Sept., 1947
2247
COMMUNICATIONS T O T H E EDITOR THE USE OF SODIUM IN THE PREPARATION OF METHYLENE-LINKED SILANES
0 1 2 and ( C H ~ ) Z S ~ [ C H Z S ~ ( Chave H ~ ) ~been ] ~ Oisolated and identified. Sir: A typical experiment in this series of reactions The use of sodium in the preparation of com- involves the following procedure: 800 g. of tolupounds of the type 4Si(CH&[CHzSi(CH&],B ene and 4 moles of sodium were placed in a flasl? has been investigated. These compounds have and heated to 110’ with vigorous stirring. A been made wherein the A and/or B m?y be mixture of 2 moles of (CH&SiCl and 2 moles of methyl, chloride, or ethoxy. The compounds CICHZS~(CH&OCZHE, was added at such a rate where both A and B are methyl groups have been that the temperature was maintained at 110’. tentatively called “silahydrocarbons.” The materials were then filtered and distilled. Compounds of the above type where A and B Distillation gave 1.57 moles of (CH3)zSi[CHzSiare methyl groups may be prepared from reactions (CH&]10CzHs, b. p. 160’ at 740 mm., n z 51.4148, ~ of materials such as (CH3)3SiCl, CH,[(CH&- dZ50.8060, a yield of 78.5%. Anal. Calcd. for SiCHz],Cl and sodium. This reaction gives C&izHzzO: Si, 29.51 C, 50.55; MRD, 59.15. products of the type formula (CH&Si [CHzSi- Found: Si, 29.65; C, 50.6; M R D 58.9. Similar (CH&],CH3. Yields of these reactions are experiments have produced the compounds indi6570% of the desired product. Two of these cated up to n values of 4. compounds also have been prepared by reacting There is a good reason for using ClCH2Si(CH&SiCl and (CH&SiClz with (CH&SiCHz- (CH3)20C2Hsrather than C ~ C H Z S ~ ( C H ~ in) ~ C ~ these reactions. The reaction of ClCHzSi(CH3)2MgCl. The preparation of compounds where both A C1 with other molecules like itself is so rapid that and B are ethoxy groups may be carried out by the simpler members of the series are very difficult to isolate. The products of the reaction of several (1) and (2) as follows. molecules of ClCHzSi(CH&Cl and sodium are materials with high molecular weights and with the basic unit [Si(CH&CH2], predominating in + ClCH2Si(CH3)zCI+ 2Na + the molecule. (2) (CH3)zSi(OC2Hs)z
+
C2H60Si(CH3)z [CH2Si(CH3)2]10CzH62NaCl
DEPARTMENT O F CHEMISTRY OF THE
In (2) it appears that NaOC2H6 is formed and UNIVERSITY OF PITTSBURGH, AND J. T. GOODWIN, JR. W. E. BALDWIN reacts with the CIS~(CH~)ZS~CHZ(CH~)ZOCZHS to THEMELLONINSTITUTE 13, PENNA. R. R. MCGREGOR give CZHSOS~(CH~)~CH~S~(CH&OCZHS. PITTSBURGH RECEIVED AUGUST15, 1947 The preparation of compounds where. A is a methyl group and B is ethoxy is easily effected by a reaction such as A NEW SYNTHESIS OF 1-(2’,6’,6’-TRIMETHYL(CH&SiCI ClCHzSi(CH&0C2H~ 2Na ----f (CH&SiCHzSi(CH&OCZH6 2NaCl CYCLOHEXEN-1’-YL) -3-METHYLHEXA-l13,5-TRIEN-
+
+
+
7-ONE (Cis KETONE)
This reaction gives yields of 7540% of the de- Sir: sired product and smaller amounts of higher The Cl8 ketone (1I)l is an important intermembers. The subsequent preparation of higher mediate in the synthesis of “vitamin A acid” members of this series is best achieved by conver- and vitamin A itself. Recently we have synthesion of the ethoxy group to the chloride by reaction with acetyl chloride or benzoyl chloride and the H3C CHs CHa reaction of the chloride with C1CH2Si(CH3)20C2H~ and sodium. In this way materials of the type (CH3)3Si[CH2Si(CHa)2]nOC2H6 may be produced. Hz The reaction of either the ethoxy materials or Hz I the chloride-ended materials with Grignard reagents will give the corresponding “silahydroHsC CHI CHI carbons.” The monofunctional ethoxy and chlo\/ ~H=CH-&=CH-CH=CH-C=O I ride compounds also may be hydrolyzed to give materials of the type [(CH3).Si[CHzSi(CHa)2],]20 while hydrolysis of the difunctional compounds gives cyclic materials with the type formula Z;@CH, Hz I1 [ [-(CH3)2SiCH,]nSi(CH3)z0-]m. Two cyclic (1) (a) k e n s and van Dorp, Nature, 167, 190 (1946); Rcc. IraEi. materials with formulas [(CH&SiCHzSi(CH&- chim., 613, 338 (1946); (b) Heilbron, Jones a4d O’Sullivan, Nature,
~z~-~=~ -~=~ -~ z~
(1) Whitmgre, Sommer, Goldberg and Gold, THISJOURNAL, 69,
980 (1947).
167,485 (1946); J . Chem. Soc., 868 (1946); ( c ) Karrer, Jucker and Schick, Helo. Chim. Acto, 39, 704 (1946).
