Pyrrolo[2,1-b]benzothiazole derivatives

A new method for obtaining pyrrolobenzothiazole derivatives, which can be used for the specific synthesis of polymethine dyes with predesignated properties, was developed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 549–553, April, 1991.     

99mTc-radiolabeled imidazo[2,1-b]benzothiazole derivatives as potential radiotracers for glioblastoma

This study presents [^99mTc]BPTG-1 and [^99mTc]BPTG-2 for glioblastoma imaging. In vitro cellular uptakes of these radiotracers were examined in SKOV-3, MCF-7, U87-MG, HT-29, and A549 cell lines. U87-MG cell line displayed the highest radiotracers uptakes. Biodistribution study in U87-MG tumor bearing mice revealed higher uptake of radiotracers in tumor than muscle and brain. Liver, intestine, and kidneys displayed the highest radioactivity uptakes. The main route of radiotracers elimination was hepatobiliary. Due to the brain uptake of these radiotracers, they are promising radiotracers for future studies in the diagnosis of glioblastoma.

     

Research on heterocyclic compounds. XXI. Synthesis of imidazo[2,1-b]benzothiazole and imidazo[2,1-b]thiazole derivatives

The reaction of some 2-aminobenzothiazoles and 2-aminothiazoles with ethyl 3-bromo-4-oxopentanoate was investigated with the aim to obtain the corresponding imidazo[2,1-b]benzothiazole and imidazo[2,1-b]-thiazole derivatives, respectively. In some cases, two unexpected side products were obtained together with the required compound and their structures were elucidated: e.g., 2-aminobenzothiazole reacted with ethyl 3-bromo-4-oxopentanoate to give ethyl 2-methylimidazo[2,1-b]benzothiazole-3-acetate together with ethyl imi-dazo[2,1-b]benzothiazole-2-propionate and ethyl 3-(benzothiazol-2-yl)amino-4-oxopentanoate.     

Nitriles in Organic Synthesis: Synthesis of Pyrido[2,1-b]benzothiazole Derivatives and Polyfunctionally-substituted Pyridines

A variety of pyrido[2,1-b]benzothiazole derivatives could be prepared by reaction of 2-cyanomethylbenzothiazole, formaldehyde, and various active methylene reagents. Also some polyfunctionally-substituted pyridines were prepared by reaction of 2-cyanomethylbenzothiazole, formaldehyde, and an -functionally substituted acrylonitrile.     

Synthesis and cytotoxic activity of some novel N-pyridinyl-2-(6-phenylimidazo[2,1-b]thiazol-3-yl)acetamide derivatives

A series of novel compounds bearing imidazo[2,1-b]thiazole scaffolds were designed and synthesized based on the optimization of the virtual screening hit compound N-(6-morpholinopyridin-3-yl)-2-(6-phenylimidazo[2,1-b]thiazol-3-yl)acetamide (5a), and tested for their cytotoxicity against human cancer cell lines, including HepG2 and MDA-MB-231. The results indicated that the compound 2-(6-(4-chlorophenyl)imidazo[2,1-b]thiazol-3-yl)-N-(6-(4-(4-methoxybenzyl)piperazin-1-yl)pyridin-3-yl)acetamide (5l), with slightly higher inhibition on VEGFR2 than 5a (5.72% and 3.76% inhibitory rate at 20 μM, respectively), was a potential inhibitor against MDA-MB-231 (IC(50) = 1.4 μM) compared with sorafenib (IC(50) = 5.2 μM), and showed more selectivity against MDA-MB-231 than HepG2 cell line (IC(50) = 22.6 μM).     

Synthesis of pyrrolo[2,1-b]oxazole derivatives (microreview)

Chemistry of Heterocyclic Compounds - This review provides generalized information on the synthesis of substituted pyrrolo[2,1-b]oxazoles, including derivatives fused with other rings, covering...     

Nano-TiCl2/cellulose: an eco-friendly bio-based catalyst for one-pot synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives

Research on Chemical Intermediates - Cellulose is among the most abundant natural carbon-based biopolymers containing free OH groups with nucleophilic character for bonding to Lewis acids such as...     

