Mass spectrometry of steroid systems. VIII. The determination of the configuration at c-9 and c-10 in Δ4-3-oxosteroid series

Zaretskii, V. I.; Wulfson, N.S.; Sadovskaya, V. L.

doi:10.1016/s0040-4039(01)99984-8

Cited by 13 publications

(9 citation statements)

References 1 publication

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“…1) show that most of the fragment ion peaks in the higher mass range are formed by the loss of different combinations of [CH 3 COOH], [CH 2 =C=O], and [CH 3 ]. The formation of ions in the low mass range was reported previously [25]. For SIM analysis, two characteristic ions were selected for each compound, namely m/z 228 and 288 for T, and m/z 270 and 330 for ET.…”

Section: Analysis Of T and Et By Sbse-hd-td-gc/msmentioning

confidence: 92%

Quantification of testosterone and epitestosterone in human urine samples by stir bar sorptive extraction – thermal desorption – gas chromatography/mass spectrometry: Application to HIV‐positive urine samples

Stopforth

Grobbelaar²,

Crouch

et al. 2007

J of Separation Science

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A simple method is described for the measurement of testosterone (T) and epitestosterone (ET) in human urine samples. The deconjugated steroids were extracted directly from the samples by stir bar sorptive extraction (SBSE) and derivatized in situ on the stir bar by headspace acylation prior to thermal desorption and GC/MS. Extraction and derivatization parameters, namely salt addition, temperature, and time, were optimized to improve the recovery of T and ET by SBSE. The limits of quantification (S/N 10) were 0.9 ng/mL for T and 2.8 ng/mL for ET. Quantification of the steroids in urine samples was performed using standard addition to avoid the influence of matrix effects. The method was applied for the measurement of urinary T and ET in a group of healthy volunteers and HIV+ patients. Decreased levels of T were detected in the HIV+ group, whereas the excretion of ET was comparable for the two groups. Further clinical research is required to elucidate the biomarker significance of the T/ET ratio in HIV infection.

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Section: Analysis Of T and Et By Sbse-hd-td-gc/msmentioning

confidence: 92%

Quantification of testosterone and epitestosterone in human urine samples by stir bar sorptive extraction – thermal desorption – gas chromatography/mass spectrometry: Application to HIV‐positive urine samples

Stopforth

Grobbelaar²,

Crouch

et al. 2007

J of Separation Science

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“…Journal of the American Chemical Society / 91:1 / January No attempt was made to analyze for CO or CO, from I at 2380 Á and from II and III at both wavelengths. 6 The quantum yields are for the neat lactones. = Identity of product not certain.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, for example, irradiation of methylcyclohexanone gives rise only to cis-and írans-2-heptenals.5 Similar results have been noted in steroidal ketones. 6 In the case of lactones, however, the replacement of a hydrogen atom with a methyl group in the y position does not eliminate or even reduce the carbon-oxygen bond cleavage. This fact is consistent with the conclusion that carbon-oxygen bond fission occurs from a different state than carbon-carbon bond rupture and that this state is the precursor to the triplet state from which carbon-carbon bond fission occurs.2…”

Section: Resultsmentioning

confidence: 99%

Molecular structure and photochemical reactivity. XI. Wavelength and methyl substituent effects in the photochemistry of lactones in the liquid phase

Simonaitis¹,

Pitts²

1969

J. Am. Chem. Soc.

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The photochemistry of -butyrolactone (I) (2537 A, liquid phase) is extended to a-methylbutyrolactone (II) and -methylbutyrolactone (III) to determine (1) the effect of replacing a hydrogen atom of -butyrolactone with a methyl group in the a (lactone II) and (lactone III) positions on product quantum yields and excited-state lifetimes, and (2) the effect on product quantum yields with a change in wavelength from 2537 to 2380 Á. A methyl group in the a position increases the formate from 0.23 (allyl formate) to 0.39 (crotyl formate), and the . increases from 0.013 (cyclopropane) to 0.027 (methylcyclopropane) (2537 A, 25°, neat) while the yield of the aldehyde products does not change (succinaldehyde and methylsuccinaldehyde). A methyl group in the position does not affect the ^™^significantly but 6 » » -4-6 is very much less than Tauccinaidehyde and , succinaldehyde• A methyl group in the position decreases the lifetime of the excited state from 1.2 X 10"9 to 10"" sec, but substitution in the position has only a small effect. The change in wavelength from 2537 to 2380 A increases the yield of the dialdehydes ^2 5 37SUccinaidehyde = 0.06; 23808"™™« ß , ß = 0.11; 2337methy]succinaldehyde = 0.05; 2 ^methylsuccinaldehyde 0.13), but does not change the quantum yield of formate or cyclopropane significantly. The possibility that this wavelength effect is due to vibrational effects in solution is discussed.

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“…The syntheses of other 8-isosteroids have been studied by several groups [101,[105][106][107][108][109][110][111]. Thus the conversion of the optically active key intermediate 8 to the ketone 142 (Scheme 10-11) was accomplished [105][106][107][108] by following the usual method (cf.…”

Section: Isosteroidsmentioning

confidence: 99%

Bc → BCD → Abcd

1974

Organic Chemistry: A Series of Monographs

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Mass spectrometry of steroid systems. VIII. The determination of the configuration at c-9 and c-10 in Δ4-3-oxosteroid series

Cited by 13 publications

References 1 publication

Quantification of testosterone and epitestosterone in human urine samples by stir bar sorptive extraction – thermal desorption – gas chromatography/mass spectrometry: Application to HIV‐positive urine samples

Quantification of testosterone and epitestosterone in human urine samples by stir bar sorptive extraction – thermal desorption – gas chromatography/mass spectrometry: Application to HIV‐positive urine samples

Molecular structure and photochemical reactivity. XI. Wavelength and methyl substituent effects in the photochemistry of lactones in the liquid phase

Bc → BCD → Abcd

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