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MAURICE WELSCH
to the same mechanism. A comparative study of the D and L diastereoisomers of α-phenoxyethylpenicillin shows a definite synergism of these
compounds
(96h).
The biochemical investigations of Park and Strominger (97) and the
independent morphological observations of Lederberg (98), Hahn and
TABLE I
SIDE CHAINS OF DIFFEKENT PENICILLINS
Penicillin
Significance of R in formula XXXVIIc
Natural penicillins
Benzyl-P (G or Π)
/>-Hydroxy-benzyl-P (X or III;
A
2
-pentenyl-P (F, I, flavicidin or flavicin)
A
3
-pentenyl-P
w-Amyl-P (dihydro-F or gigantic acid)
w-Heptyl-P (K)
Cephalosporin Ν (synnematin B, salmotin)
Examples of semisynthetic penicillins
0-Chloroethyl-P
a-Br omo isobuty 1 - Ρ
Allylmercaptoethyl-P (O)
Phenoxymethyl-P (V)
a-Phenoxyethyl-P
a-Phenoxypropyl- Ρ
2,6-Dimethoxyphenyl-P
Aminobenzyl-P
3 - Phenyl -5 - methyl -4 - isoxasolyl - Ρ
C 6 H 5 CH 2
HO—C e H4—CH 2 —
CH 3 — CH 2 -CH=CH—CH 2 —
CH 3 —CH= CH- CH 2 —CH 2 —
CH 3 CH 2 CH 2 CH 2 CH 2
CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2
HOOC—CH—CH 2 —CH 2 —CH 2 —
NH 2
CH 2 C1— CH 2 —
(CH 8 ) 2 — CH 2 —CHBr —
CH 2 =CH—CH 2 -S-CH 2 —
C e H-0-CH 2 —
C e H 5 —O-CH —
CH 3
C e H 5 -0-CH—
C 2 H 5
(OCH 3 ) 2 =C e H 3 —
C e H 5 -CH—
NH 2
C e H 5 —C
C —
II II
N^ 0 /C-CH 3
Ciak (99), and Liebermeister and Kellenberger (100) have corroborated
Duguid's (101) earlier suggestion that penicillin impairs the mechanical
strength of the bacterial cell wall. Lacking the normal protection of its
outer rigid envelope, the cell shows deformations and eventually bursts
unless it is placed in an osmotically suitable environment where, instead
of being lysed, it is converted into a fragile wall-less protoplast (102-