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Patented Sept. 17, 1946
.
2,407,672
UNITED STATES PATENT, OFFICE‘
PROCESS FOR THE SYNTHESIS OF l-ALKYL
S-METHYL HEXAHYDROINDANONE-4 I
Nicholas A. Milas, Belmont, Mass, assignor to
Research Corporation, New York, N. Y., a cor
poration of New York
e
No Drawing. Application June 20, 1941,
Serial No. 399,040
10 Claims. (Cl. 260—468)
.
1.
.
2
In the synthesis of the antirachitic vitamins,
the ketone Compound I constitutes an important
intermediate product. The ‘present invention
V
Compound III is then alkylated to give Com
pound IV by heating it for several hours with 6
methy1-2-br0m0 0}‘ iodoheptane in the PI‘eSenCe
deals with a new process for the synthesis of this . of Sodium potasslum alloy 01‘ DOtaSsium. metal
ketone_
5 using a solvent such as toluene or xylene;
CH8
'
R H
H:
l/
10
o
o
/7\ /1\
H206
80
I
Compound III+
I
9
'
3
H
\
H:
0
‘
H
2r \
.
CH3
--d
Na-K or K sand H20
heat
15
.011,
‘ HawH]
(toluene or xylene)
H
.
/CH1
H?C5\4/C\——'CHI
(1?,
CH:
(lam
I—C—[CH2]a-CH
.
2011,
I
I
,
/ \
,I
‘
7
l
‘
,
O—-C 0 0 02H;
I
H2O
~.
CH:
‘
0:0
Compound IV
0
.
‘d1
'
compo“
When Compound IV is re?uxed with sodium
20 ethylate, the cyclopentanone ring opens and sub-i
‘
‘
‘
sequently closes again but in a different fashion
Although R preferably is the hydrocarbon sidechain .found in the natural antirachitic vitamins,
it is not restricted thereto but may be hydrogen
to produce Compound V.
‘
or any other monovalent aliphatic hydrocarbon .25
radical.
"
i
i
‘
(EH3
'
/CH’
H_'CI1"[CH11i‘-CH
The present process makes use of the well
0-H
known diethyl adipate, Compound II, or any
oompmmdw N29?“
other suitable ester of adipic acid. Through the 30
heat
well known process of cyclization with metallic
sodium or sodium ethylate in a suitable solvent, ~
CH:
Hzo/ \G=0
H (\J
(|3_O 0.00 H
’ ‘I’ \
‘
‘Compound 11 is converted to z-carboethoxy cy-
' “
H
‘
CompoundV
clopentanone-l, Compound III.
35
That Compound V is actually produced may be
(‘300mm
.
on,
(13H!
°’ N“
which is not given by Compound IV because the
/C\ /H
H’);
C°mP°m1d H
latter contains no active enolyzable hydrogen
c-coocim
40 atom.
7 (‘3:0
CH2
CIwOCZHB
shown by the positive ferric chloride reaction
H;
Naoczm
mo
CH”
-
‘
O°mP°Imd m
_‘
j
,
Compound V can also be prepared {by hydro
k
lyzing Compo'und‘IV with hot dilute sodium eth
' iylate orbarium hydroxide to give the open chain
dicarboxylic. acid Compound VI which upon es
45 teri?cation and subsequent cyclization in the
2,407,672
3
4
,
presence of sodium or sodium ethylate is easily
Compound XI is then treated with oc-bI‘Ol’i’lO or
chloro glutaric diethyl ester in the presence of
amalgamated zinc to give Compound XII.
converted to Compound V.
0003
CH:
H
g
H-C—~C-—[CH2]a—-C
(UV NaOCzHKdil.)
CH3
CH3
0
Ompoun
or BMOH)a
H2
(Aq') he“
(5H,
‘
5
00002115
Compound XI + Br-CH
CHE-CHPCOOCHH}
—->
OH:
('30 OH ‘
10
Zn
followed by hydrolysis
Compound VI
(‘7H5
The diethyl ester of Compound VI has also
been prepared by an alternative route through 15
the reaction of a-bI‘OIllOELdiPiC ester, Compound
\O,
VII, and methyl isohexylketone, Compound VIII,
/ \
in the presence of zinc dust or wool and subse-
0
H
a Zn dust
(CH3)2C~[OH2]— =0 —*
0000 H,
H20
quently reducing catalytically the Compound IX.
