Polyphosphate Ester

Dixon, Lisa A.

doi:10.1002/047084289x.rp185

Cited by 7 publications

(10 citation statements)

References 54 publications

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“…At the same time, data on 7-aryl-substituted derivatives are scarce. We obtained 4-aryloxazolo[5,4- b ]pyridines 6a , 10a – f , 9a , 11a , 12a by the reaction of 3-amino-4-arylpyridine-2(1 H )-ones 8a – f with orthoethers or by the reaction of compound 8a with the corresponding carboxylic acids in a polyphosphoric ester (PPE) with a yield of 84–92% for 6a , 10a – f and 58–75% for 9a , 11a , 12a (Table ).…”

Section: Results and Discussionmentioning

confidence: 99%

“… a Reaction condition A: RC(OEt) 3 , p -TSA, toluene, reflux; Reaction condition B: RCO 2 H, PPE, N 2 , 90 °C. …”

Section: Results and Discussionmentioning

confidence: 99%

“…A mixture of 3-amino-6-methyl-4-phenylpyridine-2(1 H )-one 8a (1 mmol), carbonic acid (1.1 mmol), and polyphosphate ester (P 4 O 12 (C 2 H 5 ) 4 ) (1.0 g) was heated to 90°C in an oil bath under nitrogen for 2 h. The reaction progress was monitored by TLC. After the completion of the reaction, the mixture was cooled and poured into water (10 mL) and neutralized with aqueous Na 2 CO 3 .…”

Section: Methodsmentioning

confidence: 99%

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Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

et al. 2020

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In this work, we describe the development of the rearrangement for 7-aryl-substituted oxazolo [5,4-b]pyridines treated with aluminum chloride into synthetically hard-to-reach benzo [c][1,7]naphthyridinones. The discovered rearrangement is applied to a variety of electron-rich (hetero)arene substrates. It offers the advantages of mild conditions (90 °C temperature), fast reaction rates (<4 h), compatibility with air moisture, and the use of inexpensive commercial reagents. The proposed reaction mechanism and key elementary reaction acts were studied in detail using quantum chemical calculations. The photophysical properties of the synthesized compounds were studied by steady-state UV−vis spectroscopy.

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Section: Results and Discussionmentioning

confidence: 99%

“… a Reaction condition A: RC(OEt) 3 , p -TSA, toluene, reflux; Reaction condition B: RCO 2 H, PPE, N 2 , 90 °C. …”

Section: Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

et al. 2020

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“…Mass spectra were recorded on a Finnigan MAT INCOS 50 mass spectrometer with direct sample injection (EI ionization, 70 eV). Polyphosphate ester (PPE) was synthesized according to the described method [ 21 ]. For IR spectra comparisons the SciFinder access to BIO-RAD data base was used [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

A Novel Approach to the Synthesis of 1,3,4-Thiadiazole-2-amine Derivatives

et al. 2021

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The main purpose of the study was the development of a new method for synthesis of 1,3,4-thiadiazol-2-amine derivatives in a one-pot manner using the reaction between a thiosemicarbazide and carboxylic acid without toxic additives such as POCl3 or SOCl2. The reaction was investigated in the presence of polyphosphate ester (PPE). It was found that, in the presence of PPE, the reaction between the thiosemicarbazide and carboxylic acid proceeds in one-pot through three steps with the formation of corresponding 2-amino-1,3,4-thiadiazole. Using the developed approach five, 2-amino-1,3,4-thiadiazoles were synthesized. The structures of all compounds were proven by mass spectrometry, IR, and NMR spectroscopies.

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“…Regarding the last step of the sequence leading to compounds 1 , our group has worked extensively on ring-closure reactions leading to nitrogen-containing heterocycles such as 5–8-membered cyclic amidines [ 81 – 83 ], N- aryl-2-iminoazacycloalkanes [ 84 ] and 2-oxazolines or their higher homologues [ 85 ], using polyphosphoric acid esters PPE (ethyl polyphosphate) [ 86 ] and PPSE (trimethylsilyl polyphosphate) [ 87 ] under microwave irradiation. PPE and PPSE are aprotic irreversible dehydrating agents of the Lewis acid-type, which are able at the same time, to activate nitrogen and oxygen functionalities towards nucleophilic attack.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

Gruber¹,

Díaz²,

Orelli³

2018

Beilstein J. Org. Chem.

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The sequential N-functionalization of 2-aminobenzylamine (2-ABA) followed by cyclodehydration allowed for a straightforward and efficient synthesis of 3,4-dihydroquinazolines with N-aryl substituents bearing electron-withdrawing groups. The sequence involves an initial SNAr displacement, N-acylation and MW-assisted ring closure. Remarkably, the uncatalyzed N-arylation of 2-ABA led to the monosubstitution product using equimolar amounts of both reagents. The individual steps were optimized achieving good to excellent overall yields of the desired heterocycles, avoiding additional protection and deprotection steps. A mechanistic interpretation for the cyclodehydration reaction promoted by trimethylsilyl polyphosphate (PPSE) is also proposed on the basis of literature data and our experimental observations.

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Polyphosphate Ester

Cited by 7 publications

References 54 publications

Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

A Novel Approach to the Synthesis of 1,3,4-Thiadiazole-2-amine Derivatives

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

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Polyphosphate Ester

Cited by 7 publications

References 54 publications

Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

Rearrangement of 7-Aryloxazolo[5,4-b]pyridines to Benzo[c][1,7]naphthyridine-4(3H)-ones and Thieno[3,2-c][1,7]naphthyridine-6(7H)-ones

A Novel Approach to the Synthesis of 1,3,4-Thiadiazole-2-amine Derivatives

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N3-aryl derivatives with electron-withdrawing groups

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Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups