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Aziridinimines Diaziridinimines Diaziridinones and Carbodiimides by Photolysis of 2-Tetrazolines.

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1P
l-ij-%i
(c: 11,)
N-R2
Rl-C&
\O-Si (CH,)
[2] W Wulter, H.-W Luke, and J . Voss, Liebigs Ann. Chem.. in press.
131 The free energies A G * of isomerization were determined by an approximate procedure ( H . S. G I I ~ o Hand
. ~ C~ . H. Holm, J. Chem. Phys. 25,
1228 (1956)). The error was taken as *0,2kcal/mol ( D . Kosr, E. H .
Curlson, and M . Rahan. Chem. Commun. 1971. 656).
,
imidate
amide
On silylation, primary thioamides R-CS-NH2
are converted into N-trimethylsilylthioamides, whereas some secondary thioamides having bulky substituents attached to the thiocarbonyl carbon and the nitrogen atom also afford S-trimethylsilyl thioimidatesL2].
We have now silylated N-isopropyl- ( I a ) and N-neopentylthioacetamide ( I h ) [conditions: 1) n-BuLi, 2) (CH,),SiCI,
reactions in hexane] ; these secondary thioamides bear bulky
groups only on the nitrogen.
The NMR spectra of the resulting silyl compounds ( 2 a )
and ( 2 h ) contain the signals of two isomeric forms; coalescence occurs on warming (ca. 130°C). On cooling, the signal
of only one of the isomers undergoes splitting after passing
through a second coalescence point, so that finally at ca.
-60°C the signals of three equilibrating forms can be distinguished (for the isomerization parameters AG* see Table 1 ).
Table 1. lsomerization parameter ACT,, of the S.N-silyl shift [3] and A&",
of the rotation.
Cpd.
R
AGf.3
[kcal/mol]
A&,
[kCdl/mOl]
Aziridinimines, Diaziridinimines, Diaziridinones, and
Carbodiimides by Photolysis of 2 - T e t r a z o l i n e s [ * * ]
By Helmut Quast and Lothar Bieber"]
A possible entry to hetero analogs of trimethylenemethane['.'l could be provided by ring systems ( I ) which are
transformed into methylenecyclopropane analogs (2) on photolysis. Loss of C O and N2 respectively from compounds
of type ( l a ) actually provided proof of singlet and triplet
(1)
(10)
-CO-CO-
flci
-co-co-
fldi
-N=N-
( I b)
or -N=Nor -N=N-
C and/or hetero atom
C
C
C(CH3)2
0
CH2
0
C(CH~)Z
0
trimethylenemethane[']. However, (16) and ( l c ) did not give
rise to any species detectable by ESR spectroscopy['"]. Whereas
methylenecyclopropanes[1.31and cyclopr~panones[~~
were
obtained from (1) and the photochemical generation of cycloR
From these observations and from the data listed in Table
1 we conclude that on cooling the N-silylated forms of ( 2 a )
and (26) isomerize owing to hindered rotation about the
partial double bond (E/Z isomerism) ; other silylated thioamides behave in similar fashion. The E/Z isomerism is also
indicated by the shift of the newly appearing groups of signals
on dilution with arenes. The isomerization occurring on warming can then only be attributed to a 1,3-S,N-silyl shift. Both
processes are reversible.
The S-silylated derivatives occurring in equilibrium appear
to exist in only one configuration. The long-range coupling
constant J c ~ , - ~ = ~ - c ~1.4~ Hz
= in (26) proves the presence
of the Z form.
Received: February 21, 1975 [ Z 206 IE]
German version: Angew. Chem. 87. 420 (1975)
CAS Registry numbers:
( l o ) . 5310-11-2; i l h ) . 54986-09-3; N-silyl-(2uj. 54986-10-6:
S-silyl-12uj. 54986-1 1-7; N-silyl-126). 54986-12-8; S-silyl-i2h), 54986-1 3-9
[I]
C. H . Yuder, W C . Copmhufer, and B. Du Beshrer, J. Amer. Chem.
SOC.96, 4283 (1974); J . Pump and E . G. Rochow, Chem. Ber. 97, 627
(1964): J . F. Klehe, Accounts Chem. Res. 3, 299 (1970); M. Fukui. K .
Iroh, and Y Ishii. J. C. S. Perkin I 1 1972, 1043.
428
propanirnine~[~l
and aziridinone~[~]
could be established from
the secondary reaction products, no cyclopropanone was
formed on photolysis of the thermally and photochemically
We have now discovered
surprisingly stable compound (
a photochemical synthesis of several hetero-methylenecyclopropanes [ ( 4 ) , (7), ( 9 ) ] from 2-tetrazolines (3)"l.
