Diels-Alder Type Adducts Research Articles

Biosynthesis of chalcomoracin and kuwanon J, the Diels-Alder type adducts, in Morus alba L. cell cultures.

Experiments with [1-13C]-, [2-13C]- and [1, 2-13C2]-acetates administered to Morus alba cell cultures revealed that both optically active Diels-Alder type adducts chalcomoracin (1) and kuwanon J (2) are formed through the condensation of two molecules of cinnamoylpolyketide-derived skeletons. The 2-arylbenzofuran skeleton of 1 is formed by a novel type cyclization of the cinnamoylpolyketide, followed by decarboxylation. The 13C-labeling of [2-13C] acetate was incorporated into the starter acetate carbons in the biosynthesis of the prenyl moieties of chalcomoracin (1), while that of [1-13C] acetate was not incorporated into the prenyl moieties of 1.

Constituents of [formula omitted].3 : Structure of a new diels-alder type adduct, brosimone a

From the acetone extract of the roots of Brosimopsis oblongifolia Ducke brosimone A, 1 , a new Diels-Alder type adduct, was isolated. The structure was determined on the basis of chemical and physical evidences.

Photochemical Diels-Alder addition of N-methyltriazolinedione to phenanthrene

Visible irradiation of solutions of N-methyltriazolinedione and phenanthrene results in several Diels-Alder type adducts. The mechanism for these photoadditions is discussed.

Absolute Configuration of Natural Diels-Alder Type Adducts from the Morus Root Bark

Absolute Configuration of Natural Diels-Alder Type Adducts from the Morus Root Bark

Constituents of Morus alba L. cell cultures. 1 Structures of four new natural Diels-Alder type adducts, kuwanons J, Q, R, and V.

From callus tissues of Morus alba L., four new yellow pigments, kuwanons J (1), Q (2), R (3), and V (4), have been isolated. Chemical and spectroscopic evidence revealed that these compounds are stereochemically identical Diels-Alder type adducts of two 4-hydroxyprenylchalcone moieties bearing all the four possible patterns of hydroxylation at the 2 and/or 16'' positions.

Structures of two natural hypotensive Diels-Alder type adducts, mulberrofurans F and G, from the cultivated mulberry tree (Morus lhou KOIDZ.).

Two novel 2-arylbenzofuran derivatives named mulberrofurans F and G (=albanol A), as well as albanol B (3), were isolated from the ethyl acetate extract of the root bark of cultivated mulberry tree (Japanese name "Roso, " a cultivated variety of Morus lhou KOIDZ.). The structures of mulberrofurans F and G were shown to be 1 and 2, respectively, on the basis of spectral and chemical evidence. Mulberrofurans F (1) and G (2) were derived from chalcomoracin (4) and mulberrofuran C (5), respectively, by photocyclization in acidic solution. The compounds (1, 2, and 3) are optically active and can be regarded biogenetically as variations of Diels-Alder type adducts of chalcone derivatives and a dehydroprenyl-2-arylbenzofuran derivative. Intravenous injection of mulberrofuran F (1), as well as G (2), caused a marked depressor effect in rabbit.

Structures of three new 2-arylbenzofuran derivatives from the chinese crude drug "Sang-Bai-Pi" (morus root bark).

Three new 2-arylbenzofuran derivatives named mulberrofurans K, N, and O were isolated from the extract of the Chinese crude drug "Sang-Bai-Pi" (Japanese name "Sohakuhi"), the root bark of Morus sp. (Moraceae). The structures of mulberrofurans K, N and O were shown to be 1, 2, and 3, respectively, on the basis of spectral and chemical evidence. Mulberrofurans K and O are optically active and may be regarded biogenetically as Diels-Alder type adducts of chalcone derivatives and a dehydroprenyl-2-arylbenzofuran derivative. Furthermore, mulberrofuran K seems to be derived from the Diels-Alder type adduct by intramolecular ketalization.

Kuwanon W, a natural Diels—Alder type adduct from the root bark of Morus lhou

A natural Diels—Alder type adduct, named kuwanon W, was isolated from ethyl acetate extracts of the root bark of cultivated mulberry tree, and its structure was determined on the basis of spectral and chemical evidence. Kuwanon W is regarded biogenetically as a Diels—Alder adduct of a chalcone derivative and dehydroprenyl-flavone.

Structure of Sanggenon O, a Natural Diels-Alder Type Adduct from Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)

Structure of Sanggenon O, a Natural Diels-Alder Type Adduct from Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)

Structures of a novel 2-arylbenzofuran derivative and two flavone derivatives from the cultivated mulberry tree (Morus lhou Koidz.).

A new 2-arylbenzofuran derivative, mulberrofuran H and two isoprenylated flavones, kuwanons S and T, were isolated from the ethyl acetate extract of the root bark of cultivated mulberry tree (Japanese name Roso, cultivated variety of Morus lhou KOIDZ.). The structures of mulberrofuran H and kuwanons S and T were shown to be 1, 2, and 3, respectively, on the basis of spectral evidence. Mulberrofuran H can be regarded biogenetically as a variation of a Diels-Alder type adduct of a chalcone derivative and a dehydroprenyl-2-arylbenzofuran derivative.

Structures of three new natural Diels-Alder type adducts, kuwanons P and X, and mulberrofuran J, from the cultivated mulberry tree (Morus lhou Koidz.).

