- Synthesis and antiherpetic activity of novel purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine
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[Figure not available: see fulltext.] A method for the synthesis of novel purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine containing fragments of ω-amino acids with different lengths of the polymethylene chain as a linker has been developed. It was found in experiments in vitro that the obtained compounds are active against the herpes simplex virus type 1, including the acyclovir-resistant strain.
- Andronova, Valeriya L.,Charushin, Valery N.,Galegov, Georgii А.,Krasnov, Victor P.,Levit, Galina L.,Vozdvizhenskaya, Olga А.
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p. 490 - 497
(2021/06/26)
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- Assembling of medium/long chain-based β-arylated unnatural amino acid derivatives via the Pd(II)-catalyzed sp3 β-C-H arylation and a short route for rolipram-type derivatives
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In this paper, we report the assembling of libraries of β-arylated short/medium/long chain-based non-α-amino acid (aminoalkanoic acid) derivatives via the Pd(II)-catalyzed, bidentate directing group 8-aminoquinoline-aided sp3 β-C-H activation/arylation method. Short/medium chain-based unnatural amino acid derivatives containing an aryl group at the β-position are promising small molecules with therapeutic properties. Thus, it is necessary to enrich the libraries of short/medium/long chain-based unnatural amino acid derivatives containing an aryl group at the β-position. Considering the importance of β-arylated short/medium/long chain-based non-α-amino acid derivatives, an inclusive attention was paid to explore the Pd(II)-catalyzed sp3 β-C-H arylation of short/medium/long chain-based non-α-amino acids. Representative synthetic transformations including a short route for the assembling of rolipram and related compounds and 3-arylated GABA derivatives such as, baclofen, phenibut and tolibut were shown using selected β-C-H arylated non-α-amino acid derivatives.
- Tomar, Radha,Bhattacharya, Debabrata,Babu, Srinivasarao Arulananda
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p. 2447 - 2465
(2019/03/26)
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- Synthesis of Medium- and Large-Ring Compounds Initiated by Photochemical Decarboxylation of ω-Phthalimidoalkanoates
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The synthesis of a variety of hydroxylactams from ω-phthalimidoalkanoates using a triplet-sensitized photodecarboxylation reaction initiated by intramolecular photo electron transfer is described. Ring sizes available by this method span from 4 (benzazepine-1,5-dione 7) to 26 (cyclodipeptide 26e). Ground-state template formation is proposed as the explanation for the high efficiency of this reaction and for the decrease in reactivity in the presence of organic bases instead of metal carbonates. The crucial step in this macrocyclization reaction seems to be the protonation of the intermediary ketyl radiais (Scheme 4). Spacer groups investigated were alkyl chains (C3-C11: 5c-h, 11a, 12), ether (16, 18), ester (20, 22), and amide (26a-f) linkages. Within the detection limits, no dimeric (= decarboxylative coupling) products were observed, indicating the high preference for intra-vs. intermolecular photoelectron transfer. The C,C radical combination step proceeds with low stereoselectivity (cf. products 11 and 12) in contrast to comparable singlet reactions. Except for the lactones 22, all products were stable under the photolysis conditions. Prolonged irradiation of 22 led to the formation of the spiro compounds 23, probably via an intermediary acyliminium betaine (Scheme 8). One serious limitation of the decarboxylative macrocyclization is its incompatibility with the glycine spacer (as in 27a and 27b), probably the consequence of a strong intramolecular H-bond (Scheme 10).
- Griesbeck, Axel G.,Henz, Andreas,Kramer, Wolfgang,Lex, Johann,Nerowski, Frank,Oelgemoeller, Michael,Peters, Karl,Peters, Eva-Maria
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p. 912 - 933
(2007/10/03)
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- Functionalized derivatives of benzocrown ethers, I. Ionophores containing amino and pyridinium groups derived from benzo-15-crown-5, benzo-18-crown-6, and dibenzo-18-crown-6
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Acylation reactions of benzocrown ethers with N-phthalimido-protected derivatives of β-alanine and 11-aminoundecanoic acid, respectively, were investigated in acid catalysis by using the Eaton reagent. Deprotection of the obtained compounds by hydrazinolysis afforded derivatives with free amino groups the reaction of which with one or two equivalents of 2,4,6-trisubstituted pyrylium salts furnished pyridinium derivatives. All these new benzocrown ether derivatives were characterized by elemental analysis and IR and NMR spectroscopy. VCH Verlagsgesellschaft mbH, 1996.
- Barboiu, Mihai,Supuran, Claudiu T.,Luca, Constantin,Popescu, Georgeta,Barboiu, Camelia
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p. 959 - 963
(2007/10/03)
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