Dissociation Constants of Substituted Ethylenediamines1 - Journal of

GEORGE W. WATT and DONALD G. UPCHURCH. 1967,253-271. Abstract | PDF | PDF w/ ... T. J. Lane C. S. C. , H. B. Durham. Inorganic Chemistry 1963 2 (3), ...
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n = no of monomer units per unit cell = 14 Typical spectrometer patterns of the 3.3 A. reI' = volume of unit cell = 1290 A 3 gion of sainples of rarving degrees of crystalliriitjr are presented in Fig. 1. 'l'he quick qwiichiri~t c t :L T h e c,ilculated value is 2.10 g./cc, in agreement low temperature of Idyiiicr heated alia\ e Its with the value oT 2.1% g.;'cc. determined experitransition temperature results in a glass-cleu w n - inentally by the flotation method using a solution of ple which gives a low iiitvnsif 17, 1)i oat1 diffr,tctioii r.y,n-tetrabroInocthaiie and diethyl phthalate. line characteristic of a rclati;. riy disordered diiiotAcknowledgments.--The author is grateful to phous structure (Fig. La). Extensive crystalliiiity Drs. E. Solomon, I. Fankuchen and D. Harker for with increasing opacity is developed by lengthening their h-, Experimental in the most oriented sample, sharp spots wr-e Reagents.-NN'-dihIeen, SS'-diEten, lT'-di-n-Pren formed. The spacings and relative intensities of these spots were in exact correspondence with the and NS'-di-n-Buen3 were prepared by the method of Schneider.4 SS'-di-i-Pren was prepared by a modification of the 5.5 A. region lines observed in the spectrometer procedure of Zienty,; using ethylene dibromide and isoprocurves of the niost crystalline sample. pylamine. One mole of ethylene dibromide was refluxed Measurement of the lateral spacings along the vvith five moles of isopropylamine for 2-4 hours. The mixture became almost solid with crystals. An excess of 20% row lines ol the fiber diagrams and of the lines ob- sodium hydroxide solution was added and the mixture disserved in the Debye-Scherrer pattgrns gave a se- tilled over solid sodium hydroxide. The amine was then ries of spacings, beginning with 3.6 X., which were in distilled over sodium; yield 6070. Both dl-bn ant1 iiz-bn were prepared by reduction of dithe inverse ratios oi I t/ ~'47~': : 4:). Tliese inethylglyoxime with platinum and hydrogen in a Parr ratios, being characteristic the hexagonal system, bomb iU07Gyie1d)O and also bq reduction with Raney nickelsuggested that the polymer chains were pac1;ed in aluminum alloy and aqueous alkali (41% yield).7 The hexagonal unit cells. One dimension Of the unit second method was found to be the most convenient in spite cell was calculated Irom these dat'i and found to of the low yield because it could be carried out on a larger scale. The mcsa aiid racemic bn's were separated by fracbe 6.3 4. The repwt clistarice ,t!o:ig t h e Llxr axis llization of the dihydrochlorides from methyl was determined to be 33 froin measureint sits of r. u a c e i ~ i cforin is about eight times more soluble the layer-line separation of the spots. These &ita than the wzcso form at room temperature. The free amines were liberated by the reaction of the calculated amount of established the unit cell to be hexagonal, with the sociium niethoxide with the dihydrochlorides in absolute nlrohol, followed by distillation under reduced pressure. dimensions A = ci.5 -%. and C = A. iso-1311 was prepared by the reduction of a-aminobutyroOne structure which xcountg for the extraordi- nitrile with lithium alurriinuin hydride in anhydrous ether. narily long fiber spacing of 35 A. is a spiral chain Eight>.-four grains of a-nminoisohut!-ronitrile in 200 ml. of arranged so that the spir,il starts to repeat itself mhydrous ether was added dropivise, over a period of two after approximately 1 1 iiioiioincr unit.;. This houri, to . I wcll-stirrcd clurry OC 76 g . of LiAlM4 and 2 1. of structure is similar t o that ~vlitchhas bceri ,iss;qiied rcitigation was snpported h y a p x n t - i n - a i d from the to the spiral of polyisobutylene 2nd of Teflon. tiitcs o f He:iIth; Grant S o . G-323'3. l o .ind R . K. Murmann, T H I S J O U R N A L , 74, 2373 (1932). -A planar zig-Lag chain such as in pol)-vinyl chloride mines d i s x s s e d h e r e are designated as follows: h-K'or polyethylene is ruled !>utbecause it requires a fiber dil\Icen = S,S'-diniethylethylenediamine; I\"'-diEten = N,N'axis spacing of about 5 A. d i ~ ~ t l i y l e t h y l i . i i e d i a m i n e ;S N ' - i l i - n '-di-ii-propylethylOn the basis of this assumed structure, t h e density e n e < i i a m i n e , X X ' - d - i Pren = of the po1ymc.r may be c-dculated usinr: t h r t'cjil;tti~)ri SS'-di-;z-Bricn = S,S'-di-?z-butp ~~

