bonding is discussed.     

Synthesis and polymerization of (E,E)-[6.2](9,10)anthracenophane-1,5-diene

The title compound has been synthesized by dimerization of a substituted p-xylylene, generated via a 1,8-Hofmann elimination. Several unique isomers of this dimer are also obtained. The title diene can be polymerized cationically to give low molecular weight polymer. Oxidative doping of this polymer with iodine forms a material with a conductivity of 3 × 10^?4 S/cm. In contrast to previously reported anthracenophanes this polymer is photochemically unreactive.