50-50-0Relevant articles and documents
Application of in Situ FTIR for the Preparation of 17-α-Estradiol via Mitsunobu Reaction
Cardoso, Flávio S. P.,Mickle, Gregory E.,Da Silva, Marco A.,Baraldi, Patricia T.,Ferreira, Fabio B.
, p. 306 - 311 (2016)
An efficient synthesis of 17-α-estradiol 1 is described. Utilization of in situ IR allowed for an online monitoring of the key Mitsunobu reaction and development of a safe and reliable synthesis of 17-α-estradiol 1 in 78% overall yield over three steps. Benzoylation of 17-β-estradiol 2 is conducted at high regioselectivity under phase-transfer catalysis (PTC) conditions, followed by a Mitsunobu reaction to invert the chiral center at C-17 and provide intermediate 5, containing the core structure of 17-α-estradiol 1. Finally, the desired active pharmaceutical ingredient (API) is prepared by saponification of the remaining esters.
Chemoselective Oxidation of p-Methoxybenzyl Ethers by an Electronically Tuned Nitroxyl Radical Catalyst
Hamada, Shohei,Sugimoto, Koichi,Elboray, Elghareeb E.,Kawabata, Takeo,Furuta, Takumi
supporting information, p. 5486 - 5490 (2020/07/24)
The oxidation of p-methoxy benzyl (PMB) ethers was achieved using nitroxyl radical catalyst 1, which contains electron-withdrawing ester groups adjacent to the nitroxyl group. The oxidative deprotection of the PMB moieties on the hydroxy groups was observed upon treatment of 1 with 1 equiv of the co-oxidant phenyl iodonium bis(trifluoroacetate) (PIFA). The corresponding carbonyl compounds were obtained by treating the PMB-protected alcohols with 1 and an excess of PIFA.
HYALURONAN CONJUGATES AND USES THEREOF
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Paragraph 0113-0114, (2020/12/13)
Disclosed herein is a hyaluronan conjugate, which includes a hyaluronic acid (HA), a sex hormone, and a linker for coupling one of the disaccharide units of the HA and the sex hormone. Also disclosed herein are the uses of the hyaluronan conjugate in treating or preventing neurodegenerative diseases.
Preparation method for synthesis of phenolic ester through thiocarboxylic acid mediated visible light catalyzed phenol acylation reaction
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Paragraph 0017; 0018; 0077; 0078, (2018/07/30)
The invention discloses a preparation method for synthesis of phenolic ester through a thiocarboxylic acid mediated visible light catalyzed phenol acylation reaction. Thiocarboxylic acid compounds andphenol compounds are subjected to a site specific reaction under certain conditions to produce phenolic ester compounds, wherein the certain conditions are as follows: under the conditions of normaltemperature, normal pressure and visible light, K2CO3 is used as an alkaline catalyst, terpyridyl ruthenium dichloride hexahydrate is used as a photosensitizer and acetonitrile is used as a reaction solvent. Synthesis of phenolic ester under catalysis of visible light is realized, thiocarboxylic acid is used as an acylation reagent, and the site specific phenol esterification reaction is realizedefficiently under mild conditions of normal temperature, normal pressure and visible light. The method has mild reaction conditions, large substrate functional group tolerance, high applicability andhigh yield, and an efficient, reliable and economical preparation method is provided for synthesis of phenolic ester.
Diacyl Disulfide: A Reagent for Chemoselective Acylation of Phenols Enabled by 4-(N,N-Dimethylamino)pyridine Catalysis
Liu, Hong-Xin,Dang, Ya-Qian,Yuan, Yun-Fei,Xu, Zhi-Fang,Qiu, Sheng-Xiang,Tan, Hai-Bo
supporting information, p. 5584 - 5587 (2016/11/17)
A general and excellent acylation reagent, diacyl disulfide, was uncovered for efficient ester formation enabled by DMAP (4-(N,N-dimethylamino)pyridine) catalysis. This protocol offered a promising synthetic platform on site-selective acylation of phenolic and primary aliphatic hydroxyl groups, which greatly expanded the realm of protecting group chemistry. The importance of the reagent was also reflected by its excellent moisture tolerance, high efficiency, and potential in synthetic chemistry and biologically meaningful natural product modification.
A practical solution for aqueous reactions of water-insoluble high-melting-point organic substrates
Cui, Xiaoxue,Li, Bo,Liu, Tianzhen,Li, Chunbao
supporting information; experimental part, p. 668 - 672 (2012/06/01)
A practical solution to the problem of performing aqueous reactions for very sparingly soluble high-melting-point (VSSHMP) organic substrates has been developed, which entails mechanically stirring a mixture of the substrate, the corresponding reagent(s), water, catalytic Aliquat 336 and sand. When the melting points of the substrates which include steroids, ketones, aldehydes, aromatics and alkaloids are around 200 °C, the reactions can be performed at 20 °C. The substrate solubility can be as low as 1 × 10-10 mol L-1. The Royal Society of Chemistry 2012.
Estradiol derivative-chlorambucil conjugate process for preparing the same, and pharmaceutical composition
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, (2008/06/13)
An estradiol derivative-chlorambucil conjugate of the formula (I): STR1 wherein R1 is alkyl or alkoxyl of 1 to 4 carbon atoms; R2 is acyl, dansyl, or alkyl; R3, R4, and R5 independently are H, oxo, OH, or acyloxy; m is an integer of 1 to 3; and n is an integer of 0 to 3; provided that when n is 0, all of R3, R4, and R5 are not H at the same time, and at least one of R3, R4, and R5 is a group other than H and OH; and further, when n is 2 or 3, the groups R1 are the same or different; a process for preparing the same, and a pharmaceutical composition containing the conjugate are described.
Benzoyl Trifluoromethanesulfonate. A Mild Reagent for the Benzoylation of Sterically Hindered Hydroxyls
Brown, Lindsey,Koreeda, Masato
, p. 3875 - 3880 (2007/10/02)
Benzoyl trifluoromethanesulfonate (BzOTf) is a highly efficient reagent for the benzoylation of a variety of alcohols under mild conditions.These include hindered secondary and tertiary hydroxyls, phenols, and α-glycols.Sensitive functionality is stable when the reaction is performed in the presence of pyridine.Several unique rearrangements of Lewis acidsensitive compounds were also effected.
Benzoyl Trifluoromethanesulphonate. A Highly Efficient Benzoylating Agent for Sterically Hindered Hydroxyl Groups
Koreeda, Masado,Brown, Lindsey
, p. 1113 - 1115 (2007/10/02)
Reactions of benzoyl trifluoromethanesulphonate (BzOTf) with a variety of alcohols, including some with sterically hindered secondary and tertiary hydroxy groups, with phenolic compounds, and with 1,2-diols at low temperatures provide the corresponding benzoates in high yield.