COOCzHt
/CH3
HO—[OHzlaOH
H
QH
CH3
z ‘
C—<'3—CHZ—CHQOOOCZHH
H
20
rCH
|
00002115
.
____
H”
C
,
CHg-CHg-CHn-COO‘CnH;
or wool
00002115
ZI1_d--t-»
I15 01‘ W00 1
Compound VIII
_)
(in benzene 'or toluene + heat)
25
Compound VII
Compound XII
7
00062115
This product, Compound MI, is easily dehy
drated by heating with small amounts of iodine
COOCBHE
CH3
CH3 .
/.CH3
C=C—'[CH¢]3—'CH
H,
0
‘I
CH’ 30 or p-toluene sulfonic acid to give Compound XIII.
.H —g—[GH¢]a~0
-
Ni or Pt"+ H», I' H
\CH8
.
'
cm
I
Compound XII
CH3~CH2—C 0 0 03H‘;
CHz-CHg-Z O'C’Hg
d_ th 1 t
.
16
Compound IX
0
’
'
-->
01‘ p-toluene
f
35
sulfonic acid
85 BI‘ 0
y
VI
°mp°und
(‘3H3
_
When Compound V is treated with magnesium
H
in ethyl alcohol .or with sodium ethylate, the
mag'nesio or sodio salt, Compound X, is formed 40
which reacts with ethyl chloroformate to give
Compound XI.
Compound V +
\OH
\v
0
11,0
‘
00002115
C=C_CH2CH2_COO 0,115 ‘
Mg
C O 0 02115 _
——>
'or, NaO CaHa
H20
(IJHB
(‘3H3
E—(|l-[CH¢]3CH(CH;):
/CH3 45
H-C
(3:0
11,0
ClCOOCzHs
00002115
c°mp°und XIII
CH;
1
0:0
'
,
H1C—(13—C°OC1H6
\
HC-(CHDaCE
H—/-C_
m0
/CHa
tic-{onion
Compound XIII is then hydrolyzed with alco
‘0 00 C ‘H 50 holic potash, and the tetracarboxylic acid, Com
2 5
pound XIV, formed is decarboxylated by heating
Ric-“4*
13; (Na) ‘
2
with copper powder under reduced pressure to
0000,13,
form Compound XV, in which the double bond
has rearranged ‘to conjugate with one of the car
Compound XI
CompoundX
55 boxyl groups.
(I311:
H(|3—-[CHz]aCH(CH3)z
H-C
'
alcoholic
Compound XIII
——-0
heat
H2O
potash
C=C——CH1—CH1—COOH
.
—->
Cu powder
7
COOH
H20———-—C—COOH
coon
Compound XIV
(‘111:
CH;
HC-{CH?aCHwHah
1|
11-0
/ \
H3O
vC--C1I2—CH:—CH3C00H
H —[CH1]aGH(CHa):
Esterify
l
—--——v
-
'
—C
acid catalyst
/ \
H3O
l
C—CH2—CHn-~CHz-—C'OOC:H5
H2O—C——C O 0 02H,
Compound XVI
2,407,672
5
Compound XV can easily be esteri?ed with
absolute alcohol in the presence ‘of an acid cat
alyst and'the resulting Compound XVI cyclized
according to the method of Dieckmann using
formed, which latter, upon‘ heating- with copper
powder, goes over easily‘to CompoundXXII '
treatment with methyl magnesium iodide gives
Compound I, the desired product, by a 1,4-addi
/
CH;
\
by acid- 11:0
i?catiou
‘
H;
——-b
followed
L
'
V
. .
C-‘-COOH
‘
|
heat
——»
Cu
powder
‘
H—C—C=O
10
.
'
alkali
Compound XX
/CHa
HG-[QH?aCH
with
atmosphere whereby Compounds XVII and XVIII
successively are formed. Compound XVIII upon
tion.
(EH:
hydrolysis
metallic sodium or sodium ethylate in an inert‘
OCaHf
'
Compound XXI ‘
Na
——>
Compound XVI +
t ‘CH:
|
toluene or
CHI
/
HC-[CH?aCsCH:
/O\C-—H
H2O
xylene
H:
H-C
CH,
hydrolysis
‘ 320/ \o/ \cm
H2C——g
..
