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Modified Horeau Analysis for Determination of the Chirality of Amines Alcohols and Carboxylic Acids.

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means of a 150-watt Hg medium-pressure lamp (Hanau TQ
150, quartz immersion well). Ca. 40-45 "4 of the starting
material had reacted after 30-50 h. At least eight new com-
@
22
ahv
Diademane ( 1 ) is definitely not formed on photolysis of (2).
When ( 9 ) and ( 1 0 ) are included, 23 of the 91 theoretically
possible (CH)l0 isomers['] are now known.
'Received: July 9, 1974 [Z 72 IE]
German version: Angew. Chem. N6.706 (1974)
.@.
CAS Registry Numbers:
(2): 6053-74-7 1 9 ) : 52674-18-7 ' 1 1 0 ) : 52674-19-8
D Kuufmtrnn. and 0.Schuilnrr. Angew. Chem. 83, 404
(1971): Angew. Chcm. internat. t d i t . 1 0 , 417 (1971).
[ I ] A. dt, Meijere,
ponents could be detected, ,along with polymeric material,
by gas chromatography of the reaction mixture. So far seven
of these products have been identified
First there were the three known (CH),, isomers: bicyclo[4.2.2]decatetraene ( 4 ) (relative proportion 973, tricyclo[4.2.2.02~*]deca-3,7,9-triene( 5 ) (6%). and bullvalene (6)
( 5 Yo),as well as naphthalene (7) (3 %)and azulene (8) (trace).
According to mass-spectrometric molecular weight determinations the two main products were also isomers of molecular
formula C,,H,,; on the basis of their spectroscopic and chemical behavior the hitherto unknown structures pentacyclo[4.4.0.0.2~4.03~'o.05~g]dec-7-ene
( 9 / [ 3 1 and hexacyclo[4,4,0,02.4~03.10
.O 5 . 8 .O7.Y ldecane
were assigned to them
(see Table 1).
[2] S. S. Hixsoii, P . S. Muriuno, and H. E . Zimmrrmunn, Chern. Ber. 73,
531 (1973).
[3] E . L. Allrrd (personal communication) and L. A . Puyireire (cf. M . J .
Wycrutr and L. A . Poyuettr, Tetrahedron Lett. 1974. 2433) have recently
obtained the (CH)," hydrocarbon ( Y ) indcpendently by different routes.
141 In accord with a proposal by Prof. W Walrer. Hamburg, we namc
this new (C H ) , o hydrocarbon "barertant.'since its molecular'shape IS reminiscent of a baretta.
[5] The ' C N M R spectrum was measured by Dr. S. Braun, Darmstadt.
161Prepared by catalytic hydrogenation ol pentacyclo[5.2.1 .0'~0.0J~q.04~8]decane. .I. E Rrrlilwin (Eugene, Oregon. USA), personal communication.
[7] A . T Bulabarl, Rev. Roum. Chim. I / , 1097 (1966): 17, 865 (1972): A .
L. Allred and B. R . B e d , J . Amer. Chem. Soc. 95. 2393 (1973).
Modified Horeau Analysis for Determination of the
Chiralityof Amines, Alcohols, and Carboxylic Acids[**]
By Hans Brockmann Jr. and Nikolaus RischL'1
(4) 9%
( 6 ) 5%
( 5 ) 6%
(9) 26%
(8)trace
(7) 3%
(10) 4 9 %
2 70
Table I . NMR spectra of ( 9 ) and ( 1 0 ) [a]
(T) in
CCla
Cpd.
'H-NMR
(9)
4.56 ( A ? part of an
A,X, system, H'. H")
7.1 1 (m, H S )
7.22 (m. H'. H')
7.84 (dt, H', H 3 )
7.99 (m, H i , H"')
8.79 (m. H')
(10)
7.13 (m, H ' , H', H S , H I o )
8.1 1 (m, H3, H a )
8.47 (m, H', H')
9.03 (m. H'. H9)
' T - N M R (6) [b] [ 5 ]
14.39
19.10
22.24
36.83
52.66
(d, C3, C8;
(d, C', C9;
(d, C', C';
(d, CS, C'O;
(d, C i , C':
Jl,c~~H1=179Hr)
Jiic~-tqi=163H~)
J1~-~1=183Hz)
Jiiri-~5=143H7)
Ji~-11>=149Hz)
[a] The assignment was confirmed by double resonance experiments.
[b] Relative to tetramethylsilane.
