Of myo-inositol

Figure 1. Proton magnetic resonance spectra at 14.1, 23.5, and 51.7 kilo gauss (60, 100 and 220 MHz.) of myo-inositol in deuterium oxide.

A wyo-Inositol, one of the isomers of 1,2,3,4,5,6-hexahydroxycyclohexane, acts as a growth factor in both animals and microorganisms. Draw the most stable chair conformation of myo-inositol. 

Highly phosphorylated forms of myo-inositol are present in cells 355... 

Li+ was first found to interfere with inositol lipid metabolism when significantly decreased levels of myo-inositol were observed in the cerebral cortex of Li+-treated rats [89]. Subsequent work revealed a corresponding increase in the levels of Ins( 1 )P [90] and this behavior was shown to be the result of a Li+-induced inhibition of IMPase, the enzyme which dephosphorylates the monophosphates Ins(l)P, Ins(3)P, and Ins(4)P to produce free inositol [91]. These results stimulated much research in this field involving a wide variety of cell types, tissues, and animals where the Li+ inhibition of IMPase was found to be ubiquitous. However, it was found that, in vivo, this Li+-induced effect is predominantly limited to the brain, being observed in different regions of the brain to different extents, with similar results for both acute and chronic treatment with Li+. It is probable that those cells that are able to accumulate inositol, or which are exposed to and can rapidly import an extracellular supply of inositol, may be relatively insensitive to the effects of Li+. 

Similarly, the P-phosphono-a,P-unsaturated carbonyl compounds thus synthesized have been used as dienes in a Diels-Alder approach toward the preparation of analogues of myo-inositol 1,4,5-triphos-phate,45 as well as other carbohydrate-related materials.46-48... 

Chelation complex (95) has been proposed to account for the regio- and diastereo-selective formation of myo-inositol derivatives (96) by cleavage of orthoesters with 1-2 equiv. of Grignard reagents in benzene-diethylether. ... 

Example 62 commercially available diethylphosphorochloridite (EtO)2PCl has been used by Mills and Potter in the synthesis of myo-inositol 1,2,4,5-tetrakisphosphate [101]. 

The General myo-lnositol and scyllo-Inosamine Pathway. Two distinct cyclitol pathways, which we earlier called Ca (started by myo-inositolphos-phate synthase) and Cb (started by T-deoxy-i cy/to-inosose synthase), are used in the initiation of AGA pathways. Here we will describe the Ca route and the Cb pathway in the paragraph on NEOs (see Section 2.2.2.1.3). The cyclitol pathway in the biosynthetic pathways for STRs, but also for other AGAs such as SPCs, KAS, and FORs and also the mixed type antibiotic HYG-A (see Section 2.2.4.3.1), starts with the formation of myo-inositol in a two-step pathway (Ca) that is not encoded in the itrAtt-clusters. The first step in streptidine biosynthesis (and any other myo-inositol utilising pathway) is the formation of a myo-inositol monophosphate (D-myo-inositol-3-phosphate or L-myo-inositol-1-phosphate) via L-myo-inositol-1-phosphate synthase, which in actinomycetes... 

This enzyme [EC 3.1.3.25], also referred to as myo-inosi-tol-l(or 4)-monophosphatase and myo-inositol-l-phos-phatase, catalyzes the hydrolysis of myo-inositol 1-monophosphate to generate myo-inositol and orthophosphate. Both enantiomers of myo-inositol 1-phosphate and myoinositol 4-phosphate can act as substrates. However, the enzyme does not hydrolyze inositol bisphosphates, tris-phosphates, or tetrakisphosphates. 

This enzyme [EC 1.13.99.1] catalyzes the reaction of myo-inositol with dioxygen to produce D-glucuronate and water. The enzyme requires iron for activity. 

M. Santoro, E. Caffaratti, J. M. Salas-Peregrin, L. Korecz, A. Rockenbauer, L. Sala, and S. Signorella, Kinetics and mechanism of the chromic oxidation of myo-inositol, Polyhedron, 26 (2007) 169-177. 

Manji, H.K., Betsudsky, Y., Chen, G., Belmaket, R.H., and Potter, W.Z. (1996) Modulation of protein kinase C isozymes and sub-sttates by lithium the tole of myo-inositol. Neuropsychopharmacology 15 370-381. 

