*r. 13. w R I G H T , w.E. D ~ L W ,
102
,J. ir.
\i.kItk[I,L1l.
The Antidiabetic Activity of 3,5-Dimethylpyrazoles J ~ H13. U WRIGHT,WILLIA\IE. I ) L ~ L I U ,\\-I) , ,JOHY 1%.I\I~I~KILI,IE: ll'esenrcli Laboratories of 2'hc U p j o h f i ('ompang, Kaluriaazoo, Jfzthzqnn IL'ecett etl , I icyiist $?a', 1 ~ 6 ~ 3
I'orty-one pyrazoles were investigated for antidiabetic. w t ivit? . .i r i u i i i l m - ( J t those ( olitainirig iiieth? I groups in both the 3- and 5-positions were found t o posses7 h\ pogl) wmic tu tivitie great :is 100 tinirs that o f t l J ~ h I l t amide in glucose-primed, intact, fasted rats.
Tluriiig the course of at1 iiivestigatioii in our labomtories of a series of compounds for antidiabetic activity it was found that 3,.i-diiiietliylpyrazole-l-carboxamide (I) possessed hypoglycemic activity 2,i times that of HIP
.-y
II_/PiCOSH. CHI
C,H,COCH,CH,K'
I
to1tlutamide in glucose-primed, intact, fasted rats. .lccordingly, a detailed study was made of the structure-activity relationship in compounds of this general class. Chemistry.-The uelv pyrazoles that were prepared are listed in Table I. Table I1 gives the activity of these compoiinds along with that of a number previously reported in the chemical literature. The majority of the compounds w e i t prepared by the reactioii between p-diketoiies and hydrazines or semicarbaxides. l-rz-Butylcaibamyl-~,~-diiiiethylpyrazole (11) was prepared by treatment of 3,;-diniethylpyrazole with ri-butyl isocyanate.
N-CH,
d
t
ICH3)LNH
dH
Biological Testing and Results.--The vompouuds listed in Table I1 \vere tested in inale Sprague Dowley rats follo~r-ingovernight fast. the time of trcatrneiit with the test compound the rats were injected subcutaneously with 100 nig. of glucose. The blood sugar Ion eririg ability vas compared with that for tolbutamide. I'oteiicy estimates were made by tlctermining from the dose response curves, doses of compounds which produce comparable hlood sugar lowering. I'roin thc data pivseuted in Table I1 it appears that the most activr, of the compouiids tested are thoso containing methyl groups in both the 3- aiid r)-positiotis. H I Substitution of oiie or more of the methyl groups witli :L CONHC4Hq hydrogen, ethyl, trifluoroniethyl, carboxyl, h i ~ y lplic, I1 noxyrneth\-l, or pheiiyl group in the coinpollrids teated :~,3-l)imethylpyrsxole-l-carbo.uylic acid hydrazide lowerb activitjr appreciably. The most activc coiii(111) was prepared hy treatment of 2,4pentatiedione pounds also appear to he those that arc> urisiibstituttd with carbohydrazide. ill the 4-position and in the 1-position possess either a CHoCOCH2COCH3 11. C'( )SI-Iz, COXHCGH,j, COS(CH,j),, - C O S H S I 12 or C'OCaflj 81oupjrig. Tlir possibility rsists tliat + NHzNHCONHNHz -+ CH3 pJI. sonic or all of the active cornpourids listed above tliat CONHNH~ contain groupings other than hydrogel1 in tlie I-positiou I11 o w their activity to hydrolysis t o :~,.i-diriiethylpyrA nuinher of the 1-substituted pyrazoles were prezole in the gut or t o a nietabolic traiisformatioii i n tisbiit' pared by alkylatioii or acylation of 3,ti-dimethylpyto this compouiic-l. Compounds of this geneid type razole. l-(~-Dimethylanii1ioethyl)-~3,~i-dimetIiylpyraare ki1on.11to lie hydrolyzed somewhat I eadily. zole (11') was prepared by treatment of the sodium salt
pGH3
Experimental ?T.
of :rl,.i-dimethylpyrazole with $-dimethylaminoethyl chloride. Similar alkylatioiis were carried out with chloroacetamide aiid dimethylcarbamyl cliloride t o give the correspoiidirig 1-substituted derivatives V arid \-Iq respectively. CHs -N, CH3 -N,
b;;:,,,,, V
4pC)P;
(CHB)Z
VI
fl- (:rl,.j-Dimcthyl-l-pyrazolyl)-propiopherlone (VI1 prepared by liesting tlie Maiiiiich base &dimethyl-
n as
3,B-Diethylpyrazole Hydrochloride. 8.--To a solution of 13.0 g. (0.1 mole) of hydrazine sulfate in 75 ml. o f :t l0YG aqueoris sodium hydroside solution cooled t o 10-15" was added 12.8 K. (0.1 mole) of 3,5-heptanedione. The reaction mixture was stirre(1 at this temperature for 1 hr. To t,he mixture was then added 50 ml. of water and the resulting mixture extracted with ether. The ethereal extracts were washed with a saturated salt solution :mi dried over annydrous sodiuni sulfate. The hydrochloride was prepared by addition o f g:rseous dry hydrogen chloride to the! ethereal solution. __ ~~~~
~~
~
~
(1) T. I'(imt.r, H r i... 34, 3'380 ( l < l O l ~ . ( 2 ) A detsilrd report from these Isburntorien o n t l i e iiylwglycrrnic activity
of 3,5-dimethylpyrazo'e u-BYjxesttnted ~ J S ?0 . C . Uerritaen and \V. I?. I ) i i l i n nt the Annu%! .\Iretinu of the .\merican 1)iabettv .\sstici:ttiorr, At.l:intirCity, N.d . . .Time 14. 1963 C.7. Am. Dinheteu .18. (:ij :\!I melting I i o i n t q wpre cl)rrerted and were t:&keni n u wiA:!liirJ I i i l w . .A11 hoilirrg iioints are iincorrected.
