121039-98-3Relevant articles and documents
Highly Selective One-Pot Synthesis of Polysubstituted Isoflavanes using Styryl Ethers and Electron-Withdrawing ortho -Quinone Methides Generated in Situ
Tanaka, Kenta,Kishimoto, Mami,Ohtsuka, Naoya,Iwama, Yoshinori,Wada, Hiroki,Hoshino, Yujiro,Honda, Kiyoshi
, p. 189 - 192 (2019)
A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho -quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.
Non-imidazole histamine H3 ligands. Part VI. Synthesis and preliminary pharmacological investigation of thiazole-type histamine H3-receptor antagonists with lacking a nitrogen nucleus in the side chain
Guryn, Roman,Staszewski, Marek,Kopczacki, Piotr,Walczyński, Krzysztof
, p. 65 - 76 (2017/06/05)
Background: Antagonists to the H3 receptor are considered to be potential drugs for the treatment of Alzheimer's disease, attention deficit-hyperactive disorder, memory and learning deficits, and epilepsy. The initial development of potent H3 receptor antagonists focused on extensive modification of the natural ligand histamine. However, it has appeared that imidazole-containing ligands are associated with inhibition of cytochrome P450 enzymes, caused by imidazole nitrogen complexation to heme iron in the active site of the enzyme. For these reasons, the development of potent non-imidazole H3 receptor antagonists was eagerly awaited. Objective: Previously, we reported the synthesis and pharmacological in vitro characterization of series of potent histamine H3-receptor non-imidazole antagonists belonging to the class of substituted 2-thiazol-4-n-propylpiperazines. A lead compound 1 of this family was a derivative carrying the ethylaminomethylpropyl chain. Methods: With the aim of increasing lipophilicity, that will help the ligands to cross the blood-brain barrier, we synthesized a series of new 2-thiazol-4-n-propylpiperazines where the ethylaminomethylpropyl moiety was replaced by a p-substituted-, an unsubstituted benzene ring, and ω-phenylalkyl substituent at positions 4 and 5 of thiazole ring, respectively. All compounds were tested for H3 antagonistic effects in vitro using the electrically contracting guinea pig jejunum. Results: The most active compounds of presented series 3d, 3e, and 3j showed lower affinity than the lead compound 1 and additionally, derivatives 3d and 3j possessed weak, competitive H1-antagonistic activity. This is in contrast to the lead compound 1 that has no affinity at H1 receptor. Conclusion: We can conclude that a side chain in the 2-thiazol-4-n-propylpiperazine scaffold should contain a basic center and should be present at a favorable position 5 of thiazole ring.
Hypoiodous acid-catalyzed regioselective geminal addition of methanol to vinylarenes: synthesis of anti-Markovnikov methyl acetals
Peraka, Swamy,Mameda, Naresh,Marri, Mahender Reddy,Kodumuri, Srujana,Chevella, Durgaiah,Sripadi, Prabhakar,Nama, Narender
, p. 73732 - 73736 (2015/09/15)
A novel metal-free, catalytic geminal dimethoxylation of vinylarenes based on in situ generated HOI species from iodide salt and oxone is reported. The preliminary mechanistic investigations suggest that the key factor for achieving the anti-Markovnikov regioselectivity is the semipinacol rearrangement of an iodo functionalized intermediate, which is confirmed by an isotope labeling experiment. In addition, the reaction involves the de-iodination of a co-iodo intermediate via its oxidation to hypervalent iodine species rather than a common iodide abstraction by electrophiles. The HRESI-MS studies support the conversion of monovalent iodine containing intermediates to trivalent iodine intermediates during the catalytic conversion of aromatic alkenes into the corresponding terminal acetals.
A generalized approach for iron catalyzed chemo- and regioselective formation of anti-Markovnikov acetals from styrene derivatives
Chowdhury, Abhishek Dutta,Lahiri, Goutam Kumar
supporting information; experimental part, p. 3448 - 3450 (2012/05/20)
Fe(BF4)2·6H2O in the presence of pyridine-2,6-dicarboxylic acid and PhI(OAc)2 can efficiently catalyze the formation of chemoselective dialkyl acetals from styrene derivatives with anti-Markovnikov regioselectivity in good to high yields under mild and benign reaction conditions.
