- An Improved Route to Guanines Substituted at N-9
-
2-Amino-6-chloropurines (2b)-(2e) react with trimethylamine/3-hydroxypropionitrile in the presence of 1,8-diazabicycloundec-7-ene to afford the corresponding N-9-substituted guanines (1b)-(1e) in near-quantitative yield.
- Ashwell, Mark,Bleasdale, Christine,Golding, Bernard T.,O'Neill, Ian K.
-
-
Read Online
- The discovery of purine-based agents targeting triple-negative breast cancer and the αB-crystallin/VEGF protein–protein interaction
-
Oestrogen receptor-negative breast cancer, particularly subtypes such as triple-negative breast cancer (TNBC, around 10–15% of cases), are characterised by poor long-term survival, poor response to therapy and early progression to metastasis. Purine-based compounds represent a privileged scaffold in anticancer drug design, with several clinically approved and experimental agents in clinical development comprising a purine core structure. In this study, a series of new purine-based compounds were synthesised; seven of the new analogues were found to significantly reduce the in vitro viability of TNBC cell lines (MDA-MB-231 and MDA-MB-436) with IC50 values of ≤50 μM. In previous work, we have proposed a new concept for targeting angiogenesis driving TNBC progression, by disrupting the protein–protein interaction between the molecular chaperone αB-crystallin (CRYAB) and VEGF. Since previous clinical studies applying anti-VEGF therapy to TNBC patients have met with limited success, we were interested to test our most promising purine analogues against CRYAB/VEGF, using a custom-designed cell-based CRYAB/VEGF165 interaction assay platform. Analogues 4e and 4f significantly reduced the interaction between CRYAB/VEGF165, and compound 4e (100 μM) was also found to decrease the levels of soluble VEGF expressed by MDA-MB-231 cells by 40%. In conclusion, these promising early activity profiles warrant further investigation to validate this concept.
- Fosu-Mensah, Nelly A.,Jiang, Wen,Brancale, Andrea,Cai, Jun,Westwell, Andrew D.
-
p. 182 - 202
(2019/01/04)
-
- New synthesis of 9-alkylguanines and their N2-substituted derivatives
-
A new method of synthesizing 9-alkyl guanines and their N2-substituted derivatives from 7-benzylguanine and its N2-substituted derivatives has been developed by quaternization with alkyl halides, dialkyl sulfates, or arenesulfonic acid esters, and subsequent removal of the benzyl protection by hydrogenation of the intermediate quaternary salts or of the betaines obtained from them. 1998 Plenum Publishing Corporation.
- Kochergin,Persanova,Aleksandrova
-
p. 480 - 483
(2007/10/03)
-
- Alkylpurines as immunopotentiating agents. Synthesis and antiviral activity of certain alkylguanines.
-
Several simple 8-substituted 9-alkyl- and 7,8-disubstituted 9-alkylguanine derivatives were synthesized as potential antiviral agents. These were tested for antiviral protection against a lethal Semliki Forest virus (SFV) infection in mice, and their anti
- Michael,Cottam,Smee,Robins,Kini
-
p. 3431 - 3436
(2007/10/02)
-
- Process for the preparation of 9-substituted guanine derivatives
-
A process for the preparation of 9-substituted quanine derivatives of general formula (I), in which R is C1 -C4 -alkyl optionally substituted with one or more hydroxy groups, or R is (α), benzyl, ribosyl, 2'-deoxyribosyl or (CH2)n -OR1 where n is 1 or 2, and R1 is CH2 CH2 OH or (β) or salts thereof, in which a 1-substituted5-(thiocarbamoyl)amino-1H-imidazole-4-carboxamide of general formula (III), where R has the same meaning as in formula (I), is cyclized: a) by treatment with a heavy metal salt of the group of Cu-, Ag-, Pb- and Hg-salts in an aqueous alkaline medium containing at least for equivalents of OH-ions at a temperature form about 0° C. to the reflux temperature, or b) by treatment with a peroxy compound in an aqueous alkaline medium at a temperature of about 0°-30° C., whereafter (I) is isolated by treatment with a acid and, if desired, is converted into a salt. The invention further comprises intermediates for use in the preparation of the above-mentioned compounds.
- -
-
-
- N23-ethenoguanosine and IA′-metamorphosine: 5N NMR spectroscopy and elucidation of physico-chemical properties by kinetic and equilibrium measurements
-
Tautomerism, protonation and electronic properties of the base moieties of IA′-metamorphosine (1a), N2,3-ethenoguanosine (2a) and O6-benzyl-N2,3-ethenoguanosine (3a were investigated by 15N NMR spectroscopy. pKa values of the same compounds were determined spectrophotometrically, and hydrolytic stability of the N-glycosidic bond was studied at various hydronium ion concentrations. The base stacking ability and metal ion complexation of N2,3-ethenoguanosine and its 9-ethyl counterpart (7) were elucidated by phase distribution and potentiometric measurements.
- Glemarec, Corine,Besidsky, Yevgeny,Chattopadhyaya, Jyoti,Kusmierek, Jaroslaw,Lahti, Marjo,Oivanen, Mikko,Loennberg, Harri
-
p. 6689 - 6704
(2007/10/02)
-
- Isolation and identification of products from alkylation of nucleic acids: ethyl- and isopropyl purines
-
Ethylation and isopropylation of guanine in alkaline solution, or of adenine in formic acid, by alkyl methanesulphonates gave the following products: 1, N2, 3, O6, 7 and 9 alkylguanines; 1, 3, 7 and 9 alkyladenines. The products were identified from their characteristic UV absorption spectra, by comparison with either known ethyladenines or with the corresponding known methyladenines, and were also characterized by mass spectrometry. Their chromatographic properties on paper, TLC and various columns were determined. DNA was alkylated in neutral solution with 14C labelled alkyl methanesulphonates and the ratios of the alkylpurines formed were obtained, and compared for alkylation by methyl, ethyl and isopropyl methanesulphonates and by N methyl N nitrosourea. The extents of alkylation at O 6 of guanine relative to those at N 7 of guanine varied with the reactivity of the methylating agents according to the predictions of Swain & Scott relating nucleophilicity of the groups alkylated with the substrate constants of the alkylating agents. The relative extents of alkylation at N 3 of adenine did not allow this correlation.
- Lawley,Orr,Jarman
-
p. 73 - 84,77,78
(2007/10/04)
-