THE PHOTOLYSES 0F HEPTACHLOR Thesis for the Degree of M. S. MlCHlGAD STATE UNWERSITY RICHARD DONALD FLOTARD 1968 TH E815 sBSTRACT The Photolysis of Heptachlor By Richard Donald Flotard Heptachlor (A), a widely used polycyclic chlorinated hydrocarbon insecticide, one of a family of chlorinated insecticides derived from cyclopentadiene and hexachlorocyc10pentadiene was found to give three major products on photolysis with ultraviolet light. CI Cl C! C\ / i H H H C: (B) .4 Ct P! Photolysis in hexane, a protic solvent which is not triplet sensitizing, yields mainly two photodechlorination products, l,4,5,7, 8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (B) and 1,4,6,7,8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (C), and a small amount of the cage compound 2,3,4,4,5,6,lO-heptachloro- pentacyclo [5.3.0.01't03’9.05’fldecane. The photodechlorination reaction very probably occurs via the excited singlet state. 1 H. 1 H ‘ C' c. C‘ lo H C\ H H / H " H C! C! H C\ H (C) ' (D) Photolysis in acetone, a protic solvent which is also triplet sensitizing, gives exclusively the cage compound formed by 4Tlcyclo- addition. C. M. Anderson (I) described similar results using other polycyclic chlorinated hydrocarbons. . l. C. M. Anderson, J. B. Bremner, I. W. McCay, and R. W. Warrener, Tet. Letters, 19, 1255 (1968). THE PHOTOLYSIS OF HEPTACHLOR By Richard Donald Flotard A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Chemistry 1968 ACKNOWLEDGEMENT The author wishes to express his sincere appreciation to Professor Robert D. Schuetz and Professor Matthew Zabik for their guidance and encouragement throughout the course of this investigation. 11 TABLE OF CONTENTS ACKNOWLEDGEMENTS . . . . '. . . . . . LIST OF FIGURES . . '. . . . . . . . LIST‘OF TABLES . . . . . . . . . . INTRODUCTION AND HISTORICAL . . . . . ’ . RESULTS AND DISCUSSION ‘ . _. . . . . . . EXPERIMENTAL . . . . . . . . . Purification of Heptachlor . . . , Photolysis of Heptachlor in Hexane . . . Photolysis of Heptachlor in Acetone Purification of the Cage Compound . . . . Purification of the Photodechlorination Compounds Dechlorination by Metal Reduction . . . SUMMARY . . . . . . . . . . . BIBLIOGRAPHY . . . . . . . . . . 111 page ii iv 11. 12 12 13 13 14 16 17 27 Figure LIST OF FIGURES The Infrared Spectrum of Heptachlor. The Infrared Spectrum of the First Photodechlorination Compound. . . . . . . . . . . The Infrared Spectrum of the Second Photodechlorination Compound. . . . . . . . . . . The Infrared Spectrum of 2, 3, 4, 4,5, 6, lO-—heptachloro- pentacyclo [5. 3. o. OthO?’?05’]decane. . . The NMR Spectrum of Heptachlor in CC14. The NMR Spectrum of the First Photodechlorination Compound iThe NMR Spectrum of the Second Photodechlorination Compound The NMR Spectrum of 2,3,4, 4,5, 6, 10-heptachloropentacyc10 [5. 3. 0. 0"“. 03". 05”] decane. iv page 18 19 20 21 22 23 24 .25 LIST OF TABLES Table page 1. The Intensity of Isomer Peaks Compared to The Parent Peak in theMaSS Spectrum. O...00;..0000OOOOOOOOOOCOOOOO 26 - INTRODUCTION AND HISTORICAL Heptachlor (I) is but one member of a series of highly chlorinated hydrocarbons produced by the Diels-Alder reaction of cyclopentadiene with-hexachlorocyclopentadiene. Additional members of this series includefaldrin (II), dieldrin (III), and chlordene (IV). CI (III) The use of these polycyclic chlorinated compounds in the agricultural industry is wideSpread. Attempts are being made to replace them with the phOSphate esters and phOSphate thioesters which are more toxic to mammals but are much less stable, yielding harmless residues on 1 2 hydrolysis. The strong possibility of the destruction of wildlife, both in the fields and waters by concentration of the chlorinated insecticides in animal bodies has been reported _Sterility in predatory animals is also feared. The most favorable property for the commercial use of the chlorinated hydrocarbons is their low production cost, as they are readily produced from inexpensive starting vmaterials and by simple reactions. The persistence of these compounds depends upon the method of application, the soil type, and weather conditions. Heptachlor mixed in soil showed approximately 53% retention after 21 months (1), independent of whether the soil was dry sandy soil, loam, or swamp muck. Heptachlor adsorbed to the surface of the soil was found to be nearly eliminated in from 8-11 days; the pesticide being lost most quickly from moiSt soil exposed to sunlight. Heptachlor is easily hydrolyzed to its wepoxide but otherwise is quite stable. Heptachlor is a broad spectrum insecticide and finds a wide variety of uses. Its persistence especially suits it to uses in which repeated applications are to be