ii

where

=

:tininropa?ie(~irol)~Ienediamine);iil-bn = rac-2,X-diaminohutane; l e - b n = nir,s~j-2,3-iliatiiinobutane; isu-bn = 1, 71'ctraMFc:i = 2 , 3 - d i ; i m i n o - 2 , 3 - d i n 1 c t t , ~ l t ~ ~ t a n e ; ~iii~lieiir.lrtl~ylcn~~li~ n -~s~t i~e i in e = ;: mesii-1.2 :j

mine.

March 20, 1053

anhydrous ether. The mixture was stirred overnight a t room temperature and then decomposed by the addition of 50 ml. of water, 40 ml. of 20% sodium hydroxide solution and 150 ml. of water, in that order, with cooling. The solid was removed by filtration and the ether solution dried over anhydrous sodium sulfate. Fractional distillation of this solution gave 30 g. (34%) of iso-bn. Another 10-15 g. of the amine was obtained from the solid by digesting it with hot benzene and distilling the extract. Anal. Calcd. for the dihydrochloride, C ~ H I Z N Z C C1, ~Z: 44.0. Found: C1, 43.7. TetraMeen could not be prepared from the reaction of 2,3-dibromo-2,3-dimethylbutanewith either aqueous ammonia or liquid ammonia. Likewise it was found that tetramethylsuccinamide reacted with sodium hypobromite in water to give only complex mixtures from which no TetraMeen could be isolated. TetraMeen was finally prepared by the reduction of 2,3-dinitro-2,3-dimethylbutaneswith zinc and concentrated hydrochloric acidg (40% yield). Catalytic reduction with platinum or Raney nickel and hydrogen gave very poor yields of impure product. The synthesis of m-stien involved the condensation of benzaldehyde with liquid ammonia to yield hydrobenzamide which was rearranged to amarine by heating a t 130' for five hours.'o Amarine was acetylated by refluxing with acetic anhydride and sodium acetate for four hours. Hydrolysis of the meso-K-benzoyl-N'-acetyl-1,2-diphenylethylenediamine with 50% (by volume) sulfuric acid" and treatment with sodium hydroxide gave solid m-stien, which was recrystallized several times from water t o give a pure product. rac-Stilbenediamine was prepared by rearranging amarine to isoamarine by heating four moles of amarine with five moles of sodium hydroxide in 150 ml. of water and 800 ml. of diethylene glycol to boiling for one hour. The isoamarine was then acetylated and hydrolyzed as with amarine and pure dl-stien was obtained after three crystallizations from high boiling petroleum ether. .The boiling points or melting points of the final purified amines shown in Table I are in good agreement with the values reported in the literature.

TABLE I S~\"-DI-ALKYLETHYLESEDIAMINES ( RNHCHZCHZPI'HR) B.P.,

R

Me Et n-Pr i-Pr n-Bu

B.p.,

O C .

base titrations was a sample of 99.96% potassium hydrogen phthalate obtained from the Bureau of Standards. The constant ionic strength nitric acid solution containing barium nitrate was made in the same manner as previously described.2 All measurements were made in the presence of 0.05 M Ba(NO& and 0.50 M KNOa except dland m-stien which were titrated against a standard perchloric acid solution containing 0.005 M Ba(C104)2 in 50% dioxane-water. The solutions were maintained a t constant temperature by means of a constant temperature bath a t 25 i 0.1" and by an intimate mixture of ice and water at 0 i 0.1'. A Beckman pH meter model G was standardized against Beckman standard buffers at a pH of 4.00 and 7.00 before each run. With solutions containing 50% dioxane, a calibration curve was made to correct for the change in activity coefficient of the hydrogen ion in a solvent of different dielectric constant. No such correction was necessary for the NN'-di-n-Buen because the final solutions contained less than 1% of dioxane. With each amine, one complete titration curve was made and a series of constant values obtained for pK1 and pK2. In each case either another titration was made or two separate solutions were made one of which fell in the first dissociation constant range and the other in the second dissociation range. The constants were checked by measuring the respective pH's. The constants calculated from these solutions agreed with those obtained from the titration within f O . O 1 pK unit. The dissociation constants at 0 and 25" along with the heats of neutralization are summarized in Tables 11 and 111. A, graphic representation of these pK values is shown in Figs. 1 and 2.

