VOl. 77
NOTES nitropheny1)-methane and 0.43 g. (0.0011 mole) of tri-(pnitropheny1)-carbinol were sepdrated from the reaction products. ROHMAND HAASCOMPANY REDSTONE ARSENALRESEARCH DIVISION HUNTSVILLE, ALABAMA
Selective Reduction of Aliphatic Nitroesters with Lithium Aluminum Hydride' BY HENRY FEUER A N D THOMAS J. KUCERA RECEIVED JUNE 29, 1955
dropwise over a 15-minute period and the solution n a s stirred for another 20 minutes before 5 ml. of ethyl acetate was added. Hydrolysis was then carried out at 0" with .50 ml. of 20% phosphoric acid with 6 g. of urea dissolved in it. The layers were separated and the aqueous layer extracted with two 50-mi. portions of ether The combined ether extracts were dried with anhydrous sodium sulfate and the solvent was removed by distillation. The residue was distilled to yield 0.67 g. of the starting ester, b.p. 90-94" at 2 mm. and 4-nitropentanol (6.67 g., 61% conversiou), b.p. 90-92" at 1 mm., ~ ? O D 1.4479; lit. value3 b.p. 91-92.5" a t 1 mm., nzoD 1.4475. The alcohol was converted in a Nef* reaction to 5-hydroxy-2-pentanone and the ketone was characterized by its 2,4-dinitrophenylhydrazone, m . ~ .146147'; lit. value3 m.p. 146-147'. 4,4-Dinitro-l,7-heptanediol.-The same experimental procedure was followed as above except t h a t tetrahydrofuran was employc5.d as the solvent. The diol was obtained as a u h i t e solid, m.p. 74.575' after recrystallization from methylene chloride. Anal. Calcd. for C7HlaS206: C, 37.84; 11, 6.33; S , 12.61. Found: C, 87.92; H, 6.56; N, 12.88. The bis-phenylurethan, m.p. 119.5-120°, was prcp.trcd and recrystallized from ethylene chloride. .4nnZ. Calcd. for C21H24r\r4O8: C, 54.78; H, 5 . 2 2 ; N, 12.17. Found: C, 55.50; H, 5.40; N, 12.43.
The selective reduction of ethyl fi-nitrobenzoate and ethyl P-nitrophenylacetate t o the corresponding nitroalcohols with lithium aluminum hydride at 25" has been reported by F e l k k 2 We wish to report the successful reduction of aliphatic nitroesters, containing a secondary, tertiary or gem-dinitro group, t o the corresponding nitrocarbinols in yields which compare favorably with those obtained by the reduction of aliphatic nitroaldehydes with sodium borohydride. The reductions mere Acknowledgment.--ii-e are indebted to the carried out smoothly a t - 30 to - 60" by employing a slight excess of the hydride and ether as the sol- Office of Naval Research for the financial support vent, except in the case of dimethyl 4,4-dinitropi- of this work. (8) J U Kef, A n n . , 280, 263 (1894) melate where tetrahydrofuran had to be used because of the limited solubility of this ester in ether DEPARThEENT O F CHElXISTRY PURDUE USIVERSITY at low temperatures. LAFAYETTE, INDIAX.4 Since methyl 4-nitropentanoate did not evolve hydrogen when treated with the hydride a t low temperatures, several nitroesters with more highly The Reactions of Triphenylgermyllithium with active hydrogens werc tested. It was found that Formaldehyde and with Benzophenone ethyl 2-nitropropanoate, ethyl 2-nitrocaproate and IJu HESRI' GILXASA S D CLAREW. GEROW ethyl 3-nitropropanoate reacted with lithium aluRECEIVED JTJNE 4, 1955 iiiinum hydride a t - 30 to - 60" without the evolution of hydrogen. However, great difficulty was It has been reported' previously that tripheiiylencountered in the isolation of the alcohols because silylpotassium reacts with formaldehyde in diethyl of the high water solubility of the n i t r o p r ~ p a n o l s ~ether to form, along with other unidentified maand known tendency of the 2-nitro-1-hexanol to terial, triphenylhydroxymethylsilane (I). The dehydrate to the olefin upon distillation.: same authors report2 that triphenylsilylpotsssium TABLE I Yield, Methyl ester 4-Xitropentanoate 4-Methyl-4-nitropentarioaten 4,4-Dinitropentanoateh 4,4-Dinitr~pimelate~
Product 4-Nitropentanol 4-nIethyl-4-nitror,clltanold 4,4-Dinitropentanold
4,4-Dinitro-1,7-heptanediol
70
tile 76' 53 56
OH. A. Bruson, U. S. Patent 2,342,118 (1949). " H . Shechter and L . Zeldin, THISJOURNAL, 73, 1276 (1951). c L . Herzog, et al., ibid, 73, 749 (1951). Identified by physical properties and derivatives according to H . Shechter, et al. (ref. 3 ) . e Some of the starting ester was recovered. Experimental6 The following procedure is representative of the preparation of the various nitroalcohols. 4-Nitropentanol.-Methyl 4-nitro[)cntatloatei (13.87 g., 86 mmoles) was dissolved in BO ml. of anhydrous cther and the solution cooled t o -35". Lithium aluminum hydridc solution in ether (53.7 ml. of 0.81 AI, 43 mmole) vias added ..
(1) From the Ph.1). thesis of T h o m a s J . l i t i c r r n , Purdue Univrr sity. 1953. (2) H. Felkin, Comfit. u o i d . , 230, 305 (1950). (3) H. Shechter. D. E. Ley and L. Zeldin, THISJ O U R X A I . , 74, ,3064 (1952). (4) "Nitrohydroxy Derivatives of the Nitroparaffins," Commercial Solvents Carp., New York, N. Y . (5) E. F. Degering and R. Hoaglin, P I T I C Iiiriiniia . A c o d . S c i . . 63, 119 (1942). (6) All melting points are uncorrected. (7) H. Bruson, U. S. Patent 2,390,018 (1945).
