cephalosporins

Question 1

what are the cons of having a leaving group at the C3 position for cephalosporins

Answer 1

clotting problems and alcohol intolerance, so don’t take with oral anticoagulants or heparin

Question 2

what is special about the structure of oral cephalosporins

Answer 2

have amine on the carbon next to the carbonyl of the side chain and X is not a good leaving group

Question 3

what is good about having a leaving group at the C3 position for cephalosporins

Answer 3

more resistant to beta lactamases due to a conformation change

Question 4

what is special about an OCH3 in the alpha position for cephalosporins?

Answer 4

if it is facing away or the downside of the cephem bicyclic nucleus, there is steric hindrance which makes it more resistance to b-lactamase inactivation (can also help give it GOAT)

Question 5

how can having a syn-alkoximine be beneficial for cephalosporins

Answer 5

look at the C=N, if the OR group is on the same side as the b-lactam, then it hinders hydrolysis by b-lactamases

Question 6

what can replace the C=N

Answer 6

a C=C, but same concept to help with resistance and stability, and oral activation

Question 7

what is special about having a substituent with amine in the C3 position (the carbon part of C=C but farther from the N)

Answer 7

zwitter ion which helps with crossing porins and fight against pseudomonas

Question 8

what do you want for oral activity

Answer 8

basic amine, no leaving group, to increase acid stability and absorption)