close

Вход

Забыли?

вход по аккаунту

?

Formal Criss-Cross Cycloaddition of Sulfur Trioxide to Cyanogen.

код для вставкиСкачать
dated. Neither SO3 nor (CN), has hitherto been found to
to give ( 5 ) (72 %). Opening of the epoxide ring of this r*,1-+4
undergo criss-cross cycloaddition. On bonding of ( I ) the
linked disaccharide derivative with lithium iodide dihydrate
SO3component is incorporated regiospecifically. N o monoadgives, in addition to the gluco-altro isomer, the bis-altro comduct could be isolated, even in the presence of an excess
pound (7) (56 % yield) as the major product.
On reduction with NiCl,/NaBH,['% 51, compound (7)
of cyanogen.
affords methyl 2,6-dideoxy-4-0-(2,6-dideoxy-a-~-ribo-hexopyranosy1)-cx-o-ribo-hexopyranoside(9)['], the glycoside of
the terminal disaccharide unit of neo-dig~xin~'].
The synthesis
has not yet been optimized and the present yield of 34%
should be open to considerable improvement. This synthetic
approach provides a convenient entry to other oligodeoxyoligosaccharides.
Reductive removal of the iodine from ( 5 ) with
NiClz/NaBH4''*51 gives the 2'-deoxy derivative ( 4 b). A series
of hitherto unelucidated by-products lowers the yield to 32 %.
Epoxide ring cleavage of ( 4 b ) affords not only the glucorib0 isomer but mainly the altro-ribo configurated derivative
( 6 b ) (43% yield); the 'H-NMRdatafor its reducing saccharide
(1) forms monoclinic crystals, space group A2/a with
a = 11.928(3), b = 6.81 8(2), C = 7.824(2)A, y= 96.37(2)", Z = 4 ,
ring are comparable with those of (7).
When subjected to elimination reaction with methyllithium
pcalc.
= 2.228 gcm-3. Using an automatic single-crystal diffractometer (Siemens AED), 1968 independent reflections were
in ether''), (6 b ) smoothly furnishes the disaccharide glycal
(8). The derivative (8) (45% yield) represents a disaccharide
measured with MoKTradiation (0,,,=40", 8/20 scan, 5-point
synthon, comparable with the monosaccharide synthon ( 3 a ) ,
measurement) of which 219 were regarded as unobserved
which permits further synthetic reactions. Addition of
(I 5 2 01). After Patterson and Fourier synthesis, refinement
methanol to (8) in the presence of N-iodosuccinimide affords
(complete matrix) led to Rs0.049. The molecule is centro(6a), which was transformed into ( 4 a ) with sodium methoxide
symmetric and in the crystal it deviates only slightly (mainly
and characterized.
with regard to the exocyclic oxygen atoms) from the higher
2/m symmetry. The bicyclic skeleton is planar.
Received: December 20, 1978 [Z 157 IE]
German version: Angew. Chem. 91, 242 (1979)
[I] J. Thiem, H . Karl, J . Schwentner, Synthesis 1978, 896; J . Thiem, J .
Elvers, Chem. Ber., in press.
[2] F . Micheel, Ber. Dtsch. Chem. Ges. 63, 347 (1930).
131 Cf., e.y., W Roih, W Pignian, Methods Carbohydr. Chem. 2, 405 (1963).
[4] The 2,3-anhydro derivatives ( I ), (4), and (5) probably prefer the SOs(D)
sofa conformation and are therefore drawn thus; cf. J . Thiem, J .
Schwentner, E . Schiirrpelz, J. KopJ Chem. Ber., in press.
[ 5 ] H . Paulsen, L! Sinnwetl, Chem. Ber. I l l , 879 (1978).
[6] A . Furst. P. A . Plattner, 12th Int. Congr. Pure Appl. Chem., New York
1951, Abstr. Papers, p. 409.
[7] M. Shurma, R . K . Brown, Can. J. Chem. 44, 2825 (1966).
[ S ] J. Thiem, J. Schwentner, Chem. Ber., in press.
[9] F . Kaiser. E. Haack, H. Sgingter, Naturwissenschaften 46, 447 (1959).
122
Fig. I . Molecular structure of ~,2,3-oxathiazolo[4,5-d][t,2,3]oxathiazole
2,2,5,5-tetroxide ( I ) in the crystal. Standard deviations 0.002-0.003 A for
bond lengths and 0.1-0.2" for bond angles.
ban:
Formal Criss-Cross Cycloaddition of Sulfur Trioxide
to C y a n o g e n [ * * l
Compound ( I ) exhibits unusual
lengths: the S-0
bond in the ring is extremely long at 1.71 A, while the exocyclic
S=O bonds are shortened to 1.39.k This finding suggests
a description of the molecule in terms of bond-non bond
resonance [ ( 1 a ) t ) ( l b), ( I c)], the resonance formulas ( I b)
and (1 c) also pr?viding some rationalization for the short
C-0 bond (1.29 A).
By Herbert W Roesky, Nurul Amin, Graalf Rernmers, Alfred
Gieren, Uwe Riemann, and Bernhard Dederer[*l
Procedure
Cyanogen reacts with sulfur trioxide in the molar ratio
1 :2 to give a compound which was formulated['] as the (bis)adduct of a Lewis acid and a Lewis base. However, its sensitivity
towards hydrolysis is incompatible with the properties of the
known adducts of SO3 with Lewis
X-ray structure
analysis has now shown this compound to be 1,2,3-oxathiazolo[4,5-d][1,2,3]oxathiazole 2,2,5,5-tetroxide ( I ), the product of a formal criss-cross cycloaddition (1,3;2,4 cycloaddit i ~ n ) [ ~However,
].
the reaction mechanism has yet to be eluci-
Cyanogen (0.1mol) is passed into ice-cooled sulfur trioxide
(0.15 mol) with exclusion of moisture. As soon as the solution
has solidified to a gel, the excess of SO3 is stripped off in
uacuo. Vacuum sublimation gives colorless crystals of ( I );
yield 80%. IR: v(CN) and/or v(C0) 1690, 1670cm-'. MS
(70eV):mle = 106(1OO%)M,/2,80 SO3,64 SOz,48 SO,42 NCO.
Received: December 21, 1978;
supplemented: January 4, 1979 [Z 159 IE]
German version: Angew. Chem. 91, 243 (1979)
[*] Prof. Dr. H. W. Roesky, Dipl.-Chem. N. Amin, Dr. G. Remmers
Anorganisch-chemisches Institut I der Universitat
Niederurseler Hang, D-6000 Frankfurt am Main 50 (Germany)
Dr. habil. A. Gieren, U. Riemann. Dr. B. Dederer
Max-Pianck-institut fur Biochemie, Abt. Strukturforschung 1
Am Klopferspitz, D-8033 Martinsried (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
and by Hoechst AG.
H . A. Lehmann, L. Riesel, K . Hnehne, E. Maier, Z . Anorg. Allg. Chem.
310, 298 (1961).
[2] A. Girren, B. Dederer, H . W Roesky, N . Amin, 0 . Petersen, 2. Anorg.
Allg. Chem. 440, 119 (1978).
[3] K . Burger, W Thenn, R . Rau, H . Schickaneder, A . Gieren, Chem. Ber.
108, 1460 (1975); cf. also 71 Wagner-Jouregg, Synthesis 1976, 349.
[t]
223
Ariqrir. Chem. Itit. E d Engl. 18 (1979) No. 3
0 Vri-lag Chrmie, G m b H , 0-6940 Wemheim, I979
0570-0833/79,'i1303-0221
S02.SOjO
Документ
Категория
Без категории
Просмотров
0
Размер файла
135 Кб
Теги
forma, cycloadditions, cyanogenic, sulfur, crisp, trioxide, cross
1/--страниц
Пожаловаться на содержимое документа