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Elimination of the Nitrile Group from o-Amino Nitriles.

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compounds [see the synthesis of (Sj)] a 5- to 10-fold
excess of dimethylformamide and lithium diisopropylamide
is to be used.
Received: June 12, 1973 [Z 862 IE]
German version: Angew Chem 85. 861 (1973)
B
(ZU), R' = C H B
( Z h ) , R'
CZH,
R' zN-C -Li
I
1. K3t'CO
2 . H20
[ I ] U . Srhiillkopfand F . Grrhurt. Angew. Chem. 79, 819 (1967): Angew.
Chem. internat. Edit. 6 , X05 (1967).
(4)
123 P. Schmidt, Dissertation, Universitat Gottingen 1970.
[3] D. Srrbach, Angew. Chem. X i , 690 (1969): Angew Chem. internat.
Edit. X , 639 (1969); Synthesis 1Y69, 17.
[4] C;. Srhiillkopfand F . Grrhurt. Angew. Chem. 78, 675 (1966): Angew.
Chem. internat. Edit. 5 . 664 (1966).
YH 9
R~-c-&-N(cH~),
I
R3
151 Further experiments will show whether compounds ( 2 ) are better
formulated as dialkylamino(1ithium 0xy)carbenes.
(5)
[6] Dimethylformamide is a reagent for formylation of orgdnohthium
compounds. cf. (i.Schiillkopfm Hoirhrn-Wi~y1.Methoden der organischen
Cheniie. Thieme Stuttgart 1969, 4th Edit.. Vol. 13:l. p 187.
We have now found that a-hydroxy N,N-dimethylcarboxyamides ( 5 ) are obtained, sometimes in good yield, by
Table I rr-Hydroxy carboxyamides ( 5 ) prepared
c'pd
R2
R3
Yicld
M p
[?"I
[-Cl
IR(KBr)
v OH
[cm-'1
vCO
(Sc)
C,H,
C,H,
C,H,-CH=CH
H
C,H,
H
45
85
48
155[b]
129[b]
89[c]
3310
3315
3310
1625
1620
1620
isdl
(sel
(CH,),C
-(CH2),-
H
(5fi
Cal
76
62
72
66[d]
105[d]
189[e]
3335
3340
3500
1620
1620
1605
( 5 ~ )
isb)
NMR
(CDCI,) IT values)
2 . 6 5 ( ~ , 5 H ) , 4 . 8 0 ( s , l H )5, . 2 8 ( s , i H ) [ ~ , 6 . 9 8 ( ~ . 3 H ) , 7 . 2 4 ( ~ , 3 H )
2.67 (5, lOH), 4.12 (br. s, 1 H ) [fl, 7.24 (br. s,6 H )
2.4~3.00(m,5H),3.28(d,1H),3.91(q,lH),5.12(d,lHj.
5 7 (br. s, 1 H) [fl. 7.05 (s,6 H )
5.81(s,lH),6.68(s,lH)[fl,6.94(s,3H),7.00(s,3H).9.02(s.9H)
5.76 (s, 1 H j [fl, 6.86 (s,6H). 7.9-8.8 (m, 1 0 H )
2.86-3.45 (m, 3aromat. H). 6.26 (s. CH,-0-).
6 88 (s. -NMe,),
6.9-8.90(m,16Hj, 7.9 (s,mamultiplet.l H ) ~ ~ ] , ~ - ~ ~ ( S . I X - C H . , I
[a] 17-Hydroxy-3-methoxy-N,N-dimethyl-1,3,5(
IO)-estratriene-I7-~arboxyamide,
prepared from the corresponding ketone.
[b] From benzene.
[c] From chloroform.
[d] From cyclohexane.
[e] From cyclohexane/chloroform (5: 1).
