Патент USA US2610977

2,610,969
ii’atented Sept. 16, 4.1952
UNITED ,sTA-TEs
i
. 2,610,969
PRODUCTION or 111mm. PYRAZOLINES
mi. Dam main and George Frank Du?m'.
'Ilford, England,_ assignors to Ilford‘ Limited,
I‘lford, England, a British company -
- No Drawing. Application May 29, 1950, Serial No.7,
>
- a 165,117. In Great Britain June 3,1949 '
_ 30mins‘. (crate-731p);
solved in 2.5 parts‘ byfvolume ‘of concentrated hy
drochloricacid and 2.5 parts‘ of'water. cooled to
I > This invention relates to the production of di
arylpyrazolines,
.‘1
,'
'
.
.
. If a‘ l-‘aryl'pyrazoline is-ooupled in acidsolu
tion with a diazonium salt of an aromatic amine,
an azo dye is obtained and this is believed to be a
3-arylazo-l-arylpyrazoline. It has now been dis
covered, however, thatii the reaction is carried
out in a basic medium the main product formed
is a 1:3-diaryl pyrazoline.
According to the present invention, therefore,
5° C. and diazotised by the addition of an aqueous
solution of. 0.7 .part by weight‘of sodium nitrite.
The solution was added to‘a vstirred solutionof 1.6
parts by weight of '1;-m-.tolyl_ pyrazoline in 10
parts by ‘volume of pyridine.‘ After standingvfor
onehour the mixture was diluted with 100 parts
oflwaterf and the solid‘removed by ?ltration; The
productjwas puri?ed by recrystallisation from
methyl _ alcohol to give yellow plates. , M. pt.
a process for the production of 1:3-diaryl pyraz
olines comprises reacting in a basic medium a
l-aryl pyrazoline with a diazonium salt prepared
from a primary arylamine. Conveniently the re
action may be effected in aqueous pyridine or al
coholic alkali.
‘
;
'
The reaction is‘somewhat surprising since'azo
dye formation u'suallyoccurs when azo‘ dye com
ponents are coupled‘in alkaline media.
.
The process of the present invention is believed
to follow the equation:
CH2
illryll
120°
C.‘
'
'
>
EXAMPLEG'
p
l
'
.
,
‘
j
,
‘ Preparation of 3ephenyl1+(m-tolyllpwazolia
~,1.1,8 parts by volume of anilinewere dssolved
in 3 parts by volume of concentrated hydrochloric
acid and 3 parts of water, cooled to 5° C., and di
azotised by the addition of an aqueous solution of
0.93 part by weight of sodium nitrite. This solu
tion was added to a stirred solution of 2.00 parts
by weight of l-m-tolyl pyrazoline in 14 parts by
volume of pyridine while maintaining the tem
perature between 0° and 5° C. After standing for
CH2
one hour the mixture was diluted with 100 parts
of water when a reddish oil was precipitated. The
Aryll
oil solidi?ed on treatment with methyl alcohol
and the solid was recrystallised from methyl al
cohol to give yellow crystals. M. pt. 885° C.
V and the nitrogen can be observed to bubble away
from the reaction mixture. In the foregoing 30
EXAMPLE 4
formulae the aryl groups may be, for example,
Preparation
of
I-phenyl
3-(m-tol1/Dpyrazolme
phenyl or naphthyl groups, or aryl groups carry
ing alkyl, aralkyl, aryl, nitro, alkoxy, hydroxy,
1.09 parts by volume of m-toluidine were dis
‘ hydroxyalkyl, carboxylic or sulphonic groups, or
solved in 2.5 parts by volume of concentrated hy
halogen atoms. The aryl group in the l-posi
drochloric acid and 2.5 parts of water, cooled to
tion can also be substituted by amino or sub
5° C. and diazotised by the addition of an aqueous
solution of 0.‘? part by weight of sodium nitrite.
stitutedamino groups.
‘
The acid HX is absorbed by the basic medium
The following examples will serveto illustrate
the invention:
The solution was added to a stirred solution of
1.48 parts by weight of l-phenyl pyrazoline in 10
parts by volume of pyridine. After standing for
'
EXAMPLE 1
Preparation of 1:3-diphenyl pyrazolme
one hour the mixture was diluted with 100 parts
of water and the solid removed by ?ltration. The
0.93 part by weight of aniline was dissolved in
2.5 parts by volume of concentrated hydrochloric
product was puri?ed by recrystallisation from
M. pt.
methyl alcohol to give yellow crystals.
acid and 2.5 parts of water, cooled to 5° C. and 45
diazotised by the addition of an aqueous solution
of 0.7 part by weight of sodium nitrite. The
77° 0.
solution was added to a stirred solution of 1.45
Preparation of i-phenyl 3-(p-bromophenyD
EXAMPLE 5
parts by weight of l-phenyl pyrazoline in 10 parts
by volume of pyridine while maintaining the tem 50
perature between 0° and 5° C. After standing for
one hour the mixture was diluted with 100 parts
pyrazoline
.
