Zobrazeno 1 - 10
of 43
pro vyhledávání: '"M. L. Sa E Melo"'
Publikováno v:
Bulletin of Environmental Contamination and Toxicology. 70:1264-1268
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a133f05b110968a0b7af43382001d733
https://doi.org/10.1007/s00128-003-0119-9
https://doi.org/10.1007/s00128-003-0119-9
Publikováno v:
Tetrahedron Letters. 37:687-690
The β-epoxidation of 3 β -acetoxy-Δ 5 -unsaturated steroids has been achieved with mmerous potassium permanganate-metal sulphates and nitrates with a high degree of stereoselectivity. 5β,6β-Epoxides are formed in a one step reaction in good yiel
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::20a1111f850c9b52623cb29583b2477a
https://doi.org/10.1016/0040-4039(95)02243-0
https://doi.org/10.1016/0040-4039(95)02243-0
Autor:
H. I. M. Soares, M. J. M. de Almeida, M. J. S. M. Moreno, A. S. Campos Neves, José A. Paixão, M. L. Sa E Melo, L. C. R. Andrade, R. M. L. M. Martins
Publikováno v:
Acta Crystallographica Section E Structure Reports Online. 59:o299-o301
The title compound, C25H34O6, has a 3β,21-configuration, with the epoxy O atom at 16α,17α. Rings A and C have chair conformations which are slightly flattened. Because of the presence of a double bond, ring B assumes an 8β,9α-half chair conforma
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::d885b573a51b52b85a8ff7bf63f47358
https://doi.org/10.1107/s1600536803002721
https://doi.org/10.1107/s1600536803002721
Autor:
José A. Paixão, M. L. Sa E Melo, Fernanda M.F. Roleira, L. C. R. Andrade, E. J. Tavares da Silva, A. S. Campos Neves, M. J. M. de Almeida
Publikováno v:
Acta Crystallographica Section E Structure Reports Online. 59:o21-o23
The ring conformation of the title compound, C19H30O3, is similar to that of the 5α-epimer except for the cis A/B ring junction. Ring D adopts a 13β,14α-half chair conformation. The molecules are linked together by a two-dimensional network of h
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::91ff2cb469b60873307ebf5ce5979655
https://doi.org/10.1107/s1600536802022055
https://doi.org/10.1107/s1600536802022055
Autor:
José A. Paixão, M. M. Cruz Silva, M. J. M. de Almeida, M. J. S. M. Moreno, M. L. Sa E Melo, A. S. Campos Neves, L. C. R. Andrade
Publikováno v:
Acta Crystallographica Section E Structure Reports Online. 58:o898-o900
The title compound, C25H36O5, has two independent molecules in the asymmetric unit with similar geometry. The main difference between the two molecules relates to the conformation of the 17β-methyl ketone and 3β-acetoxy groups, the latter being
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e7d60a4ecb9713a09de68ac326db8974
https://doi.org/10.1107/s1600536802012862
https://doi.org/10.1107/s1600536802012862
Publikováno v:
Acta Crystallographica Section E: Structure Reports
The title hydrated tetrol, C(19)H(32)O(4)·3H(2)O, was synthesized by stereoselective reduction of the compound 3β,5α,6β-trihy-droxy-androstan-17-one. All rings are fused trans. The organic mol-ecules are connected head-to-tail along the c axis vi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::47d6be5314175a7eaf603a3b8ef63c81
https://pubmed.ncbi.nlm.nih.gov/21837048
https://pubmed.ncbi.nlm.nih.gov/21837048
Publikováno v:
Acta Crystallographica Section E: Structure Reports
The title compound, C(19)H(30)O(4), is an androstan-17-one derivative synthesized from the dehydro-epiandrosterone through a sequential addition of an oxidant, followed by a trans-diaxial opening of the epoxide generated, with Bi(OTf)(3) (OTf is trif
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3d364a875fd1fff478f9907ff21d187e
https://pubmed.ncbi.nlm.nih.gov/21754383
https://pubmed.ncbi.nlm.nih.gov/21754383
Publikováno v:
Tetrahedron Letters. 34:357-360
Zinc reduction of α, β-unsaturated ketones in acetic acid has been efficiently accomplished under sonochemical conditions. Different α-enone systems give two kinds of products: olefins and allylic alcohols. Regio- and stereoselective are reported.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::744c21660e18a359d841acabde017961
https://doi.org/10.1016/s0040-4039(00)60587-7
https://doi.org/10.1016/s0040-4039(00)60587-7
Publikováno v:
Tetrahedron Letters. 34:353-356
The sonochemical reductive opening of α, β-epoxy ketones and their α′-oxygenated (-OH or -OAc) analogs by aluminium amalgam allows shorter reaction times, better yields of the respective β-hydroxy ketones and minimization of by-products. The ra
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::41f8ca05b32a83e5f0371e1dbf7a3ae8
https://doi.org/10.1016/s0040-4039(00)60586-5
https://doi.org/10.1016/s0040-4039(00)60586-5
Autor:
José A. Paixão, R. M. L. M. Martins, M. L. Sa E Melo, M. J. S. M. Moreno, M. J. M. de Almeida, L. C. R. Andrade, A. S. Campos Neves, H. I. M. Soares
Publikováno v:
Acta Crystallographica Section E Structure Reports Online. 57:o571-o573
In the title compound, C23H34O4, the two saturated six-membered rings have slightly flattened chair conformations and the unsaturated ring assumes a 8β,9α-half chair conformation distorted towards a 8β-sofa. The five-membered ring has an unusual c
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a60b7064b6c15246ef6bb3c30eb38c64
https://doi.org/10.1107/s1600536801008996
https://doi.org/10.1107/s1600536801008996