Although crystalline ( l o ) (m.p. 42°C) is a highly strained
molecule since it contains two bicyclopentyl units, it is nevertheless relatively stable thermally : no rearrangement could be
detected after heating a toluene solution for 5 h at 200°C.
Upon catalytic hydrogenation (10% Pd/C) (/O) readily took
up two moles of hydrogen yielding the known tetracy~lo[5.2.1.0~~~.0~~~]decane
(m.p. 158 "C), which was identified
by comparison of its characteristic NMR spectrum with that
of an authentic sample['].
664
Stereospecific reactions can be applied for correlation of configurations of chiral compounds if their course can be predicted
on the basis of empirical rules or theoretical considerations.
If the absolute configuration of one reactant is known, the
chirality.of a second can then be derived. Two procedures
based on this principle have proved of value for determination
of the configuration of secondary alcohols: the asymmetrically
induced synthesis ofatrolactic esters"], which can be described
by Ruch and Ugi's stereochemical analogy model[21,and the
method of partial kinetic resolution of bis-(2-phenylbutyric)
anhydride developed by Horeau13,41. Unfortunately Horeau
analyses cannot be applied to determine the configuration of
amine~[~l.
We replaced bis-(2-phenylbutyric) anhydride by 1-(2-phenyIbutyroy1)imidazole (1 ), which is easily accessible from 2phenylbutyric acid and N,N'-carbonyldiimidazole, and we
then found (Table 1) that its alcoholysis and aminolysis in
benzene or THF as solvent occurred with equal stereoselectivity. Although the new procedure-which can be carried out
with pure ( 1 ) or in a single vessel without intermediate isolation-requires longer reaction times for determination of the
chirality of alcohols and gives somewhat lower optical yields
than the conventional Horeau analysis, the stereoselectivity
in aminolyses of ( 1 ) is generally higher than in aminolyses
of bis-(2-phenylbutyric) anhydride (the optical yield in expt.
No. 6 of Table 1 amounts to 14 to 36"h depending on the
reaction temperatureI61).
( 1 ) can be easily prepared in high enantiomeric purity from
optically active 2-phenylbutyric acid and then used for
partial resolution of racemic alcohols and amides. If (-1)
is used for this purpose, the chirality ( 2 a ) of the residual
excess of compound ( 2 ) can be predicted.
,
["I
Dor. Dr. H. Brockmann and Dipl.-Chem. N. Risch
Gesellschaft fur Molekularbiologische Forschung mbH
33 Braunschweig-Stockheim, Mascheroder Weg I (Germany)
[**I This work was supported by the Technology Program of the Bundesministerium fur Forschung und Technologie and by the Fonds der Chemischen
Industrie.
Angew. Chem. internat. Edit.
1 Vol. 13
(1974)
1 No.
10
class Al'l], a description of the reaction course by Ruch and
Uyi's stereochernical analogy model[21seems to us to meet
as many problems as that of conventional Horeau analyses,
since the two diastereoisomeric products can be formed
through more than two corresponding transition complexes.
0
racem. ( I )
(2), X
I
= O H , NH2
Experirnerird:
NazCO,
"lo
0
Table 1 . Experiments for determination of the absolute configuration of
alcohol\ and amines Experiment? Nos. 1-3, 6 and 7 were carried out i i l x
with the enantiomers.
Cpd. studied ( 2 )
No.
( +)-x-Meth)lhenryl alcohol
( +)-l-(l-Naphth~.l)ethanol
( - )-Pinacolyl alcohol
1
>
3
4
5
6
7
(-)-Menthol
+ )-Testosterone
( + )-x-Methylhenr~laniiiie
(+)-l-(l-Naphthyl)ethyl~niine
L-Alanine ethyl ester
L-Leucine methyl ester
L-Tryptophan methyl ester
(
8
9
10
Signof
optical
rotn. of / 3 j
Ahs. confign
Found Lit
+
+
+
+
R
R
R
R
R
R
R
-
+
+
-
+
R
S
R
R
S
s [a]
s
s [a]
s [a]
R
R
s
s
[a] I t is assumed that the ethoxycarhonyl and methoxycarbonyl groups are
bulkier than CH, or (CH,),CHCH,. but less bulky than the indole group of
tryptophan
The acid (3) (328rng, 2mmol) is added to a suspension of
1,I'-carbonyldiimidazole(324 mg, 2 mmol) in anhydrous benzene (4ml) and the mixture is stirred at 22°C until evolution
of CO, ceases. Then the base ( + 5 ) (121 mg, 1 mmol) in anhydrous benzene(1 ni1)isaddeddropwise and thereaction mixture
is left for 15h at 22°C. The mixture is then separated by
repeated shaking between benzene (20ml) and 10% aqueous
NaOH solution (20ml), the aqueous phase is washed again
with benzene, acidified with SN HCI, and the (3) precipitated
is extracted in benzene. Evaporation of this solution after it
had been washed twice with water and dried over Na2S0,
yielded 140mg of ( 3 ) , [z]::~= 13.4' in benzene. Chromatography of the benzene phase on silica gel affords the mixture
of diastereoisomeric amides, whose isomer proportions were
found by 'H-NMR spectrometry to be 57 :43.