:07,
\C/?
3%
Compound XVII
CH3
CHr%—[OH2]aCH(CHa):
H-C
CH: ‘
Hé-[CHzIrC?
CH3‘
CH3
ter can easily be converted to Compound XXIV
by heating withsmall quantities of iodine or p
toluene sulfonic acid, or by treating with thionyl
CH3
HaC-——C
it
r
I
‘
chloride in the presence of a tertiary base. Com
pound XXIV can be easily hydrogenated cata
lytically to Compound XXV. ‘
B:
PG’
CompoundXVIII
Compound XXII +
(g
‘
CaHs
CompoundXXII
When Compound XXII is treated with o-meth
oxy n-butyl magnesium bromide in anhydrous
25 ether and the product is hydrolyzed in the usual
manner, Compound XXIII is formed, which lat
CH3
1120/
\?‘l/ \(IJHr
MgI ‘ H20H7C\ 0/Cg|CH:
H: _‘C
OH:
C
H‘-C——(]J=O
20
(5-00001115
ether followed by hydrolysis
CompoundI
Compound XVI, one of the key intermediates,
can also be synthesized by the following alterna
tive route. This proceeds through the prepara
tion of the halogeno Compound XIX from Com
pound IV. Compound XIX is then easily con
verted to the phenoxy Compound XX by treat
ment with" sodium phenolate.
'
50
0
Compound XIX ‘
Compound XIX‘ +‘ sodium phenolaétlez -—-->
so i
a
+ NaBr
Compound XXV
When Compound XXV is hydrolyzed With
either hydriodic or hydrobromic acid Compound
70 IQIVI is formed, which latter can be converted
to Compound XXVII by oxidation with chromic
acid. The sodium salt of Compound XXVII is
When Compound XX is hydrolyzed with alkali
then treated with sodium cyanide and the nitrile
and the salt formed isacidi?ed with dilute hy
hfnormedois . hydrolyzed’, by. boiling, with, I hydro
drochloric acid, the acid Compound XXI is
chloric acid yielding Compound XXVIII. This
2,407,672
8
ing a-halogeno glutaric diethyl ester, in the pres
ence of amalgamated zinc, on Compound XXII,
followed by dehydration to form Com-pound
. is esteri?ed- and the resulting idiester dehydrated
to form, Compound
I.
‘
o o 0 0,11‘
Compound XXII + BrCH
CECE-000C135
_-->
"
Zn + dehydration
CrOa
-—->
(i‘IH:
in (1“. 11:80;
or acetic acid
HC--(CH2)3"’CH(OH3)2
H-0
15
mt‘:
0 0 0 02m
7
<[?,= "—QHr-OHQ—COOC2H‘I
H2C———-?—O @5115
H
Compound XXIX
20
Compound XXVII
No.0 N
Mesa '9; Compound XXVII +
’
v
'
-—.->
Compound XIUX is then hydrolized with al
coholic potash, and the hydrolyzed product is
partly decarboxylated by heating with copper
powder to form Compound XXX.
_
followed‘ by acidi?cation
2.5
esteri?cation
——>
C 2115 O H
acid catalyst
30
I
I
_ by acidi- H2C—.C—O CsHs
?cation
H
and heat
a
COOH
7
7
Compound XXX
7
XXX is catalytically hydrogenated
35 andCompound
the product hydrolyzed:- with hydrobromic
Compound xxvm
acid to form compound XXXI,
--——v
by heat with I:
diester of Compound XXXIII
40
45
50
' Compound XVI can also he prepared by react
Compound XXXI is then oxidized with chromic
acid to Compound XXVII, followed by reaction
with NaC__N to form the nitrile compound, and
the latter is hydrolyzed to Compound XXVJII
from which Compound XVI can be prepared as
A more detailed account of the‘ principal vand
2,407,672
10
novel reactions of theipresent process is to be
the well known Dieckmann method by heating in
found in the following: '
toluene with metallic sodium. The ‘principal
product formed is ketone Compound V, which lat
"
Synthesis of 2- [1’,5’-dimethyZl-hexyl carboeth
oxy cyclopentanone-1-Compound IV
0
Z-carboethoxy cyclo-pentanone-l (94 g.) was
dropped slowly into 22.9 g. of potassium sand in‘
635 g. of anhydrous xylene heated in an oil bath
to 125-130°: To this mixture was then added 150
g. of 6-methyl-2-iodo heptane and the mixture
heated at 1305135‘ for 43 hours. After cooling to
ter is separated by fractional distillation under re
duced pressure.