11.0

10.0

% 9.0

O C .

118-119* 148-1504 186-188" 171-171.5 111-113 (10 mm.)e

8.0 7.0

C-SUBSTITUTED ETHYLENEDIAMINES (n"zCRR'CR"R'"SH~) Amine

1479

NOTES

M.P.,

R = Me Et 'n-Pr n-Bu i-Pr Fig. 1.-Dissociation constants of N,N'-dialkylethylenediamines, RNHCHzCH2NHR.

oc.

Pn 118-11Qb dl-bn 44-45 (25 mm.)' m-bn 46-48 (25 mm.)' iso-bn 36-38 (15 mm.)ll TetraMeen 147-148' 97-98' dl-stien 80-82" m-stien 119-12010 a J. A. King and F. H. McMillan, THIS JOURNAL, 68, 1774 (1946). Beilstein, "Organische Chemie," Band IV, p. 257. Preparation of Solutions and Titrations.-The amines were diluted with water until they were 1.5 to 5 molar and then standardized against standard acid by means of conductometric and pH titrations. Because of the low solubility of NN'-di-n-Buen, dl-stien, and m-stien, they were dissolved in 15, 50 and 50% by volume dioxane-water solutions, respectively. The primary standard for all acid(8) L. W. Siegle and H. B. Hass, J. O i l . Chein., 6, 100 (1940). (9) J. Bewad, Bev., S9, 1233 (1906).

(10) I. Lifschitz and J. G. Bos, Rec. Iraq. chim., 59, 173 (1940); 0. F. Williams. Ph.D. Thesis, University of Illinois (1952). ( 1 I ) W. 1%.Mills and T. H. H. Quibell, J. Chcm. S u c . , I, 843 (1935).

Qt %

8

7 6

5

t

'I,

1 pn dl-bn nz-bn i-bn tetra- dl- mMeen stien stien Fig. 2.-Dissociation constants of C-substituted ethylenediamines: -, water; - - -, 50% dioxane-water. 4

NOTES

1480

Results The acid-base dissociation constants of the N,N'dialkylethylenediamines are nearly the same from methyl to n-butyl with a slight rise in pK1 and pK2 wit5 NN'-di-Eten. This same maximum was noted previously for pKz of the N-alkylethylenediamine series2 a t N-ethylethylenediamine, although it was not found in pK1. As is the case in the Nalkylethylenediamine series, NN'-di-i-Pren is a stronger base than NN'-di-n-Pren. It is likewise noteworthy that although the pK2 values of the N,N'-dialkylethylenediamines are similar to the pK2 values of the N-alkylethylenediamines, these are not the same. 1)ISSOCIATION

TABLE I1 CONSTASTS AND HEATSO F

hTEUTRALIZATIOS

O F I\',I\J'-DIALKYLETHYI,ENEDI4MINES

Amine NN'-diMeen5 NN'-diEten NN'-di-n-Pren NN'-di-n-Buen NN'-di-i-Pren

9x1

0' 8.30 8.53 8.14 8.18 8.26

P Kz

0' 10.89 11.06 10.97 10.93 11.12

25'

7.47 7.70 7.53 7.46 7.39

25' 10.29 10 46 10 27 10.19 10.40

AH, kcal. AH1 -12.4 -12.4

-

9 1

-10 7 -10.0

AH1 8.9 8 9 -10.4 -11.0 -10.7

-

a 7.28,10.06 (No specific temperature was given). Irving, Paper No. 4, "A Discussion on Coordination Chemistry," Butterwick Research Laboratories, I.C.I., Sept. 21-3, 1950.

TABLE 111 DISSOCIATION CONSTANTS AND HEATSO F SEUTRALIZATION OF C-SUBSTITUTED ETHYLENEDIAMISES fiKi

Amine

ma dl-bn m-bn

iso-bn TetraMeen dl-stien(50% dioxane) m-stien(50%dioxane)

0' 7.81 7.60 7.55 7.41 7.18 4.60 5.55

AH, kcal.

9K?

25'

0'

7.13 6.91 6.92 6.79 6.56 3.95 4.78

10.76 10.69 10.63 10.74 10.73 8.85 8.59

25' 10.00 10.00 9.97 10.00 10.13 8.09 7.85

AH1

-10.1 -10.3 - 9.4 - 9.2 9.2 - 9.7 -11.6

-

AH? -11.3 -10 3 - 9.8 -11.0 8.9 -11.3 -11.0

-

a 7.00, 9.78 (30°, 0.5 KNOz). Carlson, McReynolds and Verhoek, THISJOURNAL, 67, 1334 (1945).