[g Proton exchangeable with D n O .
treating dimethylformamide ( I ) with lithium diisopropylamide in tetrahydrofuraniether at - 78°C in the presence
of carbonyl compounds ( 4 ) (Table 1). We assume the
decisive intermediate to be (dimethy1carbamoyl)lithium
(2~)~
We
~~
have
. not succeeded in metalating ( I ) smoothly
and unambiguously by, e. g., butyllithium[bJ.
Analogously, a-hydroxy N,N-dimethylthiocarboxamides
[C=S in place of C=O in ( 5 ) are obtained with N , N dimethylthioformamide cia (dimethy1thiocarbamoyl)lithium [C=S in place of C=O in ( 2 a ) ] and carbonyl compounds.
a-Hydroxy N,N-dimethylcarboxyamides( 5 )
Dimethylformamide (40 mmol) and a carbonyl compound
( 4 ) (40 mmol) are dissolved in etheritetrahydrofuran (4: 1 ;
100ml) (if necessary in tetrahydrofuran alone). To this
solution is added at - 78 'C a solution of lithium diisopropylamide that has been prepared in situ from diisopropyiamine and butyllithium in ether (50 ml) and precooled to
- 65 C. The whole is stirred for 6 h at - 78 "C, allowed
to reach room temperature, and hydrolyzed with saturated
ammonium chloride solution. The phases are then separated; the organic phase is dried over sodium sulfate and
the solvent is removed in a rotary evaporator at waterpump vacuum. The crude amides ( 5 ) are digested with
a little ether, then collected and purified (they are often
very clean) either by recrystallization or by column chromatography. In particular, the a-hydroxy dimethylthiocarboxyamides are best purified by chromatography on
silica gel with etheripentane. For very expensive carbonyl
Angov Chrm. infernut. E d i f . / Vol. 12 ( 1 9 7 3 )
/ Nu. 1 0
Elimination of the Nitrile Group
from o-Amino Nitriles
By Julian Mirek and Janusz Sepid']
10-Amino-1,2,3,4,5,6,7,8-octahydro-9-phenanthrenecar
bonitrile ( l a ) can be prepared in almost quantitative yield
by cyclization of (2-cyclohexylidenecyclohexylidene)malonodinitrile by concentrated sulfuric acid at 0 C"]. (2Cyclopentylidenecyclopenty1idene)malonodinitrile was
recently cyclized thermally (160°C) to 5-aminohexahydroas-indacene-4-carbonitrile (2)Iz1. Similarly, (r-methylphenethy1idene)malonodinitrile is converted by concentrated sulfuric acid at room temperature into I-amino-3methyl-2-naphthonitrile (3) in high yieldI3l.
According to Jiiger['] the cyano group of ( l a ) cannot
be hydrolyzed because of steric hindrance, and in ( 2 )
[*] Doz. Dr. J. Mirek and Dipl.-Chem. J. S e p i d
Department 01 Chemistry
Jagiellonian University
PL 30-060 Krak6w (Poland)
837
and (3) it is hydrolyzed only to the amide group and
then with diffi~ulty1'.~1.We, however, have found that
the o-amino nitriles ( 1 a), ( 1 b), ( 2 ) , and (3) are converted
into the amines by heating (200°C) for several hours with
alcoholic sodium hydroxide in an autoclave. This "denitrilation" probably occurs by way of the o-amino carboxylic
acid (or its anion), which is unstable under the reaction
conditions (Table 1).
Table I . Denitrilation of f 1 a ) , ( 1 b ) , (2). and (3)
Nitrile
IlU)
(Ih)
(2)
(3)
Reaction
time [h]
Yield [%]
Amine
M.P. [ CI
8
8
7
6
14
71
46
82
65-66
76-11
4546
50-51 [a]
.....
[a] M.p. 51-52
. .~
.
C [4].
General experimental procedure:
The o-amino nitrile ( 5 g) and sodium hydroxide ( 5 g) are
heated in ethanol (80ml) in an autoclave for some hours
at 200 ' C . The alcoholic solution, which contains ammonia,
is filtered from sodium carbonate, the filtrate is diluted
with water (60ml), and the ethanol is distilled off. The
precipitate, at first oily, crystallizes on cooling. The amine
that crystallizes from the solution is purified by sublimation
in a vacuum and subsequent recrystallization from light
petroleum.
