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Remarkable regioselectivities in the course of the synthesis of two new Luotonin A derivatives
- Source :
- Tetrahedron. 73:3231-3239
- Publication Year :
- 2017
- Publisher :
- Elsevier BV, 2017.
-
Abstract
- Ethyl 4-oxo-3,4-dihydroquinazoline-2-carboxylate reacts selectively with trimethylaluminium-activated 2-amino- or 4-aminobenzoic acid ethyl esters to give the corresponding anilides without self-condensation of the aminobenzoate building blocks. After propargylation, the quinazolinones were treated with Hendrickson's reagent, but only the para-substituted ester was found to undergo the expected [4 + 2] cycloaddition reaction, affording a new Luotonin A derivative. A different regioselectivity was observed with the ortho-substituted ester which affords a benzoxazinone under identical conditions. When the ester group in the ortho-substituted intermediate is replaced with a nitrile function, the outcome of the reaction with Hendrickson's reagent depends on the absence or presence of a base (DBU), yielding either a triphenylphosphonium-substituted iminobenzoxazine or a 4-cyano-substituted Luotonin A derivative.
- Subjects :
- chemistry.chemical_classification
Nitrile
Base (chemistry)
010405 organic chemistry
Chemistry
Organic Chemistry
Regioselectivity
Ethyl ester
010402 general chemistry
01 natural sciences
Biochemistry
Cycloaddition
0104 chemical sciences
chemistry.chemical_compound
Derivative (finance)
Reagent
Drug Discovery
Organic chemistry
Subjects
Details
- ISSN :
- 00404020
- Volume :
- 73
- Database :
- OpenAIRE
- Journal :
- Tetrahedron
- Accession number :
- edsair.doi...........11559837239d65f4cdc6c27b4c1fe0c5