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Formation of 2-Oxazolidones from -Iodourethanes. A Stereospecific Synthesis of cis--Amino-Alcohols

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Our findings regarding the esterification of amino acids and
dipeptide derivatives by acetals formed from N,N-dimethylformamide and either benzyl or p-dodecylbenzyl alcohol
[ ( 4 ) and (S), respectively] are reproduced in Table 1. The
benzyl ester of L-valine hydrochloride was isolated in 83 %
yield after removal of the N-protecting group from the b e n q l
ester of N-DOBC-L-valine with trifluoroacetic acid [4], and
corresponds in melting point (138OC) and in specific
rotation (+9.7" in pyridine) with data reported in the
literature [5].
The acetals of N,N-dimethylformamide were obtained
from N,N-dimethylformamide by transacetalization [I]
using the diethjl- [I] or diniethylacetal [6]. This method
failed in the case of p-nitrobenzyl alcohol.
hexano[b]-2-oxa~olidone[ 6 ]is obtained on pyrolysisofmethyltrans-2-iodo-cyclohexane carbamate. Alkyl iodides have been
isolated as by-products in almost quantitative yield in these
reactions. Hydrolysis of the 2-oxazolidones leads to cis+
amino-alcohols. For example Cholcstano [3P, 2P-b]-2-oxazolidone was hydrolysed by methanolic potassium hydroxide to
give a 93 "/, yield of 2P-aminocholestan-3~-ol,m.p. 166 OC;
N,O-diacetyl derivative, m.p. 194 "c'.
The P-iodo-urethanes (2) can be hydrolysed with base to give
the corresponding ethylene-imines ; the imine ring can then
be opened with acid to give trans-p-amino-alcohols [I]. These
reactions make available a stereospecific route to cis- as well
as to trans-P-aminoalcohols from olefins.
Received, February 5th, 1963
[Z 452/273 IE]
IZ 450/283 IE]
Received, February 4th, 1963
[ I ] H. Meerwein, W. Florian, N . Schb'n, and G. Stopp, Liebigs
Ann. Chem. 641, l(1961).
[2] W. Huusermann, diploma thesis, Eidgenossische Technische
Hochschule, Zurich (Switzerland), 1962.
[3] Estimated by recovery of unesterified benzoic acid.
[4] F. Weygund and K . Hunger, Chem. Ber. 95, 1 (1962).
[ S ] J. Shields, W. H. McGregor, and F. Carpenter, J. org. Chemistry 26, 1491 (1961).
[6] H . Bredererk, F. Effenberger, and G. Simchen, Angew. Chem.
73, 493 (1961).
[I] Communication No. 2 on "The Chemistry of Urethanes".
Communication No. 1: A . Hassner and C. Heathcock, Tetrahedron Letters, in the press.
121 National Science Foundation Prcdoctoral Fellow.
[3] Financial assistance by the U. S. National Jnstitutes of
Health, Grant CY-4474 is gratefully acknowledged.
[4] L. Birclcenbach and M . Lindhard, Ber. dtsch. chem. Ges. 64,
1076 (1931); G. Drefahland K . Ponsold, Chern. Ber. 93,519(1960).
[ 5 ] R . Wiltekind, J . Rosenau, and G. Poos, J. org. Chemistry 26,
444 (1951).
[6] M. Mousseron et al., Bull. SOC.chim. France 1953, 737.
[7] M. S. Newman and A . Kulner, J. Amer. chem. SOC.73, 4199
(19.51).
Formation of 2-Oxazolidones from p-Iodourethanes
A Stereospecific Synthesis of cis-3-Amino-Alcohols [ 11
By Dr. C. Heathcock [2] and Prof. Dr. A. Hassner [3]
Acylation of Enamines with Lactimsulfonic
Ester8 111
By Prof. Dr. S. Hunig, Dr. W. Luclte, Dr. V. Meuer [2], and
cdnd. chem. W. Grassmann
Department of Chemistry, University of Colorado,
Boulder, Colorado (U.S.A.)
Chemisches lnstitut der Universitiit Wurzburg (Germany)
Iodine isocyanate adds to olefins to yield P-iodo-isocyanates
which react with alcohols to give P-iodo-urethanes [1,4].
When the olefin used is cyclic, a trans-adduct (2) is obtained
[1,5], which can be converted into a 2-oxazolidone (3).
The smooth acylation of enamines with carbonyl chlorides
[3] can also be applied to iminosulfonic esters, which are
formed for example on Beckmann rearrangement of cyclic
ketoximes ( I ) and which condense with enamines to give (4).
I I1
-C-N
I
F=o
-c-0
I
The results obtained so far are given in Table 1. The 2-oxazolidones were produced by pyrolysis of the corresponding
P-iodo-urethanes, either by heating alone at 100-190 'C, or
in a refluxing solvent. That the reaction involves inversion at
the carbon bearing iodine is shown by the fact that cis-cycloTable I . 2-Oxazolidoncs prepared so far
Olefin
2-Cholestene
1,2-Dihydronaphthalene
Indene
Styrene
Cyclohexene
I
2-Oxazolidone
Cholestano[3f3, 2f3-b]cis-Tetralino[2,1-b]cis-Indano[2,1-b]4-Phenylcis-Cyclohexano[b]-
53
35
61
81
41
227
141
160
136 [7]
55 t61
Compound ( 4 ) is isolatable and is split by dilute acid to give
the equally stable iminoketone ( 5 ) [4], which, when the ring
sizes are suitable, are split by alkali or strong acids into w amino-keto-acids (6). Long chain co-aminocarboxylic acids
are obtained finally by reduction (examples, see Table 1).
Angew. Chem. internat. Edit. 1 Vol. 2 (1963) / No. 4
213
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synthesis, stereospecific, formation, amin, oxazolidonen, alcohol, iodourethanes, cis
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