The Absorption Spectra of Certain Aldazines

Blout, E. R.; Gofstein, Ralph M.

doi:10.1021/ja01217a005

Cited by 34 publications

(5 citation statements)

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“…To synthesize the 20-hydrazone 7 , the exchange reaction of dimethylhydrazone 6 with anhydrous hydrazine was used to avoid the formation of azines as impurities. The 20- N , N -dimethylhydrazone 8 was prepared from the reaction of 16-ene pregnenolone 25 with N , N -dimethylhydrazine.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,

Son

et al. 1996

J. Med. Chem.

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The pregnene derivatives with modifications at the 17,20-side chain and D-ring were synthesized and evaluated as inhibitors of human testicular 17 alpha-hydroxylase/C17,20-lyase. The results demonstrate that compounds which have 20-substituents with moderate to strong dipole properties, such as 20-oxime (3, 20), 20 beta-ol (24, 30), and 20 beta-carboxaldehyde (27), are potent inhibitors of this enzyme complex. The 20-substituents with hydrophobic property were devoid of inhibitory activity, e.g., the dimethylhydrazones 8 and 9. The 16-ene together with 20-oxime (20) showed the most potent inhibition of this enzyme complex, whereas 17(20)-ene modification as in 17(20)-ene-20-carbonitrile (14) did not increase activity in comparison to the 20 beta-carbonitrile (16). The bioisotere of 27 with 20-aza (19) also reduced the inhibitory activity. The results showed that isomeric configurations at the 20-position of some steroidal compounds are important factors which influence the potency of the inhibition significantly (e.g., 20 beta-ols 24 and 30 were 3-5-fold more potent than 20 alpha-ols 23 and 29). As expected, some compounds based on the pregn-5-en-3 beta-ol skeleton, which is similar to the natural substrate of human testicular 17 alpha-hydroxylase/C17,20-lyase in A- and B-rings, showed more potent inhibition than similar compounds which are based on the pregn-4-en-3-one skeleton (e.g., 23-25 compared to 29-31). These results suggest that A- and B-rings make significant contributions to the binding of these steroidal compounds to the 17 alpha-hydroxylase and C17,20-lyase. In comparison to ketoconazole, a nonsteroidal inhibitor of 17 alpha-hydroxylase and C17,20-lyase which has been used in the treatment of prostatic cancer, the steroidal compounds 20, 24, and 27 demonstrate more potent inhibition for this enzyme complex. These inhibitors warrant further investigation in biological systems. The structural features of these compounds may serve as leads in the design of new inhibitors.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,

Son

et al. 1996

J. Med. Chem.

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“…The samples were provided by Clariant (Frankfurt Germany). They were synthesized by condensation of hydrazine with the corresponding naphthyl aldehydes. − Dichloromethane (LiChrosolv) was obtained from Merck and used without further purification.…”

Section: Materials Methods and Computational Approachmentioning

confidence: 99%

Ultrafast Photoinduced Dynamics of Pigment Yellow 101: Fluorescence, Excited-State Intramolecular Proton Transfer, and Isomerization

et al. 2007

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The ultrafast excited-state dynamics of the fluorescent pigment yellow 101 (P.Y.101) and the closely related 1,1'-naphthalazine, a nonfluorescent derivative that lacks the OH groups at the naphthyl rings, are studied combining femtosecond spectroscopy and high-level quantum chemical calculations. The observed ultrafast dynamics and the spectral signature of photoexcited 1,1'-naphthalzine can be consistently explained with a previously proposed mechanism, suggesting fluorescence quenching via an optically forbidden npi* state. In contrast, for a description of the excited-state dynamics of P.Y.101, the expected simple absorption/fluorescence model is not adequate. Instead, besides fluorescence as the main decay channel of the excited-state population, ultrafast excited-state intramolecular proton transfer (ESIPT) and isomerization processes have to be considered for a complete understanding of the complex subnanosecond dynamics. Combining experiment and theory, the following kinetic model is derived: upon photoexcitation a major part of the excited-state population decays via fluorescence from an enol-type isomer of P.Y.101, while a small part of the population undergoes ESIPT and fluoresces from a keto-type form. Furthermore, arguments are given that, to a minor extent, also trans-cis isomerization of the keto form takes place on the S1 surface leading probably to a long-lived cis-keto form in the ground state. The remarkable photostability of this organic pigment is thus achieved by the interplay of different ultrafast nondestructive decay channels.

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“…After purging the acidified mixture for 2 h, the mixture was adjusted to pH 11, and the sparging was continued for an additional 2 h. The resulting purged aqueous phase was neutralized and subjected to continuous ether extraction for 24 h. The aqueous phase was adjusted to pH 3 and similarly extracted with ether. Finally, the aqueous phase from the pH 3 ether extraction was adjusted to pH 11 and again extracted with ether for 24 h. Samples (usually 1.0 ml) were placed in scintillation vials to which 10 ml of Aquasol- 2 (New Enkland Nuclear) was added. Measurements for radioactivity were carried out in a model 3255 Packard Tri-Carb liquid scintillation spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

McCormick

Cornell

Kaplan

1981

Appl Environ Microbiol

278

143

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Biodegradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) occurs under anaerobic conditions, yielding a number of products, including: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine, hexahydro-1,3,5-trinitroso-1,3,5-triazine, hydrazine, 1,1-dimethyl-hydrazine, 1,2-dimethylhydrazine, formaldehyde, and methanol. A scheme for the biodegradation of RDX is proposed which proceeds via successive reduction of the nitro groups to a point where destabilization and fragmentation of the ring occurs. The noncyclic degradation products arise via subsequent reduction and rearrangement reactions of the fragments. The scheme suggests the presence of several additional compounds, not yet identified. Several of the products are mutagenic or carcinogenic or both. Anaerobic treatment of RDX wastewaters, which also contain high nitrate levels, would permit the denitrification to occur, with concurrent degradation of RDX ultimately to a mixture of hydrazines and methanol. The feasibility of using an aerobic mode in the further degradation of these products is discussed.

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The Absorption Spectra of Certain Aldazines

Cited by 34 publications

References 0 publications

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,

Ultrafast Photoinduced Dynamics of Pigment Yellow 101: Fluorescence, Excited-State Intramolecular Proton Transfer, and Isomerization

Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

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The Absorption Spectra of Certain Aldazines

Cited by 34 publications

References 0 publications

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C17,20-Lyase,

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C17,20-Lyase,

Ultrafast Photoinduced Dynamics of Pigment Yellow 101: Fluorescence, Excited-State Intramolecular Proton Transfer, and Isomerization

Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

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Resources

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Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,

Synthesis and Evaluation of Pregnane Derivatives as Inhibitors of Human Testicular 17α-Hydroxylase/C_17,20-Lyase^,