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Reactions of tricyclohexylboron with nitrosyl compounds.
Tetrahedron LettersNo.12,pp, 755-756, 1965. PergamonPreer Ltd. Printedin GreatBritain.
REACTIORS OF T'RICICLOHEXYLRORON WITH NITROSIL COKPOURDS.
Zen-ichl Toshida Department of Synthetic Chemistry,Kyoto Uairereity, Ioshida, Kyoto, Japan. Tsuaeo &uehi, Osamu Manabe and Rachiro Riyama The Oseka Municipal Technical Reeearch Institute,Osaka, Japan.
(Received2 February1965)
Very few rorke (1) hare been reported on the
reaction6
of tri-
alkylborons with aitroeylcompounde,detaile of which are, therefore etill unknom. We now report the reactions of
tricyclohexylboroawith aitroeyl-
sulfuric acid and aitroeylchloridein sulfuric acid. In this reaction eereral kinds of products, which may be explicable in terms of prior aitrosatioa at the a-carbon of
the cyclohexyl
group and subeequeut reactions, were obtained, e.g., E-caprolactam, etc. A8 a typical cyclohexaaoaeoxime, cyclohexylhydroxylamiae, example, nitroaylsulfuricacid
(14.7
g)
uao added to a mixture of
tricyclohexylboroa(10.0 g) (2) and aulfurlc acid (60 ml.) at room temperature
with etirriag and in an atmosphere of nitrogen. The
temperaturewae gradually raised to 50°, and kept for
five
hours at
this temperature. After the end of the reaction, the product wae cooled to room temperatureand filtered under nitrogen. White
753
No.12
754
crystals
of unreacted
tricyclohexylboron
(2.45 g) mere recovered.
The filtrate rarr poured into ice mater with sufficient In a couple of minutes brown cryntala to
identified
stirring.
(5.25 g) came out, and mere acid (m.p. 53-54.!j”)
be dicyclohexylborinic
(3).
After (separation of the acid, the filtrate was carefully neutralized below
loo with an aqueous
eolution
Thin solution maa extracted with
and then made slillhtly alcaline. chloroform,
which on evaporation
(50 %) of sodium hydroxide
gave a brown liquid of high boiling
point. It wae found by WC hydroxylanine
analysis
that the liquid contained oxime (0.36
(0.24. g), cyclohexanone
(0.99 g), and small amounts of dicyclohexylamine (Fractional
distillation
g),
cyclohexyl
e-caprolactam
and dicyclohexyl.
of the liquid gave cyclohexanone
oxime and
E-caprolactam.) In another
experiment at 8W,
solvent in place of chloroform.
ether maB used as an extracting After evaporation
there mae also obtained yellow liquid of cooling the liquid separated
naa aubdtted
addition
to cyclohexylhydroxylamine
hexanone
oxime, dicyclohexylamine
On
(0.1 g) as
to WC
analysis.
In
(0.8 g), small amounts of cycloand dicyclohexyl
were obtained.
with the result in the reaction at 50° the amount of
cyclohexylhydroxylamine decreased.
high boiling point.
cyclohexylhydroxylamine
crystals, and the liquid portion
In coapariaon
of the ether,
The yield of
ras increased e-caprolactam
while that of dicyclohexylamine was very low.
Since it is
No.12
755
already kmowa bl our own experimenta (4) that dicyclohexylaminocan bo obtained by the reaction of tricyclohexylboronwith nitrosooyolohexame in tetrahydrofuraaat se
for 5 hour+ while, if tbir reaction is
carried out in n-hoxamo, both cyclohexylhydroylamineamd cyclohoxono are obtelned, the formation of dicyclohexylemineand cyolohexylhydroxylamiae in the pre8ent reaction maj Noimq
+
Cg",,*O +
(e6H7$3B --+C6HJ?0 (C&)$
+
@&,)3B
+
interpreted 88 followo: (C6H,1)2BH804
-C6H~,NHOB(C6H,,)2
C&"HOE C&"O
be
--+
+
(11 (11)
C6H,0
1 B20 + qi,,)230H 0111
(C6B,,)2ROB~C&)2 2t$jqjB,
1 (C6H,,)21H +
a20
3(C6B,,)2BOl!*
C&-C6H,,
In aulfnrit acid a8 oolvent, both reaction8 (11, III) ownred, eowurrently, and hi&
teaporatubs (8~. 90*) may be faroreble to the
reaction (11). The foraation of e-crprolrotu is very easy &and.
Nitroeocyclohexameproduced say
spanding
oxhe,
br
converted
to
the
to under-
~orre
which them undergoes Beckmum rearrangarentto &te
the lrctm.
u
c_> (CH2f3
1110
With the we
---+
ROH +
GONE
(IV)
of nitroeyleblorid~am nitroeyl aompouad, tricyclo-
hexylboroa pre kaitrosodicyelohexyluiineend
f-caprolactu.
?ormation of these compounds may be bxplainrdl m followa:
No.12
756
mm1
+
-
(c&)9
exceee
(C#,,)ZI*~
C6H,,Y0 +
llOC1
(C6H,,)2BC1
$ (C&)$fH
t---
1. H. C. Brown, n&droboration'l.W. A. Benjamin Inc., lie8York (1962). 1. (ierrard,"The Organic Chemietry of Boroan, Academic Reee, London (1961). Il.1. Lappert, "Orxanio Compounds of Boron", Chem. Revs., 2, 2.
959 (1956).
H. C. Brown and B. C. Sabba Rae, J. Amer. Chom. Boo., &,
6428
(1959). 5.
Von H. Hartmann and I.
H. Birr, 2. Anorn.
Allrem. Chem., a,
174 (1959). 4.