Photolysis of the thermally highly stable tetrazolone (3 a)
in ether or 2-propanol afforded only secondary products of
[*] Doz. Dr. H. Quast [ +] and Dipl.-Chem. L. Bieber
Institut f i r Organische Chemie der Universitat
87 Wiirzburg, Am Hubland (Germany)
[ +] To whom correspondence should be addressed.
[**I Photochemical Formation of Methylenecyclopropane Analogs, Part 1.This work was supported by the Deutsche Forschungsgemeinschaft and
the Fondsder Chemischen Industrie. The results are taken from the Diplomarbeit of L. Birher, UniversitPt Wiirzburg 1972, and his planned Dissertation.
A u g ~ u .C
. hmi.
iiiti'niuf.
E d i f . j Val. 14 ( 1 9 7 5 ) /I No. 6
radical reactions with the solvent[81. After irrddiation'"l
in CD3CN we found the sole product to comprise a compound
which we regard as 1,2-dimethyldiaziridinone ( 4 ) [ ' O ] on the
basis of its 'H-NMR spectrum (6=2.96ppm) and an IR band
at 1882cm-I.
Under the same conditions, the thione ( 3 b ) [readily accessible by dealkylation of ( 5 ) , CH,OSO, instead of BF,["I,
with triethylamine in acetonitrile] is quantitatively converted
into sulfur and dimethylcarbodiimide ( 6 ) , which was identified
by its 'H-NMR and IR spectrum['21 and by hydrolysis to
N,N'-dimethylurea. This reaction possibly proceeds cia the same
intermediate as was recently trapped by 3 2 cycloaddition
during the thermolysis of 5-imin0-1,2,3,4-thiatriazolines['~~.
+
Preparation of the very hygroscopic imine ( 3 c ) in two
steps from ( 5 ) is an example of a new synthesis, which readily
permits variation of the substituent attached to the imino
nitrogen atom of 2-tetrazolin-5-imines. Photoly~is[~'
of (3c)
in D,-THF affords 14-17 % of (6) and 83-86
of diaziridinimine (7) which is identical with an authentic sample['41.
The methyl azide expected to accompany (6) apparently
decomposes under the reaction conditions.
(3dj, R' = RZ = CH3; (9d).
( 3 e ) , R' = H, R2 = C(CH,),;
~ 1 =%9 0
: 10
(9e), E l % = 9 4 : 6
O n treatment of (8) with sodium hydride in tetrahydrofuran
we obtained the methylenetetrazolines (3d) and ( 3 e ) as intensely yellow, extremely air- and moisture-sensitive distillable
oils. Their p h o t ~ l y s i s [at
~ ] -60°C in D,-THF (Pyrex filter)
quantitatively afforded the aziridinimines ( 9 ) . whose structure
and configuration were confirmed by spectral comparison
with authentic compounds['51.The E/Z isomer ratio remained
unchanged for weeks at -20°C. The high stereoselectivity
of this photolysis is remarkable. Methylenediaziridines could
not be detected.
Received: February 12. 1975:
in shortened form: March 14, 1975 [Z 207 IE]
German version: Angew. Chem. 87.422 (1975)
CAS Registry numbers:
13a). 13576-20-0; ( 3 b ) . 54986-14-0: / 3 c ) , 35151-69-0:
13dt. 54986-15-1 ; (3e). 54986-16-2; ( 4 ) . 54986-17-3: ( 5 ) . 54986-19-5:
(6). 4852-30-6: (71, 54986-20-8: ( 8 ) . R' =R'=CH,, 54986-22-0.
( 8 ) . R i = H , R'=C(CH,),, 54986-24-2; Z - ( 9 d ) . 54986-25-3:
E- f Yd). 54986-26-4 : Z - ( 9 e ) , 27270-90-2 ; E - ( 9 e ) , 27270-91-9
[I] a ) P. Dowd. Accounts Chem. Res. 5 , 242 (1972); b) J. J. Gqjewski. A .
Yeshurun. and E . J . Bair. J. Amer. Chem. Soc. 94. 2138 (1972): J. A . Burson. L. R . Corwin, and J . H . Dacis. ibid. 96, 6177 (1974).
Arigew.
Chem. inrcvnur. Edir. / Vul. 14 ( 1 9 7 5 ) / N o . 6
[2] J. F . Liehriian and A . Greeriberg. J. Org. Chem. 3Y. 123 (1974). and
references cited therein: M . E . Zaridler, C. E. Choc. and C. K. Jo/iri,sorr.