avoided. Toxicity studies have shown heptachlor to be moderately toxic to mammals. The L.D.50 values vary somewhat but for rats are about 400mg of pesticide per kg of body weight. It is less toxic than aldrin, dieldrin, or malathion, an example of the phosphate thibesters. Chlordane (IV) C10H6C16, the precursor of heptachlorhis formed by the Dials-Alder reaction of cyclOpentadiene with hexachlorocyclOpenta- diene. The direct chlorination of chlordene in the dark results in the formation of heptachlor. A 1:31 concentration of Fullers earth or aluminum oxide is used as a catalyst. Heptachlor is sold as a 25% wetable powder on Pullers earth, or dissolved in toluene or kerosene The photolysis of pesticides as a means of their destruction in the environment has been rather widely investigated. For this reason the study of the photolysis of heptachlor was undertaken. If the photolysis products identified in the laboratory are the same as those obtained from insecticide applied to plants in the field, a link between photolytic decomposition of heptachlor in the environment and that induced in the laboratory could be obtained. This would allow detailed study of the rates of photolysis of the pesticide, its photolytic products, and determination of their toxicity to mammals and particularly to man. RESULTS AND DISCUSSION Heptachlor undergoes a facile: photolysis. Photolysis of a 200ml. volume of a 1.5% solution of heptachlor in hexane results in the ' formation of two major photoproducts amounting to approximately 85% of the total mixture. Reaction of heptachlor with a 200W. Hanovia high pressure mercury lamp without filters and through quartz requires 130-150 minutes for complete photolytic conversion of the above solution. ' A gradual decrease in the concentration of heptachlor in the reaction mixture is observed in samples removed periodically during the photolysis and subjected to gas chromatographic analysis. With longer reaction times or higher concentrations of heptachlor, secondary reactions are observed including considerable formation of polymer from hexane. The evolution of HCl gas is noted during both primary and secondary reactions. Since a comparison between the photolysis products formed in the laboratory and those formed under field conditions was desired, and since the separation of multiple products becomes infinitely more difficult, photolysis was restricted to the shortest reaction periods consistant with the total conversion of heptachlor. Heptachlor, 1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7- :methanoindene, is a white crystalline solid melting in the range 92- 95°C. (It sublimes readily in vacuo at 60°C. It decomposes if heated much above its melting point. It gives a distinctive nuclear magnetic 5 resonance spectrum, not entirely consistent with what would be expected from analysis of models of the compound. A quartet appears at 6.57, an octet at 5.97, and a multiplet at 5.27, in the ratio 1:1:1. A two proton singlet appears at 4.17. The quartet at 6.5‘Tis assigned to Hd, a proton which is neither allylic or vinyl. The octet at 5.9T'is assigned to He' He is an allylic proton split by Ha, Hd, and the long range splitting of Hb. The multiplet at 5.27arises from Hc‘ Hcis an allylic proton but is shifted further downfield than He by the geminal chlorine. The two proton singlet at 4.1Tarises from Ha and Rh. This is consistent with the olefinic protons on norbornene which fall at 4.067. It is only by chance that H8 and Hb give a singlet. There is no plane of symmetry in the molecule. The angles between Ha and He or Rb and He are both 75., in which case splitting is expected. ' c. (I The infrared spectrum of heptachlor is quite complex, owing to the presence of a large number of chlorine atoms in the molecule. A sharp characteristic olefinic stretching frequency is evidenced by a medium a absorption at 3090 and 705 cm-1. A broad absorption at 2920 cm-1 .arises from the aliphatic C-H stretching frequency. Due to their complexity, analysis of the C-Cl absorptions which are many and 6 which fall within the 600-800 cm.’1 range is not possible. A mass Spectrum of heptachlor was obtained to determine the type of fragments which could be expected from a molecule of this type. Peaks were obtained which correSpond to m/e 369, 334, and 298, for the ion 10H3015. Two competing reactions occur when heptachlor is photolyzed in fragments C10H4Cl7, ClOH5C16, and C hexane, both of which were previously known fOr similar model compounds. The intermolecular 47“cycloaddition reaction, clOSure of two double bonds to form a cyclobutane ring, giving a birdcage compound related to the cubane system has been noted in many cases. The