Halenda SP, Volpi M, Zavoico GB, et al Effects of thrombin, phorbol myristate acetate, and prostaglandin D2 on 40-41 kDa protein that is ADP ribosylated by pertussis toxin in platelets. FEES Lett 204 341-346, 1986 Hall RC, Gardner ER, Popkin MK, et al Unrecognized physical illness prompting psychiatric admission a prospective study. Am J Psychiatry 138 629-635, 1981 Hallcher LM, Sherman WR The effects of lithium ion and other agents on the activity of myo-inositol-1-phosphatase from bovine brain. J Biol Chem 255 10896-10901, 1980... 

Tricklebank MD, Singh L, Jackson A, et al Evidence that a proconvulsant action of lithium is mediated by inhibition of myo-inositol phosphatase in mouse brain. Brain Res 558 145-148, 1991... 

T. O Donnell, S. Rotzinger, T. T. Nakashima, C. C. Hanstock, M. Ulrich and P. H. Silverstone, Chronic lithium and sodium valproate both decrease the concentration of myo-inositol and increase the concentration of inositol monophosphates in rat brain. Brain Res., 2000, 880, 84-91. 

Shears, S.B. The pathway of myo-inositol 1,3,4-trisphosphate phosphorylation in liver. Identification of myo-inositol 1,3,4-trisphosphate 6-kinase, myo-inositol 1,3,4-trisphosphate 5-kinase, and myo-inositol 1,3,4,6-tetrakisphosphate 5-kinase. J. Biol. Chem., 264, 19879-19886 (1989)... 

Hydrolysis of mt/o-inositol l(3),2-cyclic phosphate under acidic or alkaline conditions affords a mixture of myo-inositol l(3)-phosphate and myo-inositol 2-phosphate, with the former preponderating.275 As the cyclic phosphate may be prepared275 from the 2-phosphate, which is itself readily obtained from myo-inositol hexaphosphate by enzymic cleavage,268,276 and as the l(3)-phosphate may be isolated277 from the hydrolysis mixture, the reaction sequence provides a convenient way... 

Figure 5. Chair configuration of myo-inositol hexaphosphate, illustrating hydrogen bonding between phosphate groups 2 and 6. Hydrogen bonding between groups 3 and 5 is not shown for clarity.

Tanner and Kandler296 suggested that, analogously to galactinol, other glycosides of myo-inositol may play important roles in the biosynthesis of various oligosaccharides. However, little is known in this respect. 

This would, however, require the addition of myo-inositol to the reaction mixture, unless this compound should already be present in a bound form in the enzyme preparation. The preparations from V.faba, G. max,910 and the chloroplasts of P. sativum888 were all thoroughly dialyzed, and no myo-inositol was added in the assay. Thus, this controversy requires further investigation. The maturity and the physiological state of the seeds are important factors in detecting a given enzyme, and consequently, these factors should be taken into consideration in future investigations. 

The regioselectivities of myo-inositol derivatives towards electrophiles have been studied by using various levels of quantum mechanical calculation.66 The calculations appear to favour the 0(6) position, but experimentally the 0(3) position is the major site for electrophilic attack. Such experiments usually involve rather polar solvents and repetition of some of the calculations for molecules embedded in a medium of dielectric constant of 40 found 0(3) to be preferred as reaction site. 

In continuation of their studies of the resolution of myo-inositol derivatives via their orthoesters with sugar derivatives, Evstigneeva et al. [296] converted the racemic 1,2 3,4-di-O-cyclohexylidene-wyo-inositol (431) by transesterification with the mannose orthoester (425) into a mixture of diastereoisomers (426) formed by esterification of the 5- and 6-positions of (431). One of the four possible isomers was separated by crystallisation and the other three were obtained by preparative TLC. Partial hydrolysis of the resolved isomers gave both enantiomers of 1,2-0-cyclohexylidene-myo-inositol (432). 

Partial benzylation with powdered potassium hydroxide as a base and toluene as a solvent was used some 50 years ago for the preparation of 1,6-anhydro-2,4-0-benzyl-P-D-glucopyranose [79]. Since that time, other solvents, such as benzene [80-82], 1,4-dioxane-toluene mixtures [83, 84], or excess benzyl chloride [82, 85] were used as well, with apparent effects on the regioselectivity. Thus, the axially oriented secondary hydroxyl group of lL-l,2,3,4-tetra-0-benzyl-c/i ro-inositol is more reactive than the equatorial one using benzyl chloride alone (ratio of 79 21), whereas the opposite is true (35 65) in benzene as a solvent [82]. Benzylation of myo-inositol derivatives in the latter solvent was also described [80, 81, 86]. 

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