78591-52-3Relevant academic research and scientific papers
Convenient synthesis of bioactive pyranonaphthoquinones (±)9-demethoxyeleutherin and (±)9-demethoxyisoeleutherin
Limaye, Rohan A.,Joseph, Augustine R.,Natu, Arun D.,Paradkar, Madhusudan V.
, p. 568 - 570 (2014/12/11)
A convenient synthesis of (±)9-demethoxyeleutherin and (±)9-demethoxyisoeleutherin, the analogues of naturally occurring pyranonaphthoquinone antibiotics eleutherin and isoeleutherin, is described. The synthesis was achieved from 4-methoxy-1-napthol in four simple steps including Claisen rearrangement and oxymercuration-demercuration reactions.
Synthesis of naturally occurring pyranonaphthoquinones: (±) 9-demethoxyeleutherin, (±) 9-demethoxyisoeleutherin, and pentalongin via nef reaction
Limaye, Rohan A.,Natu, Arun D.,Paradkar, Madhusudan V.
, p. 2503 - 2509 (2014/08/05)
GRAPHICAL ABSTRACT The article describes alternative method for the synthesis of (±) 9-demethoxyeleutherin and (±) 9-demethoxyisoeleutherin, the analogs of naturally occurring pyranonaphthoquinones antibiotics eleutherin and isoeleutherin. This methodology has provided the target molecules using a shorter route involving five simple chemical transformations with Nef reaction as a key step. All the intermediates and target molecules were completely characterized by spectral techniques and confirmed by comparison with literature data. Further we have extended Nef protocol toward formal synthesis of naturally occuring pyranonaphthoquinone pentalongin. We accomplished synthesis of of 2-(1,4-dimethoxynaphthalen-2-yl) acetic acid devoid of very toxic cyanide intermediates, which has been converted into pentalongin.
An efficient method for the one-pot construction of the 1H-naphtho[2,3-c]pyran-5,10-dione system
Kobayashi, Kazuhiro,Uchida, Masaharu,Uneda, Tomokazu,Yoneda, Keiichi,Tanmatsu, Miyuki,Morikawa, Osamu,Konishi, Hisatoshi
, p. 2977 - 2982 (2007/10/03)
2-(1-Hydroxyalkyl)-1,4-naphthoquinones are found to react with pyrrolidino enamines in toluene to give 1H-naphtho[2,3-c]pyran-5,10-diones in good yields via a tandem conjugate addition-cyclization sequence, followed by an elimination of pyrrolidine. 2-Hydroxymethyl-1,4-naphthoquinone and morpholino enamines undergo a similar sequence, without loss of morpholine, to yield 3-morpholino-3,4-dihydro-1H-naphtho[2,3-c]pyran-5,10-diones. The 3-morpholino group of these products can be replaced with a hydro, a hydroxy, or a methoxy group. Imines also react with 2-(1-hydroxyalkyl)-1,4-naphthoquinones to give the corresponding 1H-naphtho[2,3-c]pyran-5,10-diones, including a natural product (pentalongin). The utility of these reactions is demonstrated in the synthesis of pyranonaphthoquinone antibiotics, viz. (±)-eleutherin and (±)-isoeleutherin.
Allylation of 2-Alkanoyl 1,4-Quinones with Allylsilanes and Allylstannanes. Efficient Synthesis of Pyranonaphthoquinone Antibiotics
Uno, Hidemitsu
, p. 350 - 358 (2007/10/02)
Total syntheses of pyranonaphthoquinone antibiotics eleutherin, isoeleutherin, nanaomycin A, and deoxyfrenolicin are described.The crucial step in the route is a regioselective allylation of alkanoyl quinones with allylsilanes and allylstannanes.The allyl
Reduction of Cyclic Hemiacetals. The Synthesis of Demethoxyeleutherin and Nanaomycin A
Kraus, George A.,Molina, Maria Teresa,Walling, John A.
, p. 1568 - 1569 (2007/10/02)
The reduction of cyclic hemiacetals containing two stereogenic centres is highly stereoselective.
Pyranonaphthoquinone Antibiotics. Part 1. Syntheses of 9-Demethoxyeleutherins and 9-Deoxynanaomycin A Methyl Ester.
Kometani, Tadashi,Yoshii, Eiichi
, p. 1191 - 1196 (2007/10/02)
The syntheses of 9-demethoxyeleutherins and 9-deoxynanaomycin A methyl ester starting from indan-1-one derivatives are described.Lemieux-Johnson oxidation of the indene (15) derived from 4,7-dimethoxy-2-methylindan-1-one (14) afforded the diketone (16).The diol (17) obtained by lithium aluminium hydride reduction of (16) was treated with hydrochloric acid to give a ca. 1:2 mixture of cis-5,8-dimethoxy-1,3-dimethylisochroman (18) and the trans-isomer (19).Treatment of (16) with hydrogen bromide in acetic acid followed by catalytic reduction gave exclusively the cis-isochroman (18).Oxidative demethylation of the isochromans (18) and (19) afforded the quinones (22) and (23), benzannelation of which in two steps yielded 9-demethoxyeleutherin (24) and 9-demethoxyisoeleutherin (25) respectively.The same oxidation of the indene (32) derived from 4,7-dimethoxyindan-1-one (28) afforded the keto-aldehyde (33), which was treated with methoxycarbonylmethylenetriphenylphosphorane to give the conjugated ester (34).Reductive cyclisation of (34) with sodium borohydride afforded a ca. 1:3.5 mixture of cis-5,8-dimethoxy-3-methoxycarbonylmethyl-1-methylisochroman (35) and the trans-isomer (36).Oxidative demethylation of (36) followed by benzannelation produced 9-deoxynanaomycin A methyl ester (39).
Synthesis of (+/-)-Eleutherin, (+/-)-Isoeleutherin, and their Demethoxy Analogues. A Novel Synthetic Approach
Naruta, Yoshinori,Uno, Hidemitsu,Maruyama, Kazuhiro
, p. 1277 - 1278 (2007/10/02)
(+/-)-Eleutherin (1) and (+/-)-isoeleutherin (3) are prepared by intramolecular cyclization to the naphthopyrans of 2-acetyl-3-allyl-8-methoxy-1,4-naphthoquinone, which is itself obtained by the Lewis acid-mediated allylation of 2-acetyl-8-methoxy-1,4-naphthoquinone (5) with allyltrimethylstannane (7).
