Pseudomonas aeruginosa PRG-1, an isolate from oil-contaminated soil, degrades benzothiophene (BT) and other related compounds in a 5% oil-basal medium system. The organism cannot grow on BT alone; 0.05% yeast extract is a suitable substrate for its growth and for its attack on BT. Although BT is partially toxic to the bacteria, toxicity is reduced when BT is added in this oil system. The oil phase is emulsified by bacterial action during the process. Oxygen uptake studies with washed cell suspensions show increased respiration in the presence of BT. Endogenous respiration is markedly decreased by p-hydroxy-mercuribenzoate, whereas respiration due to BT is scarcely affected, suggesting that oxygen is added directly to BT. Results obtained both in direct degradation and in respiration studies indicate that 3-methyl-thiophene is more rapidly and extensively degraded than BT and other related compounds.
We find that the manganese dioxide oxidation of optically active «-methylbutyraldehyde (from the oxidation of sec-butylcarbinol from fusel oil) gave in agreement with the previous report a mixture of 2b and 2c, as shown by the nmr,6 with no detectable rotation (<0.01°n eat in a 1-dm tube). The oxidation of a mixture of isobutyraldehyde and a-methylbutyraldehyde gave a complex mixture. After steam distillation, the volatile fraction showed upon gas chromatographic analysis peaks of retention time corresponding to 2a, the mixture of 2d, 2e, and 2f, and the mixture of 2b and 2c. It was possible by preparative gas chromatography to further isolate and characterize 2f and the mixture of olefinic stereoisomers 2d and 2e. All of these results are consistent with the proposed freeradical mechanism.
Pure samples of the diastereomeric 2-methylthiolane 1-oxides were isolated and characterized by chromatographic retention time and nmr spectroscopy. The cis isomer exhibits the shorter retention times on chromatography. The methyl resonance of the trans isomer shows the greater benzene-induced shift. The stereochemistry of oxidation of 2-methylthiolane by a variety of reagents is recorded.
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