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xpubs.acs.org/doi/pdf/10.1021/ja01623a091Similarby JR Van Wazer - ‎1955 - ‎Cited by 34 - ‎Related articlesout purification to the ethyl ester,7 ...
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COMMUNICATIONS TO THE EDITOR

Sept. 20, 1955

(dec.) (Found: C, 59.66; H, 5.13), secured by saponification of the diethyl ester which results from interaction of sodio malonic ester with 2(a-pyridy1)-allyl acetate,0 was condensed with benzylamine and formaldehyde; the Mannich reaction, accompanied by decarboxylation and cyclization, yielded N-benzyl-3- (a-pyridy1)-piperidine-5-carboxylic acid, which was converted without purification to the ethyl ester,7 b.p. 183-184" (0.1 mm.) (Found: 3, 74.45; H, 7.84). Lithium aluminum hydride reduction afforded N-benzyl-3CH,=C-< \\

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CaH5CHx-S

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have been previously obtained by alkylation of cytisine,Sslo the synthetic route described above thereby embraces these natural products as well. Acknowledgment,-This work was supported by grants from the Research Committee of the Wisconsin Alumni Research Foundation and from the National Science Foundation. The authors wish to express their gratitude to Professors Marion and Galinovsky for gifts of cytisine. (10) A Partheil, Bcr., 24, 635 (1891).

DEPARTMENT O F CHEMISTRY EUGEXE E. VAN TAMELEN UNIVERSITY OF WISCONSIX JOHNS. BARAN MADISON,IVISCOSSIK RECEIVED J U N E 17, 1955

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" 'x-- Br\--J,L NUCLEAR MAGNETIC RESONANCE SPECTRA OF IV THE CONDENSED PHOSPHATES

(a-pyridyl)-5-methylolpiperidine (111),7 b.p. 193194" (0.1 mm.) (Found: C, 76.78; H, 8.24; N, 9.84). Refluxing I11 with hydrobromic acid led to the 5-bromomethylpiperidine, which, as the free base, was quaternized without isolation to the tricyclic pyridinium bromide IV, m.p. 170.5171.5" (Found: C, 62.80; H, 6.29; N, 8.23). The salt, on oxidation with alkaline ferricyanide, gave rise to dl-N-benzylcytisine, m.p. 137.5-139" (Found: C, 77.16; H, 7.22), the infrared spectra (obtained in chloroform and carbon disulfide) of which were identical in every detail with the corresponding spectra of N-benzylcytisine, m.p. 140-142" (Found: C, 77.23; H, 7.39), obtained by monoalkylation of the alkaloid. Hydriodic acid cleavageSof dl-N-benzylcytisine afforded dl-cytisine, m.p. 145-146' (Found: C, 69.53; H, 7.46); the infrared spectra of the synthetic base and natural alkaloid were indistinguishable. The key intermediate I11 was also attained by an alternate series of steps. The addition of apyridylacetamide, m.p. 119-120" (Found: C, 62.06; H, 6.19), to methylenemalonic ester yielded the Michael product (V), m.p. 106" (Found: C, 58.15; H, 6.57), which was cyclized by means of sodium methoxide to 3- (a-pyridyl) -5-carboethoxyNHzCO-CH-

4945

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CH2

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H C( COOC2Hs)z V

Sir: As part of a general study of the chemical shifts in the nuclear magnetic resonance spectral of phosphorus compounds, some observations were made which give fundamental support to the idea previously developed, x 3 that in the phosphates there is a difference between isolated, end, middle, and branching-point PO4 groups. These four kinds of PO4 groups each give a separate resonance peak in the nuclear magnetic resonance spectrum. When the chemical shift is measured in parts per million of the applied magnetic field (7140 gauss) and phosphorus tribromide is used as the reference standard, the positions given in Table I are found for the resonance peaks of various types of PO4 groups. TABLE I Type of PO, group

Chemical shifta p.p.m.

