215F07-notes-11-9-07-carbsa

215F07-notes-11-9-07-carbsa - 2-Carb-6 and 2-Carb-7 07:01...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
11/02/2007 07:01 PM 2-Carb-6 and 2-Carb-7 Page 1 of 8 Nomenclature of Carbohydrates (Recommendations 1996) 2-Carb-6 and 2-Carb7 Continued from 2-Carb-5 Contents 2-Carb-6. Anomeric forms; use of α and β 6.1. The anomeric centre 6.2. The anomeric reference atom and the anomeric configurational symbol 6.3. Mixtures of anomers 6.4. Use of α and β 2-Carb-7. Conformation of cyclic forms 7.1. The conformational descriptor 7.2. Notation of ring shape 7.3. Notation of variants 7.4. Enantiomers References for this section 2-Carb-6 Anomeric forms; use of α and β 2-Carb-6.1. The anomeric centre The new centre of chirality generated by hemiacetal ring closure is called the anomeric centre. The two stereoisomers are referred to as anomers, designated α or β according to the configurational relationship between the anomeric centre and a specified anomeric reference atom. 2-Carb-6.2. The anomeric reference atom and the anomeric configurational symbol ( α or β ) The anomeric reference atom is the configurational atom (see 2-Carb-4.2 and 2-Carb-4.3 ) of the parent, unless multiple configurational prefixes (see 2-Carb-8.3 ) are used. If multiple configurational prefixes are used, the anomeric reference atom is the highest-numbered atom of the group of chiral centres next to the anomeric centre that is involved in the heterocyclic ring and specified by a single configurational prefix. In the α anomer, the exocyclic oxygen atom at the anomeric centre is formally cis , in the Fischer projection, to the oxygen attached to the anomeric reference atom; in the β anomer these oxygen atoms are formally trans. The anomeric symbol α or β , followed by a hyphen, is placed immediately before the configurational symbol D or L of the trivial name or of the configurational prefix denoting the group of chiral carbon atoms that includes the anomeric reference atom. Examples:
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
11/02/2007 07:01 PM 2-Carb-6 and 2-Carb-7 Page 2 of 8 α - D - gluco α - D -Glucopyranose β - D - gluco β - D -Glucopyranose α - L - arabino Methyl α - L -arabinopyranoside β - L - threo Methyl β - L -threofuranoside
Image of page 2
11/02/2007 07:01 PM 2-Carb-6 and 2-Carb-7 Page 3 of 8 β - D - galacto Methyl β - D -galactofuranoside L - glycero - α - D - manno Methyl L - glycero - α - D - manno -heptopyranoside β - D - arabino Methyl β - D -fructofuranoside D - glycero- β - D - galacto Methyl 5-acetamido-3,5-dideoxy- D - glycero- β - D - galacto -non-2-ulopyranosonate (see 2-Carb-14.2 )
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern