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Cyanic Esters from Thiocyanates.

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cyclohexanediol. In the hydrogenation of ( I ) under pressure
the a-hydroxyl group had thus been eliminated and a ring
had been formed by 1,6-C-C linkage.
The composition of the mixture was ascertained by oxidation
with alkaline permanganate solution and detection of adipic
acid by paper chromatography. The isomers were separated
by way of the benzylidene derivative [41 of the cis-compound
and were compared by 1R spectroscopy with the same compounds obtained from pyrocatechol by hydrogenation over
the same Ni-MgO catalyst. Finally the phenylurethane
derivatives[5] of both isomers were prepared by means of
phenyl isocyanate; they agreed in melting points and I R
spectra with data recorded in the literature and found for the
derivatives obtained by hydrogenation of pyrocatechol.
Synthesis and Pyrolysis of 3-Azaquadricyclane
Derivatives. - A New Azepine Synthesis [*I
By H . Prinzbach, R . Fuchs, and R . Kitzing[*]
The oxepine synthesis that starts from furan and acetylene
derivatives and consists of the Diels-Alder addition ( l a ) --f
(2a), photochemical valence isomerization (2a) + (3a), and
the pyrolysis (3a) + (4a) has repeatedly proved its valuerzl.
We have prepared, by an analogous route, the first derivatives [(3b) and (3c)I of the thermally labile 3-azaquadricyclane system, and thence the azepines (46) and (4c).
Received: October 31, 1967
[ Z 647 IE]
German version: Angew. Chem. 80, 42 (1968)
[*I Dr. H. Feichtinger and Dr. H. Noeske
Organisch-Chemisches Forschungslaboratorium
der Ruhrchemie Aktiengesellschaft
42 Oberhausen-Holten (Germany)
111 H . Schulz and H . Wagner, Angew. Chem. 62, 117 (1950).
[2] H . - W . Linden and H . Feichtinger, German Pat. 1176117,
Ruhrchemie AG; Chem. Zbl. 1965,5364.
[3] H . Heckel, 0. Roelen, W . Rottig, and K . Schenk, German
Pat. 897547, Ruhrchemie AG; Chem. Zbl. 1954,9434; Commercially available as Catalyst 55j5.
[4] N . A . B. Wilson and J . Read, J. chem. SOC.(London) 1935,
1269.
[ S ] R. Cornubert, A . Rio, and P . Sdnichal, Bull. SOC. chim.
France, Mem. 1955,46.
Cyanic Esters from Thiocyanates
By W . - D .Habicher and R . M a y e r [ * ]
Iminothiocarbonates ( 2 ) , which are readily accessible from
alcohols and thiocyanates (1) [I], can, as we have found, be
converted into cyanic esters (3) 121 in good yield, with loss of
a thiol, preferably in presence of a thiol-trapping agent.
(2b): M.p. 146°C.
UV (CH3CN): 288 nm (sh), e = 1150 [a]; 227 nm, E = 15900.
NMR (CDCls): T (TMS = 10): 2.41 (2, D), J = 8.0 Hz; 2.74
( 2 , D ) ; 2 . 9 6 ( 2 , T ) , J = 1 . 5 H ~ ; 4 .5 8 ( 2 ,T ) ,J = 1 .5 Hz; 6 .2 8 ( 6 ,S);
7.59 (3, S ) .
(3b) : M.p. 97 "C (isomerization).
UV (CH3CN): 230 nm, E = 11450 [a].
NMR (CDC13): T (TMS = 10): 2.40 (2, D), J = 8.0 Hz; 2.75
(2, D), J = 8.0 Hz; 5.75 (2, D), J = 4.5 Hz; 6.45 ( 6 s ) ;7.30(2, D),
J = 4.5 Hz; 7.55 (3, S).
( 4 6 ) : M.p. 111 "C.
UV (CH3CN): 350 nm, E = 810 [a]; 214 nm, E = 23400.
NMR (CDC13): T (TMS = 10): 2.17 (2, D), J = 8.0 Hz; 2.60
(2, D), J = 8.0 Hz; 4.00 (2, D), J = 7.5 Hz; 4.15 (2, D), J =
7.5 Hz; 6.22 (6, S); 7.55 (3 S).
R' may be aliphatic, cycloaliphatic, arylaliphatic, or aromatic. Aliphatic and arylaliphatic groups are particularly suitable
for use as R groups.
Examples: From ethyl thiocyanate ( I ) , R' = C2H5, were
obtained 76% yields of n-butyl ( 3 ) , R = n-C4H9, n g =
1.4009, and 8 4 % yields of n-pentyl (3), R = n-C5HII, n g =
1.4101, and isopentyl (3), R = iso-CSHII, n g = 1.4089.
General Procedure :
An iminothiocarbonate (2) (0.1 mole) is vigorously stirred
in ether for 2-3 h at O°C in presence of a thiol-trapping
agent (e.g. a mixture of 27 g of HgO and 20 g of anhydrous
MgS04). Then the mixture is filtered, the solvent removed at
0 "C in a vacuum, and the residue distilled in a vacuum at a
bath temperature not exceeding 30 "C. The cyanic esters (3)
are condensed in a cold trap.
Received: October 30, 1967
[Z 648 IEI
German version: Angew. Chem. 80, 42 (1968)
_ _ __
[*] Dipl.-Chem. W.-D. Habicher and
Prof. Dr. Roland Mayer
Institut fur Organische Chemie
der Technischen Universitdt
DDR 8027 Dresden, Mommsenstr. 6 (Germany)
[l] R. Mayer and W.-D. Habicher, unpublished; A. Knorr, Ber.
dtsch. chem. Ges. 49, 1735 (1916).
[2] E. Crigat and R . Putter, Angew. Chem. 79, 219 (1967);
Angew. Chem. internat. Edit. 6, 206 (1967); D . Martin, Z . Chem.
7 , 123 (1967).
.. - -
Angew. Chem. internat. Edit.
/ Vol. 7 (1968) / No. I
(2c) : B.p. 125-130 "C/lO-3 torr; molecular ion at m/e = 251 191.
UV (C2H50H): 290 nm, E = 1240.
NMR (CDCI,) [b]: 7 (TMS= 10): 2.77 (2, M); 4.21 (1, M),
4.36 (1, M); 6.19 (6, S); 8.07 (3, S).
(3c) : M.p. 81 "C (isomerization).
UV (CH3CN): 219 nm, E = 12100.
NMR (CDC13) [b]: T (TMS = 10): 5.39 (2, D), J = 4.5 Hz;
6.28 (6, S); 7.10 (2, S), J = 4.5 Hz; 7.70 (3, S).
(4c) : Molecular ion at m/e = 251.
UV (CH3CN): 355 nm, E = 780; 226 nm, E = 19700.
NMR (CDCI,) [b]: T (TMS = 10): 3.2-3.8 (br. M); 3.93 (2, D),
J = 8.5 Hz; 6.10 (6, S); 7.79 (3, S).
[a] The weak maxima of the toluenesulfonyl group are not listed.
[b] Measured at ca. 36 "C. The spectrum shows the temperaturedependence expected from hindered rotation around the C-N
bond.
Pyrrole derivatives containing a strong electron acceptor as
N-substituent [(lb) and ( l c ) ] react with dimethyl acetylenedicarboxylate, t o afford the 7-azanorbornadienes (2b) and
(2c) in 30-40 % yield [31. As in the UV spectra of 7-0Xa and
7-methylene analogs [41, in the region 280-290 nm, maxima
or shoulders are found, more or less pronounced according
t o the polarity of the medium, that may arise from interaction between the homoconjugated C = C double bonds.
67
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