Novelllber, 19ei
831
XEW C O M P O U N D S
of the acetonitrile by ethyl acetate; 1.22-g. yield (53.5%),
n1.p. 158.5-160.5O. The C14-labeled protected tripeptide was prepared by the carbodiimide method also.la Glycyl-a-aminoisobutyryl-L-alanine.-Hydrogen was passed through a solution of 1.37 g. (0.03 mole) of the protected tripeptide in 50 ml. of absolute ethanol containing 2.0 ml. of glacial acetic acid for 4 hr. in the presence of 0.5 g. of fresh palladium black with agitation by means of a Vibro-RIixer.9 The product was obtained as shiny plates and recrystallized from waterac-etone; 0.66-g. yield (95VC), m.p. 238.5-240" dec., [a] -26.3" ( c 0.457, 1 S HCI); R f 0.34 in 2-butanol-formic acidwater (75: 15: 10) and 0.70 in phenol-water (80:20), descending 15 hr., Whatman S o . 1 paper. A n a l . Calcd. for C7HliS304: C, 46.74; H, 7.41; S , 18.17. Found: C,46.78; H, 7.56; S , 17.57.1° The C14-labeledfree tripeptide was prepared by a similar procedure; specific activity was 16.8pc./mmo1e.la Carbobenzoxyglycyl-a-aminoisobutyryl-L-valineBenzyl Ester. -To a solution of 1.47 g. (0.005 mole) of carbobenzoxyglycyl-aaminoisobutyric acid in 100 ml. of acetonitrile was added 1.03 g. (0.005 mole) of dicyclohexylcarbodiimide; the mixture was stirred at, room temperature for 1 hr. A fresh filtered solution of L-valine benzyl ester in acetonitrile [from 1.83 g. (0.005 mole) of L-valine benzyl ester benzenesulfonate and 0.75 ml. (0.005 mole) of triethylamine] was added; stirring was cont'inued for 20 hr. at room temperature. The acetonitrile was removed in vacuo, and the residue was taken up in ethyl acetate and worked up as usual. Recrystallization from hot absolute ethanol and ethanolether yielded 1.60 g. (66%) of protected tripeptide, m.p. 114-116.5', [ a ] * 6 ~-26.7" ( e 0.457, ethanol). A portion was recrystallized from ethanol-ther for analysis, m.p. 115.5-118'. A n a l . Calcd. for C26H33?1T306: C, 64.58; H, 6.88; N, 8.69. Found: C, 64.66; H, 6.98; S , 8.59. Glycyl-a-aminoisobutyryl-L-valine.-Catalytic hydrogenolysis \vas carried out as described above on 0.97 g. (0.002 mole) of the protect,ed tripeptide. To remove any acetate associated with the free tripeptide obtained, the product was dissolved in 20 ml. of water containing a sixfold molar excess of ammonia, lyophilized, redissolved in water, and lyophilized three more t.imes. Recrystallization from water-alcohol-acetone yielded 0.50 g. (96%) of shiny plates, m.p. 240.5-241.5", [ L X ] ' ~ D -11.0' ( c 1.486, 1 A' HC1); R f 0.49 in 2-butanol-formic acid-water (75:15: 10) and 0.86 in phenol-water (80:20), descending 15 hr. A n a l . Calcd. for C11H21S3024: C, 50.95; H, 8.94; N, 16.21. Found: C,50.99; H,8.70; S , 16.02.
with hot water and with hot methanol, then recrystallized twice from dimethylformamide. The tan crystals melted a t 340" 3 ; they formed an orange solution in acetic acid which bccame colorless on addition of a little concentrated HCl. A n a l . Calcd. for C22H2iN402: C, 70.20; H, 6.41. Found: C, 69.98; H, 6.1K4 \Valker 256 tumor screening test showed C/T 0.85 at 400 nig./ kg.5; tissue culture screening t'est against KR cells in vitro: ED,,, 43 -j/nil.6 (3) Corrected for stem exposure: determined b y use of Thiele tube. ( 4 ) Average of two analyses by Weiler and Strauss, Oxford, England. ( 5 ) We are grateful t o Professor Alexander Haddow, Rlr. J. E. Everett, and X r . B. C. 1'. Rfitchley of the Chester Beatty Research Institute for d a t a on toxicity and activity against the Walker 256 tumor in rats weighing 200250 g. Each compound was administered as a single i.p. injection in aracliis oil on the day following tumor implantation or on the first day of the toxicity observation. Tumor bearing animals were sacrificed approximately 8 days later and the average weights of tumors in treated and untreated hosts reported as the ratio C/T. (6) Results of the standard KB tumor cell inhibition tests carried o u t under sponsornhip of the Cancer Chemotherapy National Service Center.