Woodward-Hoffman rules (2) predict this to be an allowed photochemical processLl Examples of compounds which are known to undergo reactions of this type are 3a,4,7,7a-tetrahydro-4,7-methanoindene (the dicyclopentadiene dimer) (3) and aldrin (II) l,2,3,4,10,10-hexachloro-l,4,4a,5,8,8a-hexahydro-1,4- endo, endo-5,8- dimethanonaphthalene (4). The cage compound 2,3,4,4,5,6,10-heptachloropentacyclo[5.3.0.01’103'105’jdecane (V). is obtained in 5% yield from the photolysis of heptachlor in hexane. Photolysis of heptachlor in acetone yields the cage compound (v)‘ as the exclusive product. Initially, the cage compound was obtained by column chromatography from the photolysis mixture in hexane. It was later obtained in larger quantities by vacuum sublimation of-the residue from photolysis in acetone. Final purification in both cases was injection_through a 6' X 1/8", 5% DC 11 on 60/80 mesh Gas-Chrom Q column in the gas chromatograph. Fraction collection gave a white crystalline compound melting in the range 118-119 . Analysis of the infrared 7 .Spectrum showed both compounds to be the.same. The cage compound gives a nuclear magnetic resonance Spectrum with only two absorptions, a multiplet (4H) at 6.6T'and a multiplet (1H) at 5.457. The latter absorption arises from the proton geminal to a chlorine. .The other four protons are non-identical but have similar environments. The mass Spectrum shows peaks correSponding to m/e 369,335, and 298, for ion fragments C10H4C17, C10H5C16’ and C10H3C15. The absence of ion fragments above 369 proves that the compound is not a dimer of heptachlor formed by intramolecular 41'cycloaddition. The infrared Spectrum differs from that of heptachlor and the two other photoproducts in the absence of the olefinic stretching 1, and the olefinic stretching frequency absorptions at 3090 and 705cm.’ frequency absorptions at 1580cm.'1. This is consistent with the loss of the double bonds and ring closure. ‘The other two products result from photodechlorination of the olefinic chlorines in the 5 or 6 positions of heptachlor. Photolysis in hexane gives an 85% yield of these two products. In acetone no photodechlorination products are obtained. Due to the asymmetry of the molecule resulting from the chlorine in the 1 position, the two photoproducts are not identical but posses very similar properties. The close similarity led to considerable difficulty in the Separation and purification processes of these materials. ISeparation'was laboriously brought aboutiusing the gas chromatograph. Separate, consecutive injections and passages through two columns were used. Samples were separated into two fractions by passing them through a 4' X 1/8" column packed with 5% carbowax 20 M on 60/80 mesh Gas—Chrom 8 Q. Attempts at separation using thin layer or column chromatography were unsuccessful. Structural assignments for the photodechlorination products, li4;5:7,8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (VI) she.1,4,6,7,8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7emethanoindene (VII), are based on the NMR, infrared, and mass Spectral data dgterhihed forithese compounds. iIt is not possible to determine which 饥héih}é belongs tofwhich isomer. .They are referred to here in terms 6f the brder of elution from the carbowax gas chromatbgraphy column. ,7. g“-- 1.: “Mgr-J 34:21“: :"-:;' ::' '1‘ _. _, p - A (VIII) ”(VII) 9 The nuclear magnetic resonance Spectra for the two photodechlorination compounds are similar to that of heptachlor with the exception of an . extra singlet (1H) and slight shifts in the field positions of all groups. For the first photOproduct, multiplets are found. at 6.50,6.07, Q and 5.427. In heptachlor these correspond to Hd, H , and He respectively. e A singlet (2H) is observed at 4.257, and a singlet (1H) is observed at 4.207. The latter reflects the proton added due to photodechlorination. This singlet is shifted someWhat downfield from the singlet (2H) at 4.251'. and falls mostly under the base of the larger singlet absorption. A peak at 4.1T is due to a small amount of heptachlor in the sample.r For the second photodechlorination product, peaks were obtained at 6.52 (1H), 6.09 (1H), 5.50 (1H), 4.30 (2H), and 4.20"(1H). The infrared spectra for the photodechlorination products are nearly identical except for slight differences in the intensities of ssome peaks. The intensity of the vinyl proton C-H stretching frequency absorption is greater than that of heptachlor, reflecting the influence of the added proton. The absorptions due to unsaturation and mentioned for heptachlor are all present in the spectra of the two photodechlorination compounds. Since the total change in the structure is small, little‘ I change in the infrared spectrum is expected. The mass Spectra of the two photodechlorination products were essentially the same. Peaks were obtained for m/e 335, 300, and 264 'for ionic fragments C10H5C16, ClOHSCIS’ and C10H4C14 respectively. No evidence of any fragment is the m/e 369-379 region or above was found. This rules out the formation of a dimer. 