Structure-gas chromatographic electron capture sensitivity relationships of some substituted 17alpha-acetoxyprogesterones.
Structure-electron capture sensitivity relationships were established for underivatized 17alpha-acetoxyprogesterones. While progesterone was very insensitive, 17alpha-acetoxyprogesterone had a response of 4.8 X 10(2) C/mole. Methyl groups in the A or B ring of 17alpha-acetoxyprogesterone had no effect. A keto group at C-6 was 25 times more sensitive (1.2 X 10(4) C/mole). A double bond at C-6,7 enhanced the sensitivity sevenfold (3.5 X 10(3) C/mole), but double bonds at C-1,2 or C-9,11 had only slight effect. Substitution at C-16 was important. A methyl group at C-16 had two and three times the sensitivity in the 3-keto delta4 and 3-keto delta4,6 series (1.1 X 10(3) and 1.1 X 10(4) C/mole), respectively. A methylene group at C-16, in contrast showed a six-and twofold greater sensitivity over the C-16 methyl in the two series (7 X 10(3) and 2.2 X 10(4) C/mole), respectively. The most sensitive compound was 6-dehydro-6methyl-16-methylene-17alpha-acetoxyprogesterone (melengestrol acetate). Its sensitivity was 2.2 X 10(4) C/MOL, Comparable to the most sensitive halo esters of steroid alcohols reported in the literature. Its electron capture coefficient was 3-7.6X 10(10) 1/mole. The coef-icient was independent of the detector temperature, indicating low activation energy for electron absorpiton.
Preparation and physico-chemical properties of some steroid heptafluorobutyrates and 3-enol heptafluorobutyrates.
Heptafluorobutyrates of estrone and pregnanediol as well as 3-enol heptafluorobutyrates of several 3-oxo-4-ene steroids have been prepared on a preparative scale. In addition to melting points, elemental analysis, optical rotation, optical rotatory dispersion and circular dichroism, these derivatives have been characterized using ultraviolet-, infrared-, nuclear magnetic resonance- and mass spectrometry. Gas liquid chromatography was performed on two stationary phases (OV-1 and OV-17) and the relative molar responses to electron capture were determined. Rf values for thin-layer chromatography are given. The reaction mechanism of the enol heptafluorobutyration is discussed.
Electron attachment and negative ion-molecule reactions in nitrous oxide
The negative ions formed in N2O and N2O and N2O + O2 mixtures have been studied in the gas phase using a drift tube and mass filter. Gas pressures were in the Torr range, and reduced fields were varied between 10–17 and 10–15 V cm2 molecule–1. The observed ion spectrum was found to be governed by the following reaction, with their associated thermal rate constants: e + N2O → N2+ O–, k1= 4 × 10–15 cm3 molecule–1 s–1, O–+ N2O → NO–+ NO, k3=(1.95 ± 0.06)× 10–10 cm3 molecule–1 s–1, NO–+ N2O → NO–2+ N2, k4=(2.8 ± 0.2)× 10–14 cm3 molecule–1 s–1, NO–+ 2N2O → N3O–2+ N2O, k5=(8.5 ± 1.5)× 10–30 cm6 molecule–2 s–1, O–+ 2N2O → N2O–2+ N2O, k6=(4.2 ± 0.5)× 10–29 cm6 molecule–2 s–1, NO–+ N2O → N2O + NO + e, k11=(6.0 ± 1.0)× 10–12 cm3 molecule–1 s–1, O–2+ N2O → O–3+ N2, k10 < 10–12 cm3 molecule–1 s–1. The rates of reaction, (5), (6) and (11) were weak functions of reduced field. In no experiment was any evidence found for the existence of a long-lived N2O– ion.