8’-Hydroxy-abscisic acid

OH-ABA 8 -hydroxy-abscisic acid r-XAN 2-rrans,4-rrans-xanthoxin... 

The phenolic acids of interest here [caffeic acid (3,4-dihydroxycinnamic acid), ferulic acid (4-hydroxy-3-methoxycinnamic acid), p-coumaric acid (p-hydroxycinnamic acid), protocatechuic acid (3,4-dihydroxybenzoic acid), sinapic acid (3,5-dimethoxy-4-hydroxyxinnamic acid), p-hydroxybenzoic acid, syringic acid (4-hydroxy-3,5-methoxybenzoic acid), and vanillic acid (4-hydroxy-3-methoxybenzoic acid)] (Fig. 3.1) all have been identified as potential allelopathic agents.8,32,34 The primary allelopathic effects of these phenolic acids on plant processes are phytotoxic (i.e., inhibitory) they reduce hydraulic conductivity and net nutrient uptake by roots.1 Reduced rates of photosynthesis and carbon allocation to roots, increased abscisic acid levels, and reduced rates of transpiration and leaf expansion appear to be secondary effects. Most of these effects, however, are readily reversible once phenolic acids have been depleted from the rhizosphere and rhizoplane.4,6 Finally, soil solution concentrations of... 

Racemic cis- and tran.s-nor-abscisic acid (132) and (133) have been prepared in five steps from the protected hydroxy-ketone (134) and the acetylene (135). Reaction between the dianion of 3-methylbut-2-enoic acid (136) and... 

The saxl (hypersensitive to abscisic acid and auxin) mutant probably has a defect in the oxidation and isomerization of 3p-hydroxy-A precursors to 3-oxo-A steroids (Ephritikhine et ah, 1999). AtHSDl (At5g50600) encodes a protein with homology to animal ll- 3-hydroxysteroid dehydrogenase (Li et ah, 2007) however, no obvious sequence similarities exist with the 3P-HSD involved in cardenolide bios)mthesis (see Section 6.3.1.2). 

A new synthesis of abscisic acid from ) -ionone claims an overall 43 % yield of the ketone (54). The selective oxidation of the 5,6-double bond is of note (Scheme 5). Treatment of a-ionone with selenium dioxide selectively oxidized the bisallylic position to give 6-hydroxy-a-ionone. Ketone (54) was used in a synthesis of [2- C]abscisic acid (55). Numerous compounds related to abscisic acid have been prepared to test their biological activity. 

Further studies of abscisic acid (53) biosynthesis showed that the epoxyacid (52) was incorporated into tomatoes whereas the all-trans-isomer was not. In beans, [2- C]abscisic acid is rapidly (15 min) metabolized and the products are neither a glucoside nor a b-hydroxy-derivative. " ... 

Degraded Carotenoids. Several new natural products have structures similar to carotenoid end-groups and thus may be considered as degraded carotenoids. A new abscisic acid (31) metabolite from seeds of Robinia pseudacacia has been identified as the 3-hydroxy-3-methylglutaryl ester of hydroxyabscisic acid (32). 

Pentadienoic acid, 5- 1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-, [S-(Z, )]- abscisic acid 1156, 3216, 3218, 1206a, 3973,4090 ... 

Figure 1 Relation of CAS systematic name to structure for abscisic acid, otherwise known as 2,4-pentadienoic acid, 5-(l-hydroxy-2,6,6-tri-methy l-4-oxo-2-cyclohexene-1 -y l)-3 -methy I-...

In Reference 58, 6-0-(2-hydroxy-3-trimethylammonio-propyl)-(3-CD (6-HPTMA-(3-CD), a highly water-soluble CD, was synthesized and used as CS for the separation of naproxen, ofloxacin, warfarin, ibuprofen, indoprofen, ketoprofen, flurbiprofen, DL-3-phenyllactic acid, mandelic acid, abscisic acid, and tropic acid. A 75-p,m i.d. fiised-sil-ica capillary (45/36 cm total/effective length) was used and the BGE consisted of a 20-mM phosphate buffer with pH... 

Abscisic add [abscisin II, ABA histor. name dormin (2Z,4 )-5-((5)-l-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexenyl)-3-methyl-2,4-pentadienoic acid]. 

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