Synthesis
of
2,2 - dicarboethoaty - 5 - [ll',5'-di
methyl] -he:cyl cyclopentanone - 1—Compound
XI
10>
‘
f
An equivalent quantity of Compound V is treat
ed in anhydrous other with one mole of ethyl
room temperature, water was added to the mix
magnesium bromide, and to the product, Come
ture and the xylene layer separated; the latter
pound
X, without separating it from the solvent,
was washed three times with water, dried, and
fractionated under reduced pressure, the product 15 is added one mole of ethyl chloroformate; the
mixture, is well stirred for several hours. At the
boiling at 165-170° (14 mm.) being collected;
end of the reaction the product is treated with
yield, 55 g.; B. P. at 3 mm. 142-146°; now, 1.4473.
water, the ethereal solution is separated, and from
This ketone does not give a color with ferric
the latter Compound XI is isolated and puri?ed.
chloride.
'
The ketone was also preparedv in about 18% 20 synthesis of 1-carboetho:vy-2-carboethorybutyl
yields by using sodium-potassium alloy and the
5- [1',5’-dimethyl] -he:ryl - cyclopentene-A1,2 corresponding 6-methyl-2 bromo heptane and
Compound XVI
z-carboethoxy cyclopentanoneel‘ and re?uxing
'
the mixture for 70 hours at 135-140°. ‘
Compound XVI is prepared by a series of sim
Synthesis of 5- [1 ’,5’-dimethyl] ~hexyl-2-carbo 25 ple reactions as follows:
Compound XI is heated in anhydrous toluene
with an equivalent quantity of a-bromoglutaric
diethyl ester in the presence of amalgamated zinc
ethomy cyclopentanoneé1-—Compound V 4
Twenty-six g. of 2-[1',5'-dimethyl]-hexyl car
boethoxy cyclopentanone-l .was dissolved in the
for several hours. The reaction is activated from
minimum quantity of absolute ethyl alcohol and 3.0. time to time by the addition of small quantities .
to this was added'3 g. of metallic sodium. The
of iodine. At the end of the reaction the product
mixture was then re?uxed for eight hours, cooled,
is poured in water and the toluene layer separated
poured into water and neutralized with diluted
and dried. This gives Compound XII. When a
hydrochloric acid. The aqueous mixture was ex
few crystals of iodine or anhydrous p-toluene sul
tracted several times with ether, the ethereal ex 35 fonic acid is added and the mixture heated, water
tract was dried and thereafter was fractionated
splits out and distils over yielding Compound
Finally, the toluene is removed and the
product saponi?ed by heating on the water bath
under reduced pressure, the product boiling be
tween 190-205° (20 mm.) being collected and
XIII.
used for the nextstep. The fact of such a wide
40 with 10% alcoholic potash. The mixture is then‘
poured in water, acidi?ed with hydrochloric acid
ence of cis and trans isomers in the mixture. This
and the organic acid extracted with ether. When '
product gives the ferric chloride coloration while
the ether is removed and the tétracarboxylio acid,
Compound IV does not, showing that it has un
Compound XIV, heated with copper powder un
dergone the rearrangement shown above.
45 der greatly reduced pressure, the acid, Compound
melting point range is probably due to the pres
Hydrolysis of Compound IV and preparation of
Compound VI
XV, distills over; this latter can easily be esteri
?ed with absolute alcohol in the presence of small
amounts of sulfuric acid to form Compound XVI,
'
Compound V may also be prepared from Com
pound 1v yia the Compound v1 by hydrolyzing‘ 50. which is puri?ed by fractionation, under reduced
Compound IV in hot‘dilute alcoholic solution of
sodium ethylate or by boiling for several hours
Synthesis of ketone Compound I from Compound
with aqueous ‘barium hydroxide. In both cases
XVI
the salt of the acid Compound VI is formed. Com
pound VI can be obtained by acidifying with di
One mole of metallic sodium is treated in an
lute hydrochloric acid and extracting with ether. 55.‘ ' hydrous toluene under re?ux with vigorous stir
By esteri?cation and cyclization, Compound V
ring to produce ?nely divided sodium. To the
may be formed. The diethyl ester of Compound
mixture is then added slowly one mole of Com
IV can easily be prepared by heating Compound
pound XVI. After all of Compound XVI has been
IV with absolute ethyl alcohol in-the presence
60 added, the mixture is heated for several. hours,
of small quantities of sulfuric acid.