The structures of the new amines from ( I a), ( 1 b ) , and
(2) are proved by analytical and spectroscopic studies.
Received: June 12, 1973 [Z X66 IE]
German version: Angew. Chem 85, 861 (1973)
.~
[I]
H . Jiigrr. Chem. Ber. Y3, 242 (1962).
[2] G . Le Guillunton, C. R. A a d . Sci. C274, 895 (1972).
[3] E. Cumpaignr, D. R. Maulding. and M! L. Rorlofs, J. Org. Chrm.
2Y. 1543 11964)
[4] 1.' Ve.se1f and J. Kapp, Chem. Listy 18, 201 (1924).
anti-Benzene Dioxide
By Emanuel Vogel, Hans-Josef Altenbach, and Erich Schmidbaued'l
of the as yet unknown (1) was provided by the discovery
of an antibiotic with the anti-benzene dioxide structure
(2) reported very recently by Borders e t ~ l . [ ~Pre~.
paration of ( I ) appeared all the more desirable since
our investigations of syn-benzene dioxide ( 5 ) have cast
doubts upon the configuration tentatively assigned to the
natural productf21.
The relatively easily accessible dibromo epoxides (3) and
( 7 ) provided starting materials for the preparation of the
syn- and anti-benzene dioxides, respectively.
As already reported[2b1,reaction of ( 3 ) with acetic anhydride and sulfuric acid"" leads to a diacetate that affords
the desired syn-benzene dioxide ( 5 ) on treatment with
methanolic potassium hydroxide. The structure of the diacetate was not clarified at that time, but it was apparent
that it could not be the cis- 1Jdiacetate (3t,6t-dibromolr,2c-diacetoxy-4-cyclohexene[''I) expected from the projected synthesis of (5).
The intermediate diacetate has now been recognized as
the cis-1,3-diacetate ( 4 ) . The structure ( 4 ) is indicated
in particular by the chemical finding that the diacetate
is converted by catalytic hydrogenation over Pd/BaS04
in ethanol into 2t-bromo- 1r,3c-diacetoxycyclohexane~'I
(m. p. 79-80 "C),from which cis- 1.3-diacetoxycyclohexane
is obtained on reductive elimination of bromine with Raney
nickel in ethanol''']. (4) corresponds in configuration and
with great certainty also in conformation to conduritol
B (5-cyclohexene-lr,2t,3c,4t-tetrol),
which is known from
NMR studied' 31 to assume the energetically favorable
half-chair conformation with four equatorial substituents.
In actual fact, an NMR analysis of (4)["] carried out
on the basis of a half-chair conformation by double
resonance and partial INDOR technique provided coupling constants that accord excellently with those for
conduritol B. The formation of ( 4 ) becomes intelligible
if one assumes that a neighboring group effect['51 comes
into play on opening of the epoxide ring, as indicated
in (6).
Benzene is theoretically capable of forming five oxidesbenzene oxide['], syn-benzene dioxide['], anti-benzene
dioxideE3,
1' , syn-benzene trioxideE5.'I, and anti-benzene
trioxideL5.'*']-of
which all except the anti-benzene
dioxide ( 1 ) have been prepared within the last few years.
An important stimulus for attempting the synthesis
The synthesis of anti-benzene dioxide (1) was realized
starting from the dibromo epoxide (7).
draB=
-
Br -
\
AcO
Br
[*] Prof. Dr. E. Vogel, Dr. H.-J. Altenbach, and DipLChem. E. Schmidbauer
Institut fur Organische Chemie der Universitat
5 Koln I , Ziilpicher Strasse 47 (Germany)
838
Anyew. Chem. internut. Edit. f Vol. I 2 f 1973) f No. 10
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