Al(OTf)3: an efficient recyclable catalyst for direct nucleophilic substitution of the hydroxy group of propargylic alcohols with carbon- and heteroatom-centered nucleophiles to construct C-C, C-O, C-N and C-S bonds

A general and highly efficient Al(OTf)₃-catalyzed methodology has been developed for the direct nucleophilic substitution of the hydroxy group in propargylic alcohols with a variety of carbon- and heteroatom-centered nucleophiles such as alcohols, aromatic compounds, amides, and thiols, leading to the construction of C-C, C-O, C-N and C-S bonds.     

Probes for Narcotic Receptor Mediated Phenomena

The synthesis of a series of epoxy 5‐phenylmorphans is being explored in order to determine the conformational requirements of the phenolic ring in a phenylmorphan molecule that may be needed both for binding to a specific opioid receptor and for exhibiting opioid agonist or antagonist activity. Of the twelve possible ortho‐ and para‐bridged isomers (a–f) (Fig. 1), we now report the synthesis of the para‐d isomer, rac‐(3R,6aS,11aR)‐2‐methyl‐1,3,4,5,6,11a‐hexahydro‐2H‐3,6a‐methanobenzofuro[2,3‐c]azocin‐8‐ol ( 3 ). Compound 3 was synthesized via construction of the 5‐phenylazabicyclo[3.3.1]non‐3‐ene skeleton (Scheme 1) and subsequent closure of the epoxy bridge (Scheme 2). As determined by an X‐ray diffraction study, the epoxy bridge, restricting the phenyl‐ring rotation, fixed the dihedral angle between the least‐squares planes through the phenyl ring and atoms N(2), C(3), C(11a), and C(6a) of the piperidine ring (Fig. 2) at 43.0°, and the torsion angle C(12)? C(6a)? C(6b)? C(10a) at ?95.0°.     

GC-MS analysis of the PCB substitute Ugilec 141 and its occurrence in waste mineral oils

After the restrictions on production and use of PCBs, Ugilec 141, a technical mixture of dichlorobenzyldichlorotoluenes (DBDTs), has been used as a PCB substitute in hydraulic systems. In the Netherlands, the production, import and use of Ugilec 141 has been forbidden since 1988. A method has been developed for the analysis of Ugilec 141 in waste mineral oils to control waste oil import and processing. The method development was based on modification of procedures for the analysis of PCBs in oil and dioxins in fatty matrices and analysis was performed with gas chromatography with mass spectrometry. For sample clean-up, several combinations of column chromatography with activated carbon, alumina, and silica gel have been tested to obtain extracts free from matrix interferences. An internal standard of ¹³C-labeled DBDT was examined to check recoveries from the clean-up procedures. Quantification was performed by comparison with the six most abundant peaks of an external Ugilec 141 standard mixture. Validation experiments showed a linear range from 0.25 to 60 mg Ugilec 141 kg^?1 oil, a reproducibility of 3% and a limit of determination of 0.25 mg Ugilec 141 kg^?1 waste oil. The method was applied in a survey of 70 samples of waste mineral oils from producers all over the Netherlands; this revealed levels below the limit of determination and one positive sample with a concentration of 5.7±0.1 mg Ugilec 141 kg^?1 oil. In an inspection inquiry, one contaminated oil was found containing 116 ± 9 g Ugilec 141 kg^?1 oil.