Margaret-Ann Armour

Synthesis of 1,2,4-tri-O-acetyl-3,6-di-O-benzyl-5-deoxy-5-C-[(S)-phenylphosphinyl]-β-d-glucopyranose: The first gluco type of hexopyranose derivative having phosphorus in the hemiacetal ring

Abstract Oxidation of 3,6-di- O -benzyl-1,2- O -isopropylidene-α- d -glucofuranose with pyridinium chlorochromate in the presence of molecular sieves, followed by conversion into the p -tolylsulfonylhydrazone, addition of methyl phenylphosphinate, and reduction with sodium borohydride, provided the key intermediate, namely, 5( R , S )-3,6-di- O -benzyl-5-deoxy-1,2- O -isopropylidene-5- C -[(methoxy)phenylphosphinyl]-α- d - xylo -hexofuranose, in 23% overall yield. Treatment of this compound with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the action of mineral acid and acetic anhydride, yielded the crystalline title compound, the structure of which was established on the basis of mass and 400-MHz, 1 H-n.m.r. spectra. A general dependence of 2 J PH values on the OPCH dihedral angles effectively served for assigning the configuration of C-1, C-5, and the ring-phosphorus atom of the present product and other such 5- C -phosphinylhexopyranoses.

Synthesis of 4,5-dideoxy-4-C-[(R,S)-phenylphosphinyl]-d-ribo- and l-lyxo-furanose and their 1,2,3-triacetates

Abstract 2,3- O -Isopropylidene- d -ribose diethyl dithioacetal, prepared from d -ribose, was converted in three steps into the corresponding dimethyl acetal, which was monotosylated at O-5, and the ester oxidized at C-4 with pyridinium chlorochromate; addition of methyl phenylphosphinate to the resulting pentos-4-ulose derivative then provided (4 R,S )-4,5-anhydro-2,3- O -isopropylidene-4- C -[( R,S )-(methoxy)phenylphosphinyl]- d - erythro -pentose dimethyl acetal. Hydrogenation of this compound in the presence of Raney Ni, followed by reduction with SDMA, hydrolysis, and acetylation, yielded the title compounds (seven kinds), the structures of which were established on the basis of their 400-MHz, 1 H-n.m.r. and mass spectra. A general dependence of the 2 J PH and 3 J PH values on the OPCH and PCCH dihedral angles provided an effective method for the assignment of the configurations and conformations of these 4-deoxy-4-phosphinyl-pentofuranoses.

An improved synthesis of 1,2,3,4,6-penta-O-acetyl-5-deoxy-5-C-[(R,S)-ethylphosphinyl]-α,β-D-glucopyranoses, and formation of 2,3,4,6-tetra-O-acetyl-1,5-anhydro-5-deoxy-5-C[(R)-ethylphosphinyl]-D-glucitol

Abstract Treatment of 3- O -acetyl-5-deoxy-5- C -[ethyl(methoxy)phosphinyl]-1,2- O -isopropylidene-6- O -(triphenylmethyl)-α- d - xylo -hexofuranose conveniently prepared from 1,2:5,6-di- O -isopropylidene-α- d -glucose in 8 steps, with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by methanolic hydrochloric acid, and then acetic anhydride in pyridine, gave the title d -glucopyranoses in a higher overall yield than by the previous, alternative route. A minor amount of the title d -glucitol was also isolated, and characterized. Accurate 1 H-n.m.r. parameters for these ring-phosphorus-containing sugar analogs were obtained by the simulation analysis of their 400-MHz spectra.

Chapter 13 – Transitions

As women progress through careers in the sciences, they encounter many changes. Changes are external, but they require the internal process of transition. William Bridges defines transition as the psychological process people go through to come to terms with a new situation. We share the stories of women in the sciences who have navigated these transitions including during their education and move into the workforce, during changes in their career, after 10 years in the workforce, and from one type of lifestyle to another, and explore the factors which have allowed them to be successful.

Chapter 12 – Transitions

Publisher Summary Transitions, changes, promotions, setbacks, turning points, and passages: these are inherent in careers. Of course, specific patterns of change are individual. This chapter focuses on stories from women scientists rather than on specific strategies for navigating change. It is clear from these examples that transition does not always follow change, but may in fact precede it. The researcher who tires of her project, but finds a different question very appealing has begun the inner process of transition before she makes the change in her work, whereas the one who switches to a new project because she cannot obtain funds to carry on her current project may well have to come to terms with that change after she makes it. The process of transition is less obvious than a change—at least from an observers point of view—and usually takes much longer. While some transitions occur almost overnight, many transitions are so slow as to be imperceptible. All the stories in this chapter have positive outcomes. Even if the transitions were painful or much courage was required, in the end, the women were happier in their work than previously. Transitions, rough or smooth, lead to growth.

Chlorpyrifos Decontamination Procedures for Clothing and Equipment

The safe clean-up of pesticide spills in the workplace and decontamination of equipment and clothing are important in minimizing pesticide exposure. The objectives of the research were: to develop a detoxification procedure for chlorpyrifos which would enable safe clean-up on the job site; to determine if a 3-hour chlorine bleach pretreatment of fabrics contaminated with dilute chlorpyrifos is as effective in pesticide removal from 65/35 polyester/cotton as from 100% cotton; and to determine whether the chlorine bleach pretreatment is effective for removal of concentrated chlorpyrifos residues. The researchers make specific recommendations for chlorine bleach detoxification of chlorpyrifos, and for use of a bleach/soak laundry protocol for removal of dilute chlorpyrifos from cotton and polyester/cotton. Concentrated chlorpyrifos cannot be effectively removed from either fabric by laundering.