MILTONB. FRANKEL AND K ~ R KLAGER L
5428
(C) The Cyanoethylation of Methanol.-Similarly, the experimental data suggest the mechanism CHiO-
+ CHz=CHCN
---+ CHaOCHzCHCN (slow) (14)
+
CH30CHzCHCN C&OH + CH30CHzCHzCN 4- CH&
(fast) (16)
Therefore d x l d t = ~ ~ ~ [ C H Z C H[CHaO-] CN] = k’(a
- x)c
[ C O N T R I B U l 7 O N FROM THE
(16)
Vol. 78
I t is not possible to estimate the conceiitratioii 01 methoxide ion in equation 16. However, it was found that the observed rate constants k’ a t various alkaline concentrations hold constancy, hence the dissociation of sodium methoxide seems to be almost complete in such a dilute solution. Acknowledgments.-The authors thank Prof. K. Oda for his advice and Teikoku Jinkcn Co. for their material assistance. KYOTO,JAPAN
RESEARCH LABORArORIES, AEKOJET-GENERAL CORP.]
Derivatives of 4-Nitrazap entanonitrile B Y &TILTON ?d.F R A N K E L AND KARLKIAGER RECEIVED MAY25, 1056 4-IUitrazape1itario1iitrilehas been prepared and converted to 4-nitra~3peiitatioylchloridc, 3-nitrazdiutyl isocyaii‘ite 3-nitrazabutylamine. Derivatives of these compounds are reported.
atit1
CHARTI The preparation of aliphatic gem-dinitro dinitriles, such as 4,4-dinitroheptanedinitrile, and 1, CHIOH HC1 HCt soc1, monoesters, such as methyl 4,4-dinitro~entanoate,~ RCN IICOIH has been reported recently. Aliphatic secondary RCOzCH:, 2, HzO nitraza dinitriles such as nitrimino-bis-acetonitrile3 and nitrimino-bis-propionitrile4 have also been synthesized, but the secondary nitraza aliphatic mononitriles have not been reported. Because of the desire for comparing the physical properties and chemical reactions of the aliphatic gem-dinitro compounds and the nitramino analogs, i t was of interest to study the chemistry of a simple aliphatic secondary nitramine containing a mononitrile group. For this purpose 4-nitrazapentanonitrile (111) was chosen since 4-azapentanonitrile (I) was readily available from the Michael reaction of methylamine and acrylonitrile.6 Using the Wright procedure4 for the nitration of secondary amines, Compound I was converted v b the nitric acid salt I1 H CHz NO2 so2 into 111. __f
H CH3SHz
I
+ C H F C H C N +CHaNCHzCHzCN
“03 L_j
1
I AczO I CHaNCH2CHzCN eCH3NCHzCHzCN HC1 I1 I11 The chemical reactions of 4-nitrazapentanonitrile (111) are summarized in Chart I. 4-Nitrazapentanonitrile (111) was converted via the imino ester hydrochloride to methyl 4-nitrazapentanoate (IV). The ethyl ester was prepared in the same manner. Hydrolysis of I11 or I V with concentrated hydrochloric acid gave 4-nitrazapentanoic acid (V), which was refluxed with thionyl (1) L. Herzog. M. H. Gold and R. D. Geckler, THIS JOURNAL, 73, 749 (1951). (2) H. Shechter and L. Zeldin, i b i d . , 73, 1276 (1951). (3) A. P.N. Franchimont and J. V. Dubsky, Rcc. Irao. chim., 36, 80 (1916). (4) G. F. Wright, el al., Can. J. Rescarch, [Bl 26, 114 (1948). (5) A. H . Cook and K. J. Reed, J. Chcm. SOC.,399 (1945).
RNCOzCHa 1 IX
[k triniethyiethylene > anethole > isobutylene >asym-diphenylethylene > butadiene > cyclopentene > cyclohexene = styrene > 1-hexene > allylbenzene > vinyl bromide. Since essentially the same sequences of rates and stereospecificity is observed for bromination and epoxidation of olefins, a common intermediate complex is suggested for these three-center-type addition reactions. It is proposed that the intermediate complex (111) in carbene-olefin reactions is a partially-formed cqclopropane with carbonium ion character developed on one of the carbons of the double bond.
The reaction of dibromocarbene, :CBr2, with I and I1 on experimental grounds we sought evicis- or trans-2-butene is stereospecific and produces dence for the radical nature of the intermediate. If I1 has a lifetime longer than a vibration period the cis- or trans-l,l-dibromo-2,3-dimethylcyclopropane from the respective olefin.' It follows sec.) the interaction of the trivalent cara distance of 2.54 A. (c&, distance in bons over H H propane) should make a minor contribution to the \C-C / :CBr2+ ground state of 11. Thus if I1 correctly represents / \ CHz\//Br the structure of the intermediate in this reaction, CHI CIT3 the relative rates of reaction of olefins should be CHa essentially the same for :CBr2and a radical such as .cc13. Whatever structural factors operate to make one olefin more reactive than another in addition of CC13, should operate equally well in the addition of :CBrB,if I1 is an intermediate. To ascertain the necessary relative rate confrom these observations that the intermediate had stants, :CBr2was generated in t-butyl alcohol solueither (a) a cyclopropane structure (I) in which tion (from bromoform and potassium t-butylate) bond formation to both carbons was established in the presence of known quantities of two olefins. simultaneously, or (b) the structure of biradical Preliminary experiments had demonstrated that 11, with propane bond angle and bond lengths, the olefins were utilized solely in the production of which cyclized with a half-life less than to dibromocyclopropanes and that these products second to a cyclopropane. The limits set on were stable. The amounts of the two dibromothe half-life of I1 resulted from a theoretical consid- cyclopropane products were determined and by eration of the rates of rotation about the single difference the amounts of unreacted olefin. For bond. two parallel bimolecular reactions (1) the ratio of rate constants is given by equation 4,C and C' be-
+
1-B'
R-CH=CH2
k + :C13rz --+
R-CH-CFTz (1)
/ \
0 1
I
Br
I1
Relative Rates of Addition of :CBr2and ' CC1, to Olefins.-With the hope of distinguishing between ( 1 ) P S Skell and A
Y.Garner, TITI?TnrmNAr,, IS, 3409
(1956)
Br
ing the concentrations of the respective olefins atid nl, nr, nf and n; being the initial and final molar amounts of the respective olefins. Since the volume of the solution V increased during the renctim
