Synthesis and antioxidant properties of N-substituted aminomethyl derivatives of 2-isobornylphenol

A series of 2-isobornylphenol derivatives containing aminomethyl groups either at ortho-(monoderivatives) or ortho- and para-positions (bis-derivatives) relative to the hydroxy group of phenol moiety was synthesized. Antioxidant properties of the obtained compounds were comparatively evaluated using in vitro models. It was demonstrated that Mannich bases containing an n-octylaminomethyl group are significantly exceeding both starting 2-isobornylphenol and the standard antioxidant, 2,6-di-tert-butyl-4-methylphenol, by their ability to inhibit H₂O₂-induced erythrocyte hemolysis.

     

Synthesis and biological properties of C-2 triazolylinosine derivatives

O(6)-(Benzotriazol-1H-yl)guanosine and its 2'-deoxy analogue are readily converted to the O(6)-allyl derivatives that upon diazotization with t-BuONO and TMS-N(3) yield the C-2 azido derivatives. We have previously analyzed the solvent-dependent azide·tetrazole equilibrium of C-6 azidopurine nucleosides, and in contrast to these, the O(6)-allyl C-2 azido nucleosides appear to exist predominantly in the azido form, relatively independent of solvent polarity. In the presently described cases, the tetrazole appears to be very minor. Consistent with the presence of the azido functionality, each neat C-2 azide displayed a prominent IR band at 2126-2130 cm(-1). A screen of conditions for the ligation of the azido nucleosides with alkynes showed that CuCl in t-BuOH/H(2)O is optimal, yielding C-2 1,2,3-triazolyl nucleosides in 70-82% yields. Removal of the silyl groups with Et(3)N·3HF followed by deallylation with PhSO(2)Na/Pd(PPh(3))(4) gave the C-2 triazolylinosine nucleosides. In a continued demonstration of the versatility of O(6)-(benzotriazol-1H-yl)purine nucleosides, one C-2 triazolylinosine derivative was converted to two adenosine analogues via these intermediates, under mild conditions. Products were desilylated for biological assays. The two C-2 triazolyl adenosine analogues demonstrated pronounced antiproliferative activity in human ovarian and colorectal carcinoma cell cultures. When evaluated for antiviral activity against a broad spectrum of DNA and RNA viruses, some of the C-2 triazolylinosine derivatives showed modest inhibitory activity against cytomegalovirus.     

Synthesis of aminomethyl derivatives of sophoricoside

Aminomethylation of the natural isoflavonoid sophoricoside (genistein-4-O-β-D-glucoside) was studied. It was shown that the most convenient method for performing the aminomethylation was the use of aminals. 6,8-bis-Substituted derivatives of sophoricoside were synthesized.     

Synthesis and membrane-protective activity of 4-aminomethyl derivatives of 2,6-diisobornylphenol

A series of 4-aminomethyl derivatives of 2,6-diisobornylphenol containing tertiary and secondary amino groups were synthesized. Their toxicity and the membrane-protective and antioxidant activity were assessed using red blood cells of laboratory mice as the test object. These compounds were shown to exhibit high membrane-protective and antioxidant activity, which substantially depends on the structure of the substituent and the concentration of the substance.     

Synthesis and antioxidant properties of (dodecylsulfanyl)methyl quercetin derivatives

Mono-, bis-, and tris[(dodecylsulfanyl)methyl]-substituted quercetin derivatives were obtained by the reaction of quercetin with (N,N-diethylaminomethyl) dodecyl sulfide. These compounds under the conditions of AIBN-initiated oxidation of styrene (37 °C) terminated oxidation chains with a stoichiometric inhibition coefficients of 2.0±0.1 and rate constants of 5.1 · 10⁵, 4.8 · 10⁵, and 2.9 · 10⁵ L mol^-1 s^-1, respectively. Based on the rate constants, the O-H bond energy values in the molecules of quercetin and its mono-, bis-, and tris- [(dodecylsulfanyl) methyl]-substituted derivatives were calculated and found to be equal to 334.4, 341.4, 341.7, and 344.7 kJ mol^-1, respectively. It was established that the ability of the synthesized thio derivatives of quercetin to inhibit thermal autooxidation of lard (133 °C) is 1.3-2.7 times higher than that of the reference antioxidants (a-tocopherol, BHT, and BHA). According to the in silico assessment of acute toxicity for rats, the synthesized derivatives are low-toxic and non-toxic compounds.

