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Highly Chlorinated Systems by Ring Closure Reactions.

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Highly Chlorinated Systems by Ring Closure Reactions
By Gunther Beck (lecturer), Helmut Heitzer, and Hans HoltSchmidt [‘I
Cyanornethylated and cyanoethylated secondary aliphatic
amines ( I ) are converted by chlorination at 20-50 C cia
isolable dichloro derivatives (2) into highly reactive non-isol-
aminopropionitrile], or conjugated bicycles [ e . 9. (7) from
Still further chlorination between 100 and 200 C leads to
cleavage of onr of the three N--C bonds marked A, B, and
C in ( 4 ) (special case of “dealkylating high-temperature chlorination” of amines). Obviously the N-C bonds that are
cleaved are those which lead to formation of the thermodynamically most stable end products.
a-chloroalkylamines f 3 ) , which
into five- and six-membered ring
very sensitive to hydrolysis.
f 4 / that are
Further chlorination of compounds ( 4 ) at 50-1 3 0 - Caffords
stable imidazoles [ e . y. ( 5 ) from dimethylaminoacetonitrile],
I-alkylpyrimidinium chlorides [e.9. (6) from 3-dimethyl-
Cleavage at “A” usually occurs when n = I, and affords pyrimidines, (,, 9- 4,5,6-trichloropyrimidine
[from (6 )] or ( 8 ) (from
3 ~ m o r p ~ o ~ ~ n o p r o p ~ oWhen
n ~ ~ r 12=
~ ~ 0,
e )cleavage
occurs at
“B” and leads to perchlorodiazaalkadienes, e. g. (9) [from
(511. The onecase ofcleavage at “C”observed so far occurred
with bicyclic intermediate ( 4 ) from 3-piperidinopropionitrile: the 2-aminopyridine derivative (10) is the major
product obtained.
[*] Dr. G. M. Beck, Dr. H. Heitzer, and Prof. Dr. H. Holtschmidt
Bayer AG
509 Leverkusen (Germany)
Lecture at Miinchen, November 6, 1973 [VB 376 I E ]
German version: Angew. Chem. 86. 234 (1974)
The chalones are the subject of a review by J . C. Houck
and H . Hmnings. These compounds are cell specific, but not
species specific mitotic inhibitors. which have been detected
in mammals. Chalones from epidermis, melanocytes, fibroblasts, and lymphocytes are discussed. These involve proteins
or glycoproteins, whose molecular weights differ very widely
from one another, The article concludes with a discussion
of the experimental difficulties and sources of error in the
measurement of mitosis. [Chalones. Specific Endogenous
Mitotic Inhibitors. FEBS Lett. 32, 1-8 (1973); 50 references]
[Rd 680 IE-R]
The role of soluble protein factors in the translational control
of protein synthesis in eukaryotic cells is the subject of a
review by I.: M . Pain and M . J . Clemens. As the slowest
step, chain initiation is assumed to be the most important
starting point of the regulating initiation factors. Under certain
conditions the elongation or the loading of the t-RNA can
be the site of regulation. Also included among the soluble
factors are ribonucleases and their inhibitors which may likewise have a controlling function. [The Role of Soluble Protein
Factors in the Translational Control of Protein Synthesis
in Eukaryotic Cells. FEBS Lett. 32,205-212; 160 references]
[Rd 681 IE-R]
The reactivity and stability of arenediazonium ions constitute
the subject matter of a report by H . Zollingyrr. After classifying
the reactions of these ions the author goes on to consider
nucleophilic reactions at Np and at C-l and the homolytic
cleavage of the C-1-N, bond. It remains to be established
Angrw. Chum. biternot. Edit.
1 Val. 13 (1974) I No. 3
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closure, reaction, chlorinated, ring, system, highly
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