New Dibenzofurans and Depsides From the Lichen Bunodophoron patagonicum

1994 ◽  
Vol 47 (7) ◽  
pp. 1335 ◽  
Author(s):  
JA Elix ◽  
JA Elix ◽  
DA Venables ◽  
DA Venables ◽  
M Wedin ◽  
...  
Keyword(s):  
Natural Products ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Benzoic Acid ◽  
Total Synthesis

The lichen Bunodophoron patagonicum has been shown to contain five new dibenzo -furans: ascomatic acid (3,7-dimethoxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (2) and the corresponding methyl ester (3); 7-O-methylnorascomatic acid (3-hydroxy-7-methoxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (4) and the corresponding methyl ester (5); and norascomatic acid (3,7-dihydroxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (6). The lichen also contains two new depsides : patagonic acid [2-hydroxy-4-(2′-hydroxy-4′-methoxy-6′-methyl-benzoyloxy)-6-(2′-oxononyl)benzoic acid] (10) and isopatagonic acid [2-hydroxy-4-(2′-hydroxy-4′-methoxy-6′-(2′-oxononyl) benzoyloxy )-6-methylbenzoic acid] (11). The structure of all new natural products was confirmed by total synthesis.

Three New Benzoic Acid Derivatives from the Glandular Excretion of Eriodictyon sessilifolium (Hydrophyllaceae)

1988 ◽  
Vol 43 (5-6) ◽  
pp. 337-340 ◽  
Author(s):  
Francisco J. Arriaga-Giner ◽  
Eckhard Wollenweber ◽  
Ingrid Schober ◽  
George Yatskievych
Keyword(s):  
Natural Products ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Benzoic Acid ◽  
Glandular Trichomes ◽  
Acid Methyl Ester ◽  
Spectroscopic Methods ◽  
Flavonoid Aglycones ◽  
Benzoic Acid Derivatives ◽  
Acid Methyl

Eriodictyon sessilifolium, an endemic Hydrophyllaceae of Baja California (Mexico), has been studied for the natural products exuded by glandular trichomes covering its leaves and stems. Major components of this exudate were isolated and identified by spectroscopic methods to be 4-hydroxy-3-(2,3-dihydroxy-3-methylbutyl)-benzoic acid methyl ester (1), the natural methyl ester of anodendroic acid (2), and 2,2-dimethyl-3-hydroxychroman-6-carboxylic acid methyl ester (3). Possible biosynthetic relations between these new natural products are considered. In addition, 9 known flavonoid aglycones were identified as exudate constituents.

Derivate des Benzo[1.3]dioxols, 431 Über Benzo [1.3] dioxolcarbonsäuren / Derivatives of 1,3-Benzodioxoles, 43 1,3-Benzodioxolecarboxylic Acids

1978 ◽  
Vol 33 (7-8) ◽  
pp. 465-471
Author(s):  
Franz Daliacker ◽  
Volker Mues ◽  
In-O Kim
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Benzoic Acid ◽  
Myristic Acid ◽  
Good Yield ◽  
Acid Ester ◽  
Acid Methyl Ester ◽  
Acid Methyl ◽  
Derivatives Of

Abstract We describe the possibilities of formation and preparation of the “natural” 1,3-benzodioxolecarboxylic acids 1, 2, 4, 6 b, and 7, already mentioned in literature. Myristic acid (3e) was prepared in good yield from 3-methoxy-4,5-dihydroxy-benzoic acid ester (3c) , which could be easily made from 3-methoxy-2,3-carbonyldioxy-benzoic acid methylester (3b). Myristicic acid methylester (3d) could be subjected to methylation and hydrolysis leading to 3e without any difficulties. 4.6-dimethoxy-1,3-benzodioxole-5-carboxylic acid (5b) was prepared in good yields by oxidation of 4,6-dimethoxy-1,3-benzodioxole-5-aldehyde (5a). 5.7-dimethoxy-1,3-benzodioxole-carboxylic acid (13f), one of the “unnatural” 1,3-benzodioxolecarboxylic acids, derivatives of o-ipiperonylic acid (8), was prepared from 5-amino-7-methoxy-1,3- benzodioxole-4carboxylic acid methyl ester (13b) by diazotisation, elimination of nitrogen, methylation, and hydrolysis. A comparison of our measured pkA-values showed the strongest acidity belonging to 5,6-dimethoxy-1,3-benzodioxole-4-carbocylic acid (11).

scholarly journals Dibromopyrrole Alkaloids from the Marine Sponge Acanthostylotella sp