The Preparation of 4-Substituted Benzothiadiazines
C S . T'ztavizn & Pharinaceirtzcnl C'orporatzon, Yonkers, S e w York 10701 Recezted J u n e 29, 1964 During our attempts to prepare cgclic analogs ( I ) of tctlbutamide, a publication2 appeared setting forth the synthesis of Ia. We have prepared I a and twelve other 4-substituted analogs by an alternate route according to Scheme I.
SCHEME I
SOzNHi
(9) T h e Vibro-Mixer was obtained from Fisher Scientific Co. (10) A second portion of the carbobenzoxytripeptide benzyl ester was dissolved in methanol and subjected t o hydrogenolysis a s above, b u t in the absence of acetic acid. The melting point of t h e free tripeptide obtained was identical with t h a t of the analytical sample and with t h a t of a n equal mixture of the tu-o preparations.
3,6-Bis-p-dimethylaminobenz~-lidene-2,5diketopiperazinel
Cursou-Sewman College. J e f e r s o n City, Tennessee
Receiced A u g u s t 19, 2064
In preparing conipounds containing systems of conjugated d(iuh1e bonds b y reaction of dialkylaminobenxaldehyde with suitable ring compounds,2 we attempted unuuccessfully to ronclense p-dimetjhylaminobenzaldehyde with 2,kIiketopiperazine. The desired compound was obtained, however, by use of the methiodide salt of this aldehyde. A mixture of 11.6 g. of the quaternary salt, 2.2 g. of 2,5-diketopiperazine, 4.0 g. of sodium acetate. and 12.0 g. of acetic anhydride was heated 3 hr. in an oil bath at 170'. The resulting insoluble product was washed (1) This research was supported by a. L-nited States Public IIealtli Service Grant C.\-03717-5 from the r a t i o n a l Cancer Institute. (2) C. T. Baliner, J. \Vilsun. 31. \Vest, G. Rrowder. J. 13. Goan, C. Cook, J. Fain, E. Franklin, aiid A. Myers, J . Org. Cliern., 22, 683 (1Y57).
Ia, R = CH3; R ' = (CH*),CH, In only one instance (15), when using 10% palladium on carbon in acetic acid solution, was catalytic reduction of a Schiff base successful. When the Schiff bases were refluxed in acetic acid with either di- or trimethylamine borane for 0.5 hr., pure reduction products were obtained in yields ranging from 8499%. Schiff bases (12-14) prepared from para-substituted benzaldehydes did not give pure products by this procedure. The 4-pyridylethj-1 compound (21j was prepared by addition of 4-Yinylpyridine to o-aminobenzenesulfonamide. All cyclizations n-ere carried out by heating the ?;-substituted sulfonamides with urea a t 20Q-205°.3 The iY-pyridylethylsulfonamide was heated a t lower temperatures (ca. 170') since at 200" deconiposit'ion occurred with loss of 4-vinylpyridine. Experimental4 were prepared by mixing equimolar amounts of the appropriate aniline and aldehyde in ethanol. The mixtures were allowed to stand from 7-24 hr. a t room t'emperature, and the solvent was removed. Yields, analyses, recrystallization solvents, and melting points are indicabed in Table I.
Schiff Bases.-These
(1) Author t u n l i o n i inquiries sliould be addressed. ( 2 ) I>. L. Siinnions, .T. A I . I>,rilsnortli, a n < l 1. 1,. ('hubb, C ' U I I . J . ( ' h c v , , 41, 804 (1963). (3) D. V. Park aiid It. T. MXliatiis, J . ClienL. S o c . , 1760 (lt1.50). (4) 1Ielting puiiits n e r e determined on I:islrer-.Jolins block w i t h a rruli-
brated therniuiiieter.
Analyses a e r e performed by Midwest Microlab, Inu.