Z. Ioclhida,T. &uehi,
0. Manabo and H. HiJama, unpublished.
REACTIORS OF T'RICICLOHEXYLRORON WITH NITROSIL COKPOURDS.
Zen-ichl Toshida Department of Synthetic Chemistry,Kyoto Uairereity, Ioshida, Kyoto, Japan. Tsuaeo &uehi, Osamu Manabe and Rachiro Riyama The Oseka Municipal Technical Reeearch Institute,Osaka, Japan.
(Received2 February1965)
Very few rorke (1) hare been reported on the
reaction6
of tri-
alkylborons with aitroeylcompounde,detaile of which are, therefore etill unknom. We now report the reactions of
tricyclohexylboroawith aitroeyl-
sulfuric acid and aitroeylchloridein sulfuric acid. In this reaction eereral kinds of products, which may be explicable in terms of prior aitrosatioa at the a-carbon of
the cyclohexyl
group and subeequeut reactions, were obtained, e.g., E-caprolactam, etc. A8 a typical cyclohexaaoaeoxime, cyclohexylhydroxylamiae, example, nitroaylsulfuricacid
(14.7
g)
uao added to a mixture of
tricyclohexylboroa(10.0 g) (2) and aulfurlc acid (60 ml.) at room temperature
with etirriag and in an atmosphere of nitrogen. The
temperaturewae gradually raised to 50°, and kept for
five
hours at
this temperature. After the end of the reaction, the product wae cooled to room temperatureand filtered under nitrogen. White
753
No.12
754
crystals
of unreacted
tricyclohexylboron
(2.45 g) mere recovered.
The filtrate rarr poured into ice mater with sufficient In a couple of minutes brown cryntala to
identified
stirring.
(5.25 g) came out, and mere acid (m.p. 53-54.!j”)
be dicyclohexylborinic
(3).
After (separation of the acid, the filtrate was carefully neutralized below
loo with an aqueous
eolution
Thin solution maa extracted with
and then made slillhtly alcaline. chloroform,
which on evaporation
(50 %) of sodium hydroxide
gave a brown liquid of high boiling
point. It wae found by WC hydroxylanine
analysis
that the liquid contained oxime (0.36
(0.24. g), cyclohexanone
(0.99 g), and small amounts of dicyclohexylamine (Fractional
distillation
g),
cyclohexyl
e-caprolactam
and dicyclohexyl.
of the liquid gave cyclohexanone
oxime and
E-caprolactam.) In another
experiment at 8W,
solvent in place of chloroform.
ether maB used as an extracting After evaporation
there mae also obtained yellow liquid of cooling the liquid separated
naa aubdtted
addition
to cyclohexylhydroxylamine
hexanone
oxime, dicyclohexylamine
On
(0.1 g) as
to WC
analysis.
In
(0.8 g), small amounts of cycloand dicyclohexyl
were obtained.
with the result in the reaction at 50° the amount of
cyclohexylhydroxylamine decreased.
high boiling point.
cyclohexylhydroxylamine
crystals, and the liquid portion
In coapariaon
of the ether,
The yield of
ras increased e-caprolactam
while that of dicyclohexylamine was very low.
Since it is
No.12
755
already kmowa bl our own experimenta (4) that dicyclohexylaminocan bo obtained by the reaction of tricyclohexylboronwith nitrosooyolohexame in tetrahydrofuraaat se
for 5 hour+ while, if tbir reaction is
carried out in n-hoxamo, both cyclohexylhydroylamineamd cyclohoxono are obtelned, the formation of dicyclohexylemineand cyolohexylhydroxylamiae in the pre8ent reaction maj Noimq
+
Cg",,*O +
(e6H7$3B --+C6HJ?0 (C&)$
+
@&,)3B
+
interpreted 88 followo: (C6H,1)2BH804
-C6H~,NHOB(C6H,,)2
C&"HOE C&"O
be
--+
+
(11 (11)
C6H,0
1 B20 + qi,,)230H 0111
(C6B,,)2ROB~C&)2 2t$jqjB,
1 (C6H,,)21H +
a20
3(C6B,,)2BOl!*
C&-C6H,,
In aulfnrit acid a8 oolvent, both reaction8 (11, III) ownred, eowurrently, and hi&
teaporatubs (8~. 90*) may be faroreble to the
reaction (11). The foraation of e-crprolrotu is very easy &and.
Nitroeocyclohexameproduced say
spanding
oxhe,
br
converted
to
the
to under-
~orre
which them undergoes Beckmum rearrangarentto &te
the lrctm.
u
c_> (CH2f3
1110
With the we
---+
ROH +
GONE
(IV)
of nitroeyleblorid~am nitroeyl aompouad, tricyclo-
hexylboroa pre kaitrosodicyelohexyluiineend
f-caprolactu.
?ormation of these compounds may be bxplainrdl m followa:
No.12
756
mm1
+
-
(c&)9
exceee
(C#,,)ZI*~
C6H,,Y0 +
llOC1
(C6H,,)2BC1
$ (C&)$fH
t---
1. H. C. Brown, n&droboration'l.W. A. Benjamin Inc., lie8York (1962). 1. (ierrard,"The Organic Chemietry of Boroan, Academic Reee, London (1961). Il.1. Lappert, "Orxanio Compounds of Boron", Chem. Revs., 2, 2.
959 (1956).
H. C. Brown and B. C. Sabba Rae, J. Amer. Chom. Boo., &,
6428
(1959). 5.
Von H. Hartmann and I.
H. Birr, 2. Anorn.
Allrem. Chem., a,
174 (1959). 4.
Z. Ioclhida,T. &uehi,
0. Manabo and H. HiJama, unpublished.