‘ then cooled and poured in water and‘ the toluene
The diethyl ester of Compound VI may also be
pressure.
tion and is easily converted to the diethyl ester
using platinum oxide or nickel catalyst.
Cyclization of the diethyhester of Compound VI
to form Compound V
The ketone Compound‘V is ‘prepared by cycli
zation of the diethyl ester Compound VI using
'
‘
layer separated, dried and the toluene removed.
prepared by reacting, in dry benzene, oc-bI‘OmO
adipic ester VII with‘methyl isohexyl ketone VIII
in the‘presence of amalgamated zinc dust or wool,
using small amounts of iodine to catalyze the‘
reaction. 'Product IX is isolated from'the reac
product VI by catalytic hydrogenation in alcohol
I
The toluene-free residue is puri?ed ‘by fractiona- '
tion under reduced pressure. The product, Com
‘ pound XVII, is then saponi?ed by heating‘ on the
water bath with alcoholic‘ potash,‘ poured into
water, and the mixture is acidi?ed with hydro
chloric acid and extracted with ether. When the
ether is removed from the extract the product,
70
‘7 upon heating, loses carbon dioxide very easily to
form Compound XVIII. ‘
. Compound XVIII is easily converted to Corn
75
pound I by treating it in anhydrous ether with
methyl magnesium iodide.
2,4673%
11
‘IcIaim:
1.
i
r
12
' v5. in the process of producing a compoundof
'
‘a new product, a compound of the for
mula
‘
‘
'
'
'
the formula
'
lz
'
Ion-3
I.GHO
pound of'the ‘formula
ZIH
l/
‘
cmomcmo o O.alky1
o.
1314+
II
.
C\
30
H
H 0la
C'OOnilkyl
ll
0 000.81k'y1
J/
'
\c'o Oialkyl
wherein Z is ‘a. substituent of ‘the group consist- 35 wherein Z represents a substituent of the group
ing'jof hydrogen and a monovalent aliphatic hy
consisting of hydrogen and a. mohovalent a-li
drocarbon radical and treating the resulting‘
product with methyl magnesium iodide to form
a compound of the formula
wherein Z is 1a substituent of the group con-
phatic hydrocarbon radical, s'aponi'fying and de
carboxyl'ating the latter, and ‘esterifying the de
40 carboxylated product to yield a compound of
Vw'hei'é’ih 'z-i‘éb‘réée‘riliis asubstiwe'nt ofjth'e ‘group
sisting of hydrogen and a monovalent aliphatic 50 consisting”. _Of”“hy7d‘r0§éi1 (and “a "inofi'ovale'nt ali
hydrocarbon radical.
phatic hydrocarbon radical.
4. Process which ‘comprises cyclizing a co . -
pound of the formula
_ ‘ "6. ‘I In the processor producing a "compound of
the formula
’
13
2,407,672
-
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent‘ ali-,
phatic hydrocarbon radical, and thereafter re
placing the metallo radical by a .carboxyalkyl
radical to produce a compound of the formula
\cooamyr-
14
per powdersto produce a compound of the for-n
mula
"
I
.
3
‘
-
‘
-
‘E Z
H\é
H—-(lJ/I\2C=O
H~(|:-§l-o 00115
t i
0 wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent ali
'
phatic‘ hydrocarbon radical,v treating the latter
wherein Z represents a substituent of the ‘group
consisting of hydrogen and a monovalent ali
phatic hydrocarbon radical, reacting the latter
15
product with an alpha halogeno glutaric dialkyl
with t-methoxy-n-butyl magnesium bromide in
anhydrous‘ medium and then hydrolyzing, where
., by to form a compound of the formula
ester in the presence of zinc, hydrolyzing and
dehydrating the resulting product to yield a com
pound‘ of the formula
Z H C O O.alkyl
20c
ll]:
:éI\O.CaH5
_
‘_
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent ali
phatic hydrocarbon radical, successively dehy
wherein Z represents a substituent of the group
drating, hydrogenating and hydrolyzing the lat
ter, oxidizing the resulting 3-hydroxy compound
consisting of hydrogen and ‘a’ monovalent ali
phatic hydrocarbon radical, successively hydro
lyzing and decarboxylating the latter, and es
terifying the decarboxylated product to yield a
with chromic acid to form a 3-keto compound,
30 ‘ converting the 3-keto compound to the corre
sponding nitrile, and hydrolyzing with mineral.
