Synthesis and reactions of N-methylbenzylammonium fluorochromate(VI) on silica gel, a selective and efficient heterogeneous oxidant.
N-Methylbenzylammonium fluorochromate(VI) (MBAFC) is easily synthesized by addition of N-methylbenzylamine to an aqueous solution of CrO3 and HF. MBAFC shows selectivity in the oxidation of aryl alcohols to their corresponding aldehydes and ketones under mild conditions. The durability, ease of work up and efficiency of MBAFC are considerably increased upon its absorption on silica gel.
N-Methylpiperidinium Chlorochromate Adsorbed on Alumina: A New Deoximation Reagent
Summary. N-Methylpiperidinium chlorochromate adsorbed on alumina was found to be an efficient and selective reagent for the mild oxidative cleavage of oximes.
Palaeocarpinus (Extinct Betulaceae) from Northwestern China: New Evidence for Paleocene Floristic Continuity between Asia, North America, and Europe
Spiny-bracted fruits of Palaeocarpinus Crane, a genus of Betulaceae previously known only from Europe and North America, have been discovered in the Paleocene of Altai, northwestern China. The fruits are found in association with abundant Corylus-like foliage and staminate catkins containing Corylus-like pollen. Because of problems distinguishing leaves of Corylus from those of extinct betulaceous genera, we place these leaves in the genus Corylites Gardner ex Seward & Holttum. The fruits, staminate catkins, pollen, and leaves from Altai were probably all produced by a single species. Palaeocarpinus orientalis is nearly identical in its morphology to Palaeocarpinus joffrensis from the Paleocene of North America except in the more rounded primary bracts of the associated staminate catkins. The species is less similar to Palaeocarpinus laciniata from the Paleocene of southern England.