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ortho-Semidine Rearrangement of 1 2-Diphenyl-1 2-diazetidinone.

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I
I
(3). Xo = HSOP
shows (see Fig. l), however, an AB system (TA = 5.9 and TB =
6.5, with JAB = 11 Hz) for the two methylene protons. The
AB system is also conserved on heating the compound (6)
to 15OOC.
A fixed, non-planar, and therefore chiral, conformation of the
eight-membered heterocycle can thus be assumed, at least
for temperatures up 150°C. The compound (6) should
therefore be resolvable into optical antipodes - experimental
work with this aim in view is in progress.
(31,
XQ = 1€3
M.p.
( "C)
H
H
CH3
243
70
H
CsHs H
242
CHI NO2 270
P6
82
H
CH3
CH3
CH,
CH,
(decomp.)
245
230
(decomp.)
H
NO2
30
70
24 1
300
(decomp.)
300
Received: May 12th and June 5th 1967
[Z 532 IE]
German version: Angew. Chem. 79 618 (1967)
180
[*I Dr. G. Ege
Organisch-Chemisches Institut der Universitat
Tiergartenstr.
69 HeideIberg (Germany)
[l] T. Safo and M. Ohm, Yakugaku Zasshi 77, 771 (1957);
Chem. Abstr. 51, 17941 (1957).
121 G. Ege, K . Gessner, and H . Schildknecht, unpublished; cf.
H . Schildknecht, Angew. Chem. 78, 841 (1966) and especially
p. 847; Angew. Chem. internat. Edit. 5, 751 (1966) and p. 757.
[3] Cf. The Preparation of Thiazolo[2,3-b]thiazolium Salts:
C. K. Bradsher, D. F. Lohr, and W. J. Jones, Tetrahedron Letters
1965, 1723.
H1C
r
1
ortho-Semidine Rearrangement of
1,2-Diphenyl-1,2-diazetidinone
The fact that (5) is actually present as a salt and not as an
ether follows from the NMR spectrum. The spectrum shows
that the methyl group protons and olefinic protons from the
cation and anion are not equivalent (two doublets at T = 7.3
and T = 8.1 for each of the three protons, a quartet at T = 4.2
for one proton, and one multiplet for eleven protons between
T = 1.9 and 2.9).
When (5) is boiled in aqueous methanolic hydrochloric acid,
the compound 7-methyl-4-phenyl-8H-1,3,5,6-dithiadiazocin2-one (6) [colorless crystals, m.p. 120°C, yield 90% with
respect to the anion of (5)] is formed by transannular ring
opening of the anion. The cation of (5) can be precipitated
unchanged as the perchlorate.
The structure of (6) follows from the IR spectrum: a CO
band at 1695cm-1 and absence of absorption in the NH
region.
One would expect the methylene protons, HA and HB, in
(6) to be equivalent if they were to rapidly oscillate about the
plane of the ring. The NMR spectrum of (6), at ca. 20"C,
By W. Fischer and E. Fahr[*J
According to work by Wittig et al. [21, 1,2-diazacycloalkanes
of type (1) undergo the ortho-semidine rearrangement only
when n is at least 4. We have, however, found that the
rearrangement occurs also with 1,2-diazetidinones of type(2).
If the 1,Zdiazetidinone ( 2 4 (3 mmoles) is boiled under reflux
(2 h) in methanolic solution (300 ml) with sulfuric acid
(3 ml)[31, a mixture is obtained from which compound
(3a) (m.p. 192"C, 34 % yield) separates, having been formed
.
3
(
by an ortho-semidine rearrangement [41. The structure of )
was proved by synthesis (86 % yield) from o-aminodiphenylamine hydrochloride and phenylglyoxylic acid (equimolar
amounts in a little water at room temperature). Use of
preparative thin-layer chromatography (silica gel, CHC13) led
to isolation, from the rearrangement mixture, of the hydrazide
( 5 2 ) [m.p. 145 OC; yield 23 %; IR (KBr), 3280 (NH), 1660
(conj. C=O) cm-1; NMR (CDCl3), aromatic CH and NH
signals between T = 2.43 and T = 3.37, T = 4.82 (t-CH),
T = 6.67 (OCH3)], which is formed from (4) by rupture of
the C-N bond.
Received:rMarch 6th,'*1967
IZ 470 IE]
German version: Angew. Chem. 79,619 (1967)
2
4
TI
Fig. 1. NMR-spectrum of compound (6)
630
I
I
I
6
8
10
[*I Dr. W. Fischer and Prof. Dr. E. Fahr
Institut fur Organische Chemie der Universitat
Rontgenring 11
87 Wiirzburg (Germany)
Angew. Chem. internat. Edit. 1 VoI. 6 (1967) / N o . 7
[l] Part 111 of 1,2-Diazetidines. - Part 11: E. Fahr, W. Fischer,
A. Jung, and L. Sauer, Tetrahedron Letters 1967, 161.
[Z] G. Wirrig, P. Borzel, F. Neumann, and G . Klar, Liebigs Ann.
Chem. 691, 109 (1966).
[3] Use of hydrochloric acid in place of sulfuric acid results in
a reaction in which the chloride ion takes part.
[41 We obtained (36) analogously from (Zb).
A New Fragmentation Reaction of
2O-Chloro-16p-hydroxy Steroids
By G . A d a m [ * ]
the stereospecific formation of the trans-aldehyde (4) from
( I ) and of the cis-aldehyde (8) from (2) js explained.