3.42 parts by weight of p-bromoaniline were dis
solved in 5 parts by volume of concentrated hydro
of water and the product removed by ?ltration.
It was puri?ed by recrystallisation from ethyl
alcohol to give very pale yellow needles. M. pt.
chloric acid and 10 parts of water, cooled to 5° C.
and diazotised by the addition of an aqueous solu
152° C.
solution was added to a stirred solution of 2.9
EXAMPLE 2
Preparation of 1 :3-di- (m-tolyl) pyrazoline
1.09 parts by volume of m-toluidine were dis
tion of 1.4 parts by. weight of sodium nitrite. The
parts by weight of l-phenyl pyrazoline in 20 parts
by volume of pyridine while maintaining the tem
perature between 0° and 5° C. After standing
60 for one hour the mixture was diluted with 200
2,610,969
parts of water and the solid removed by ?ltra
tion. The product-was puri?ed‘by-recrystallisae
tion from-methyl alcohol to give small light yel
low plates. M. pt. 130° C.
EXAIVIPLE 6
Preparation of I-phenyl S-(p-suZphopIienyDpy- _
razoline'
1.73 parts by weight of sulphanili'ci acid'vwerer
dissolved in 2.5 parts by volume of concentrated‘v
hydrochloric acid and 5 parts of? water; cooled-to;
5° C. and diazotised by the addition-ortin-aqueousR
4
and are of use where compounds having such
properties; are of .value, e. g.; as textile‘; whitening
agents’ as described in- co-pending application
Serial No. 165,116 ?led on even date herewith.
What we claim is:
1. Process» for the production of 1:3-diaryl
pyrazolines which comprises reacting in a basic
mediumi'a; 1_-aryl:pyrazoline wherein the 3-posi
tion- is‘ unsubstituted, with a diazonium salt of a.
. primary arylamine:
2: Process: for the production of 1:3-diaryl
pylazolines, which comprises reacting in aqueous
solution of 0.7 part by weight of sodium- nitrite; - _ pyridine a l-aryl pyrazoline wherein the 3-posi
This solution was added'with stirring to a solu
tion- is~ unsubstituted. with a diazonium salt of
tion-oi 1.46 parts of l-rphenyl pyrazoline‘ in .10
parts; by volume of, pyridine: while“ maintaining
the temperature between'ftrf and"? CI A?’er
standing. one 110111",t11'e mixture was". diluted ‘with
a primary arylamine.
3lzProcessz for‘ tliezproductiomot: lz?sdiaryl
pyrazolines which comprises reactingi'imthepreae
ence;ofialcoliolicalkaliza,learylrpymwlinewhere
imthe ‘3epositi0n'. issunsubstitutedi. with; a" dine
by volume‘ of‘ concentrated; hydrochlori'o'aeid. 20 zoniumasalti of sriprimary'arylaminezp
strong, salt" solution was~ then. added" when a; yel
low‘ solid was precipitated? The~ mixture‘: was
GEORGE‘FRANK,DUFFIN:;
JOHNTDAVID
cooled in‘ ice, ?lteredlan‘d' the‘ solid, washed‘ with
water; The: product was ?nally? puri?ed‘ by'rea
crystallisation‘ from. water. containing :som‘eiani
R-EFERENGES: CITED‘ I
mal charcoal to givev small buiT-colouredlpl‘ates;
The following’ references‘ are of record? inl the
M. pt. 300° C.
?le oft-his patent‘: '
e
'
The 1:3-diaryl pyrazolines: produced by the
50 ' parts‘ of ‘water; stronglyacidi?ed'with 20*parts
process of thisinventionare in many- cases. en
Chem; Abstl, vol"; 32,: p.. 1667?.“ (1‘938)1',_ citing
tirel'y new compounds, and’ such new‘ compounds 30 Jacob etall, Jr..Chem.. Society-- (liond'omi 1937,
pp. 1929-1931;
~
1
,
per‘ se' form part of this invention.- In: general
Chem.
Abstm
vol.
41,
p.v1221,wcitihg41’ani_zzi
the‘. compounds‘ exhibit? 'a- strong" violet; or; lilue
Gazz. Chim. ital‘ 73L .pp..3'35.'-343T'( 195101,
?uorescence'in; daylightl or: ultras-violet lights-mi
a1 lesser“ ?uorescence? in oniinameiect'nlcl light,
Beil'stein,_Vierte Au?auge, I-l'andliucli den Qr
ganischen Chemie,‘ voll. 23,. pp.- 153 andi16'8‘.