acid to yield a compound of the formula
compound of the formula
W‘
H~cEll/0'\elz /
CHz.CH2.CH2-C O O.alkyl
35
H_4|>___o\
‘
H
COO.alky1
wherein Z represents asubstituent of :the group
consisting of .~hydrogen and a 'monovalent I alie
phatic hydrocarbon radical.
wherein Z represents av substituent of the group
consisting of hydrogen and ,a monovalent ali
phatic hydrocarbon radical, and successively es
terifying and dehydrating the resulting product
whereby to produce a compound of the formula
7. In the process of producing a compound of
‘ the formula
45
50
151
C0O.alky1
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent ali
wherein Z represents a substituent of the group
phatic hydrocarbon radical.
consisting of hydrogen and a monovalent ali
8. Process of producing a compound of the
55
phatic hydrocarbon radical, the steps Which com
formula
prise halogenating a compound of the formula
Z
O O 0 .alkyl
H—-Cll5/1‘\2C=O
4
H-
.
1i
60
a
—
-H
i
wherein Z represents a substituent of the group 6
consisting of hydrogen and a monovalent ali
phatic hydrocarbon radical, to introduce a halo
gen substituent in the 3-position, reacting the
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent ali
phatic hydrocarbon radical, which comprises hy
drolyzing a compound of the formula
halogenated compound with sodium phenolate
whereby to substitute a phenoxy radical for the 70
halogen substituent in the 3-position, hydrolyzing
with alkali and then acidifying with dilute min
eral acid whereby to convert the —-COO.alkyl
group in the l-position to —COOH, and heating
the resulting carboxylic acid compound with cop 75 wherein Z represents a substituent of the group
9,407,672
15
16
ating the hydrolyzed product to produce a com
wherein Z represents ‘:a substituent of the group
consisting ‘of hydrogen and a monovalent ali
phatic hydrocarbon radical, to yield a compound
pound of the formula
of the :formula
consisting of hydrogen and a monovalent ali-'
phatic hydrocarbon radical, partially decarboxyl
,
.
z
ill
‘
wherein Z represents a substituent of the group
10 consisting of hydrogen and a monovalent ali
phatic hydrocarbon radical, esterifying the lat
ter open chain dicarboxylic acidcompound, and
wherein vZ represents a substituent of the group
consisting of ‘hydrogen and a monovalent ‘ali
cyclizing the esteri?edcompound.
phatic hydrocarbon radical, hydrogenating the
V
'
10. Process of producing a ‘compound of the
latter and thereafter hydrolyzing the hydrogen
formula
ated product, oxidizing the hydrolyzed compound
.to the corresponding B-keto compound, convert
‘
ing the 3-keto compound to the corresponding
nitrile, and hydrolyzing the latterto the corre
sponding dicarboxylic acid, esterifying ‘the acid
and dehydrating the resulting diester.
9. Process of producing a compound of .the
formula
7
H—— -——+——COO.alkyl
o
a.
I!
I
H
H
,
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent ali
25 phatic'hydrocarbon radical, which comprises re
acting an alpha-bromoadipic acid alkyl ester
with methyl isohexylketone under conditions to
yield a compound of the formula
0 o 0 .alkyl
130
wherein Z represents a substituent of the group
consisting of hydrogen and a monovalent‘ ali
phatic hydrocarbon radical, which, comprises hy
drolyzing a compound of the formula
z J CQO.a1kyl
35
i5“20:0
11-0
3'
H-
—-
H
--11
H
catalytically hydrogenating the latter compound,
and cyclizing the hydrogenated product.
'
- NICHOLAS A. MILAS. '
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