Mass Spectrometric Evidence for Heptaborane

Abstract

Communications to the Editor 3157 pyridine-dimethylformamide provided 6a-fluoro-16 -methyl-4•9 11} -pregnadiene -3,20-dione-17 ,21diol 21-acetate (m.p. 188-190°, [a]o +74°(all rotations in CHCE), ®1° 235, log e 4.17; Anal. found for C24H3i06F: C, 69.28, H, 7.24, F, 3.99), which was treated with N-bromoacetamide in aqueous dioxane in the presence of perchloric acid7 and the bromohydrin cyclized directly with potassium acetate in acetone to afford 6a-fluoro-16a-methyl-9/3,lld-oxido-A4-pregnene-3,20-dione-17,21-diol 21acetate (m.p. 188-191°). Opening of the epoxide with hydrogen fluoride in methylene chloride-tet-rahydrofuran8 led to 6 a, 9 a-difluoro-16 a-methylhydrocortisone acetate (II) (m.p. 255-260°, [a]D

Are there heptaboranes

“…Carbon monofluoride of a composition CF0.92 was first prepared by Ruff, Bretschneider, and Elert in 1934. 3 In 1959, Rudorff and Rudorff4 reported a preparation of carbon monofluorides of compositions CFo.es to CFo.98 which ranged from black to off-white in color.4 '8 The techniques at Rice University1 employed both high-temperature and high-pressure syntheses to prepare the first perfluorinated carbon monofluoride which had a stoichiometry of CFi .12 and was snow white. These syntheses were adaptable to the production of 40 g quantities of pure white carbon monofluoride and also overcame the disadvantage of poor reproducibility which was characteristic of the previous syntheses.…”

A Thermodynamic Study of Homopiperazine, Piperazine and N-(2-Aminoethyl)-Piperazine and Their Complexes With Copper(ii) Ion

“…Further, the difference between the two protonation constants is greater for these secondary-amine nitrogens than is the difference between the two primary-amine nitrogens in ethylenediamine (log Kn at 30°are 9.81 and 6.79). 7 In contrast to the simple cyclic compounds, X -(2-aminoe thyl) -piperazine has one primary-, one secondary-and one tertiary-amine nitrogen. The first protonation constant (log Ki) represents either the primaryamine or the secondary-amine nitrogen (probably the former) while the second protonation constant (log K2) represents the other of these two nitrogen atoms.…”

Mass Spectrometry

“…Mass spectrometric studies of structural relations between dextropimaric, isodextropimaric, and cryptopimaric acids are presented by Brunn, Ryhage, and Stenhagen (48). Applications to other structural problems include: amino acid sequence in peptides (31), stereochemistry of spimeric cyclic alcohols (32), and evidence for the existence of a heptaborane, C-H13 (405). Specific molecular rearrangements in organic compounds are discussed by Beynon, Lester, and Williams (29).…”