Ti(iv)-catalyzed cascade synthesis of tetrahydrofuro[3,2-d]oxazole from arene-1,4-diones

2015 ◽  
Vol 13 (15) ◽  
pp. 4418-4421 ◽  
Author(s):  
Gang Li ◽  
Li Li ◽  
Haihong Huang ◽  
Dali Yin
Keyword(s):  
Intramolecular Cyclization ◽  
Room Temperature ◽  
Ionic Hydrogenation ◽  
Oxazole Derivatives

The tandem ionic hydrogenation, ketalization, and intramolecular cyclization of arene-1,4-diones with a combination of TiCl4/Et3SiH give facile access to tetrahydrofuro[3,2-d]oxazole derivatives in good yields at room temperature.

Synthesis and conformational studies of 9-benzyloxy-18-substituted [3.3]metacyclophanes

2015 ◽  
Vol 93 (11) ◽  
pp. 1161-1168 ◽  
Author(s):  
M. Monarul Islam ◽  
Tomiyasu Hirotsugu ◽  
Taisuke Matsumoto ◽  
Junji Tanaka ◽  
Takehiko Yamato
Keyword(s):  
Solid State ◽  
Intramolecular Cyclization ◽  
Acid Treatment ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Chair Conformation ◽  
Cyclization Reaction ◽  
Conformational Studies ◽  
X Ray ◽  
H Nmr

A series of syn-[3.3]metacyclophanes (MCPs) containing internal substituted benzyloxy group have been synthesized by the modified TosMIC coupling reaction followed by acid treatment and Wolff–Kishner reduction. anti-Mono- and di-benzyloxy[3.3]MCPs are synthesized by O-benzylation of the corresponding hydroxy[3.3]MCPs, which are obtained by demethylation of methoxy[3.3]MCPs with BBr3 at room temperature. An interesting and intriguing result was obtained when syn-6,15-di-tert-butyl-9-methoxy-18-methyl[3.3]MCP-2,11-dione was treated with TMSI to afford the formation of a dihydrobenzofuran ring by a nucleophilic intramolecular cyclization reaction. The 1H NMR and X-ray analysis of 6a confirms that it adopts a syn (chair–chair) conformation in both solution and solid state.

scholarly journals Catalyst-Free Cascade Synthesis of Densely Functionalized Chromenes in Water

2019 ◽  
Vol 31 (11) ◽  
pp. 2532-2536
Author(s):  
Subrahmanya Ishwar Bhat
Keyword(s):  
Intramolecular Cyclization ◽  
Room Temperature ◽  
Product Yield ◽  
Catalyst Free ◽  
Environmental Friendly ◽  
Simple Filtration ◽  
High Product Yield ◽  
Filtration Technique

An expeditious and environmental friendly, general protocol has been developed for the synthesis of 2-amino-3-cyano-4H-chromenes via cascade Knoevenagel-Michael-intramolecular cyclization in water. Pure solid products were obtained by simple filtration technique. The aqueous catalyst-free reactions lead to high product yield at room temperature.

Metal-free synthesis of 1H-isochromenes via benzyl ether-assisted, electrophilic addition of diaryl acetylenes

2021 ◽  
Author(s):  
Tzu-Hsuan Kuan ◽  
Trimurtulu Kotipalli ◽  
Cheng-Chun Chen ◽  
Duen-Ren Hou
Keyword(s):  
Intramolecular Cyclization ◽  
Room Temperature ◽  
Electrophilic Addition ◽  
Benzyl Ether ◽  
Metal Free ◽  
Benzyl Ethers ◽  
The Stability ◽  
Diaryl Acetylenes

Bromotrimethylsilane (TMSBr) promoted, intramolecular cyclization of (o-arylethynyl)benzyl ethers to form 1H-isochromenes at room temperature is reported. Further studies indicated that the stability of vinyl carbocations is crucial, similar to the...

The photochemistry of aliphatic and alicyclic α,β-unsaturated nitro compounds. A study of double bond cleavage following intramolecular cyclization and nitro-nitrite rearrangement

1984 ◽  
Vol 37 (6) ◽  
pp. 1231 ◽  
Author(s):  
RD Grant ◽  
JT Pinhey
Keyword(s):  
Double Bond ◽  
Intramolecular Cyclization ◽  
Methyl Acrylate ◽  
Room Temperature ◽  
Bond Cleavage ◽  
Nitro Compounds ◽  
Significant Extent ◽  
Cleavage Reaction ◽  
Nitrile Oxides ◽  
Bond Cleavage Reaction

The light-induced intramolecular cyclization of α, β-unsaturated nitro compounds leading to double bond cleavage, which had previously been detected in a small number of β-nitrostyrenes and α-nitro-stilbenes, has been shown to occur in a range of aliphatic and alicyclic α, β -unsaturated nitro compounds. At room temperature the reaction competes to a significant extent with the well known nitro-nitrite rearrangement in the irradiation of 1-nitro-2-phenylcyclohexene (2), 1-methyl-2-nitro-cyclohexene (6), 1-methyl-2-nitrocycloheptene (11), 2-methyl-3-nitrobut-2-ene (23) and 2-nitro-3-phenylbut-2-ene (24), while it was the only reaction detected in the case of 1-methyl-2-nitrocyclo- octene (12) and 1-nitrocyclooctene (19). No evidence for the cleavage reaction was found with 1-methyl-2-nitrocyclopentene (10), 1-nitrocyclohexene (17), 1-nitrocycloheptene (18) and 3-nitropent-2-ene (25). The nitrile oxides produced in the double bond cleavage reaction were trapped in a cycloaddition with methyl acrylate, yielding 3-substituted methyl 4,5-dihydroisoxazole-5-carboxylates. Irradiations of 1-methyl-2-nitrocyclohexene (6) and 1-methyl-2-nitrocycloheptene (11) in refluxing benzene afforded only the bridged ring isoxazolines (30) and (31) respectively. Syntheses of a number of nitro-olefins are also reported.

6,7-Dimethyl-3a,8a-dihydro-3H-8-oxacyclopenta[a]inden-5-yl benzoate

2000 ◽  
Vol 57 (1) ◽  
pp. o37-o38
Author(s):  
Mátyás Czugler ◽  
Petra Bombicz
Keyword(s):  
Crystal Structure ◽  
Intramolecular Cyclization ◽  
Structure Determination ◽  
Title Compound ◽  
Room Temperature ◽  
Sigmatropic Rearrangement ◽  
Crystal Structure Determination ◽  
Aryl Ether ◽  
Compound C ◽  
One Step

The title compound, C20H18O3, was prepared in a one-step synthesis by intramolecular cyclization following the sigmatropic rearrangement of the allyl aryl ether intermediate. The room-temperature crystal structure determination reveals acisconformation of the ring annellation.

Metal-free Brønsted acid mediated synthesis of fully substituted thiophenes via chemo- and regioselective intramolecular cyclization of α,α′-bis(β-oxodithioesters) at room temperature

2016 ◽  
Vol 14 (2) ◽  
pp. 434-439 ◽  
Author(s):  
B. Janaki Ramulu ◽  
Suvajit Koley ◽  
Maya Shankar Singh
Keyword(s):  
Intramolecular Cyclization ◽  
Room Temperature ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Metal Free ◽  
Brönsted Acid

Metal-free Brønsted acid mediated synthesis of tetrasubstituted thiophenes via intramolecular cyclization of α,α′-bis(β-oxodithioesters) is devised at room temperature.

scholarly journals Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings

2021 ◽  
Vol 17 ◽  
pp. 1490-1498
Author(s):  
Ivan P Mosiagin ◽  
Olesya A Tomashenko ◽  
Dar’ya V Spiridonova ◽  
Mikhail S Novikov ◽  
Sergey P Tunik ◽  
...  
Keyword(s):  
Free Radical ◽  
Intramolecular Cyclization ◽  
Room Temperature ◽  
Radical Cyclization ◽  
Quantitative Yield ◽  
Pyridinium Bromide ◽  
Wide Range ◽  
Selectivity Control ◽  
Isoquinoline Derivatives ◽  
Dibromo Derivative

