Diols and Related Compounds

Asymmetric dihydroxylation (AD) represents a general and reliable tool for obtaining chiral 1,2-diols, due to its high enantioselectivity and substrate tolerance. The AD reaction of special olefins using (DHQD)2PHAL 65 affords the diol, which is an intermediate for the potent COX-2 inhibitor L-784512 (Merck Co.), in 90% yield with 79% ee [93]. 

A synthesis of phyllodulcin, which is a sweet component of the amacha plant in Japan that exhibits antimicrobial activity, relies on an AD reaction using commercially available AD-mix-a [95]. Another practical application of an AD reaction using A-methylmorpholine A-oxide as a reoxidant has been reported for the 2.5-kg scale synthesis of a chiral diol [96], 

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Hydrolysis of the Cyclic Sulphates of Cyclohexane-c/r- and trans-1,2-Diol and Related Compounds, . S. Brimacombe, A. B. Foster, and M. Stacey, Chem. Ind. (London), (1959) 262-263. 

Steenken S, Davies MJ, Gilbert BC (1986a) Pulse radiolysis and electron spin resonance studies of the dehydration of radicals from 1,2-diols and related compounds. J Chem Soc Perkin Trans 2 1003-1010... 

Many examples of the synthesis of tetrahydropyrans are based on the cyclization of 1,5-diols and related compounds which can provide an electrophilic site for ring closure . Thus, pentane-1,5-diols can be quantitatively cyclized to the pyran in the presence of BuSnCl3 <1988G483> or via an intramolecular Mitsunobu condensation with cyanomethylenetributylphosphorane <1996TL2463>. Tetrahydrothiopyrans are prepared similarly by cyclizations of suitably substituted thiols . 

While anodic oxidation of simple alcohols is of limited utility, direct oxidation of vicinal diols and related compounds is an excellent method for achieving oxidative cleavage to the corresponding carbonyl or carbonyl-acetal products, as in Eqs. (53) and (54). Unlike certain chemical glycol cleavage reactions, the anodic method is not limited by the stereochemistry of the substrate oxygens [132]. 

Heartwoods of many tropical species are rich in tannins. The basie unit in some of these structure is considered to be derived from flavan-3,4-diols and related compounds, for example melacacidin from Acacia melanoxylon (Hathway, 1962), the structure of which is shown in Figure 2.17. The stereochemistry of the flavan-diols has been the subject of much study by Roux and his collaborators (Fengel and Wegener, 1984). 

Noma, Y. and M. Iwami, 1994. Separation and identi cation of terpene convertible actinomycetes S. bottro-pensis SY-2-1, S. ikutamanensis Ya-2-1 and S. humidus Tu-1. Bull. Tokushima Bunri Univ., 47 99-110. Noma, Y., F. Kamino, T. Hashimoto, and Y. Asakawa, 2003. Biotransformation of (+)- and (-)-pinane-2,3-diol and related compounds hy Aspergillus niger. Proceedings of the 47th TEAC, pp. 91-93. 

Noma, Y, F. Kamino, T. Hashimoto, andY. Asakawa, 2003. Biotransfoimation of (H-)- and (-)-pinane-2,3-diol and related compounds by Aspergillus niger. Proc. 47th TEAC, pp. 91-93. 

Protein-Pak packings are designed for the size exclusion chromatography of proteins and related compounds. They are based on silica, which is deactivated with glycidylpropylsilane. The diol function prevents the interaction of the target analytes with the silica surface. However, because coverage of the silica surface is always incomplete, residual acidic silanols can interact with the analytes. For this reason, most applications are carried out with a salt concentration above 0.2 mol/liter, which eliminates the interaction of analytes with surface silanols. Protein-Pak packings are stable from pH 2 to pH 8. 

Aspects of Stereochemistry. Part III. Acidic and Basic Hydrolysis of Some Diol Cyclic Sulphates and Related Compounds, J. S. Brimacombe, A. B. Foster, E. B. Hancock, W. G. Overend, and... 

Organozinc Alkoxides Derived From Diols, Triols, and Related Compounds 369... 

The reaction of metabolically generated polycyclic aromatic diol epoxides with DNA Ua vivo is believed to be an important and critical event in chemical carcinogenesis Cl,2). In recent years, much attention has been devoted to studies of diol epoxide-nucleic acid interactions in aqueous model systems. The most widely studied reactive intermediate is benzo(a)pyrene-7,8-diol-9,10-epoxide (BaPDE), which is the ultimate biologically active metabolite of the well known and ubiquitous environmental pollutant benzo(a)pyrene. There are four different stereoisomers of BaPDE (Figure 1) which are characterized by differences in biological activities, and reactivities with DNA (2-4). In this review, emphasis is placed on studies of reaction mechanisms of BPDE and related compounds with DNA, and the structures of the adducts formed. 

Borane and aluminum hydrides modified by chiral diols or amino alcohols are well-known, effective reagents for the stoichiometric enan-tioselective reduction of prochiral ketones and related compounds (34). Reduction of prochiral aromatic ketones with the Itsuno reagent, which is prepared from a chiral, sterically congested /3-amino alcohol and borane, yields the corresponding secondary alcohols in 94-100% ee... 

Treatment of diethyl malonate and related compounds with 1,2-dihaloethane in the presence of base constitutes a classical method of cyclopropane synthesis296"300. The reaction can be conveniently carried out under PTC conditions. An improved method utilizing solid-liquid phase transfer catalysis has been reported298. The reaction of dimethyl or diethyl malonate with 1,2-dibromoalkanes except for 1,2-dibromethane tends to give only low yields of 2-alkylcyclopropane-l, 1-dicarboxylic esters. By the use of di-tm-butyl malonate, their preparations in satisfactory yields are realized (equation 134)297. The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1,2-diols (equation 135)301. Asymmetric synthesis... 

Bonded diol Si-O-Si-C OH OH 1 1 -c—c-1 Polar bonded phase A polar phase that has a hydrogen bonding capability similar to that of unbonded silica useful in size-exclusion chromatography and in the analysis of glycols and glycerol, oils, lipids, and related compounds... 

Neutral corticosteroids are prone to the formation of acid adducts [M+RCOO] in negative-ion mode [20-21]. Abundant acetate adducts are observed for steroids with a relatively acidic hydroxyl group [22]. In negative-ion TSP ionization, Kim et al. [23] observed more abundant acid adducts with decreasing pK, of the acid. Marwah et al. [24] showed signal enhancement for a variety of steroids like dehydroepiandrosterone (DHEA) and related compounds due to the addition of low concentration of acid, i.e., typically 1-5 mmol/1 formic acid, 1-8 mmol/1 acetic acid, or 0.05-0.15 mmol/1 trifluoroacetic acid, while higher acid concentrations were found to compromise the response. Formic acid was the best choice for the neutral steroids, while acetic acid is preferred for sulfate conjugates. Post-column addition of 10 nmol/1 silver nitrate resulted in a ten-fold increase in the response for androst-5-ene-3p,17P-diol. [M+Ag] is observed instead of [M+H-HjO] [24]. 

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