aldehydes and ketones

which is more reactive? aldehydes and ketones

aldehydes

which has a stronger dipole? haloalkane or aldehyde/ketones

aldehyde/ketone

what is a hemi-ketone and hemi-aldehyde?

have an -OH and -OR

what is the mechanism of nucleophilic addition to ketones and aldehydes

what is tautomerisation?

interconversion between 2 isomers by a shift of a proton & double bond

what is the mechanism of hemi formation?

what is an imine?

what is transamination?

swap carbonyl w an amine group

difference between a phenyl and benzyl?

how are imines formed from aldehydes and ketones?

how is benzene different from other cyclenes?

all carbons now sp2 hybridised so electrons shared all around

where are aromatic compounds found?

nature- vitamins, DNA, health-curcumin- found in turmeric, Benzo[α]pyrene- in environments -carcinogenic

what is the friedel craft alkylation? (electrophilic attack)

what directing is an activating group?

o,p directing

what directing is an deactivating group?

m directing

what are the complexities of -OH as a group of benzene

O in -OH is electron withdrawing

overall though acts as e- donor (so activator)

what are the characteristics of monosaccharides?

colourless, crystalline solids

how do you calculate the number of stereoisomers?

n= no chiral centres formular= 2ⁿ

how do you know if its an L- or D- isomer

based on spatial orientation of C₅ group, only D in vertebrates

what are anomers?

diastereoisomers for rings

what are Haworth projections

e.g. where B is where OH in C₁ is Same side as C₆, a is where it is opp side

which is sterically hindered boat or chair

boat

what is pyranose and furanose?

pyranose- 6 membered ring

furanose- 5 membered ring

what is derivatisation?

replacement of hydroxyl groups with phosphate, sulphate, alkyl groups, hydrogen, amine group

what is an oligosaccharide

Les than 20 residues

what are some examples of oligosaccharides

-lactose

-trehalose (in insects)

-maltose (in starch breakdown)

-sucrose (in plants)

what type enzymes synthesise oligosaccharides

glycosyltrasnferases

what are lectins used for?

to recognise old erythrocytes

used by viruses for toxin entry

what are selectins

a family of lectins used in cell cell recognition