610
VOL.
NOTES
20%. On standing, the precipitated hemicellulose flocculated and was separated by centrifuging. The separated hemicellulose was treated with 95% alcohol, acetone, and ether in the usual manner. Two and five-tenths grams of dry, white hemicellulose, identified by hydrolysis and chromatography as 9570 xylan, was obtained. The use of other sequences of reagents for the preparation of cellulose was not so successful as the one described above. The sequences of treatment and results are shown in Table 11. Fractionatzon and characterization. One-tenth gram of the cellulose obtained above was transferred into a 100-ml. centrifuge bottle to which 10 glass beads and a selected amount of water was added. The bottle was then stoppered with a serum-bottle rubber stopper. The stopper was pierced with a syringe needle, to which, in addition to a cupriethylenediamine reservoir, nitrogen and vacuum lines nith appropriate stopcocks were also connected. The air in the bottle was first evacuated and then replaced with purified nitrogen. The bottle was again evacuated and filled with cupriethylenediamine to make up 100 ml. and finally filled with nitrogen. The bottle was then shaken for 2 hr. and centrifuged. Ten milliliters of the supernatant solution was withdrawn with a syringe and transferred into an Ubbelohde viscometer in which the viscosity was detei mined. The transferring and the measurement of viscosity were conducted under nitrogen. The viscosities of the samples obtained with varied concentrations of cupriethylenediamine solution are shown in Table 111. The residue mts separated and washed with lYG acetic acid and water. Fifty milliliters of the supernatant solution was neutralized Tvith 50%) acetic acid. Precipitation occurred. The precipitate n-as centrifuged, separated, n-ashed, and weighed. Thirty milligrams each of the residue and of the regenerated cellulose were hydrolyzed with sulfuric acid, chromatographed and analyzed for glucose and xylose.5 The results are shown in Table 111.
Acknowledgment.The author thanks Miss Florence Link for supplying the gourd obtained during a vacation in Mexico. The author is also indebted to Mr. Kei Matsuzaki for determination of sugars. INSTITL TE OF PAPER CHEMISTRY APPLETON,\TIS. (5) J. F. Saeman, \T. E. Moore, R. L. Mitchell, and M. A. hlillett, Tappi, 37, 336 (1956); J. Pridham, Anal.
take place in the 4-position. The attack at this position is believed to be due to the greater electron density a t the 4- and 7-positions of the dicationic salt of I as compared to the 5- and 6-positions.' Because of the ortho-para directing effect of the methyl group, the nitration of 5-methyl-2,1,3benzoselenadiazole (11) could be expected in the 4position. The following facts bear this out. The nitration of I1 gave a nitro derivative (111) whose TABLE I ULTRAVIOLET-VISIBLE ABSORPTIOKSPECTRA O F SOME 2,1,3-BENZOSELENADIAZOLEDERIVATIVES Substituted 2,1,3-Benzoselenadiazole 5-Nitro-
'
(1) Paper 11: E. Sawicki and A. Carr, J. Org. Chem., 22, 507 (1957). (2) Thie investigation was supported by research grants (2-1066 from the National Cancer Institute, National Institutes of Health, U. 5. Public Health Service and CH-14 from the American Cancer Society. (3) Present address: Robert A. Taft Sanitary Engineering Center, 4676 Columbia Parkway, Cincinnati 26, Ohio.
