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 Now online (2)recycle big ...and 237 guests Last 5 registered Oplandisks nothingstar N_loop yipe foxtrotromeo Browse members... |
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Members 8025Messages 2614103 Today 16 Topics 127542 |
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fireworks |
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looks more like a sea urchin gay pride parade |
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OMG SANTA EXPLODED |
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#43 2,5-DIMETHOXY-4-(n)-PROPYLTHIOPHENETHYLAMINE SYNTHESIS: To a solution of 3.4 g of KOH pellets in 50 mL hot MeOH, there was added a mixture of 6.8 g 2,5-dimethoxythiophenol (see under the recipe for 2C-T-2 for its preparation) and 7.4 g (n)-propylbromide dissolved in 20 mL MeOH. The reaction was exothermic, with the deposition of white solids. This was heated on the steam bath for 0.5 h, added to 800 mL H2O, additional aqueous NaOH added until the pH was basic, and extracted with 3x75 mL CH2Cl2. The pooled extracts were washed with dilute NaOH, and the solvent removed under vacuum. The residue was 2,5-dimethoxyphenyl (n)-propyl sulfide which was obtained as a pale yellow oil, and which weighed 8.9 g. It had a light pleasant fruity smell, and was sufficiently pure for use in the next reaction without distillation. A mixture of 14.4 g POCl3 and 13.4 g N-methylformanilide was heated for 10 min on the steam bath. To this claret-colored solution was added 8.9 g of 2,5-dimethoxyphenyl (n)-propyl sulfide, and the mixture heated an additional 25 min on the steam bath. This was then added to 800 mL of well-stirred warm H2O (pre-heated to 55 °C) and the stirring continued until the oily phase had completely solidified (about 15 minutes). The resulting brown sugar-like solids were removed by filtration, and washed with additional H2O. After sucking as dry as possible, they were dissolved in an equal weight of boiling MeOH which, after cooling in an ice-bath, deposited pale ivory colored crystals. After filtration, modest washing with cold MeOH, and air drying to constant weight, there was obtained 8.3 g of 2,5-dimethoxy-4-(n-propyl-thio)benzaldehyde with a mp of 73-76 °C. Recrystallization from 2.5 volumes of MeOH provided a white analytical sample with mp 76-77 °C. The NMR spectrum in CDCl3 was textbook perfect, with the two aromatic protons showing singlet signals at 6.81 and 7.27 ppm, giving assurance that the assigned location of the introduced aldehyde group was correct. |
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i love IDM-techno-babble. Microbial mat biotas dominated by cyanobacteria, are commonly preserved in Meso- and Neoproterozoic carbonate facies, the first well-documented case being the Bitter Springs biota of central Australia (Schopf, 1968Go). Such microfossils are preserved in three dimensions due to the very early (i.e., prior to degradational collapse) diagenetic emplacement of silica, from which point they become more or less impervious to subsequent diagenetic, and even low grade metamorphic alteration (Knoll, 1992Go). The quality of preservation can be spectacular but, unfortunately, the view is profoundly biased. The Bitter Springs-type "taphonomic window" is limited to conspicuously shallow-water/supratidal carbonate environments and is conspicuously absent in the Phanerozoic. The reason lies in the disjunct history of silica biogeochemistry. Prior to the appearance of silica biomineralizers in the terminal Proterozoic, surface waters of the oceans would have been saturated with respect to silica, and supersaturated in restricted peritidal settings (Maliva et al., 1989Go). These restricted environments would also have been dominated by prolific microbial mats which, as they decayed, served as foci for the nucleation and precipitation of silica (Knoll, 1985Go). Such paleoenvironments were far from equable and, with a few notable exceptions (e.g., Zhang et al., 1998Go; Butterfield, 2000Go), tended to exclude eukaryotic organisms. So despite its exceptional preservation, this taphonomic mode fails to offer even a broad approximation of paleodiversity. Moreover, the disappearance of Bitter Springs type biotas at the end of the Proterozoic in no way reflects biological extinction; rather, it is a taphonomic signal induced by the evolution of silica-biomineralizing sponges and consequent draw-down of marine silica concentrations. |
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will your diagenetic silica infusion make my pupils dilate? DIDN'T THINK SO |
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anyway is it talking about silicon based life or just stupid bacteria remotely involved in silicon? |
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