I
.l Phenyl Cyclohrxyl Benzyl Benzyl 2-Pyritlyl :3-Pyritij-I 4-Pj-rid)-l I-Pgridyl n-HrxyI I-Hydrrnypheii>.l 4-Hydrc is>--:lJnei hits!-phenyl 4- I )i ~iiet,liyI:iniinoplieiiyl
Reduction of Schiff Bases. N-Butyl-2-sulfamylaniline(15):- ;\ solution of 3.0 g. (0.133 iiiole) of r-butylidene-'2-sulfarn!.l:~iiiline(1) in 230 nil. of wetic: ac.id was hydrogenated with 1.0 g. of lo(; palladiuin on carbon :it 30' at an initial pressure of 4 :it in.: the required :tiiiount of hydrogen was taken up in about 15 IN. Filtration and removal of solvent left, a residue (3.0 g . ) which was rer.r?-stallizedtvie,e by dissolving in a minimum amount of boiling benzene and adding hexane to incipient turbidity to give 100 rng., 11i.p.80-83' (Tab12 11). N-Butyl-5-methyl-2-sulfamylaniline ( 16).'---A mixture of 14.0 e. (0.058 mole) of ?;-hutylidene-5-niethyl-2-sulfaniylariiliiie (2) :11id:35 rul. of wetic. acid was stirred, and 1.9 g. (0.026 mole) of tribrraiie (Gallery Cheinic-als)in 10 1111. of acetic: :rcitl 11ielhy1~~1iii11~ was atldetl i n one portion. The clear solution its refluxed for 0..i lit,. Atidit ion of w:tt,erresulted ili cyystallimtion of the prciduc>tt o yiclcl 12.4 fi. 1, iii.11. 11 1-112". Two crystallix:ati~~iif r o i i i
heiizenc !'sild
io
r:tise t,ho riirltilig
pi)iiii
: t IN:
fiiid
11i.1). \V:IS I!h
109".
N-(4-Pyridylethyl)-2-sulfamylaniline(ZI).--~-Aiiiiatrire oC 2 . I 3.4 g. (0.0% niole) of sulf:tt~iyl-. aniline, and 1.3 g. (0.02 mole) of acetic acid was refluxed in 1 0 nil. of absolute ethanol for 41 hr. The colorless solid vias filtered nff and washed with water t o yield 2.9 g. (53CG),m.p. 170-1 Two crystallizations froiii methanol raised the n1.p. to 187-1 4-Butyl-6-methyl-3-oxo-3,4-dihydro-l,2,4-benzothiadiazine 1,l-Dioxide (28).-An intimate mixture of 14.0 g. (0.058 I I I ( J ~ ) of 16 and 3.9 g. (0.063 mole) of urea was heat,ed at 200-20.5' for (i.5 hr. in a st,reain of anhydrous nitrogen. The residue wits partitioned between 1 .\- NaOH and chloroforni. The alkaline ~'11r:tct was acidified with 1 S HC1. A n oily inaterial sel)aratc~ti which gradually bec~:~riia c-l,ystnlline l o yield 9.7 g. (G2.5' , 'l, 111.1). l i l -172" (Ttd)Ie 111). g. (0.02 mole) of .i-vinylpyridine,
823
NEW COMPOUNDS
November, 1964
TABLEI11 BESZOTHIADIAZINES
Sield,
R' n-Butyl 27 H 28 CHI n-Butyl Benzyl 29 H Cyclohexyl30 H methyl Phenethyl 31 H 32 CH3 Phenethyl 4Pyridyl33 H ethj1 2-Pyridyl34 H methyl 3-Pyridyl35 H methyl 3-Piperidyl36 H methylc CPyridyl37 H methyl 38 CH3 4-Pyridylmethyl n-Hept yl 39 H a See Table I. * Lit.2 m.p.
so.
R
%
Recrystn. solventa
Xp.,
oc.
--Carbon, 70Calcd. Found
-Hydrogen, 70Calcd. Found
-Kitrogen, %Calcd. Found
139-140 171-172b 205-207 202-204
51.96 53.72 53.33 57.13
51.76 53.70 58.56 56.94
5.55 6.01 4.20 6.17
5.45 6.07 4.44 5.99
11.02 10.44 9.27 9.52
10.86 10.57 9.68 9.33
B D
160 155-156 249-252 dec.
59.60 60.75 55.44
59.71 61.02 55.16
4.67 5.10 4.32
4.65 5.17 4.95
9.27 8.86 13.86
9.43 8.68 13.99
59
D-H-Et
259-264 dec.
53.98
53.83
3.83
4.04
14.53
14.36
65
D
289-290 dec.
53.98
53.53
3.83
3.97
14.53
14.63
20
\v
332 dec.
52.87
52.98
5.80
6.02
14.23
14.15
92
D
300
53.98
53.82
3.83
4.03
14.53
14.41
48
D-H-Et
297-307 dec.
55.44
54.39
4.32
4.64
13.86
13.72
89 92-93 B-H 56.74 By catalytic reduction of 35 with PtO,. 173-174".