ANTIDIABETIC 3,%DIMETHYLPYRAZOLES
January, 1964
103
" h
3
h
ci
W
m
G
I
8 v, 2
m
i:
104
1-( ~-Dimethylaminoethyl)-3,5-dimethylpyrazoleDihydrochloride.--A mixture of 19.2 g. of 3,5-dimethylpyrazole, 200 mi. of d r y toluene, and 15.6 g. (0.4 mole) of sodamide n.as refluxed with stirring for 2.5 hr. The iiiixturr K:E crooled. 26.0 8 . (0.2 mole) of p-di~iiethylurn~~ioethyl c-hloritie 1ij.drochloride n-as added, :ind the niiitnre heated under reflux for 5 Iir. 1T:cter (200 nil.) vas :idded, the toluene layer sep:iruted. :ind the :rclueous layer ('xtr:icttd with ticlnzene ( 100 nil. j. The cornbined to!uene-benzcw cB\;tr:ic,ts \\-ere distilled through :I Vigreux colunin. There \vas ci1)t:iineti 25.28 g. (76';) of LI colorless oil boiling at, 79-82' (0.45 iiiiii.), ) t u L ' 1.4800. The dihydrochloride \vas prepared by :idding ~:ISCYIC~ li>~drogen S chloride to an othered solution of the free l~tsc,.
4-Diethylaminoethyl-3,5-dimethylpyrazole Dihydrochloride. B.-To LL stirred solution of 6.0 g. (0.03 mole) of 3-diethyla1ninoetli2-1-2,~-pent;ine(~i(inc' in 5 nil. of water wits added at 5-10' :I solution of 1 ..? g. (0.0:3 mole) r i f hydrazine hydrate in 3 1111. of water. The rriiiturc FV:IY I1e;ited under reflux for 1 lir. T h c x solution w t s s:itur:it ed wit 11 pot ium c:wbonitte and extracted n i t l i ether. T l i e (it lirrenl extr.ac.ts were dried over :inhytIrous iiingnesiuni sulfate and tlic dihydrochloride prepared I Jaddition ~ of nn etliercnl solution IJf li,i.tircign 1-hloritie. The solid wxs sep-
January, 1964
NOTES
arated by filtration and purified by recrystallization from 2-propanol t o give 0.65 g. of colorless prisms. 3,5-Dimethylpyrazole-l-acetamide. C.-To 4.3 g. (0.11 mole) of sodamide was added a solution of 9.6 g. (0.1 mole) of 3,j-dimethylpyrazole in 100 ml. of dry benzene. The reaction mixture was heated under reflux for 30 min. To the mixture was then added 9.4 g. (0.1 mole) of chloracetamide and refluxing was continued for 1 hr. The mixture was allowed to cool to room temperature and was filtered. The solid was slurried with hot chloroform, filtered, and the filtrate evaporated to dryness. The residue was recrystallized from ethanol. p-( 3,5-DimethyIpyrazole-l)propiophenone.-A mixture of 17.7 g. (0.1 mole) of p-dimethylaminopropiophenone and 9.67 g. of 3,5-dimethylpyrazole was heated on a steam bath for 3 hr. The mixture, which partially solidified upon cooling, was triturated with a small amount of petroleum ether. The solid was removed by filtration and recrystallized from petroleum ether (Skellysolve B). 3,5-Diethylpyrazole-l-carboxamide.-To a solution of 11.2 g. (0.1 mole) of semicarbazide hydrochloride in 30 ml. of water was added a solution of 12.8 g. (0.1 mole) of 3,Sheptanedione in 10 nil. of ethanol over a period of 10 min. Stirring was continued for 4 hr., the solid removed by filtration, and purified by recrystallization. N-Butyl-3,5-dimethylpyrazole-l-carboxamide.-A mixture of 9.6 g. (0.1 mole) of 3,5-dimethylpyrazole and 19.8 g. (0.2 mole) of n-butyl isocyanate was heated on the steam bath for 1 hr. To the reaction mixture was then added 25 ml. of ether and the ethereal solution washed with 25 ml. of 5% sodium carbonate solution and then with 25 ml. of water. Removal of the ether gave a colorless oil which solidified upon standing. 3,5-Dimethylpyrazole-l-carboxylic Acid Hydrazide.-To a solution of 9.0 g. (0.1 mole) of carbohydrazide in 35 ml. of water a t 15" was added a solution of 10.0 g. (0.1 mole) of 2,4-pentanedione in 5 ml. of ethanol and the mixture stirred a t 10-15' for 30 min. The mixture was extracted 3 times with 10-ml. portions of ether. The aqueous layer on standing overnight precipitated a colorless solid. This was removed by filtration] washed with cold water and ether, and purified by recrystallization from ether. p-(3,5-Dimethylpyrazole-l)benzoic Acid.-A mixture of 9.55 g. (0.096 mole) of 2,4-pentanedione, 14.55 g. (0.096 mole) of p-hydrazinobenzoic acid, 7.84 g. (0.096 mole) of anhydrous sodium acetate, 10 ml. of ethanol, and 25 ml. of water was heated under reflux for 1 hr. The mixture was cooled in a n ice bath and