Substitution of methyl groups in the carbons of a n ethylenediamine skeleton only slightly decreases the base strength of the amine. However, substitution of phenyl groups, as in stilbenediamine, appears to decrease the base strength but i t must be remembered that much of this decrease may be due to a change in solvent. Little difference was noted between dl-bn and m-bn although the former was slightly more basic, while pK1 of dl-stien is slightly larger than that for m-stien and the reverse is true for their pK2 values, The heats of neutralization are in the range of - 9 to -12 kcal. which is slightly higher than that found for the N-alkylethylenediamines. DEPARTMENT OF CHEMISTRY NORTHWESTERN UNIVERSITY EVANSTON, ILLINOIS

A6*'-Steroids.

XV.'

A3+6*7-Cholestatriene-3-ol Acetate

BY SEYMOUR BERNSTEIN, MILTONHELLERAND WILLIAMS RECEIVED SEPTEMBER 25, 1952

JAMES

H.

I n the previous paper of this series, there was deXIV, R. Antonucci, s. Bernstein, M. Heller and J. H.

(1) Paper

Williams, J . Org. Chcm., 17, 1446 (1962).

IToL75

scribed the preparation of A3J~7-cholestatriene-3-ol acetate by the treatment of A4f7-cholestadiene-3one with acetic anhydride and pyridine. The physical constants [m.p. 101.5-103"; A$!; 302.5303, 315 and 330.5 nip, eli900, 221300, and 16200, respectively; [ a l Z b-~147" (chloroform)] of this preparation were strikingly different than those reported by Dauben and co-workers,2who prepared this enol acetate from A4t6-cholestadiene-3-onewith acetic anhydride and acetyl chloride. In view of the reported conversion of A4'6*22-ergostatriene-3one with acetic anhydride and acetyl chloride to A2~4~6~22-ergostatetraene-3-ol acetate (64% yield), it was proposed' that the California preparation may have consisted of mixed crystals of A2*4*sand A3~5~7-cholestatriene-3-ol acetates. We now wish to report that, in our hands, treatment of the A4v6-3-ketonewith acetic anhydride and acetyl chloride gave A3J~7-cholestatriene-3-ol acetate (27% yield), identical in all respects with the compound prepared from the A4f7-3-ketone.A spectral analysis of the initial mother liquors obtained on the recrystallization of the enol acetate indicated the presence of only starting material (?), and no A3r5s7- or A2*4*6-enol acetates. This may be accounted for by incomplete reaction, or by unintentional hydrolysis of any enol acetate present. Whether or not a A4f6-3-ketoneunder these conditions gives rise to a mixture of enol acetates remains unsolved. To substantiate further this method of preparing a A3t5t7-enolacetate from a A4*6-3-ketone,A4e6androstadiene-17/3-01-3-one benzoate was transformed into A3~6~7-androstatriene-3,17/3-diol-3-acetate-1$-benzoate. Finally, mention should be made of a pertinent optical rotational analysis. I t is known that if C-17 "vicinal action" is absent, a compound with an "ergosterol" side chain will have a specific rotation of about 20' ( A [ ~ ? ] D 78') more negative than the corresponding "cholesterol" compound. An examination of the rotations of the four compounds compiled in Table I reveals gross irregularities which unequivocally indicate "vicinal action." These anomalies may be explainable by the suggestion of Barton and Cox6 of a possible qualitative correlation between anomalies and the ultraviolet absorption spectra of the compounds. TABLE I AXALYSIS ROTATIONAL Compound

A4*'-Cholestadiene-3-one ~i~*'*~~-Ergostatriene-3-one A"5~7-Cholestatriene-3-olacetate A3*5~7*22-Ergostatetraene-3-ol acetate See ref. 1. b This work.

[.lo

(CHCla)

A[P]D

+33"" ... - 12" 45 - 147; - 145'' . . ,

O

- 144"

D

(2) W. G. Dauben, J. 17. Eastham and R. A. Micheli, THIS JOURNAL, 73, 4496 (1951); m.p. 91-93', h i & 305, 316 and 330 m p , ESM 20,000; [ a l Z 5 D -69" (chloroform). (3) I. M. Heilbron, T. Kennedy, F. S. Spring and G. Swain, J. Chem. Soc., 869 (1938). (4) S. Bernstein, W. J. Kauzmann and E. S. Wallis, J . Org. Chem., 6, 319 (1941). ( 5 ) D. H. R. Barton and J. D. Cox, J . C h e m . SOC., 783 (1948).