     

Synthesis,molecular structure and optical properties of glycidyl derivatives of quercetin

Structural Chemistry - Synthesis of glycidyl ethers of quercetin and studies of their structure and spectral properties have been carried out. Using FTIR spectroscopy, 1H and HSQC NMR spectroscopy,...     

Synthesis of anabasine-containing aminomethyl derivatives of 6-hydroxyaurones

Chemistry of Heterocyclic Compounds - Aminomethylation of aurones was studied by using anabasine. The reaction in the case of 6-hydroxyaurones was shown to selectively provide...     

Synthesis of aminomethyl derivatives of phosphonocarboxylates of the furan series

By reaction of halomethyl derivatives of phosphonocarboxylates of the furan series with sodium azide corresponding azidomethyl compounds were synthesized. Treating them with triphenylphosphine in ethanol results in primary amines. Seven of the twelve possible position isomers of the aminomethyl phosphonocarboxylates were obtained. Method was found of selective dealkylating phosphonates leaving intact the ester group present in the molecule.     

A lithiation approach to cordycepin analogues variously substituted at the C-8 position

Several 8-substituted cordycepins were prepared via LDA lithiation of 2′,5′-bis-O-(t-butyldimethylsilyl)-cordycepin and successive reactions of its C-8 lithiated species with various types of electrophiles. Wittig reaction of the 8-formyl derivative was also examined.     

Synthesis and antibacterial properties of new 8-nitrofluoroquinolone derivatives

The objective of this research was the preparation of new 8-nitrofluoroquinolone models and investigation of their antibacterial properties. The work initially involved large scale preparation of the synthon 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (3), followed by introduction of substituted primary amine appendages at the C-7 position to give derivatives 9a-g, in which the amino group is appended to substituted benzenes or aromatic heterocycles, is part of a primary alpha-amino acid or just a simple primary aliphatic amine. This nucleophilic aromatic substitution step was a very simple procedure since the 8-nitro group of the above synthon facilitated the addition of weak nucleophiles at C-7. All compounds prepared were fully identified and characterized using NMR, IR, EA and MS, and were consistent with expected structures. The prepared targets and the intermediates have shown interesting antibacterial activity against gram positive and/or gram negative strains. In particular, the p-toluidine, p-chloroaniline and aniline derivatives showed good activity against S. aureus with MIC range approximately 2-5 microg/mL. In conclusion, more lipophilic groups seem to enhance activity against gram positive strains.     

Preparation of C-(aminomethyl)cellulose

Conclusions The reaction of keto-6-O-tritylcellulose with nitromethane, followed by reduction of the condensation product with aluminum lithium hydride, gave C-(aminomethyl)cellulose with a degree of substitution equal to 0.35.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 879–881, April, 1971.     

Synthesis of C-2 substituted vitamin D derivatives having ringed side chains and their biological evaluation, especially biological effect on bone by modification at the C-2 position

In order to obtain vitamin D derivatives, which have strong activity for enhancing bone growth, we designed vitamin D derivatives with various substitutions at the C-2 position. Novel 2 α-substituted vitamin D derivatives were synthesized starting from d-glucose as a chiral template of the A-ring with a CD-ring bromoolefin unit using the Trost coupling method. We evaluated these compounds by two in vitro assays, affinity to VDR and transactivation assays, using human osteosarcoma (Hos) cells, and demonstrated the SAR of the C-2 position of VD(3). Furthermore, by using the OVX model, we found that compound 5c, which has a hydroxypropoxy side chain at C-2 and 2,2-dimethyl cyclopentanone in the CD-ring side chain, has a strong activity for enhancing bone growth, same as the reported compound, 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D(3)1d, and this derivative shows a possibility that calcemic activity is less than 1d in vivo.     