Structures of three new natural Diels-Alder type adducts, kuwanons P and X, and mulberrofuran J, from the cultivated mulberry tree (Morus lhou Koidz.).

ChemInform Abstract: STUDIES IN 1‐AZA‐1,3‐BUTADIENES: DIELS‐ALDER CYCLOADDITION REACTION OF 1‐AZA‐1,3‐BUTADIENES WITH KETENE LEADING TO THE SYNTHESIS OF Δ‐LACTAMS

AbstractDie Aza‐butadiene (I) reagieren mit Bromessigsäureester (II) unter Zugabe von Zink in einer 1,4‐Cyclo‐ addition zu den Pyridinonen (III).

Four new natural Diels-Alder type adducts, mulberrofuran E, kuwanon Q,R, and V from callus culture of Morus alba L.

From callus tissues of Morus alba L. the four new Diels-Alder type adducts mulberrofuran E (3), kuwanon Q (4), R (5), and V (6) have been isolated. Their structures were established by chemical and spectroscopic means. Mulberrofuran E (3) was found to be an adduct of a chalcone and a dehydroprenyl-2-arylbenzofuran, whereas kuwanon Q (4), R (5), and V (6) were identified as adducts of two prenylchalcone derivatives.

Structure of mulberrofuran H, a novel 2-arylbenzofuran derivative from the cultivated mulberry tree (Morus lhou(ser.) Koidz.).

From an ethyl acetate extract of the root bark of cultivated mulberry tree (Morus Lhou (ser.) Koidz.), a 2-arylbenzofuran derivative was isolated and named mulberrofuran H. Its structure was shown to be 1 on the basis of spectral evidence. Mulberrofuran H is regarded biogenetically as a variation of a Diels-Alder type adduct of a chalcone derivative and a dehydroprenyl-2-arylbenzofuran derivative.

Structure of mulberrofuran I, a novel 2-arylbenzofuran derivative from the cultivated mulberry tree (Morus bombycis Koidz.).

From an acetone extract of the reddish violet powder obtained from the surface of the Morus root bark (Morus bombycis Koidz.), a 2-arylbenzofuran derivative was isolated and named mulberrofuran I. Its structure was shown to be 1 on the basis of spectral evidence. Mulberrofuran I is regarded biogenetically as a variation of a Diels-Alder type adduct of a chalcone derivative and a dehydroprenyl-2-arylbenzofuran derivative.

Structure of Mulberrofuran K, an Optically Active Natiral Diels-Alder Type Adduct from Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)

Structure of Mulberrofuran K, an Optically Active Natiral Diels-Alder Type Adduct from Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)

Structure of kuwanon P, a new Diels-Alder type adduct from the root bark of the cultivated mulberry tree (Morus lhou (ser.) Koidz.).

Structure of kuwanon P, a new Diels-Alder type adduct from the root bark of the cultivated mulberry tree (Morus lhou (ser.) Koidz.).

Isolation and identification of by-products of gas phase catalytic oxidation of anthracene to 9,10-anthraquinone

A total of 29 associate components were identified in technical 9,10-anthraquinone. The product contained all the prominent impurities present in the starting anthracene except for 9,10-dihydroanthracene and fluorene. 9-(9'-Anthryl)-carbazole and Diels-Alder type adducts of anthracene with maleic anhydride and with maleinimide were also detected. The isolated and identified by-products of oxidation of anthracene were 1,4-anthraquinone, 4,4'-dioxo-1,1'-bianthrylidene, 4,10'-dioxo-1,9'-bianthrylidene, 1-(4'-oxy-1'-naphthylidene)-4-oxyanthracene, 2,3-naphthalenedicarboxylic acid and anhydride, and 5,7,12,14-tetrahydro-5,14;7,12-di(o-benzeno)pentacene-6,13-dione. Of the compounds formed by oxidation of the anthracene impurities, isolated and identified were dibenzo[b,d]pyrone, xanthone, 1,8-naphthalenedicarboxylic acid anhydride,9-fluorenone, and naphthol[2,3-b]thiophene-4,9-dione. As products of a deeper oxidation of the starting compounds, phthalic anhydride, maleic anhydride, maleinimide, phthalic acid, and maleic acid were found. Four additional components whose structure could not be determined were also isolated. The pathway of the anthracene oxidation is suggested.

A TRANSIENT FORMATION OF N-SUBSTITUTED ISOINDOLE BY MEANS OF PHOTOCHEMICAL INTRAMOLECULAR HYDROGEN ABSTRACTION

Abstract Isoindole derivative 2 was formed transiently by means of intramolecular hydrogen abstraction of 1. The intermediacy of 2 was confirmed by the good yields of Diels-Alder type adducts of it with dienophiles.

含窒素共役系の反応(第8報)Dimethyl Inidazole-4,5-dicarboxylateとAnetholeとの反応生成物の構造について

It was revealed from our previous investigation that the product obtained from the reaction of dimethyl imidazole-4, 5-dicarboxylate (Ia) with anethole (II) is not a Diels-Alder type adduct (III), as proposed by Lora-Tamayo, et al., but probably a heterocyclic compound (VI). The structure of this product is assumed from the basis of its chemical behavior and spectral data. Similar treatment of Ia with butoxyethylene (IV) as in the case of II afforded dimethyl 1-(1-butoxyethyl)imidazole-4, 5-dicarboxylate (V). The evidence for this structure assignment is described.