Formation of 2-acetylpyridines by the base-catalysed ring opening of dihydro-4H-furo[2,3-e]oxazines

Gilchrist, T. L.; Hughes, D.; Stretch, W.; Chrystal, Ewan J. T.

doi:10.1039/p19870002505

Cited by 18 publications

(9 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then, upon heating, a rearrangement leads to the furan-bearing α-hydroxyimino esters 2 . Reports have thus described the preparation of 2ae in a 46% yield from furan ( 48ae ) [ 24 ] and compound 2af in a 50% yield from 2-methylfuran ( 48af ) [ 25 ]. For our part, we first made extensive trials to improve such yields using 2-methylfuran ( 48af ) as a model substrate.…”

Section: Resultsmentioning

confidence: 99%

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

Coutant¹,

Hervin²,

Gagnot³

et al. 2018

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates – using Suzuki–Miyaura coupling or cycloadditions – before undertaking the oximation step – provided accesses to further α-amino esters. Moreover, other pathways to α-hydroxyimino esters were explored including an attempt to improve the cycloadditions between ethyl β-bromo-α-hydroxyiminocarboxylate and various alkylfuranes.

show abstract

Section: Resultsmentioning

confidence: 99%

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

Coutant¹,

Hervin²,

Gagnot³

et al. 2018

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…The main methods for the preparation of 6 H -1,2-oxazines 2 start from the corresponding 5,6-dihydro-4 H -1,2-oxazines 1 . The first consists of the elimination of HX molecule, where X is a good leaving group at position C-4 or C-5 (see Scheme , eqs 1 and 2). ,,,, …”

Section: Synthesis Of Six-membered Cyclic Oxime Ethers 1 Andmentioning

confidence: 99%

Chemistry of Six-Membered Cyclic Oxime Ethers. Application in the Synthesis of Bioactive Compounds

2011

View full text Add to dashboard Cite

CONTENTS 1. Introduction 5004 2. Synthesis of Six-Membered Cyclic Oxime Ethers 1 and 2 5005 2.1. [4 þ 2]-Cycloaddition Reactions 5005 2.2. Intramolecular Cyclization of γ-Functionalized Oximes 5009 2.3. Intramolecular Cyclization of Functionalized O-Substituted Hydroxylamines 5012 2.4. Synthesis of SCOE from N-O-Containing Heterocyclic Derivatives 5012 2.4.1. Synthesis of SCOE from Other 1,2-Oxazines 5012 2.4.2. Synthesis of SCOE from Isoxazolines and Five-Membered Cyclic Nitronates 5014 2.5. Other Methods 5014 3. Chemical Properties of SCOE 5016 3.1. Reduction of SCOE 5016 3.1.1. Reduction of SCOE to Tetrahydro-2H-1,2oxazines 5018 3.1.2. Reduction of SCOE with 1,2-Oxazine Ring-Opening 5020 3.1.2.1. Reduction of SCOE to 1,4-Amino Alcohols. 5020 3.1.2.2. Reduction of SCOE to Carbonyl Compounds. 5021 3.1.2.3. Reduction of SCOE to γ-Hydroxyoximes. 5022 3.1.3. Reduction Reactions of SCOE with 1,2-Oxazine Ring Contraction 5022 3.1.3.1. Reduction of SCOE to Pyrrolidines. 5022 3.1.3.2. Reduction of SCOE to N-Hydroxypyrrolidines. 5023 3.1.3.3. Reduction of SCOE to Pyrroles. 5024 3.1.3.4. Reduction of SCOE to Aziridines. 5025 3.1.3.5. Reduction of SCOE to Furan Derivatives. 5025 3.2. Addition Reactions to the CdN Double Bond of SCOE 5026 3.3. 1,2-Oxazine Ring-Opening in SCOE 5027 3.4. Deoximation of SCOE 5028 3.5. 1,2-Oxazine Ring Rearrangements in SCOE 5028 3.6. 1,2-Oxazine Ring Fragmentation Reactions in SCOE 5030 4. SCOE in the Synthesis of Natural Products and Biologically Active Compounds 5031 4.1. Synthesis of Amino Acids 5032 4.2. Synthesis of Polyhydroxylated Pyrrolidines 5033 4.3. Synthesis of Pyrrolizidine and Indolizidine Alkaloids and Their Analogs 5033 4.4. Synthesis of Biologically Active 2-Aryl-Substituted Pyrrolidines and Amines 5035 4.5. Synthesis of Other Natural Compounds 5036 5. Conclusion 5037 Author Information 5037 Biographies 5038 Acknowledgment 5038 References 5038

show abstract

“…In some cases, the primary adducts were found to be unstable and to rearrange readily. 113 ± 115 The reactions with less aromatic substrates such as furan, 16,18,93 2-metyl-, 116 2,5-dimethyl-, 16,18,116,117 and benzofuran 16 always afford cycloadducts 78 and 79, which readily undergo selective cleavage on treatment with acids 16,118 or bases 116 to give either products of oxazine ring opening or products of more extensive transformations. 116,118…”

Section: Reactions With Nucleophilesmentioning

confidence: 99%

Conjugated nitrosoalkenes

Lyapkalo¹,

Ioffe²

1998

Russ. Chem. Rev.

View full text Add to dashboard Cite

Published data on the preparation, structure, physical and chemical properties, and reactivity of nitrosoalkenes are described systematically. The influence of the structure and stereoelectronic effects of substituents at the double bond on the stability of nitrosoalkenes is analysed. Primary attention is paid to concerted cycloaddition of nitrosoalkenes to miscellaneous multiple bonds, in particular, to the problems of regio-, stereo-, and enantioselectivity of [4 + 2]-cycloaddition of nitrosoalkenes to alkenes. The bibliography includes 183 references.

show abstract

Formation of 2-acetylpyridines by the base-catalysed ring opening of dihydro-4H-furo[2,3-e]oxazines

Cited by 18 publications

References 1 publication

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate

Chemistry of Six-Membered Cyclic Oxime Ethers. Application in the Synthesis of Bioactive Compounds

Conjugated nitrosoalkenes

Contact Info

Product

Resources

About