A wide range of derivatives with new pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline skeleton was synthesized by free-radical intramolecular cyclization of o-bromophenyl-substituted pyrrolylpyridinium salts using the (TMS)3SiH/AIBN system. The cyclization provides generally good yields of pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline hydrobromides having no additional radical-sensitive substituents. The free bases can be obtained from the synthesized hydrobromides in quantitative yield by basification at room temperature. The selectivity control of intramolecular arylation was achieved by replacing the halogen: the use of 1-(2-(ortho-bromophenyl)-4-(ortho-iodophenyl)pyrrol-3-yl)pyridinium bromide makes it possible to obtain a monocyclization product, and the bicyclization product from the dibromo derivative. The procedure is also applicable to obtain 3-arylpyrido[2,1-a]pyrrolo[3,2-c]isoquinoline derivatives including 2-unsubstituted skeletons that are inaccessible via Pd-catalyzed cyclization.

Synthesis of Acyclic Adenine 8,N-Anhydronucleosides

2000 ◽  
Vol 65 (7) ◽  
pp. 1109-1125 ◽  
Author(s):  
Kateřina Meszárosová ◽  
Antonín Holý ◽  
Milena Masojídková
Keyword(s):  
Intramolecular Cyclization ◽  
Thionyl Chloride ◽  
Room Temperature ◽  
Main Product ◽  
Alkaline Solutions ◽  
Diphenyl Carbonate ◽  
Butyl Chloride

9-(4-Hydroxybutyl)adenine (10) was obtained by reaction of adenine with 4-[(2-tetrahydropyran-2-yl)oxy]butyl chloride (7) in the presence of DBU. 8-Bromo-9-(4-hydroxybutyl)adenine (13) was prepared by bromination of 10 or by alkylation of 8-bromoadenine (11) with 4-bromoethyl acetate followed by methanolysis. Tosylation of compound 13 afforded the 4-tosyloxy derivative 15 which gave on heating with methylamine or cyclopropylamine 6-methyl- (17a) or 6-cyclopropyl-7,8,9,10-tetrahydro-6H-[1,3]diazepino[1,2-e]purin-4-amine (17b), while the reaction with hydrazine afforded 7,8,9,10-tetrahydro-6H-[1,3]diazepino[1,2-e]purine-4,6-diamine (17d). Treatment of compound 13 with thionyl chloride gave 9-(4-chlorobutyl)-8-chloroadenine (18) as the main product which was transformed to 17b, 6-propyl-7,8,9,10-tetrahydro-6H-[1,3]diazepino[1,2-e]purin-4-amine (17c) or 7,8,9,10-tetrahydro-6H-[1,3]diazepino[1,2-e]purin-4-amine (17e) by reaction with cyclopropylamine, propylamine or ammonia, respectively. Compound 17e was quite stable both in acid and alkaline solutions, at room temperature or at 90 °C. Compound 13 was converted to 9-(4-hydroxybutyl)-8-methylaminoadenine (19) by reaction with methylamine. Compound 19 failed to undergo intramolecular cyclization to diazepine 17a on treatment with diphenyl carbonate, bis(4-nitrophenyl) carbonate or 1,1'-carbonyldiimidazole.

scholarly journals Novel library synthesis of 3,4-disubstituted pyridin-2(1H)-ones via cleavage of pyridine-2-oxy-7-azabenzotriazole ethers under ionic hydrogenation conditions at room temperature

2021 ◽  
Vol 17 ◽  
pp. 156-165
Author(s):  
Romain Pierre ◽  
Anne Brethon ◽  
Sylvain A Jacques ◽  
Aurélie Blond ◽  
Sandrine Chambon ◽  
...  
Keyword(s):  
Room Temperature ◽  
Kinase Inhibitor ◽  
Ionic Hydrogenation ◽  
Library Synthesis ◽  
Full Paper ◽  
Efficient Access

In our hands, efficient access to the 4-amino-3-carboxamide disubstituted pyridine-2(1H)-one kinase hinge-binder motif proved to be more challenging than anticipated requiring a significant investment in route scouting and optimization. This full paper focuses on the synthesis issues that we encountered during our route exploration and the original solutions we found that helped us to identify two optimized library-style processes to prepare our large kinase inhibitor library.

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