Perkin-Elmer magnetic standards

Nuclear magnetic resonance (- -H NMR) spectra were recorded on either a Varian T-60 or a Varian FT-80A with Me Si as an internal standard. Infrared spectra were obtained on a Perkin-Elmer 735B infrared spectrophotometer. All boiling points and melting points are uncorrected. Thin layer chromatography (TLC) utilized silica gel 60 F-254 chromatoplates (0.2-5 mm thickness). 

The nuclear magnetic resonance (NMR) spectra were recorded on a Varian A-60 spectrometer, using deuterated dimethyl sulfoxide (DMSO) as solvent and tetramethylsilane as internal standard. IR spectra were obtained on a Perkin-Elmer 237B IR spectrophotometer. 

In preparative-scale (10 M 1-naphthol) experiments, an Ace-Hanovia 450-W medium-pressure mercury arc was used with a Pyrex filter sleeve and a magnetically stirred Ace water-cooled reaction vessel. In experiments involving rose bengal as a sensitizer, tungsten lamp illumination was used. Ultraviolet spectral changes were measured with a Perkin-Elmer model 552A spectrophotometer. For GC-MS analysis, a Hewlett-Packard 5985A instrument was used with a fused silica capillary column coated with a bonded nonpolar polymethyl silane phase introduced directly into the electron Impact ionization source. Compounds were tentatively identified by comparison to published spectra and confirmed where possible with authentic standard materials. 

Melting points were measured in open capillary tubes in a Scientific Glass Co. melting point apparatus. Melting points and boiling points are uncorrected. The nuclear magnetic resonance spectral data presented were obtained with a Varian model T-60 spectrophotometer using dimethylsulfoxide or tetramethylsilane as an internal standard. A Perkin-Elmer Model 137 Sodium Chloride spectrophotometer was used to record infrared spectra. 

Fig. 18. Representative curves for a series of magnetic standards (a) Thermomagne-tometry (TM) curves using Perkin-Elmer TGS-1 and their materials and recommended temperatures. The values in parentheses were the observed values prior to calibration, (b) DTM (derivative) curves after conversion of the sensor voltage to actual temperature (43).

Purification was performed by preparative TLC. The compounds obtained were analyzed by Ultraviolet, Infrared and Nuclear Magnetic Resonance spectroscopy and by Gas Chromatography-Mass Spectrometry (GC-MS). The GLC analysis was carried out with a Perkin Elmer mod.990 equipped with a flame ionization detector, on a glass column OV 17 3%. NMR spectra were measured with a Varian 100 MHz for solutions in deuterated chloroform with tetramethyl-silane as internal standard. IR spectra were performed on a Perkin Elmer mod. 157 G in chloroform solution. GLC-MS spectra were carried out with an LKB 9000 at 70 eV. and a glass column OV 17 at 235 C. 

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