603-72-5Relevant academic research and scientific papers
Multiple Fluorescences. 6. The Case of 1,8-Naphthosultam
Kanety, H.,Kosower, E. M.
, p. 3776 - 3780 (1982)
The emission from 1,8-naphthosultam (2H-naphthisothiazole 1,1-dioxide) (1a) is composed of two bands, one for the acid (λmax=480 nm) and one for the corresponding anion (2, λmax=600 nm).The fluorescence of both 1a and 2, as well as that of the N-methyl- and N-ethyl-1,8-naphthosultams (1b and 1c), has a modest sensitivity to solvent polarity.The ground-state pKa for 1a is 6.2, with pKa* of -3.0.The proton transfer rate for 1a to water is >5xE10 s-1, from the rise time of anion fluorescence by picosecond pulse techniques.The fluorescence lifetimes for 1a and 2 are 16 (Φf = 0.37, dioxane) and 1.4 (Φf = 0.005, H2O pH 10) ns, respectively.
Tosvinyl and besvinyl as protecting groups of imides, azinones, nucleosides, sultams, and lactams. Catalytic conjugate additions to tosylacetylene
Petit, Elena,Bosch, Llus,Font, Joan,Mola, Laura,Costa, Anna M.,Vilarrasa, Jaume
, p. 8826 - 8834 (2015/01/08)
The use of the 2-(4-methylphenylsulfonyl)-ethenyl (tosvinyl, Tsv) group for the protection of the NH group of a series of imides, azinones (including AZT), inosines, and cyclic sulfonamides has been examined. The Tsvprotected derivatives are obtained in excellent yields by conjugate addition to tosylacetylene (ethynyl p-tolyl sulfone). The stereochemistry of the double bond can be controlled at will: with only 1 mol % of Et3N or with catalytic amounts of NaH, the Z stereoisomers are generated almost exclusively, while the E isomers are obtained using a stoichiometric amount of DMAP. Analogous phenylsulfonylvinyl-protected groups (with the besvinyl or Bsv group instead of Tsv) are obtained stereospecifically by reaction with (Z)- or (E)-bis(phenylsulfonyl)ethene. For lactams and oxazolidinones, this last method is much better. The Tsv and Bsv groups are stable in the presence of non-nucleophilic bases and to acids. They can be removed highly effectively via a conjugate addition-elimination mechanism using pyrrolidine or sodium dodecanethiolate as nucleophiles.
General synthetic approach towards annelated 3a,6-epoxyisoindoles by tandem acylation/IMDAF reaction of furylazaheterocycles. Scope and limitations
Zubkov, Fedor I.,Nikitina, Eugenia V.,Galeev, Timur R.,Zaytsev, Vladimir P.,Khrustalev, Victor N.,Novikov, Roman A.,Orlova, Daria N.,Varlamov, Alexey V.
, p. 1659 - 1690 (2014/02/14)
An efficient and versatile one-pot synthesis of 3,6a-epoxyisoindoles annelated with oxazine, oxazole, thiazine, thiazole, pyrimidine fragments and with their benzoannelated analogues is presented. The method is based on tandem N-acylation/intramolecular cycloaddition (the intramolecular Diels-Alder reaction of furan, IMDAF) reaction between α,β-unsaturated acid anhydrides and α-furyl substituted azaheterocycles. The latter can be easily prepared by condensation of diverse furfurals and 1,2- or 1,3-N,X-binucleophiles (aminoalcohols, aminothiols, diamines). The observed IMDAF reaction is stereoselective: exo-adducts are formed exclusively with large prevalence of one of the diastereoisomers. In most cases, the condensation/N-acylation/IMDAF reaction sequence may be carried out via a one-pot domino protocol. The scope and limitations of the proposed approach are thoroughly investigated. The obtained Diels-Alder adducts are attractive and useful substrates for further transformations. Fused isoindoles can be prepared from them in one-step by aromatization of the 7-oxabicyclo[2.2.1]heptene ring. Other transformations, including halogenation, ring cleavage, and Wagner-Meerwein skeletal rearrangement, are also demonstrated. The spatial structures of the obtained compounds have been established by X-ray diffraction analyses.
Design and synthesis of benzo[c,d]indolone-pyrrolobenzodiazepine conjugates as potential anticancer agents
Kamal, Ahmed,Ramakrishna,Lakshma Nayak,Raju,Subba Rao,Viswanath,Vishnuvardhan,Ramakrishna, Sistla,Srinivas
experimental part, p. 789 - 800 (2012/03/27)
A series of benzo[c,d]indol-2(1H)one-PBD conjugates (11a-l) have been designed and synthesized as potential anticancer agents. These compounds were prepared by linking the C8-position of DC-81 with a benzo[c,d]indol-2(1H)one moiety through different alkane spacers in good yields and confirmed by 1H NMR, mass and HRMS data. The DNA binding ability of these conjugates was evaluated by thermal denaturation studies and interestingly, compound 11l showed enhanced DNA binding ability. These compounds were also evaluated for their anticancer activity in selected human cancer cell lines of lung, skin, colon and prostate by using MTT assay method. These new conjugates showed promising anticancer activity with IC50 values ranging from 1.05 to 36.49 μM. Moreover, cell cycle arrest in SubG1 phase was observed upon treatment of A549 cells with 1 and 2 μM (IC50) concentrations of compound 11l and it induced apoptosis. This is confirmed by Annexin V-FITC, Hoechst staining, caspase-3 activity as well as DNA fragmentation analysis.
1,2,3-Benzoxathiazole 2,2-Dioxides: Synthesis, Mechanism of Hydrolysis, and Reactions with Nucleophiles
Andersen, Kenneth K.,Bray, Diana D.,Chumpradit, Sumalee,Clark, Michael E.,Habgood, Gregory J.,et al.
, p. 6508 - 6516 (2007/10/02)
The rate of base-induced hydrolysis of some five-membered cyclic sulfamates, X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides (1a, X = H; 1b, X = 5-Me; 1c, X = 5-t-Bu; 1d, X = 5-Br; 1e, X = 5-Cl; 1f, X = 5-Ac; 1g, X = 5-NO2; 8a, X = 6-NO2) were measured in aqueous acetonitrile.The hydrolyses occurred with cleavage of the endocyclic N-SO2 bond.A Hammett plot using ?m values for 1a-g and ?p for 8a had ρ = +2.20.Activation enthalpies and entropies were measured for 1a and for 3-methyl-1,2,3-benzoxathiazole 2,2-dioxide (10).Volumes of activation weredetermined for 1g and for 8a.The mechanistic profile for hydrolysis resembled that for the saponification of the analogous sultones and cyclic sulfates.These first examples of 1,2,3-benzoxathiazole 2,2-dioxides (1a-g, 8a) were prepared by treating N-(2-hydroxyphenyl)-p-toluenesulfonamides with sulfuryl chloride and triethylamine or by oxidizing the monoxide precursors using m-chloroperbenzoic acid.Treatment of 1a with potassium fluoride gave 1,2,3-benzoxathiazole 2,2-dioxide (9), which was methylated to give 10.Sulfamate 1a was treated with various nucleophilic reagents: phenyllithium, methyllithium, potassium fluoride, methylamine, tert-butylamine, and sodium methoxide.The first three attacked the tosyl sulfur atom and cleaved the exocyclic N-SO2 bond.The amines attacked the endocyclic sulfonyl sulfur atom and cleaved the endocyclic N-SO2 bond.Sodium methoxide attacked both sulfonyl groups.