Orthophosphate ions (isolated groups) trisubstituted (normal) salts 233 1 to 3 hydrogens/P atom 238 End groups doubly substituted (no H+ions) 244 1 to 2 hydrogens/P atom 247 Middle groups short chains 256 259 long chains Branching points 268 alkali metal ultraphosphates 272 azeotropic phosphoric acid6 a The chemical shifts of the various phosphates are measured i o ca. + 2 p.p.m. with respect t o each other. The actual measurements were made relative t o 85% orthophosphoric acid ; however, the values reported are referred t o phosphorus tribromide as the zero reference and were obtained by adding the value of the phosphorus tribromide shift, relative to orthophosphoric acid, to each result.

glutarimide, m.p. 136-138" (Found: C, 59.65; H, 5.81). Alkylation of the glutarimide, accomplished by heating the sodium salt with benzyl chloride, followed by lithium aluminum hydride reduction, gave rise to: (1) N,5-dibenzyl-3-(apyridyl)-5-methylolpiperidine, m.p. 146-147" Examination of the spectrum of sodium tri(Found: C, 80.52; H, 7.51; N, 7.69), resulting from dialkylation, and ( 2 ) the desired alcohol 111, polyphosphate solutions shows two peaks, one for identified by boiling point, infrared spectral com- the end groups and one for the middle groups. parison, and conversion to IV. (1) E. M. Purcell, Science, 118, 431-436 (1953); F. Bloch, Sciencc, Since the alkaloids caulophylline (N-methyl- 118, 425-430 (1953); Varian Associates, Palto Alto, Calif., "RodioSpcclroscopy," 1 , KO.1 (14531, No. 2 (1934) and A'o. 3 ~ y t i s i n e and ) ~ rhombifoline (N-but-3-eny1cytisine)S frequcircy (1953). (6) F. Bohlmann, N. Ottawa and R . Keller, Awn., 687, 162 (1954). (7) The ratio of c i s and trans isomers was not determined. (8) W. F. Cockburn and L . Marion, Can. J . Chem.. 3 0 , 9 2 (1952). (9) J. U. Lloyd, Proc. A m . Pharm. Assoc., 41, 115 (1893); F. B. Power and A. H. Salway, J . Ckcm. Soc., 103, 191 (1913).

(2) J. R . Van Wazerand IC. A. Holst. THISJ O U R N A L , 72, 631) (1950); J K Van Wazer, ibid., 72, 647 (1950); ibid., paper X in press; and "Encyclopedia of Chemical Technology" (Kirk and Othmer, editors), Interscience. New York, 1953, Vol. X , pp. 403-429.469-472. (3) J. R. Van Wazer, THISJOURNAL, 73, 644 (1950).

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COMMUNICATIONS TO THE EDITOR