Received: April 27th, 1967
[Z 500 IEI
German version: Angew. Chem. 79, 619 (1967)
[*] Dr. G. Adam
Institut fur Kulturpflanzenforschung der Deutschen
Akademie der Wissenschaften zu Berlin
X 4325 Gatersleben, Kreis Aschersleben (Germany)
[l] G. Adam and K . Schreiber, Chem. and Ind. 1965,989; Tetrahedron 22, 3581 (1966).
[2] I thank Dr. R. Tummler, Dresden, for measurement of the
mass spectra, and Dr. W . v. Philipsborn, Zurich, for measurement
of the NMR spectra.
[3] C. A . Grob and P . W. Schiess, Angew. Chem. 79, 1 (1967);
Angew. Chem. internat. Edit. 6, 1 (1967).
When heated with 5 % methanolic potassium hydroxide (3 h;
80 "C), 20-chloropregnan-16P-01s111 fragment with loss of
HCl and opening of ring D to form 17(20)-unsaturated 16,17seco-16-aldehydes in 80-90 % yield. The reaction is stereoA Continuous Process for the Preparation of
specific, its course being determined by the configuration at
Diphenylketene
C-20. In this way (20R)-20-chloro-5a-pregnane-3P,16P-diol
(1) affords truns-3~-hydroxy-16,17-seco-5a-pregn-17(20)-eneBy W. Ried and P. Junker[*]
Idaldehyde (4) (m.p. 121-122°C; [cr]: = -22.3 " (CHC13)).
and the (20s)-stereoisomer (2) affords the cis-aldehyde (8)
Up to the present, diphenylketene has been prepared either
(double m.p. 82-85 and 113-116'C; [x]g = -9.2").
by heating a benzene solution of azibenzil to 70"C[ll or by
allowing this solution to drip, in a Nz stream, into a flask
heated to 105-110 " C W
R
( S ) , -4 = €i; Z
=
CH3
( 7 ) , A = CH3; Z =
-4.
R'O
,z
JdJ
A = H, Z
=
H
CH3:
Both methods suffer from the disadvantage that the diphenylketene already formed must be heated until all the azibenzil
has decomposed and rearranged. With large batches (>0.5
mole) this leads to considerable losses since diphenylketene
readily polymerizes when heated and, further, can also react
with both azibenzil and the intermediate carbene. Good
yields of diphenylketene are obtained, however, by use of the
apparatus shown in Figure 1, by means of which the ketene
formed is at once removed from the hot reaction zone.
-4= CH3, Z = H:
(8). R' = H , K 2 = 0
(91,
(lo).
K' = .Ac, R 2 = 0
R' = H , K 2 = NOH
The structure of the steroidaldehydes (4) and (8) was proved
as follows: In the mass spectra (negative ionization) 121 main
peaks occur at m/e = 317 = M -.l, corresponding to a
molecular formula .CZ1H3402. The 100 MHz NMR spectra I21 for the trans- and cis-isomers, respectively, contain
quadruplets at 6 = 9.5 and 9.6 ppm (aldehyde-proton), multiplets at 5.25 and 5.15 ppm (vinyl-proton), 3.55 ppm (H on
C-3), doublets centered at 1.62 and 1.71 ppm (21-methyl),
and two singlets each at 0.78 and 0.87, and 0.77 and 1.08 ppm
(19- and 18-methyl). The IR spectrum of (4) shows bands at
975 (trans-CH=CH-), 1678 (C=C), 1731, 2710, 2815 (aldehyde), 3025 (-CH=CH-), and 3629cm-1 (OH). In the IR
spectrum of (7) the absorption at 975 cm-1 is replaced by a
band at 700 cm-1 (cis-CH=CH-). The two seco-steroids
were also characterized as their U-acetyl derivatives (5) and
(9) with, respectively, m.p. 84-86'C, [cr]$9 = -34.2O, and
double m.p. 85-90" and 98-1OO0C, [a]; = -19.1 O , and as
the oximes (6) and (10)with, respectively, m.p. 196-198 OC,
[a]: = -31.0°, and m.p. 194-198 "C, [a]; = -17.6O.
The fragmentations observed can be regarded as special
cases of olefin-forming Grob fragmentation 131. When regard
is paid to the trans-elimination principle and the known configurations of (1) and (2) at C-20 a synchronous reaction
mechanism such as (3) and (7) can be formulated, whereby
Angew. Chem. internat. Edit.
CsHs, CH3
Vol. 6 (1967) / No. 7
E j j C
Fig. 1. Apparatus for continuous preparation of diphenylketene.
A heating fluid (e.p. paraffin oil), heated to 130 "C, is passed
through the jacket C of the inclined condenser A, and a slow
stream of N2 is passed through the apparatus from the lower
end of the heated tube. As soon as the air is removed, a
benzene solution of azibenzil is added slowly from the dropping funnel. The solvent evaporates at once, while the azibenzil decomposes and rearranges; the benzene vapors are
condensed in the condenser B. The rate of drip of the solution
is determined so that evolution of nitrogen terminates about
5 cm above the lower end of the heated zone. The diphenylketene formed is washed out of the heated tube into the
cold receiver by the reaction solution. After vacuum distillation the yield amounts to about 80 %.
63 1
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semidine, rearrangements, ortho, diphenyl, diazetidinones
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