56.60
6.80
7.14
9.45
9.24
45 62.5 50 37
JJ' B
82.5 58 20
E-H
171 E-H
3-0xo-4-( 4-pyridylethyl)-3,4-dihydro-l,2,4-benzothiadiazine 1,l-Dioxide (33).-A mixture of 21.5 g. (0.078 mole) of 21 and 4.65 g. (0.078 mole) of urea was heated for 1 hr. at 150-170" under a stream of nitrogen. The residue was heated with ethanol and cooled, and a colorless solid was filtered off, yield 6.0 g., m.p. 239-245'. Crystallization from methanol, then from a minimum amount of hot dimethylformamide to which ether was added to incipient turbidity gave 2.1 g., m.p. 253-256'. When heated a t 200-205", the product obtained analyzed for loss of vinylpyridine.
The Synthesis of N-Substituted 2-Aminoethanethiosulfuric Acids DANIELL. KLAYMAN and W. FRANKLIN GILMORE Walter Reed Army Institute of Research, Department of Medicinal Chemistry, Washington, D.C. 20012 Received May 1, 1964 Alniost all aminoalkylthiosulfuric acids Those pharmacological properties have been reported in the literature thus far have a priniary amino group. A series of iY-monosubstituted 2-aminoethanethiosulfuric acids was, therefore, synthesized to determine the effect of the presence of secondary amino groups in alkyl thiosulfates (Bunte salts) on their biological activity. The procedures employed in their synthesis n-ere method A, used when the direct alkylation of the sodium salt of 2-aminoethanethiosulfuric acid was feasible, and method B, used mainly to prepare those Bunte salts in which the amino group is attached to a secondary carbon atom of an alkyl chain. This latter method involved the conversion of an K-alkylaminoethanol to the bromide hydrobromide n-hich was allowed to react subsequently with one equivalent of sodium thiosulfate in aqueous or aqueous-ethanolic solution. Experimental 1 Method A. N-AlkylaminoethanethiosulfuricAcids.-To 0.25 mole of sodium hydroxide dissolved in 300 ml. of warm 95%
ethanol was added rapidly with stirring a hot solution of 0.25 inole of 2-a1ninoethanethiosulfuric acid2 in 23 ml. of water. To the mixture, which was then heated under reflux, there was added dropwise over 1.5 hr. 0.20 mole of the primary alkyl bromide. Heating and stirring were continued for 4.5 hr. after the complete addition of the halide. About 150 ml. of ethanol was then distilled from the mixture and replaced with an equal volume of water. The solution was neutralized with glacial acetic acid and cooled overnight causing the crystalline product to separate. The Bunte salt was collected by filtration, air-dried, and recrystallized several times to remove the contaminant resulting from dialkylation. Method B. 2-(se~-Alkylamino)ethanols.-These compounds were prepared from 2-aminoethanol and sec-alkyl bromides by the method previously described3 except that xylene was used as the solvent instead of benzene. A mixture of 0.5 mole of the alkyl bromide, 1.5 moles of 2-aminoethanol, and 150 ml. of xylene was heated under reflux with stirring for 21-37 hr. The two layers were separated and the lower layer containing mainly 2-aminoethanol was washed with three 20-ml. portions of benzene. The benzene extracts and the xylene layer were combined, washed with three 20-ml. portions of water, and dried over anhydrous magnesium sulfate. The solvents were removed on a steam bath by the use of an aspirator and the residue was distilled under reduced pressure through a T'igreux column. Yields ranged from 56-707c. N-Alkylaminoethyl Bromide Hydrobromides.-These coinpounds were prepared according to the procedure of Cortese* b y treating the corresponding S-alkylaminoethanol with 48y0 hydrobromic acid and by slowly distilling the water formed in the course of the reaction.
(1) Melting points are uncorrected and were determined on a Fieher-Johns melting point apparatus. T h e rate of heating influences the melting and decomposition points of aminoalkyl Buute salts. Microanalyses were performed by Schwarzkopf l\licroanalytical Laboratory, Woodside, N. Y . , and b y Nr. Joseph Alicino. Metuchen, N. J. (2) H. Bretschneider, Monatsh., 81, 372 (1950). (3) J. B. Wright, E. H. Lincoln, R. V. Heinzelmann, and J. H. Hunter, J . Am. Chem. Soc., 1 4 , 3536 (1950). (4) F. Cortese, "Organic Syntheses," Coll. Vol. 11, John Wiley a n d Sone, Inc., N e e York, N. Y.. 1943 D. 91.
