ChemInform Abstract: Intramolecular Carbocyclizations of 1,5‐Diketones and Oxo‐1,5‐diketones.

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reactivity of pyrrol-2-ones. (review)

“…Pyrrol-2-ones are present entirely in the lactam form, and this determines their ability to participate in the Michael condensation [66]. 5-Aryl(alkyl)-3H-pyrrol-2-ones 24 are capable of acting as methylene component (addend) in the Michael reaction with electron-deficient unsaturated ketones under the conditions of base catalysis [65][66][67][68][69][70][71][72][73][74][75].…”

“…Michael condensation takes place with higher speed the more readily the enolic form is transformed into the ketone form [65]. Pyrrol-2-ones are present entirely in the lactam form, and this determines their ability to participate in the Michael condensation [66].…”

Investigation of the products of interaction of cyclic diketones with nitrogen-containing 1,4-binucleophiles

“…Doubling of the signals was not recorded in the spectrum of compound 7b containing p-fluorophenyl substituent in position 9, nor in compound 6 having ortho-substituted aryl radicals in positions 9 and 10. (2) 3707 (2) 6126 (1) 680(1) C(9') 6766 (2) -2141 (2) 1235 (1) C(1) 1864 (2) 6052 (2) 67(1) C(10') 5824 (2) -1682 (2) 829(1) C (2) 1136 (2) 5576 (2) -331(1) C(11') 4883 (2) -992 (2) 1001(1) C (3) 1417 (2) 4596 (2) -479(1) C(12') 4056 (2) -487 (2) 574(1) C (4) 2430 (2) 4113 (2) -223(1) C(13') 3098 (2) 956 (1) 1005(1) C (5) 3176 (2) 4587 (2) 174(1) C(14') 7734 (3) -2151 (2) 2166(1) C (6) 4931 (2) 4100 (2) 855(1) C(15') 7728 (2) -550 (2) 1623(1) C (7) 5912 (2) 3272 (2) 894(1) C(16') 2735 (2) -930 (2) 484(1) C (8) 6429 (2) 3018 (2) 1460 (1) C(17') 2098 (2) -793(2) -9(1) C (9) 6743 …”

“…In cyclic 1,5-diketones the position of the carbonyl groups determines exclusively the ease of their cyclization and makes them as convenient basis for the synthesis of nitrogen-, oxygen-, and sulfur-containing heterocycles [1,2].…”

“…

In cyclic 1,5-diketones the position of the carbonyl groups determines exclusively the ease of their cyclization and makes them as convenient basis for the synthesis of nitrogen-, oxygen-, and sulfur-containing heterocycles [1,2].The aim of the present work is the study of the reactivity of the Michael adducts 1a-j [3,4], obtained from dimedone and aromatic aldehydes or furfural (adduct 1j), in relation to the bidentatic nucleophiles o-phenylenediamine 2 and o-aminophenol 3. The cyclic tetraketones 1a-j exist in the enolic form which makes them structurally close to α,β-unsaturated ketones, the reactivity of which in relation to 1,4-dinucleophiles has been studied previously [5,6].

The electronic character of the substituents in R influence the direction of the interaction of compounds 1a-i with o-phenylenediamine 2 on boiling these reactants in 2-propanol (method A).

…”