2009 ◽  
Vol 4 (1) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Sherif Saeed Ebada ◽  
RuAngelie Edrada-Ebel ◽  
Nicole J. de Voogd ◽  
Victor Wray ◽  
Peter Proksch
Keyword(s):  
Natural Products ◽  
Carboxylic Acid ◽  
Methyl Ester ◽  
Marine Sponge ◽  
Two Dimensional ◽  
New Compounds

Fourteen dibromopyrrole alkaloids were isolated from the marine sponge Acanthostylotella sp. collected in Indonesia. In addition to the known compounds 4,5-dibromo-N-(methoxy-methyl)-1 H-pyrrole-2-carboxamide (7), 4,5-dibromo-1 H-pyrrole-2-carboxamide (8), mukanadin D (9), (±)-longamide B methyl ester (10), (±)-longamide B (11), (±)-longamide (12), 3,4-dibromo-1 H-pyrrole-2-carboxamide (13), 2-cyano-4,5-dibromo-1 H-pyrrole (14), six compounds were isolated that proved to be new natural products including acanthamides A – D (1 – 4), methyl 3,4-dibromo-1 H-pyrrole-2-carboxylate (5) and 3,5-dibromo-1 H-pyrrole-2-carboxylic acid (6). The structures of the new compounds were unequivocally identified based on one and two dimensional NMR and on HRFTMS as well as by comparison with the literature.

SN2-Type Glycosylation with Unprotected Pyranoses

2019 ◽  
Author(s):  
Hironori Takeuchi ◽  
Yusuke Fujimori ◽  
Hiromitsu Shibayama ◽  
Masaru Nagaishi ◽  
Yoshihiro Ueda ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Antitumor Activity ◽  
Benzoic Acid ◽  
Total Synthesis ◽  
Carboxylic Acids ◽  
Stereoselective Glycosylation ◽  
Wide Range ◽  
High Stereoselectivity ◽  
Glycosyl Donors

<p>An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-D-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism seems to be responsible for non-stereoselective glycosylation in DMF. The SN2-type glycosylation can be applicable to various unprotected pyranoses as glycosyl donors and a wide range of carboxylic acids, phenols, and imides as glycosyl acceptors, retaining its high stereoselectivity (34 examples). Glycosylation of a carboxylic acid with unprotected α-D-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-<i>cis</i>-mannoside. An extremely short-step total synthesis of a middle molecule (1874 Da) natural glycoside with antitumor activity, coriariin A, was achieved via a double SN2 glycosylation strategy with two molecules of unprotected α-D-glucose.</p>

A Synthesis of the Lichen Dibenzofuran Pannaric Acid 6-Methyl Ester

1990 ◽  
Vol 43 (12) ◽  
pp. 2107 ◽  
Author(s):  
JA Elix ◽  
SJ Pratt ◽  
JR Laundon
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Major Metabolite

A total synthesis of pannaric acid 6-methyl ester (3,9-dihydroxy-6-methoxycarbonyl-1,7-dimethyldibenzofuran-2-carboxylic acid) (2) has been achieved by a biomimetic -type approach with palladium(II) acetate in the key cyclization step. This acid (2) was shown to be identical with the major metabolite of the lichen Leproloma vouauxii.

SN2-Type Glycosylation with Unprotected Pyranoses

2019 ◽  
Author(s):  
Hironori Takeuchi ◽  
Yusuke Fujimori ◽  
Hiromitsu Shibayama ◽  
Masaru Nagaishi ◽  
Yoshihiro Ueda ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Antitumor Activity ◽  
Benzoic Acid ◽  
Total Synthesis ◽  
Carboxylic Acids ◽  
Stereoselective Glycosylation ◽  
Wide Range ◽  
High Stereoselectivity ◽  
Glycosyl Donors

<p>An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-D-glucose under Mitsunobu conditions in dioxane, while an SN1 mechanism seems to be responsible for non-stereoselective glycosylation in DMF. The SN2-type glycosylation can be applicable to various unprotected pyranoses as glycosyl donors and a wide range of carboxylic acids, phenols, and imides as glycosyl acceptors, retaining its high stereoselectivity (34 examples). Glycosylation of a carboxylic acid with unprotected α-D-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-<i>cis</i>-mannoside. An extremely short-step total synthesis of a middle molecule (1874 Da) natural glycoside with antitumor activity, coriariin A, was achieved via a double SN2 glycosylation strategy with two molecules of unprotected α-D-glucose.</p>

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