2248
~ U R I M U N L C A l l U N b'10 % H E EDI'IUH
VOl. ti9
sized this ketone by the application of the 01)- .hydrate the hydroxy ester and reduce the final penauer oxidation2 on P-ionylidene ethyl alcohol ester to vitamin -4 with lithium alurninum hydride. (I) which was prepared by the reduction of ethyl DEPARTMENT OF CHEMISTRY NICHOLAS A. MILAS p-ionylidene acetate with lithium aluminum MASSACHUSETTS INSTITUTE O F TECHNOLOGY CAMBRIDGE, MASS. THERESE M. HARRINGTON hydride. AUGUST26, 1947 RECEIVED Ethyl p-ionylidene acetate (b;p. 141-144' (2-3 mm.); n2'D 1.5320; Xmax. 2850 A., log E 4.42) was , ~ the PHOSPHITE ISOMERIZATION IN THE SYNTHESIS prepared according to Karrer, et ~ l . by Reformatsky condensation of 0-ionone (12% OF THIOPHENE PHOSPHONIC ACIDS 1.5180) and ethyl bromoacetate. The inter- Sir: mediate hydroxy ester was dehydrated with #In view of the very poor yields heretofore toluene sulfonic acid in toluene. This ester attainable in the preparation of thiophene-sub(180 g.) was reduced in an ethereal solution at 0' stitutkd phosphonic acids, the classical isomerizawith lithium aluminum hydride (32 g.) prepared tion of alkylphosphites was tried in an attempt to essentially by the recently published method. make the compounds of this type more available The product (163 g.) was recovered after acidi- for study. fication with a mixture of ice and glacial acetic Sodium dibutylphosphite (from 45 g. of dibutyl acid and fractionated under reduced presswe and phosphite) was treated in hexane solution with 31 the fraction (113.6 g.) boiling at 137-144' (4 g. of a-chloromethylthiophene to give, after three mm.), collected and analyzed; n Z 5 '1.5496; ~ hours of reflux, 71% yield of dibutyl a-thienylA,., 2740 A., log E 4.45. methanephosphonate, b. p. 147-150' a t 3 mm. Anal. Calcd. for C15H240: C, 81.76; H, 10.98; Hydrolysis by boiling with hydrochloric acid, folactive hydrogen, 1.0. Found: lowed by evaporation and recrystallization of the unsaturation, 3 residue from water, gave a substantially quantitaC, 81.42; H, 10.92;unsaturation, 3.12,3.17 (Pt) tive conversion of the ester to a-thienylmethaneactive hydrogen (Zerewitinoff),0.99, 1.01, l.02. 0-Ionylidene ethyl alcohol (44.8 g.) was dis- phosphonic acid, which formed yelldwish plates ; Anal. Calcd. : S , 16.3. Found: solved in a mixture of thiophene-free benzene m. p. 108-109'. (1000 cc.) and purified acetone (400 cc.) and to S, 16.46. (1) Sachs, Ber., 86, 1514 (1892). the mixture was added 60 g. of freshly prepared RESEARCH DEPARTMENT aluminum t-butoxide and refluxed in nitrogen for CENTRAL CHEMICAL COMPANY forty-four hours. The mixture was cooled, hydro- MONSANTO 7, OHIO GENNADY M. KOSOLAPOFF lyzed with 1 liter of water and filtered and the DAYTON RECEIVED AUGUST11, 1947 benzene layer separated from the filtrate, dried and the benzene removed under vacuum; yield CARCINOGENESIS of the crude product, 40 g. (active hydrogen, 0.55). This dark brown product was distilled under a Sir: high vacuum and the fraction (32 g.) disti1:lingat Concerning the excellent paper by L. F. 80-85' (10--e10-6 mm.) collected and analyzed. Fieser and S. T. Putnam on the Oxidation of Carbon and hydrogen showed the presence of Carcinogenic Hydrocarbons in the May issue of about 10% ketol, so that the product was further THISJOURNAL, I should like to suggest that dehydrated with 2y0 p-toluene sulfonic acid in peroxidation is more important than oxidation in toluene. The ketone was recovered and, after determining their carcinogenicity. Since the preliminary purification in petroleum ether and ionization potential decreases with the number of in methanol at - 78') was fractionated under high conjugation centers, a simple electron transfer vacuum and the fraction (yellow oil, 24.5 8.) process involving the non-localized i~ electrons boiling at 80-82' (10-4-10-6 mm.) was collected can readily occur with these hydrocarbons. This and analyzed; n17D 1.5685; Xmax. 3330 A,., log may be followed by a proton transfer resulting in the formation of a free-radical. This radical E 4.2. Anal. Calcd. for ClgHzsO: C, 83.67; H, 10.14; reacts with oxygen to form a peroxide free-radical unsaturation, 4.0 Found: C, 83.67; H, 10.43; capable of initiating a branched-chain, free-radical oxidation of intracellular nutrient material, unsaturation, 4.15 7. The ketone had a negligible active hydrogen thus increasing cell-metabolism and cell-growth. (Zerewitinoff) and gave a wine red color with In the presence of trace quantities of such maantimony trichloride in chloroform. We expect terials as chromium, iron, cobalt, arsenic, ascorto carry out a Reformatsky on this ketone, de- bic acid, etc., the activation energy required for the decomposition of the hydroperoxides into (2) Batty, Burawoy, Harper, Heilbron and Jones, J . Chcm. Soc., free radicals may be low enough to accelerate 175 (1938). tissue growth to the extent that it is entirely out (3) Finholt, Bond and Schlesinger, THISJOURNAL, 6!1, 1199 1947). of proportion to the growth rate of the normal (4) Nystrom and Brown, ibdd., 69, 1197 (1947). surrounding tissues. ( 5 ) Karrer. Salomop, Mod and Walker, Hdo. Chim. Acta, 16, The hydroperoxides will increase until limited by 878 (1932); Kames, Morf and Schoepp, Ibid., 16, 817 (1933); Karthe supply of arterial oxygen. Since they are a rer, Ruegger and Solmasea, ibid., 91, 448 (1988). 394
r;
r.
r;
