- Radical dehydroxylative alkylation of tertiary alcohols by Ti catalysis
-
Deoxygenative radical C?C bond-forming reactions of alcohols are a long-standing challenge in synthetic chemistry, and the current methods rely on multistep procedures. Herein, we report a direct dehydroxylative radical alkylation reaction of tertiary alcohols. This new protocol shows the feasibility of generating tertiary carbon radicals from alcohols and offers an approach for the facile and precise construction of all-carbon quaternary centers. The reaction proceeds with a broad substrate scope of alcohols and activated alkenes. It can tolerate a wide range of electrophilic coupling partners, including allylic carboxylates, aryl and vinyl electrophiles, and primary alkyl chlorides/bromides, making the method complementary to the cross-coupling procedures. The method is highly selective for the alkylation of tertiary alcohols, leaving secondary/primary alcohols (benzyl alcohols included) and phenols intact. The synthetic utility of the method is highlighted by its 10-g-scale reaction and the late-stage modification of complex molecules. A combination of experiments and density functional theory calculations establishes a plausible mechanism implicating a tertiary carbon radical generated via Ti-catalyzed homolysis of the C?OH bond.
- Xie, Hao,Guo, Jiandong,Wang, Yu-Quan,Wang, Ke,Guo, Peng,Su, Pei-Feng,Wang, Xiaotai,Shu, Xing-Zhong
-
supporting information
p. 16787 - 16794
(2020/11/09)
-
- 20-triazole-20-hydroxyl-pregnane derivatives, method for preparing same and medical application of 20-triazole-20-hydroxyl-pregnane derivatives
-
The invention belongs to the field of medicines, and particularly relates to a series of 20-triazole-20-hydroxyl-pregnane derivatives, a method for preparing the same and medical application of the 20-triazole-20-hydroxyl-pregnane derivatives. The 20-triazole-20-hydroxyl-pregnane derivatives are particularly used for preparing medicines for treating androgen receptor related diseases such as cellproliferation, prostate cancer, polytrichia, acne and androgenic alopecia which are dependent on androgens. Structural general formulas of compounds of the 20-triazole-20-hydroxyl-pregnane derivativesare shown. Details of definition of various groups in the general formulas are attached to specifications.
- -
-
-
- A nitrogen-ligated nickel-catalyst enables selective intermolecular cyclisation of β- And γ-amino alcohols with ketones: Access to five and six-membered N-heterocycles
-
Owing to the great demand for the synthesis of N-heterocycles, development of new reactions that utilise renewable resources and convert them into key chemicals using non-precious base metal-catalysts is highly desirable. Herein, we demonstrated a sustainable Ni-catalysed dehydrogenative approach for the synthesis of pyrroles, pyridines, and quinolines by the reaction of β- and γ-amino alcohols with ketones via C-N and C-C bond formations in a tandem fashion. A variety of aryl, hetero-aryl, and alkyl ketones having free amine, halide, alkyl, alkoxy, alkene, activated benzyl, and pyridine moieties were converted into synthetically interesting 2,3 and 2,3,5-substituted bicyclic as well as tricyclic N-heterocycles with up to 90% yields. As a highlight, we demonstrated the synthesis of an interesting pyrrole derivative by intermolecular cyclisation of a steroid hormone with phenylalaninol.
- Singh, Khushboo,Vellakkaran, Mari,Banerjee, Debasis
-
supporting information
p. 2250 - 2256
(2018/05/30)
-
- Non-Bioconvertible C3-Substituted Pregnenolone Derivatives for Use in the Treatment of Treatment-Resistant Depression
-
The present invention relates to methods for the treatment of treatment-resistant depression (TRD), comprising the administration of compounds of formula (I), which are blocked in C3 position and cannot metabolize in vivo into pregnenolone deri
- -
-
Paragraph 0099
(2017/12/17)
-
- Stereochemical assignment of c-24 and c-25 of amarasterone a, a putative biosynthetic intermediate of cyasterone
-
A C29 phytoecdysteroid named amarasterone A (1) has been isolated from Cyathula capitata (Amaranthaceae), Leuzea carthamoides (Asteraceae), and Microsorum scolopendria (Polypodiaceae). We recently isolated amarasterone A from C. officinalis. Am
- Hirayama, Yui,Okuzumi, Keiko,Masubuti, Hironori,Uekusa, Hidehiro,Girault, Jean-Pierre,Fujimoto, Yoshinori
-
p. 5471 - 5477
(2014/07/08)
-
- PROGESTERONE RECEPTOR ANTAGONISTS AND USES THEREOF
-
The present invention relates to a compound of formula (I): for its use as progesterone receptor antagonist, in particular for its use for the prevention and/or the treatment of cancer or uterine pathologies.
- -
-
Page/Page column 57
(2011/11/30)
-
- Use of 3-methoxy-pregnenolone in the production of a medicament for treating neurodegenerative diseases
-
The invention relates to a novel use of derivatives of neurosteroids, particularly pregnenolone, for the treatment of acute or chronic lesions of the nervous system, especially certain neurodegenerative diseases, related in particular to the ability there
- -
-
Page/Page column 5
(2008/06/13)
-
- Structure - Activity relationship of Aza-steroids as PI-PLC inhibitors
-
A number of aza-steroids were synthesized as potent phosphatidylinositol phospholipase C (PI-PLC) inhibitors. The epimeric mixtures 22,25-diazacholesterol (8a) and 3β-hydroxy-22,25-diazacholestane (8b) were among the most active of these inhibitors, with IC50 values of 7.4 and 7.5 μM, respectively. The 20α epimer, 8a2 (IC50 = 0.64 μM), whose stereochemistry at C-20 coincides with that of cholesterol, was found 50 times more potent than the 20β epimer, 8a1 (IC50 = 32.2 μM). In diaza-estrone derivatives, the 3-methoxy group on the aromatic A-ring of 23 exhibited moderate PI-PLC inhibitory activity (IC50 = 19.7 μM), while compound with a free hydroxyl group (21) was inactive. However, in diaza-pregnane derivatives, epimers with a 3-hydroxyl group (8a, IC50 = 7.4 μM) exhibited more potent PI-PLC inhibitory activity than their counterparts with 3-methoxyl group on the non-aromatic A-ring (26, IC50 = 17.4 μM). We have illustrated in our previous publication that 3-hydroxyl-6-aza steroids are potent PI-PLC inhibitors. However, simultaneous presence of the 6-aza and 22,25-diaza moieties in one molecule as in 13, led to loss of activity. Epimeric mixture 8a showed selective growth inhibition effects in the NCI in vitro tumor cell screen with a mean GI50 value (MG-MID) of 5.75 μM for 54 tumors.
- Xie, Wenge,Peng, Hairuo,Kim, Deog-Il,Kunkel, Mark,Powis, Garth,Zalkow, Leon H.
-
p. 1073 - 1083
(2007/10/03)
-