Synthesis of Functionalized Oxazolines and Oxazoles with DAST and Deoxo-Fluor

Phillips, Andrew J.; Uto, Yoshikazu; Wipf, Peter; Reno, Michael J.; Williams, David R.

doi:10.1021/ol005777b

Cited by 445 publications

(241 citation statements)

References 26 publications

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“…2 The second building block, corresponds to an oxazole or thiazole ring, and was synthesized from serine dipeptides. 3 Using this aproach, we proposed 4 zones which can be appropiate for modifications. This way, we synthesized 16 new compounds, and they were assayed in vitro to determine their antiproliferative activity against five human solid tumor cell lines.…”

Section: Resultsmentioning

confidence: 99%

New modular structures constructed by click chemistry

Valdomir¹,

Padrón²,

Padrón³

et al. 2013

Proceedings of the 15th Brazilian Meeting on Organic Synthesis Proceedings

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Section: Resultsmentioning

confidence: 99%

New modular structures constructed by click chemistry

Valdomir¹,

Padrón²,

Padrón³

et al. 2013

Proceedings of the 15th Brazilian Meeting on Organic Synthesis Proceedings

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“…Due to the considerable instability of the 2-vinyloxazole moieties under basic and dehydration conditions, we planned to introduce the vinyl group to the oxazole ring after construction of the tris-oxazole structure. Dehydrating cyclization of 4 by diethylaminosulfur trifluoride (DAST) 17 gave an oxazoline intermediate (85%), which was oxidized with a combination of bromotrichloromethane and 1,8-diazabicycloundec-7-ene (DBU) 18 at room temperature to give tris-oxazole 5 (98% based on recovered starting material). 19 We found that acetonitrile is a better solvent than the conventional CH 2 Cl 2 in this reaction.…”

Section: Pergamon Tetrahedron Lettersmentioning

confidence: 99%

Synthetic studies of mycalolide B, an actin-depolymerizing marine macrolide: construction of the tris-oxazole macrolactone using ring-closing metathesis

Kita

Watanabe

Ishitsuka

et al. 2010

Tetrahedron Letters

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Abstract-Tris-oxazole macrolactone 2, a key intermediate of mycalolide B (1), which has 13 stereogenic centers, was synthesized through the use of ring-closing metathesis (RCM). The E/Z ratio of the RCM product 2 was reversed by the use of CH 2 Cl 2 and toluene, whereas a cross metathesis reaction yielded the C1-C35 long-chain compound 19 in a highly E-selective manner. Thus, the loss of flexibility in aliphatic carbon chains and the steric hinderance of β-and γ-substituents of the C20 olefin in the precursor 11 may affect the stereoselectivity in RCM reactions.

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“…[15][16][17] We, however, have found that our fluorinated derivatives (7)(8)(9)(10)(11)(12) were readily hydrolyzed and solvolyzed at room temperature confirming the enhanced eletrophilicity of C 2 and thereby allowing an easy opening of the heterocyclic ring. Difluoroacids (13)(14)(15)(16) were produced in water, difluoroesters (17)(18)(19)(20), in alcohols and difluoroamides (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) in amines. Esterified aminoacids (41) and thiosemicarbazides derivatives (42-46) were obtained on reaction with thiosemicarbazides.…”

Section: Reactions Of 7-12 With Nucleophilesmentioning

confidence: 99%

“…IR (KBr) max /cm -1 : 3321 (NH), 1673 (COMe), 1079 (CF 2 ). m/z (%): 298 (17), 256 (7), 238 (12), 198 (8), 183 (26), 164 (3), 156 (100), 137 (19), 109 (7), 74 (14). 1 9.62 (bs, NH).…”

Section: -(2-acetamido-5-methylphenyl)-n-butyl-22-difluoroacetamideunclassified

N-Acyl-3,3-difluoro-2-oxoindoles as versatile intermediates for the preparation of different 2,2-difluorophenylacetic derivatives

Boechat¹,

Kover²,

Bastos³

et al. 2008

J. Braz. Chem. Soc.

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Este trabalho descreve a versatilidade sintética dos derivados N-Acil-3,3-diflúor-2-oxoindóis, obtidos a partir da reação de N-acilisatinas com dietilaminotrifluoreto de enxofre (DAST) que, através da reação com diferentes nucleófilos, promovem a abertura do anel heterocíclico, levando à formação de vários produtos. A reação de N-Acil-3,3-diflúor-2-oxoindóis com água fornece os ácidos 2-(2-N-acilfenil)-2,2-difluoracéticos e com álcoóis fornece os ésteres correspondentes. Reações com aminas e glicina levam à formação das correspondentes amidas 2-(2-N-acilfenil)-2,2-difluoracetamidas. Na reação com tiossemicarbazidas os derivados difluortiossemicarbazidas são obtidos. Estes últimos sofrem uma ciclização catalisada por ácido para fornecerThis paper describes the versatility of N-Acyl-3,3-difluoro-2-oxoindoles, obtained from the the reaction of N-acylisatins with (diethylamino)sulphur trifluoride (DAST) which, on opening of the heterocyclic ring by reactions with nucleophiles, lead to the formation of a variety of products: reaction with water yields 2-(2-amidoacyl)-2,2-difluoroacetic acids, with alcohols yields alkyl 2-(2-amidoacyl)-2,2-difluoroacetates, with amines and glycine yields 2-(2-amidoacyl)-2,2-difluoroacetamides and with thiosemicarbazides yields difluorothiosemicarbazide derivatives. The latter undergo acid-catalysed cyclizations to yield N- (2-((5-aminoaryl-1,3,4-thiadiazol-2-yl) difluoromethyl)-4-(R)-phenyl)acetamide. The X-ray structure of N- (2-((5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl)-4-methylphenyl)acetamide has been determined.

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Synthesis of Functionalized Oxazolines and Oxazoles with DAST and Deoxo-Fluor

Abstract: [formula: see text] A mild and highly efficient cyclization of beta-hydroxy amides to oxazolines is described using DAST and Deoxo-Fluor reagents. A one-pot protocol for the synthesis of oxazoles from beta-hydroxy amides is also presented.

Cited by 445 publications

References 26 publications

New modular structures constructed by click chemistry

New modular structures constructed by click chemistry

Synthetic studies of mycalolide B, an actin-depolymerizing marine macrolide: construction of the tris-oxazole macrolactone using ring-closing metathesis

N-Acyl-3,3-difluoro-2-oxoindoles as versatile intermediates for the preparation of different 2,2-difluorophenylacetic derivatives

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