Synthesis of 2,3,3a,8a-tetrahydroindeno[2,1-b]pyrrole derivatives

A new entry into the 2,3,3a,8a-tetrahydroindeno[2,1-b]pyrrole system, 1 , has been investigated. 2,3,3a,8a-Tetrahydro-3a,8a-dihydroxy-1-methylindeno[2,1–6]pyrrole-2,8-dione, 3 , formed from the reaction of ninhydrin and N-methylacetamide has been subjected to catalytic hydrogenation, hydride reduction, and chlorination reactions to afford a variety of substituted derivatives of 1 .     

Photo-Switchable Aggregation-Induced Emission of Bisthienylethene-Dipyrimido[2,1-b][1,3]benzothiazole Triad

A bisthienylethene-dipyrimido[2,1-b][1,3]benzothiazole (BTE-2PBT) triad has been designed and synthesized based on our recent discovery of PBTs as atypical propeller-shaped novel AIEgens. The triad not only maintains the photochromic properties of BTE moiety in solution, film, and solid state but also exhibits remarkable AIE properties. Moreover, the fluorescence of BTE-2PBT PMMA film could be modulated with high contrast by alternate UV and visible light irradiation. Photoerasing, rewriting, and non-destructive readout of fluorescent images on BTE-2PBT PMMA film well demonstrate its potential application as optical memory media.     

Synthesis of indeno[2,1-b][1,4]benzothiazine derivatives from 2-bromoinden-1-ones

2-Bromoinden-1-ones 2 were condensed with 6-substituted 3-aminopyridine-2(1H)-thiones to produce a new type of 4-azaindeno[2,1-b][1,4]benzothiazine derivatives 3 . Substituted 6-phenylindeno[2,1-b][1,4]benzothiazines 4 were also prepared by reacting 2-bromo-5-methoxy- and 2,6-dibromo-5-methoxyinden-1-ones with o-aminobenzenethiol.     

New derivatives of imidazo [5, 1-b] benzothiazole

1-Cyano-3-phenylimidazo[5, 1-b]benzothiazole (II) has been obtained from 1-formyl -3-phenylimidazo[5, 1-b]benzothiazole (I) and from 1-brono-3-phenylimidazo[5, 1-b]benzothiazole (III) and has been converted into the corresponding amide (IV) and thioamide (V). New 1-alkyl-3-phenylimidazo[5, 1-b]benzothiazoles (VI) have been synthesized.     

Synthesis of pyrido[2,1-b]- and thiazolo[2,3-b]purines

Some pyrido[2,1-b]- and thiazolo[2,3-b]purines, tricyclic compounds structurally related to [1,2,4]triazolo[1,5-c]quinazolines 1 have been synthesized with a view to study their possible adenosine and benzodiazepine receptors affinity.     

苯并咪唑并[2,1-b]噻唑衍生物的合成

以2-巯基咪唑类化合物为原料,室温下与含有端基炔的二芳基高碘盐反应,一步合成苯并咪唑并[2,1-b]噻唑衍生物,其结构经¹H NMR、¹³C NMR、 单晶X-衍射和HR-MS表征。在最佳反应条件［n(2-巯基苯并咪唑)/n(二芳基高碘盐)=1/1,二氯甲烷为溶剂,反应12 h］下,目标化合物的产率最高为84%。同时对该反应的机理进行了详细探讨,并采用MTT法研究了目标化合物对人肝癌细胞（HepG2）生长情况的影响。结果表明：当浓度为4 μg/mL时,化合物3b具有较强的抑制HepG2细胞增殖的活性,抑制率为52%。     

Synthesis of 2,3,4,5-tetrahydropyrimido[2,1-b]-benzothiazoles

1-Thiocarbamoyl-2-phenylpyrazolidines are cyclized to give 2,3,4,5-tetrahydropyrimido[2,-1-b]benzothiazoles, the structure of which was proved by mass spectrometry.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 495–496, April, 1973.