VOl. 77

The area of the peak corresponding to the end similar compound containing iron. A crystalline group is exactly twice as large as the middle-group substance having the empirical formula Fe&H408 peak in a pure sample of Na6P3O10. As expected, has been obtained by Reppe2 from the reaction of pyrophosphate solutions show only the end-group acetylene a t 20 atmospheres and 50" with an peak. Spectra of solutions of the various phos- alkaline solution of iron hydrocarbonyl. phate glasses exhibit end- and middle-group peaks We have now synthesized this compound (I) of the heights to be expected from the average in 70% yield by treating an alkaline solution of chain length.2*3 For glasses having chain lengths NaHFe(C0)d with acetylene a t atmospheric presgreater than ca. 75, the end-group peak is so small sure and room temperature. The compound cryswe have not been able to detect it because of signal- tallizes as the monohydrate. Calculated for to-noise limitations. * The trimeta- and tetra- FezC1&08.Hzo: C,31.45; H, 1.58; Fe, 20.25. metaphosphate rings show only one peak in solu- Found: C, 31.40; H, 1.64; Fe, 29.06. We suggest tion-the peak corresponding to middle groups. structure ,4 €or the anhydrous compound based on Because of rapid hydrolysis5 a t branching points, the following evidence. the peak corresponding to this type of PO4 group c r H :, could not be determined for aqueous solutions but '\L ,was measured on solid ultraphosphates heated to ",\ ,/" \ 4)" ce -- L- -- o c=C=FQ their softening temperatures. Azeotropic phos-';/ 4 1C' phoric acid6 and several sodium ultraphosphates/+ \\ 1 \Tn all of which should have shown middle-group as well as branching-point peaks-exhibited only one peak, which we have tentatively ascribed to aw branching points in Table I. This peak is very broad and, for the azeotropic phosphoric acid, .4 disappeared immediately upon dissolution. The The infrared spectrum of Fe&&lO8 (I) in fresh solution of the azeotropic acid showed only end- and middle-group peaks, with the ratio of these carbon disulfide shows two bands in the -OH region a t 3565 cm.-l and 3463 cm.-', three bands peaks being of the expected magnitude. A second-order effect is observed when weakly in the C-0 single bond region a t 1271, 1174, and acidic hydrogens are substituted for alkali metal 1093 cm.-l and three bands in the C=O triple ions in phosphate solutions. Hydrogen covalently bond region a t 1998, 2033, and 2073 crn.-'. These bonded to isolated or end groups leads to a positive last three bands are similar to the three bands shift of approximately 4 p.p.m. This effect is in which appear in the spectrum of dicobalt octaaccord with the fact that the electronegativity of carbonyl3 and in that of the cobalt acetylene hydrogen and phosphorus are equal-a fact which complex1 where these bands have been attributed is very important in phosphate chemistry, as we to CEO stretching vibrations of the six terminal have previously pointed These results and carbonyl groups. The PKu values4 of the first some other interesting findings (such as fine struc- and second hydrogen of I are 6.30 and 9.14. Eviture in the tripolyphosphate spectrum) will be dis- dence for the presence of phenolic type hydroxyl groups is the shift to longer wavelengths and incussed in more detail in a forthcoming paper. crease in intensity of the ultraviolet spectrum when (4) Measurements were made on t h e high resolution spectrometer excess alkali is added to an aqueous solution of I. (Model V 43000 B) manufactured by Varian Associates, Palo Alto, This change is similar to that accompanying the Calif., equipped with a 12.3 rnc. probe. B y going t o a 17.2 mc. probe on t h e same instrument, t h e resolution will increase b y a factor of 1.4 phenol -+ phenolate ion transformation. The and t h e signal-to-noise ratio will be improved by a n approximate factor presence of two hydroxyl groups was also demonof 2 . strated by the preparation of the dibenzoate. ( 5 ) See refs. 2 and 3 a s well a s U. P. Strauss, E. H . Smith and R . L. Addition of benzoyl chloride to a solution of I in Wineman, THISJ O U R N A L , 7 8 , 3935 (1953); U. P. Strauss and T. L. Treitler, ibid., 7 7 , 1473 (1955); and R . Pfanstiel and R. K.Iler, i b i d . , dry pyridine and dilution of the reaction mixture 7 4 , 6062 (1952). with water gave the dibenzoate (11) in theoretical (6) G. Tarbutton a n d M. E. Deming, THISJ O U R N A L , 7 2 , 2086 yield. Crystallized from ethanol-water, I1 forms (1950); E. H. Brown a n d C . D. Whitt, I n d . Eng. Chcm., 4 4 , 615 yellow microcrystals which melt a t 156" with (1952). decomposition. Calcd. for Fe2C24H1~O10:C, 50.39; INORGANIC DIVISIOARESEARCH LABORATORY J . R. VANWAZER H, 2.11; Fe, 19.53. Found: C, 50.34; H, 2.13; MOXSANTO CHEMICAL COMPANY DAYTOA-, Omo C. F. CALLIS Fe, 19.41. T?ARIAN AS~OCIATES J. X. SHOOLERY The configuration of X may be assumed to be PALOALTO,CALIFORNIA analogous to iron enneacarbonyl where all ironRECEIVED AUGUSTlti, 1952 carbon u bonds are formed by d2sp3hybrid orbitals. - h o t h e r possible configuration is one in which the r bonds from iron to the terminal carbons and to

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A BRIDGED IRON COMPLEX DERIVED FROM ACETYLENE AND IRON HYDROCARBONYL

Sir: The recent discovery' of an organometallic compound derived from acetylene and dicobalt octacarbonyl led 11s to postulate the existence of n ( I ) II. W. Sternberg. H. (:reenfielrl, R A Vriedhl, J I l n r k b g , unrl 1. Wender, THISI C I I J R N A I , 7 6 , 1457 (I95k).

Tvotiz, T i

( 2 ) W . Reppe and H. Vetter, Aizn., 682, 133 (1953). (3) H. W, Sternberg, I. Wender, R . A. Friedel and M. Orchin, THISJOURNAL, 7 6 , 2717 (1953). (4) Reppe and Vetterz observed only one acidic hydrogen, b u t thhir potentiometric titration gave a n equivalent weight of 283 instead of t h a t calculated for FezCLoHdOs which is 363. I t is possible t h a t the5e workers did not exclude oxygen during their titration: n e have ohserved t h a t unrelinble results are nhtainpd i f l h e vornpli>\ i.: t i t r n f i 4 i n t h P preqencr 01 oxygen