Enantioenriched bifunctional crotylsilanes for the asymmetric synthesis of orthogonally protected 2-methyl-1,3-diols.

Enantiomerically pure α-substituted crotylsilane reagents I and ent-I undergo asymmetric aldehyde crotylation followed by Ir(I)-catalyzed diastereoselective allylic etherification to give a variety of orthogonally protected 2-methyl-1,3-diols at the synthetically useful level of yields and stereoselectivity. The reagents are air-stable and bifunctional so that they can be used in these reactions sequentially without recourse to functional group adjustments.

Air-stable bifunctional allylation reagents for the asymmetric synthesis of differentiated syn- and anti-1,3-diols.

Turning the diols: Enantiomerically pure bifunctional reagents I and ent-I undergo asymmetric aldehyde allylation followed by Ir(I)-catalyzed enantioselective decarboxylative allylic etherification to give differentiated syn- and anti-1,3-diols with complete control of the absolute and relative stereochemistry (see scheme; PMP = para-methoxyphenyl, dbcot = dibenzo[a,e]cyclooctatetraene, DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene).

Ir(I)-catalyzed enantioselective decarboxylative allylic etherification: a general method for the asymmetric synthesis of aryl allyl ethers.

Ir(I)-catalyzed enantioselective decarboxylative allylic etherification of aryl allyl carbonates provides aryl allyl ethers. Key to the generality and high stereoselection of the reaction is the use of the intramolecular decarboxylative allylation process and [Ir(dbcot)Cl](2) as an Ir(I) source. Ir(I)-catalyzed diastereoselective decarboxylative allylic etherification, combined with asymmetric aldehyde crotylation and cross metathesis, can furnish monoprotected 2-methyl-1,3-diols (starting from simple aldehydes) with high diastereoselectivities.

Concise asymmetric synthesis of orthogonally protected syn- and anti-1,3-aminoalcohols.

Novel chiral binfunctional reagents V and ent-V undergo asymmetric aldehyde allylation followed by Ir(I)-catalyzed enantioselective allylic amidation to give orthogonally protected syn- and anti-1,3-aminoalcohols with complete control of absolute and relative stereochemistry. The Mitsunobu reaction of the initial homoallylic alcohol products followed by Ir(I)-catalyzed enantioselective allylic amidation provides orthogonally protected syn- and anti-1,3-diamine derivatives in high yields and with excellent stereoselectivities.

Complete quantification of group A and group B soyasaponins in soybeans.

A combination of high-pressure extraction and preparative chromatography was used to purify the group A and group B soyasaponins from soy germ for use as analytical standards and for use in biological assays. A standardized sample preparation and extraction method was developed for the analysis of phytochemicals found in soy and processed soy products, which is reproducible in other laboratories. The extracts can be analyzed with standard liquid chromatography-mass spectrometry and high-performance liquid chromatography methods to identify and quantitate the group A and group B forms of the soy saponins, as well as the soy isoflavones. Complete saponin analysis of the extracts prepared from soy germ (hypocots), hulls, and cotyledons shows that a significant portion of the saponins is concentrated in the germ. The germ contains nearly all of the group A soyasaponins, while the group B soyasaponins are nearly equally distributed between the germ and the cotyledons. The hulls contain little of either isoflavones or saponins. Whole (full fat) soybeans grown on a tract in central Illinois in 2003 contain approximately 4-6% saponins on a weight basis, of which about one-fifth or less of the total saponin content are group A soyasaponins; the balance is group B soyasaponins.

Determination of modafinil in plasma and urine by reversed phase high-performance liquid-chromatography.

Modafinil (Provigil) is a new wake-promoting drug that is being used for the management of excessive sleepiness in patients with narcolepsy. It has pharmacological properties similar to that of amphetamine, but without some of the side effects associated with amphetamine-like stimulants. Since modafinil has the potential to be abused, accurate drug-screening methods are needed for its analysis. In this study, we developed a high-performance liquid-chromatographic procedure (HPLC) for the quantitative analysis of modafinil in plasma and urine. (Phenylthio)acetic acid was used as an internal standard for the analysis of both plasma and urine. Modafinil was extracted from urine and plasma with ethyl acetate and ethyl acetate-acetic acid (100:1, v/v), respectively, and analyzed on a C18 reverse phase column with methanol-water-acetic acid (500:500:1, v/v) as the mobile phase. Recoveries from urine and plasma were 80.0 and 98.9%, respectively and the limit of quantitation was 0.1 microg/mL at 233 nm. Forty-eight 2-h post-dose urine samples from sham controls and from individuals taking 200 or 400 mg of modafinil were analyzed without knowledge of drug administration. All 16-placebo urine samples and all 32 2-h post-dose urine samples were correctly classified. The analytical procedure is accurate and reproducible and can be used for therapeutic drug monitoring, pharmacokinetic studies, and drug abuse screening.