Received: July 15, 1974 [Z 73 I € ]
German version: Angew. Chem. 86. 707 (1974)
CAS Regiatry Numbers:
( f ) - / / I : 52699-46-4
( -)-2-(N-carharolyl)propioiiicacid. 52730-59-3
[ I ] C: Prdoy. Bull Soc. Chim. Fr. 1956. 987.
[2] E. Rirch and 1. Lyi. Top. Stereochem. 4. 99 (1969).
[3] A. Horrriir, Tetrahedron Lett. 1961, 506: IY62, 965.
[4] A. Horrrrir and H . Kayofi, Tetrahedron 10. 2431 (1964).
[5] H . Bi-whriiuu~ij r . and J . Bode. Liehigs Ann. Chem. 748, 20 (1971).
[b] Lowering the reaction temperature lowjers the reaction rate hut increases
the stereoselectivity. The optical yield of 36 ",) is achieved at - 22°C.
0
Crown Ethers as Catalysts in Reactions of Carbanions
and Halocarbenes'']
(20)
r a c e m . (2)
(-1)
Finally, the imidazole procedure permits determination of
the configuration of chirdi carboxylic acids: thus if an excess
of racemic ( 5 ) is allowed to act on an optically active l-acylimidazole ( 4 ) , the sign of the optical rotation of the residual
amine can be used to decide the configuration of the carboxylic
acid used, as shown in the formulas (cf. Table 2).
(4)
racem. (5)
(-5 )
Table 1. Experiment5 for determination of the absolute configuration of
carboxylic acids by way of their imidazolides / 4 ) .
No
Acid studied
Sign. ofopt.
rotn. of (5)
Ahs. confign.
Found Lit.
1
( - )-2-Phenylhutyric
( - )-Hydratropic
( )-0-Acetylmandelic
( - )-2-(9-Carhazolyl)propionic
-
R
R
7
3
4
+
R
+
R
R
R
-
S
9
-
Although the reagent ( I ) used by us and also the imidazolides
( 4 ) of the carboxylic acids listed in Table 2 belong to chirality
.Angew. Chem. internat. Edit. J Vol. 13 ( l Y 7 4 ) 1 No. 10
By M . MGkosza and M . Ludwikow"'
Catalytic reactions of carbanions and halocarbenes in twophase liquid systems have become important and versatile
tools in organic synthesis in recent years. Suitable catalysts
for these reactions are quaternary ammonium[2,31 and phosphonium compounds[']. The decisive reaction step is the formation of ion-pairs of the type > k A 0 (where A0 =carbanion), which are soluble in the organic phase where they
undergo further transformations with simultaneous liberation
of the quaternary ammonium ions[51.The organic "onium"
cations can be substituted to some extent in these reactions
by inorganic cations (Na@or K @ )when the latter are strongly
solvated or cornplexed.
Among the most powerful cornplexing agents for alkali metal
ions are the crown
As we have found, many two-phase
reactions of carbanions and halocarbenes can be effectively
catalyzed by crown ethers, especially dibenzo[ 18lcrown-6 ( 1 ).
Addition of only a small amount of ( I ) (1 mol-'%,)to a twophase system consisting of C-H acid (with or without organic
solvent) and concentrated aqueous NaOH solution results
in formation of Na[crown ether]@ carbanione ion-pairs,
which are soluble in the organic phase where they undergo
further transformation.
[*] Doz. Dr. M. Makosza and Dipl.-Chem M. Ludwkow
Institute of Organic Chemistry and Technology,
Technical University (Polytechnika).
PL 00-662 Warsaw (Poland)
665
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