The structure of 7,14-dicarbonylethoxyacenaphth[l,2-k]-fluoranthene and its tetracyanoquinodimethane charge transfer complex

A molecular mechanics simulation of the structure of 7,14-dicarbonylethoxyacenaphth[l,2-k]fluoranthene,1, indicated a preferred geometry for the hindered substituents in which the carbonyl groups were constrained to an anti conformation because of the steric hindrance associated with the in-plane buttressing hydrogen atoms. X-ray crystallographic analysis of1 verifies the correctness of the computation. Compound1 and tetracyanoquinodimethane,2, form a charge transfer complex, and a crystal structure analysis shows a slightly offset, nearly parallel arrangement of the acceptor with the cloud of the donor. The interplanar distance of 3.45 Å between acceptor and donor lies within the statistical limits of the interplanar distance of complexes formed between2 and a variety of PAH donors. The steric hindrance caused by the substituents in1 appears to offer only minimal interference to the formation of the complex.     

The 2-(methylthiomethoxy)ethoxycarbonyl [mtmec] protecting group

Alcohols (ROH) may be converted into their MTMEC derivatives ($\text{6}$) by acylation with 2-(methylthiomethoxy)ethoxycarbonyl chloride ($\text{5}$); the MTMEC “protected protecting group” may be removed by treatment first with Hg(II) perchlorate in the presence of 2,4,6-collidine or pyridine in acetone-water solution, followed by hydrolysis under very mild basic conditions.     

Use of 2,4,6-tri-isopropylbenzenesulphonyl hydrazide in the mcfadyen-stevens aldehyde synthesis

Aroyl derivatives of 2,4,6-tri-isopropylbenzenesulphonyl hydrazide decompose readily in the presence of potassium carbonate in boiling methanol solution to give aldehydes and varying quantities of the corresponding alcohols and methyl esters. The formation of the latter by-products is suppressed and good yields of aldehydes are obtained when hydrazine is added to the reaction medium.     

Some observations relating to phosphorylation methods in oligonucleotide synthesis

A very convenient procedure for the conversion of ($\text{N}$),O-5′-protected deoxyribonucleosides ($\text{8}$) into the triethylammonium salts of the corresponding 3′-($\text{o}$-chlorophenyl) phosphates ($\text{9}$) is described. Good yields of partially-protected 3′→5′-dinucleoside phosphates ($\text{10}$) are obtained from the latter ($\text{9}$) and 3′-unprotected nucleoside building blocks ($\text{12a}$).     

Measuring overall efficiency and effectiveness using DEA

This paper presents a framework where data envelopment analysis (DEA) is used to measure overall efficiency and show how to apply this framework to assess effectiveness for more general behavioral goals. The relationships between various cone-ratio DEA models and models to measure overall efficiency are clarified. Specifically it is shown that as multiplier cones tighten, the cone-ratio DEA models converge to measures of overall efficiency. Furthermore, it is argued that multiplier cone and cone-ratio model selection must be consistent with the behavioral goals assigned or assumed for purposes of analysis. Consistent with this reasoning, two new models are introduced to measure effectiveness when value measures are represented by separable or linked cones, where the latter can be used to analyze profit-maximizing effectiveness.     

Oligo- and poly-nucleotides: 50 years of chemical synthesis

It is fifty years since the first chemical synthesis of a dinucleoside phosphate and a dinucleotide with natural 3'-->5'-internucleotide linkages was reported. The main developments in the methodology of oligo- and poly-nucleotide synthesis that have taken place since are described.     

Some reaction variables in the solution synthesis of lead (IV) polyesters

A number of reaction variables in the solution synthesis of lead (IV) polyesters were examined. Both electronic nature of the diacid and lead-containing material is important, with an increase in yield resulting as the nucleophilicity of the salt increases. Diffusion is also an important factor. Reaction is favored by an increase in the concentration of reactants.