Trans-communic acid

Recently, Barrero et al. have synthesized 63 from cis- and trans-communic acids (153) [14], natural substances present in the cones of Juniperus communis L. Two of the four rings, and three asymmetric carbons have the same configuration as the final molecules. These syntheses were achieved in 10 steps with overall yields of 7% and involves as key steps (Scheme 13) ... 

The second synthetic approach to oidiolactone C (61) is summarized in Scheme 20. This route also commences with the ozonolysis of trans-communic acid 180. Now, when this compound was exposed to ozone in excess, keto aldehyde 187 was obtained in 76% yield. The key step in this approach was the y-lactone closure via chemoselective reduction of the lactone moiety on compound 189 through a SN2 mechanism. Compound 189 could be prepared by saponification of the corresponding methyl ester with sodium propanethiolate. Once the primary alcohol is oxidized, the completion of the synthesis of key lactone 103 only requires the allylic oxidation of the C-17 methyl with concomitant closure of the 8-lactone. This conversion was achieved with Se02 in refluxing acetic acid to give 103 in 51% yield. 

Pinus monticola. Further studies on the oleoresin of the white cypress, Callitris columellaris, show that it contains cis- and trans-communic acids, communic acid, sandaracopimaric acid, and 7-oxo-4-epidehydroabietic acid. Dundathic acid is a polymer of communic acid containing ca. four diterpenoid units. 

Epimandol has been detected in the neutral extracts of Larix europaea and in the bark of the Sitka spruce. Cupressus resins have been examined by g.l.c. and imbricatolic acid (5) identified in all but Cupressus sempervirens. This acid co-occurs with the cis- and trans-communic acids and with sandaracopimaric acid. A -Communic acid has been isolated as its methyl ester from Callitris columellaris. During this work the thermal isomerisation of the conjugated diene of communic acid was noted. The structures and stereochemistry of some... 

The main drawback of the first method described by Barrero et al. [14] for the synthesis of podolactones, lies in the presence of a mixture of three isomers called communic acids (153), which requires a chromatographic separation over silicagel impregnated with 20% silver nitrate to eliminate mirceo-communic acid to allow use of the 2-component mixture of cis- and trans-isomers as starting material. Furthermore, some steps in this former synthetic strategy, such as the closure of the 6-lactone or the formation of the dienolide system need improvement. 

In 2012, a group of Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA examined their growth inhibitory effect of 9-cis retinoic acid (30) and a -trans retinoic acid (29) on the formation and degradation of gap junctions, and on junctional communication in three LNCaP eells of an human androgen-responsive prostate cancer cell line. 

Michaelides A, Skoulika S, Siskos MG (2013) 2D And 3D photoreactive lanthanide MOFs of trans, trans-muconic acid. Chem Commun 49(10) 1008-1010... 

Figure 4. Correlation between retinoid-induced decreases in saturation density and induction of gap junctional communication. Confluent cultures of 10 Tl/2 cells (panel A) or methylcholantlirene transformed 10 Tl/2 cells (panel B) were treated with various concentrations of retinoids for five days. At this time cells were probed by microinjection of Lucifer yellow and transfer of dye to adjacent cells was quantitated. Total cell counts were also performed at this time. Results are expressed as a percent of the untreated controls. Symbols retinol (A) retinyl acetate (A) diW-trans retinoic acid ( ) 13-cw retinoic acid ( ) TTNPB (O). The correlations were statistically highly significant, for 10 Tl/2 cells and for transformed cells, P < 0.001. Data from reference [28] with permission.

Insects communicate through the use of a great variety of volatile pheromones. As mentioned in Chapter 8, Section A,l, some moths utilize acetate esters of various isomers of A7 and A11 unsaturated C14 fatty acids as sex pheromones. Some other moths convert the trans-l 1 -tetradecenyl acetate into the corresponding C14 aldehyde or alcohol, while others use similar compounds of shorter (Cn - C12) chain length.143 Some ants use ketones, such as 4-methyl-3-heptanone, as well as various isoprenoid compounds and pyrazines as volatile signaling compounds.144 Other insects also utilize isoprenoids,145 alkaloids,146 and aromatic substances as pheromones. 

Fang X, Jin F, Jin H, von Sonntag C (1998) Reaction of the superoxide radical with the A/-centered radical derived from N-acetyltryptophan methyl ester. J Chem Soc Perkin Trans 2 259-263 Ferreri C, Costantino C, Landi L, Mulazzani QG, Chatgilialoglu C (1999) The thiyl radical-mediated isomerisation of c/s-monounsaturated fatty acid residues in phospholipids a novel path of membrane damage Chem Commun 407-408... 

Acetylcholineesterase and choline oxidase Au foil was treated with cystamine to produce a base layer of ami-nothiolate units, was derivatized by reaction of the amino group and disodium-4,4 -diisothiocyanato-trans-stilbene-2,2 -disulfonate. Enzymes were immobilized at the isothiocyanate group via thiourea link. The bifunctional sensor for ACh was prepared by stepwise immobilization of four layers of the enzyme ChO and three layers of AChE. Choline generated was detected amperometircally with the use of 2,6-dichloro-phenolindophenol as a mediator in solution. Electrical communication between the enzyme and the electrode is achieved either by the use of ferrocenecar-boxylic acid as mediator in the assay buffer or by immobilization of [(ferrocenyl methyl)amino] hexa-noic acid on the enzyme layer. [92]... 

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