(C&)3SiK
+ HCHO
H20
(C6Hh)&iCH20H
I
reacts with benzophenone in diethyl ether to give benzohydryloxytriphenylsilane (11). I n the former (C&I,)sSiK
H20 + (C6H5)2C0---+
(CCH~)~S~OCH(C~I~):!
I1
reaction the triphenylsilylpotassium adds to the carbonyl group in such a manner that in the product I the silicon atom is attached to the carbon atom of the carbonyl group. I n the latter reaction the product I1 has the silicon atom attached to the oxygen atom of the carbonyl group. I\-e have found that triphenylgermyilithiu~~l adds to formaldehyde in ethylene glycol dimethyl ether ill the same manner as tripheriylsilylpotassium to give triphenylhydroxymethylgermane. (C\dIl)aGeLi f IICHO
H?O _3
(C~H5)&eC\IId):I I11
However, we have also established that triphenylgermyllithium reacts with benzophenone in ethylenc ( I ) H. Gilrnan and T. C. IVix, Tnrs Joun~.41.,76, 2 5 0 2 (1!153). (2) H. Gilrnan and T. C. Wu, i b i d . , 75, 2935 (1958).
NOTES
Nov. 5 , 1955
5741
Experimental6 Reaction of Triphenylgermyllithium with Formaldehyde. -Triphenylgermyllithium was prepared by the cleavage of 6.0 g. (0.01 mole) of hexaphenyldigermane with 1.0 g. (0.144 H20 g. atom) of lithium in 5 ml. of sodium-dried, redistilled ethyl(C6Hd3GeLi (C6Hs)zCO ( C B H ~ ) ~ G ~ C ( O H ) ( C ~ Hene S ) glycol Z dimethyl ether using exactly the same procedure IV as previously described6 for the preparation of triphenylgermyllithium from tetraphenylgermane and lithium. In both cases the addition to the carbonyl group The time required for the cleavage to begin was 15 minutes. gives a product (111, IV) containing the germanium After 3.5 hours an additional 10 ml. of solvent was added atom bonded to the carbon atom of the carbonyl and the mixture stirred for a total of 6 hours. The dark solution was pipetted into another nitrogen-flushed flask group. formaldehyde gas, generated by heating paraformaldeTriphenylhydroxymethylgermane (111) was pre- and h ~ d e was , ~ introduced over the surface of the stirred tripared authentically by the reduction of methyl tri- phenylgermyllithium by a stream of dry nitrogen. After phenylgermanecarboxylate with lithium aluminum 3 hours the dark solution had turned white. Water was added to hydrolyze the mixture and it was filtered to give hydride. 5.2 g. of paraformaldehyde. The aqueous solution was HzO extracted three times with ether, the ether was dried over (C6H5)3GeCOOCH3 LiAIHa (C6H5)3GeCHzOH anhydrous sodium sulfate and the solvent was distilled to a liquid which was heated in a vacuum to remove all Authentic specimens of triphenylgermyldiphenyl- leave solvents. On cooling the residue it solidified. Washing carbinol (IV) were prepared by the reactions of with petroleum ether (b.p. 60-70') gave a solid weighing both phenyllithium and phenylmagnesium bro- 4.5 g. and melting over the range 96-100". This material was fractionally crystallized from petroleum ether (b.p. mide with methyl triphenylgermanecarboxylate. 60-70') to give 2.1 g. (31.4%) of triphenylhydroxymethylgermane melting a t 115-116' and 0.3 g. (4.8%) of hexaHzO GHbM (CeH5)3GeCOOCH3+ phenyldigermoxane (mixed melting point) melting a t 185(CBH5)8GeC(OH)(C6H512 187". The identity of other possible products from this reM = Li and MgBr action mixture has not been established. Calcd. for CtsHlsOGe: Ge, 21.68. Found: Ge, Triphenylgermyldiphenylcarbinol appears to be 21.84, 21.95. unstable, for when a sample is left in contact with Preparation of Triphenylhydroxymethylgermane from the the air the melting point decreases. For this rea- Reduction of Methyl Triphenylgermanecarboxy1ate.-To son purification is difficult and yields of the authen- 0.18 g. (0.0048 mole) of lithium aluminum hydride dissolved tic specimens were low due to the necessity of re- in 25 ml. of ether was added 1.7 g. (0.0047 mole) of methyl triphenylgermanecarboxylates dissolved in 30 ml. of ether peatedly recrystallizing the product. over a period of 10 minutes. After stirring for 4 hours, 20 The reaction of triphenylsilylpotassium with m1. of ethyl acetate was added, followed by water to debenzophenone2 has been interpreted as possibly stroy the excess lithium aluminum hydride. The ether occurring by initial 'hormal" adddition of the tri- layer was separated and the aqueous layer extracted twice The combined ether portions were dried over phenylsilyl group to the carbon atom of the car- with ether. sodium sulfate and the solvent distilled to leave bonyl group to give structure V followed by re- anhydrous a residue which was crystallized from petroleum ether (b.p. arrangement to the more stable structure VI. 60-70') to give 1.25 g. of impure product melting over the range 100-1 10". Recrystallization from the same solvent C6H5 0gave 0.55 g. (35%) of triphenylhydroxymethylgermane C6HH")C-oM( C6H5)a melting a t 114-115". A mixed melting point with the prodCeH?'
