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Enolization of -Lactones.

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Other workers have recently described [3] syntheses of ribodinucleotidcs using th e tetrahydropyranyl g r o u p [4]t o protect
the ?'-hydroxyl group. However, removal of this acid-labile
protecting group frequently leads t o simultaneous isomerization of the internucleotidic linkage [3,5].
VHAc
+
H0H2ca
B
I
I
\oo/
0 dAc
@
/
0-P=O
H,
/
O=,yH O 00
OH
(2)
spectra d o not show O H groups, a n d when ( I c ) is warmed
with tritiated water, its hydrogen at o ms d o not exchange. It
is probable t h at CH3MgI induces the enolization ( I ) + (2);
this enolization a n d t h e reaction of the Grignard reagent with
the C=O group probably proceed a t comparable rates, thus
enabling methane t o b e produced by reaction of the Zerewitinoff reagent with (2).
(3)
R-H F ~ ~ . Q
H2C-CH-R'
YH
R+?
Hz C-CH
-H '
(2)
(1J
R = CH3, R' = CHzCOCH,
R = CH3, R' = CHzCHZCH,
RzR1.H
Received, February 21st, 1964
[Z 696/524 I € ]
German version: Angew. Chem. 76, 376 (1964)
THAc
[ I ] W.Tlieilacker, K . Ebke, L. Seidl, and S , Schwerin, Angew.
Chem. 75, 208 (1963); Angew. Chem. internat. Edit. 2, 154
(1963).
0
@
/
0-P=O
/
dAc
7,14-DihydrotriphendithiazineBis-S-oxides
By Dr. 0. Christmanii
Farbenforschungslaboratorium der Badischcn
Anilin- & Soda-Fabrik A G ., Ludwigshafcn am Rhein
(Germany)
(4)
Dedicrited to Professor H . Bredereck on the occasion
of his 60th birthdriy
Ac = Acetyl
U = Uracil
Received, February 14th. 1964 [Z 671/495 IE]
German version: Angew. Chem. 76, 435 (1964)
[ * ] This work has been supported by grants from the National
Science Foundation, the National Institutes of Health, and the
Wisconsin, Alumni Research Fund.
[ I 1 R . Lohrniann and H . G. Khorana, unpublished work.
[2] C . A . Dekker and H . G. Khorana, J . Amer. chem. SOC.76,
3522 (1954).
[3] F. Crainer and K . H . Scheit, Angew. Chem. 74, 717 (1962);
Angew. Chem. internat. Edit. I, 510 (1962): J. Smrt and F. Sorm,
Coll. Crechoslov. chem. Cornm. 28, 2415 (1963).
[4] M . Smith, D . H . Rammler, I . H . Goldberg, and H . G. Khorana,
J . Amer. chem. SOC.84, 430 (1962).
[5] D. H . Raminler, Y.Lapidot, and H . G. Khorana, J. Amer.
chem. SOC.85, 1989 (1963); Y.Lapidot and H . G. Khorana, J.
Amer. chem. SOC.85, 3852 (1963).
Enolization of :/-Lactones
By Prof. Dr. W.Theilacker, Dr. K.-H. Bremer, a n d
Dr. L. Seidl
Institut fur organische Chemie
de r Technischen Hochschule Hannover (Germany)
T h e reaction of 2,6-dimethylphenolate with chloramine gives
a doubly unsaturated c-caprolactam which is converted with
mineral acid t o a-methyl-y-acetonyl-y-butyrolactonc ( I n ) [I].
A n incorrect structure was initially assigned t o this compound a s it was shown by th e Zerewitinoff technique t o
contain a bout o n e active hydrogen atom. After th e structure
( l a ) was confirmed, we investigated th e behavior towards
Zerewitinoff reagent (CH3Mgl) of ( l a ) , r-methyl--{-npropyl-y-butyrolactone ( I b ) [derived f r o m ( l a ) by Clemmensen reduction], a n d -{-butyrolactone ( I c ) . C o m po u n d s
( l o ) . ( I b ) , a nd ( I c ) proved t o contain, respectively, 0.5, 0.4
a n d 0.4-0.5 active hydrogen atoms. T h e infrared a n d N M R
Anyew. Cheni. internot. Edit.
1 Vol. 3 (1964) / No. 5
Triphendithiazine ( I ) [ l ] , 7,14-dihydro-6,13-dioxotriphendithiazine (2) [2,3], a n d derivatives of these t w o parent
compounds ar e known [1,2], b u t compounds derived from
7,14-dihydrotriphendithiazine (3) have not yet been described. Attempts t o prepare such derivatives remained witho u t success [4].
C o mp o u n d s of type (3) ar e distinguished from t h e deeply
colored quinonoid systems ( I ) and (2) principally by their
central benzenoid ring. Although (2) an d its derivatives can
be reduced t o hydroquinones, t h e latter ar e immediately
reoxidized by atmospheric oxygen t o t h e quinones [3].
By reductive acetylation of triphendithiazine ( I ) with zinc in
glacial acetic acid/acetic anhydride, we succeeded in preparing 7,14-diacetyltriphendithiazine ( 4 ) . Deacetylation i n
acidic or basic media immediately reconverts ( 4 ) i n t o t he
starting material ( I ) . Stable representatives of t h e benzenoid
H 2 02
type (3) ar e accessible when ( 4 ) is oxidized by 30
in glacial acetic acid t o 7,14-diacetyltriphendithiazine bis-Soxide (5) or S-dioxide ( 6 ) . Deacylation of t h e S-oxides (5)
or ( 6 ) with NaOH/N-methylpyrrolidone affords orange
alkali salts an d hence, lemon-yellow 7,14-dihydrotriphendithiazine bis-S-oxide (7) or S-dioxide (S), respectively.
C o mp o u n d s (7) a n d (8) ar e highly stable an d extremely insoluble in organic solvents, an d have properties reminescent
of quinacridone.
375
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