Xm,,
(log
Solventa
E)
230 (3.71) 274 (4.02) 342 (4.21) 224 (3.86) 274 (4.03) 348 (4 2 2 ) 400b(3.2 ) 271 (3.57) 339 (4.19) 370 (3.8)' 275 (3.73) 340 (4.16) 380 (3.7) 338 (4.27) sro (3.3)' 279 (3.61) 351 (4.22) 380 (3.7) 336 (4.26) 370 (3. 56)c 245 (3.56) 302 (3.81) 352 (4.31) $90 (3.67) 236 (4.25) 324 (3.94) 426 (3.80) 266 (3.65) 236 (3.97) 333 (4.10) 459 (3.74) 242 (4.14) 322 (4.00) 462 (3.28) 329 (4.08) 336 (4.07) 231 (3.70) 333 (4.23) 370 (3. l)c 238 (4.11) 323 (4.00) 466 (3.23) 329 (4.04) 336 (4.05) 232 (3.73) 330 (4.18) 3ro (3.4)C 232 (3.70) 333 (4.24) 370 (3.3)G 292 (4 33) 388 (4.32) I
4-Nitro-
4-Nitro-5methyl4-Sitro-5,7dimethyl5-Amino4-Amino-
4-Amino-5(and 7)methyl-
5-Methyl4-Nitro-5Chem., 28, 1967 (1956). styryl4-Nitro-5- (4 'methylStructure of 2,1,3-Benzoselenadiazole and Its stYrY1)4-Ni tro-5- (4'Derivatives. 111.' Preparation and Absorption chloroSpectra of 5-Styryl-4-nitro-2,1,3-benzoselena- styry1)4-Sitro-5diazoles' (3',4'-dimethoxys tyryl)EUGENE S,4WICE13 AND ALBERTc A R R 4 4-Nitro-5-(4'dimethylReceived June 25, 1957 aminostyry1)-
The nitration of 2,1,3-benzothiadiazole~ and 2,1,3-benzoselenadiazole' (I) has been shown to
23
E A E A
E A E A
E AC E AC E
AC E Ed
300 (4 26) 400 (4.23) Ed 295 (4.30) 382 (4,lO) Ed 240 (4.22) 335 (4,22) 408 (3.79) Ed
340 (4,38) 489 (4.32) Ed
E = 95% ethanol; A = 95% sulfuric acid; Ac = 50% alcoholic 1.2N HCl; Ed = 95% ethanol containing 0.2% dioxane. Underlined values are shoulders. Weak inflection. (4) Taken in part from the dissertation to be submitted by Albert Carr in part,ial fulfillment of the requirements for the Doctor of Philosophy Degree a t the University of Florida. (5) L. Efros and R. Levit, Z h w . Obshchef Khim., 23, 1552 (1953); Chem. Abstr., 48, 12091 (1954).
APRIL
1958
611
NOTES
length maximum in millimicrons: acetone, 335, 480; dimethylformamide, 340,487; dimethylaniline, 340, 498; dimethyl sulfoxide, 349, 501; chloroform, 337, 501 ; pyridine, 347, 502; anisaldehyde, 505; 50% aqueous acetone, 349, 513; 50% aqueous dimethylformamide, 347, 513;. and 50% aqueous pyridine, 350, 520. I n the pure solvents the long wave-length band was slightly more intense than the shorter wave-length band; in the aqueous solutions the long wave-length band was relatively less intense and shifted further into the visible. Ap-
300
350
400
450
500
h1ml.l
I1
I11
/
Fig. 1. Absorption spectra: 5-(4’-Dimethylaminostyryl)4nitro-2,1,3-benzoselenadiazole in 9570 ethanol (); 4-Dimethylami1io-2’,4’-dinitrostilbenein benzene (- - - -)
IVa spectra in alcoholic and sulfuric acid solutions more closely resembled the spectra of 4-nitro-2,1,3benzoselenadiazole in these same solvents than the spectra of the 5-nitro isomer, Table I. For the same reasons the nitration of 4,6-dimethyl-2, !,3-benzoselenadiazole is believed t o take place in the 7position, Table I. Reduction of I11 to the triamine followed by reaction with selenium dioxide gave a mixture of amin0-5-methyl-2,1,3-benzoselenadiazoles that was difficult to separate. The mixture of amino-5-xnethyl-2,.l,3-benzoselenadiazoles was found to be closely sunilar spectrally in alcoholic and acidic solution to 4-amino-2,1,3-benzoselenadiazole in the same solvents and entirely different parently the water molecules arrange themselves spectrally from 5-amino-2,1,3-benzoselenadiazole, so as to stabilize dipolar structures, such as IVa, to Table I. As I11 undergoes condensation with al- a somewhat greater extent in the excited state. dehydes (and I1 does not under identical condi- This “closing up” of the energy levels is reflected tions), the nitro group must be ortho t o the methyl. in the red shift. This means that nitration of I1 takes place in the Two protons add t o the heterocyclic nitrogens of 4-position. I in sulfuric acid’ while only one proton adds to I11 Examination of the absorption spectra of the in the same solvent. I n the styryl derivatives there stilbene derivatives (IV) in alcohol discloses that must be an increase in the basicity for two protons the long wave length band shifts toward the visible can add to the molecule in sulfuric acid, Table 11. in the order Z = H = 4’-C1 < 4’-Me < 3‘,4/- The spectra of the bases, monocationic and di(OMe)z
