Document 826GagGGNygXp2Xde8NEokZ3m

vi-n'1 J 660 April 18. 1964 CHEMISTRY AND INDUSTRY ^pyridine-jo? mixture was the same as that of the Bstarting material, agreeing with an addition-elimina tion mechanism and ruling out a rate-determining , elimination of a hydride-ion from C3) to give the error when 3-picoIinc-2ff was used instead. This could be taken as evidence that the addition step leading to (II) and (III) is the rate-determining one, which is unlikely. By analogy with the mechanism of the reaction of phenyllithium with 3-picoline1 it seems more probable that the hydride-ion elimina tion is the slower of the two steps, but that the addi tion stages are virtually irreversible so that the ratio of (IV) to (V) formed depends upon the relative rates of formation of (II) and (III)- This point is being investigated further. Received January 13, 1964 at) m 2,3-pyridyne intermediate, (ii) The reaction of 3picoline with sodamide in boiling toluene gave a mixture of (IV) and (V) (R = Me) in the ratio of 90 : 10 (product analysed by gas chromatography). The isomer ratio was unchanged within experimental References 1 Aromatic Substitution. Part VL Part V. Abramovitch, R, A. & Giam, C.-S., Canad. J. Client., 1963, 41, 3127 t Levitt. L. S. & Levitt, B. W., Client. & Ind., 1963, 1621 3 Barrett, G, C. & Schonsid, K., ibid., 1963, 1980 * Roberts, J. D., Semenow, D. A,. Simmons, H. E., Jr. & Carlsmith, L. A., J. Anter. diem. Soc., 1936, 78, 601; Roberts, J. D., Vaughan, C. W,, Carlsmith, L. A. & Semenow, D. A., J. Amer. diem, Soc., 1936, 7S, 611 3 We thank Dr. E. L. Eliel for the mass-spectroscopic analyses :Ob , y/e .0at b> tr a. s: r.v N it p: bi A- 9 R&S 136104 Chloroethylene' Oxide By M, Zief and C. H. Schramm ^ Research Laboratories, J. T. Baker Chemical Co., Phillipsburg, New Jersey, U.S.A. Sabanejeff1 reported fragmentary data on the pre It has been shown that acidic reagents, such as paration of chloroethylene oxide by heating 1-iodo- aluminum chloride, zinc chloride or sulphuric ta T 2-chloroethylene with water at 150 in a sealed tube. acid at high temperature will decompose ethylene ; Recently Walling and Fredericks2 reported the isola carbonate into ethylene oxide and carbon dioxide.3 tion of chloroethylene oxide from the reaction of Polyhalogenated hydrocarbons, such as hexachloro- t-butyl hypochlorite with ethylene oxide but no ethane, also accomplish this decomposition.6 Upon physical constants were given. We first isolated heating monochioroethylene carbonate with acidic ] ) a; chloroethylene oxide as a by-product in the prepara reagents, we obtained chloroethylene oxide. Our tion of vinylene carbonate3 according to reaction (A) best yields (34%) were obtained by heating a mixture in the presence of triethylamine. of 24-5 g. monochioroethylene carbonate and 12 drops of concentrated sulphuric acid to 230:C. The crude distillate upon careful fractionation afforded 5-2 g. of colourless oil boiling at 78-79' (Found: C, 30-40; H, 4-10; Cl, 44-S7. Calc, for C:HjClO: C, 30-57; H, 3-S2; Cl, 45-22%). The infrared curve in (taken immediately after distillation) shows that hydroxyl and carbonyl groups are absent, thus contamination with isomeric chloroacetaldehyde was x ruled out. Upon standing, however* carbonyl.ab (F to In order to produce chloroethylene oxide in improved yield according to reaction (B), triethylamine was replaced by acidic reagents, since bases favour elimination of hydrogen chloride or complete hy drolysis of the carbonate group. We first tried to adopt the synthesis reported for the analogue, bromocthylene oxide4 prepared in very low yield by treating ,3,3-dibromocthanoi with methyl alcoholic potassium hydroxide. In our hands chloroethylene oxide could not be prepared conveniently by dehydro- sorption ^develops; chloroethylene oxide_is_ readily. _ , transformed to chloroacetaldehyde. pi hi ........... 1V" rc CHj'--CH Cl ---------------- ClCHjCHO v, .")> " Vj#Chloroethylene oxide, there(Qj_e*_yzQuM_hc_expectnd_- - to~~gtve~reacttons~characteristic of chloroacetaldeiridc. / [ or c*''7 // co C'hlofoeinytene oxice gives off strongly acidic fvl fumes upon exposure to the atmosphere; it is a strong ( et lachrymator which irritates the mucous membranes. to It is soluble in ethanol and ether, insoluble in water ac halogcnation of 3,3-dichloracthanoi with sodium (chloroacetaldehyde is soluble in water). Upon hydroxide in methylene chloride, an excellent method standing at room temperature the product deposits ?' S> for routine preparation of epoxides. a solid which is insoluble in water, ethanol, ether and [ P: CHEMISTRY AMD INDUSTRY April IS, 1964 661 0-5n hydrochloric acid; the solid vaporises at 112-115 and upon distillation yields chloroacetaldchyde, boiling