J. Amer. Chem. SOC. 96. 3317 (1974). and references cited therein:
B. K. Carpenter, J. C. S. Perkin 11 1974. I .
[3] W-D. Stohrer, P. Jacob\, K . H . Kaiser. G . Wirch. and G. Quiriherr.
Fortschr. Chem. Forsch. 46, 181 (1974): S . D. Andrews and A. C. Day.
J. Chem. SOC. B 1968, 1271: R. J. Cruwford. D. M . Car?ieron, and
H . Tokunasa. Can. J. Chem. 52. 4025 (1974).
[4] H. H . Wassrrman, G . M. Clark, and P. C . Tur1ry. Fortschr. Chem.
Forsch. 47. 73 (1974). and references cited therein: K. G. Sriniuasan
and J . H . B o w r . J. C. S. Chem. Comm. 1974. 379
J . A . Schuryser and F . C . De Srhrywr, Chem. Ind. (London) IY72.
165.
P. S . Erryel and L . Slieri. Can. J. Chem 52. 4040 11974).
Photolysis of 1.4.5-trisubstituted 2-tetrazolines: T Aki?.nriiii. T Kiriiiviuru. T lsidu. and M . Kawrii.\i. Chem. Lett. IY74. 1x5.
W S . Widsivorth. Jr.. J . Org. Chem. 34. 2994 (1969).
All photolyses conducted in sealed NMR sample tubes. previouhly
repeatedly degassed at l o - ' torr, with a 150 or 450 W Hg lamp.
Only 1.2-di-rerr-alkyl-substituteddiaziridinones are so far known : F .
D. Grernr, J . C . S t o w / / . and W R. Bergmark. J. Org. Chem. 34, 2254
( 1969).
S . Huniy and K . H . Oette, Liebigs Ann. Chem. 641, 94 (1961).
G . Papi and G. Shruna. J. Amer. Chem. Soc. 93, 5213 (1971).
E. can Loork, J . - M . Vandensaael. C. L'Ahhe, and G. Snirts. J. Org.
Chem. 38, 2916 (1973): R. Neidlein and K. Sakmann. Synthesis 1975.
52: M . Recirt, J. C. S. Chem. Comm. 1975, 24.
K.-H. Ross, Dissertation, Universitat Wurzburg 1974.
( I O d ) : H. Quasr and P. SchPfer. unpublished. f l o e ) ' H . Quast and
E . Schmirr, Angew. Chem. 82. 395 (1970). Angew. Chem. internat. Edit.
9, 381 (1970). '
Change in Conformation of a Cystine Peptide on Transition from the Crystal to Solution
By Giinther Jung, Michael Ottnad, Peter Hartter, and Heinrich
Lachrnann"]
Dedicated to Professor Eugen Miiller on the occasion of his
70th birthday
During investigations on the chiroptical behavior of the
disulfide chromophore in peptides['l an initially surprising
effect was observed. On repetitive recording of the C D spectrum of tert-butyloxycarbonyl-L-cysteinylglycylcysteinedisulfide methyl ester ( 1 ) a hypsochromic shift of the longest
wavelength negative Cotton effect and a simultaneous increase
in ellipticity were registered; in addition, hypsochromism of
the disulfide Cotton effect at 245nm and hyperchromism of
the Cotton effect at 225nm (Fig. l a ) also occurred. Since
chemical reactions can be ruled out, it appears likely that
the time-dependent changes are related to a conformational
transition on going from the crystal to the solution. During
such a process a twisting of the disulfide group and E/Z
isomerization of the two peptide bonds in the heterodetic
ring and the urethane bond can occur simultaneously or consecutively. In order to establish whether the time-dependent
change of the C D and UV absorption (Fig. 1 b) is due to
only one or to several of these processes we undertook a
kinetic-spectroscopic analysis[2!
Merely the appearance of an isosbestic point in the UV
spectra and of two analogous points of constant ellipticity
in the C D spectra suggest that the overall conformational
change proceeds in a spectroscopically uniform manner. This
can be tested with the aid ofextinction (E)diagrams,extinction
[*I
Prof. Dr. G. Jung [ + ] and Dr. M. Ottnad
Chemisches Institut der Universitit
74 Tubingen I , Auf der Morgenstelle (Germany)
Dr. P. Hartter
Physiologisch-chemisches Institut der Universitit Tubingen
Dr. H. Lachmann
Physikalisch-chemisches lnstitut der Universitlt Tubingen
[ +] T o whom correspondence should be addressed.
429
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photolysis, aziridinimines, diaziridinimines, diaziridinones, tetrazolines, carbodiimides
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