neutralized with concentrated hydrochloric acid. The solid was filtered, washed with water, and recrystallized from ethyl acetate. p-( 3,5-Dimethylpyrazole-l)benzamide. D.-A stirred mixture of 4.0 g. (0.0185 mole) of p-(3,5-dimethylpyrazolyl-l)benzoicacid, 3.3 g. (0.028 mole) of thionyl chloride and 100 ml. of dry benzene was heated under reflux for 1.25 hr. The hot mixture was filtered and the solid washed nith ether. The filtrate and ether were concentrated zn v a ~ u oon a steam bath. Two 50-ml. portions of benzene were added and then were removed zn vacuo on a steam bath. To the crude acid chloride was added 6 ml. of concentrated ammonium hydroxide and the mixture stirred for 1 hr. The mixture was diluted with water and filtered. The cake was washed with water and purified by recrystallization. l-(p-Sulfamylphenyl)-3,5-dimethylpyrazole.-A stirred mixture of 19.88 g. (0.106 mole) of p-sulfamylphenyl hydrazine,s 8.70 g. (0.106 mole) of 2,4-pentanedione, 60 ml. of ethanol, and 25 ml. of water was heated under reflux for 1 hr. The mixture was then neutralized by the addition of 8.7 ml. of concentrated hydrochloric acid, the solid removed by filtration, and washed with ethanol. p-( 3,5-Dimethyl-l-pyrazolyl)benzenesulfonylurea.-A mixture of 4.0 g. (0.016 mole) of l-(p-sulfamylphenyl)-3,5-dimethylpyrazole, 1.3 g. (0.016 mole) of potassium cyanate, 20 ml. of ethanol, and 5 ml. of water was heated under reflux for 7 hr. The unchanged starting material (0.68 g.) was removed by filtration and the filtrate concentrated to dryness. The residue was diluted with 15 nil. of water and acidified with acetic acid. The resulting solid was collected by filtration and purified by recrystallization. 1-( p-Chlorobenzoyl)-3,5-dimethylpyrazole.-To a slurry of 9.6 g. (0.1 mole) of 3,5-dimethylpyrazole in 100 ml. of anhydrous ether a t 10-15' was added dropwise x i t h stirring 8.7 g. (0.05 mole) of p-chlorobenzoylchloride. The mixture was stirred a t room temperature for 1 hr. and then filtered. The filtrate was washed with water, dried, concentrated, and the residue distilled under vacuum. There was obtained 6.6 g. of material boiling a t 108" (0.1 mm.) 12% 1.5850.
105
Acknowledgments.-We are indebted t o Dr. Robert Rinehart and eo-workers for microanalyses. We are especially indebted to RIr. Albert Lallinger, Rlr. A. Lazuk, Mrs. F.L. Schmidt, and " I . M. C. Blanks for much technical assistance. (5)
K.Itano, J. Pharm. So?. Japan. 75, 441
(1955).
Notes 111.' Sulfur Analogs of 14-Hydroxydihydrocodeirlone
Derivatives o€ 3Iorphine.
interest. Because of its strong analgesic actioii, 14hydroxydihydrocodeinone (I) w ~ schosen as the starting material,
FREDERIC E. STYNLER FH3
Rome .lir DevelopnLent Center, Gri$ss A i r Force Base, Rome, S e w York AND C L R I C H !vEISS
Satzonal Institute 05 Arthritzs and Metabolic Diseases, Bethesda 14, Maryland
OCH3
0
I
Received September 24, 1963
During the search for analgesic drugs with improved therapeutic properties, it appeared desirable to prepare some sulfur analogs of ketones of the morphine series. It has long been know that ketonic compounds of this series have a particularly strong analgesic action, and indeed the majority of those transformation products of morphine and codeine which have found use in therapeutic practice are ketones. It seemed, therefore, that corresponding sulfur compounds might be of (1) Payer 11. U. Wpiss, J . Ore. Chem., 2 2 , 1505 (1957).
IVa:n=l IVb:n=2 (2) RI. Freund and E.Speyer. .J. RaX-t. Chem., 94 135 11016).