at 85-5*. The solid proved to be the amorphous trimer of chloroacetaldehyde analogous to that of , acetaldehyde. Natterer7 has reported that the purest samples of chloroacetaldchyde are obtained by heating the solid polymer of chloroacetaldehyde. Natterer's polymer had no definite melting point; it disappeared upon heating at about 100. Our purified polymer vaporised at 162-164 (Maqucnne- block) (Found: Cl, 45-14; Calc, for (C2H^CIO)3 : Cl, 45-22%). Infrared analysis showed a major peak at 9;a (ether linkage); C = 0 absorption was absent. In one experiment a sample of chloroethyiene oxide which had deposited polymer was diluted with ethyl ether. After the polymer was removed by filtration, the filtrate was fractionated. Fractions boiling from 82-85-5c, deposited crystals soluble in water, absolute ethanol and ether. After washing with chloroform and drying in vacuo, the crystals melted at 87c. (Foun'd: Cl, 40.8; Calc, for CICHiCH-O-CHCHiCl: Cl, 40-6%). ft ^ II OH OH O'* Wet ether or exposure to atmosphere converted chloroethyiene oxide into ],l'-> dihydroxy-2,2'-dichloroethyl ether, the "chloroacetal- dehyde hydrate" of the early literature.7 Chloroethyiene oxide gives an immediate precipi tate with 1% aqueous silver nitrate and a positive Tollen's test at room temperature. With concentrated sulphuric acid it gives a red colour and with 10% sodium hydroxide solution a yellow colour. With 2,4-dinitrophenyIhydrazine, chloroethyiene oxide gives chloroacetaldehyde 2,4-dinitrophenylhydrazone (m.p. and mixed m.p. with an authentic specimen, 154-156). Upon heating chloroethyiene oxide under reflux with absolute ethanol a colourless oil boiling at 152-153 was obtained. This product was chloroacetaldehyde diethyl acetal, reported b.p. 155'.3 Chloroethyiene oxide shows no oxirane ring by conventional addition of HBr solution and titration of excess of HBr. The following reaction explains the failure of the analysis: V iCH, CH--CI + HBf--OH, 8r iCH--Cl ---- 0rCH,CHO OH + HCl The addition compound loses one mole of HCl for every mole of HBr added, thus giving a negative test for the oxirane group. Infrared analysis shows absorption bands at 7-8, 8-7 and 11 -6a characteristic of the epoxy group.9 We have not determined the molecular weight, but the boiling point approximates to that for the pos tulated monomer as will be clear from the following consideration. Epichlorohydrin boils 37 higher than chloroethyiene oxide; propyl chloride boils 35 higher than ethyl chloride. In both cases the methy lene group raises the boiling point about 35c. Received February 24, 1964 References 1 Snbancjcff, A., Liebigs Ann., 1883, 216, 268 2 Wallins, C. & Fredericks, P. S., J. Amer. diem. Soc., 1962. 84, 3326 3 Newman, M. S. & Addor, R. W., ibid., 1953, 75, 1263 * Dcmole, E., Bar, dtsch. diem. Gel., 1876, 9, 45 3 Ethylene Carbonate, Technical Bulletin, Jefferson Chem. Co., 1959 4 French Patent, 1,100,S45, September 26, 1955 7 Natterer. K., Monais., 1332, 3, 442 s Fritsch, P. & Schumacher, W., Liebigs Aim., 1894, 279, 307 9 Bellamy, L. J,, Infrared Spectra of Complex Molecules, 2nd Edition p. 118 (J. Wiley & Sons, Inc.) R&S 136105 Optically Active O-Ethyl Etbylphosphonochloridothionates: A New Route to Optically Active Organophosphorus Compounds By J. Michalski and M. Mikolajczyk nvituic of Organic Synthesis, Polish Academy of Sciences and Department of Organic Chemistry, Technical University (.Politedwika) Lad:, Poland Optically active phosphinyl chlorides, R'R-PfOJCl VR1, R7=alkyl or alkoxyl),1 have recently been used to study the stereochemistry at an asymmetric phosphorus atom. Their usefulness is limited however by the fast raccmisation and low optical rotation values. We report now a synthetic route to a wide range of optically active organophosphorus compounds containing the P(S) group with optically active O-ethyl ethylphosphonochloridothionates (II) as the key intermediates. The readily-avaiiabie O-ethyl ethylphosphonothioic acids (I), resolved according to Anon et al.,1 have been converted into optically active phosphonochloridothionates (II) with phos phorus pentachloride. The analogous reaction on symmetrical phosphinothioic acids has been described previously.3 ElVp^5 ..feu, 'O [a]? -14-75 MS *f 8-25 10. S Cl Cl [a]S --73-SO MS -r41 -50 The reaction of the (--)-and (-f-)-acid (I) with a molar ratio of phosphorus pentachloride was carried out at --15 to --10 in carbon tetrachloride solution. The crude (--) and (4-) chlorides (II) were purified by distillation (b.p. 21/0-l nun., 1-4930, yield 75-85%). The phosphonochloridothionates (II) were shown by thin-layer chromatography to be free of any traces of ethyl ethylphosphonochloridate, Et(EtO)P(0)CI, as impurities.