Total Synthesis of C-8-Geranylflavonoids

Geranylflavonoids are interesting natural products isolated in recent years from some traditional medicinal plants. Some of these flavanoids have been reported to exhibit hypotensive, antibacterial and antitumor effects¹. With respect to the synthesis of geranylflavonoids, only the 8-geranylflavanone skeleton as found in compounds 1², 2³ and 3⁴ has not been yet prepared.     

Synthesis and evaluation of the antioxidant properties for some novel aminomethyl derivatives of 2,6-diisobornylphenol bearing a pinane moiety

Some new derivatives based on 2,6-diisobornylphenol and containing amine moieties of the pinane structure at the para-position relative to the phenolic hydroxy group were synthesized. The antioxidant properties of the obtained compounds were estimated using various in vitro models. The introduction of diamine moiety into a starting molecule led to a significant increase in the radical scavenging activity and the ability to chelate Fe²⁺ ions.

     

Synthesis of biologically active bromine derivatives of quercetin

The synthesis of a series of bromine derivatives of quercetin differing by the number of bromine atoms introduced is described. It has been shown that in the dynamics of the bromination process the deciding factors affecting the qualitative and quantitative compositions of the reaction products are the temperature regime and the ratio of the reactants. Thus, the use of equimolar amounts of the reactants in dioxane in the temperature interval from 20 to 25° C gives a monobromo derivative, while all other conditions give mixtures of bromo derivatives. The antiviral and antitumoral activities of the mono- and dibromo derivatives of quercetin have been studied.Al-Farabi Kazakh State National University, Almaty, fax (3272) 47 26 09. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 709–711, September–October, 1996. Original article submitted February 27, 1995.     

N—BOC—8—氨甲基—2—萘甲酸的改进合成法

以２－萘甲酸为原料，经硝化，酯化，重氮化，选择性催化氢化，ＢＯＣ酸酐保护等六步反应，完成了Ｎ－ＢＯＣ－８氨甲基－２－萘甲酸（１ａ）的合成，为化合物１的合成提供了新的合成途径。     

Synthesis and properties of derivatives of 7-aroylalkylxanthinyl-8-thioacetic acid

When 7-aroylalkyl-8-bromo-3-methyl- and 1,3-dimethylxanthines are boiled with an excess of thioglycolic acid, a reductive dehalogenation takes place, while reaction with an equimolar amount of thioglycolic acid in DMFA leads to 7-aroylalkyl-3-methyl- and 1,3-dimethylxanthinyl-8-thioacetic acids. Cyclization of the latter with acetic anhydride in the presence of anhydrous sodium acetate results in the formation of 3-aryl-1,4-dihydro-9-methyl- and-7,9-dimethylthiazino[3,2-f]xanthine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 967–970, July, 1990.     

Synthesis and structural studies of C-5 aryl- and C-6 alkyl-substituted pyrimidine derivatives

C-5 and C-6 disubstituted pyrimidine derivatives 2–7 were synthesized. Introduction of the aryl rings at C-5 of pyrimidine moiety in 5 and 6 was performed using palladium-catalyzed Stille cross-coupling reaction. The novel C-6 fluorophenylalkylated 5-phenylpyrimidine derivative (7) was prepared by lithiation of 5-phenylpyrimidine (6) and subsequent reaction of thus obtained organolithium intermediate with p-fluoroacetophenone. The structures of 3, 4 and 6 were determined by X-ray crystal structure analysis. Both methoxy groups in these structures adopt a synperiplanar conformation with respect to the N1 and N3 atoms of the pyrimidine ring. The molecules of 3 and 4 are linked through weak Br···Br interactions into zig-zag chains. The molecules of 6 are assembled into layers by one C–H···O hydrogen bond, C–H···π and aromatic π···π stacking interactions.