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Diethylselenothiophosphinic Acid Derivatives.

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triaza-2,5-diborolidine (2), R2 =. C6H5, R3 = CH3, b.p.
180-182"C/3 mm, m.p. 106-108°C (sealed tube, uncorrected), precipitates out on cooling. Concentration of the
mother liquor yields a second crop of crystals; the overall
yield is about 85 %.
appear to be stable to heat.
For example, when (2), R2 = C6H5, R3 = CH3, is heated to
225 'C in vncuu, no signs of decomposition are found. This
behavior seems to indicate the existence of resonance stabilization of the ring by participation of BN double bonds.
This assumption is supported by the presence of a peak in
the infrared spectrum of (2) near 1400 cm-1; this region is
normally assigned to BN double bonds [3]. In addition, the
chemical reactions of (2), e.g. with metal carbonyls, indicate
a strong similarity between triazadiborolidines and the
cyclopentadiene system.
However, the heterocycle (2) is not stable t o hydrolysis.
Traces of moisture first attack the B-N-B bridge to yield
202-204 "C [4]; this is followed by ring cleavage to afford
dihydroxyphenylborane and N,N'-dimethylhydrazine.
Received, April 2nd and 27th, 1964
[ Z 730/556 IE]
German version: Angew. Chem. 76. 535 (1964)
[ I ] H. Noth and W. Regnef, 2. Naturf. I86, 1138 (1963).
[2] H. Jenne and K . Niedenzu, Inorg. Chem. 3, 68 (1964).
[3] G. M. Wyman, K . Niedenzu, and J. W. Dawson, J. chem. SOC.
(London) 1962,4068.
[4] A melting point of 204 "C is given by [I].
Diethylselenothiophosphinic Acid Derivatives
By Doz. Dr. W. Kuchen and Dip].-Chem. B. Knop
Institut fur Anorganische Chemie und Electrochemie
der Technischen Hochschule Aachen (Germany)
Sodium diethylselenothiophosphinate ( l a ) has been obtained
both in the fused state according to the equation:
(ClHs)>P(S)-P(S) (C2HS)Z
+ NalSe + Se ~--+
2 h
2 (CzH&P(S)SeNa
crystalline product, m.p. 56.5 "C, which is formed in water
by the reaction:
is most probably bis(diethylselenophosphoryl)disulfane, especially since the infrared spectrum of the yellow compound
in the KBr region is practically the same as that of
Diethylselenothiophosphinicesters, e. g. ( C ~ H ~ ) Z P ( S ) S ~ C ~ H %
b.p. 135 "C/lO mm, n'," = 1.5854, and ( C ~ H ~ ) Z P ( S ) S ~ - ~ - C ~ H ~ ,
b.p. 86-87 0C/0.06 mm, n'," = 1.5738, were obtained smoothly
by refluxing (Ib) with alkyl bromides.
(C2Hs)2P(S)SeNa2H 2 0
+ RBr
+ (CZH&P(S)SeR
+ NaBr
The structures proposed for the esters are supported by the
separation of diethylphosphinothioic bromide from the
products of the reaction of any one of them with 1 mole of
bromine, the main reaction probably being the following:
+ Br2 + (C*HS)P(S)Br + RSeBr.
Compound (Ib) reacts with metals t o form non-electrolytic
inner complexes of the type:
( C : , I I ~ ) ~ P hl!n
e. g . bis(diethylselenothiophosphinato)zinc(II), m. p. 157 'C;
-cadmium(lI), m. p. 160O C ; -nickel(Il), olive-green, decomp.
> 142 OC; -lead(II), green-yellow, m.p. 132°C; orange-red
tris(diethylselenothiophosphinato)bismuth(III), m. p. 94 "C.
The zinc and cadmium complexes, like the corresponding
dialkyldithiophosphinato complexes ( 4 ) of these t w o metals,
are associated in benzene [3]. The thermal and chemical
stabilities [3] of the compounds (4) are not attained by their
seleno analogues.
Received, April 13th, 1964
[ Z 726/553 IEI
German version: Angew. Chem. 76, 496 (1964)
[I] W. Kuehen, K . Strolenberg, and J. Metten, Chem. Ber. 96
1733 (1963).
[2] According to M . J. Kabachnik, T. A . Mastrukova, A . E. Shipov, and T . A . Melentyeva, Tetrahedron 9, 10 (1960), the analogous acid (CzH&P(S)OH occurs in aqueous alcoholic solutions
almost completely in the thiono form. The negative charge is
thus, as would be expected, located almost exclusively at the
more electronegative atom.
[3] W. Kuchen and J. Metten, Angew Chem. 72, 584 (1960); W.
Kuchen, J. Metten, and A . Judat, Chem. Ber., in the press.
and in absolute alcohol by the reaction:
It was isolated as its crystalline dihydrate (C2H5)2P(S)SeNa.
2H20 ( I b ) , m.p. 124-125OC. This is isomorphous with
(CzH&P(S)SNa,2HzO [I], which also melts at 124-125 "C.
Aqueous solutions of diethylselenothiophosphinic acid
(C2H&P(S)SeH (2) were obtained from ( I b ) using a
strongly acidic cation exchanger (Ionenaustauscher I, from
E. Merck, Darmstadt, Germany). The acid gradually decomposes on standing for a few hours at room temperature
in diffuse daylight, its solutions turning yellow.
The anion (3) derived from the thiol form of (2) according
to the equilibrium
+ (GH&P(Se)SQ
is presumably practically the only species present in aqueous
solutions of ( I b ) and (2) [2]. Hence the intensely yellow,
Atigsw. Chem. internat. Edit./ Vol. 3 (1964) / NG.7
Benzo[a]quinolizinium Salts from 3,4-Dihydroxyphenethylanline Hydrobromide and Acetoacetaldehyde, a Possibly Biogenetic-Type Cyclization
By Prof. Dr. H. J. Teuber and Dip1.-Chem. D. Laudien
Institut fur Organische Chemie der Universitlt
Frankfurt/Main (Germany)
3,4-Dihydroxyphenethylamine (dopamine) hydrobromide
reacts in hot glacial acetic acid with 2 moles of either acetoacetaldehyde dimethylacetal or l-methoxy-l-buten-3-one,
analogously to tryptamine [l], to yield 40 % of the benzo[a]quinolizinium salt ( I ) and 31 % of the pyridinium salt (2)
[2]. In aqueous solution at 20"C, only about 13 % of (1) is
obtained. Product ( I ) can be separated from (2) as a red
anhydro base C16H15N03.
Pure ( I ) was characterized as its oxime, 2,4-dinitrophenylhydrazone, and diacetyl derivative as well as by the mono-
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acid, derivatives, diethylselenothiophosphinic
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