Tel. 23.029; 29.038 -— Indirizzo telegrafico: Istgenetica - Pavia

 

ISTITUTO DI GENETICA
UNIVERSITA DI PAVIA
VIA SANT’ EPIFANIO, 14

PAVIA

YUN 1 8 1969

June 15, 1963

Prof. Joshua Lederberg
Stanford University

Medical Center
Department of Genetics

Palo Alto, Calif.

Dear Josh,

this is to answer to your letter of May
23rd. I am glad to see that you will probably arrange
something with Varon.

As far as your questions on tetracyclines, |
the only information I have on Ester derivatives are the ~
following:

Soy

A) Esters from acetyl to propiongal and even longer chains
have been described where the esterification was done
in position 12a che ay

N 2
ONG e NY

K
secowte

Lo, VY

B) Many other compounds which are no really esters but
Mannich bases have been described in position 2 having
the following general formula:

Yeo Wi
CHz
/

NM
Ro ‘Ry o/
These are very instable and hydrolize@ very quickly.
These 2 groups are the only derivatives of tetracycline,
I know, which are not changed in the nucleus: unless

we consider changes out of the nucleus the decarbamino-
acetyl-derivatives in position 2 and the N-methyl-ethyl-
derivatives in position 4.

If you are interested in the detailed re-
ferences of anyone of these groups, please let me know.

Unfortunately our knowledge on antibio-
tics father than tetracyclines is limited but I will try
to find out what is known according to your request.

_ Sofar we did not get any news either from
Schering or Tepetit. On the Ist of July w let you know
something when the deadline for the discontinuation of
the present contract will be expired.

c

AS ever,

5
og ei Me cc tA

G. E, ‘Magni