10 An attempt was made to influence the ratio of the reaction products in the manner described by C. M. Anderson et. a1. (5). Anderson has 'shown that photodechlorination probably occurs via the excited singlet state while the 41fcycloaddition reaction occurs via the excited triplet state. Photolysis of the tetrachloroketal (VIII) in acetone using a vycor filter gave only the bird cage compound. Acetone acts here as a triplet sensitizer, although it may also be a Source of abstracted protons. Reaction of the tetrachloroketal (VIII) in ether by using a pyrex filter gave photodechlorination of the olefinic chlorines.- However, there were complicating secondary reactions. In a similar manner the reaction of heptachlor gave only the cage compound when photolyzed in acetone (no filter) and mainly the photodechlorination compound in hexane, a solvent which is a source of hydrogen but not a triplet senSitizer. In order to rule out a change in the carbon skeleton for the photo- dechlorination compounds, a reductive dechlorination was carried out on the total photolysis mixture. The solvent was removed from the photolysis mixture and the remainder was distilled in a molecular still .to remove polymer formed by the photolysis of the solvent. A dissolving‘ metal reduction was carried out by using lithium and tertiary butyl‘- alcohol. Gas chromatographic analysis of the recovered dechlorinated compound showed it to be 65% dicyc10pentadiene. Infrared analysis. of samples collected from the gas chromatbgraph showed this 65% portion to be identical with a commercial sample of dicyc10pentadiene. Thus changes in the carbon skeleton were ruled out for photodechlorination. EXPERIMENTAL All melting points were determined on an Electrothermal melting -point apparatus and are uncorrected. Infrared spectrawere determined Swith a Perkin-Elmer 337 grating spectrOphotometer either neat on sodium -chloride plates or as potassium iodide pellets. 'All ultraviolet spectra fwere determined in 95% ethanol uSing a Unicam SP 800 or a Beckman DB-G speétroPhotometer. Nmr spectra were obtained using a Varian A-60 Tnuclear magnetic resonance spectrometer. Cas chromatographic analyses were obtained from a Beckman GC-4 equipped with alfraction collector and employing either a hydrogen flame or a thermal conductivity detector. Mass spectra were obtained from an LKB gas chromatograph- mass spectrometer. Elemental analyses were performed by spang Micro- analytical Laboratories, Ann Arbor, Michigan. 11 12' Purification of Heptachlor Heptachlor was obtained as a 25% wettable powder or as a 25% _solution in toluene or kerosene. Heptachlor was extracted from the diatomaceous earth used as an absorbant in the wettable powder form by using acetone or ether as an extracting solvent. The extracting solvent ‘was removed and the crystalline solid was redissolved in hot ethanol. The ethanol solution was decolorized with activated charcoal. Successive recrystallization of the crystals thus obtained gave heptachlor with a purity greater than 99% as indicated by gas chromatographic analysis. For heptachlor in a toluene or kerosene solution a procedure similar to the above was followed after crystalline material had been obtained from the original solutions through evaporation of the toluene or kerosene. The wettable powder formulation is available from Stauffer Chemical Company and the solution formulations from Vesicol Chemical Company. Photolysis of Heptachlor in Hexane Photolysis reactions were carried out by'using a'200 W Hanovia high ppressure mercury lamp in a 250 ml capacity pyrex reactor vessel fitted -‘with a water cooled quartz core. The bottom of the vessel was flattened. t9 allow for a magnetic stirrer and was fitted with a st0pcock to permit nitrogen to be bubbled through the reaction mixture. In a typical ° reaction 3 g of heptachlor was dissolved in 250 m1 of hexane and the . Q C reaction solution was placed in the reaction vessel. Nitrogen was slowly bubbled through the solution and stirring was provided by using a magnetic 'stirrer. During photolysis, samples were periodically removed from the reaction vessel and analyzed gas chromatographically. Photolysis reaction periods of 130 - 150 minutes were required for complete conversion_ of the heptachlor to its photolytic products in the above solution. .0 l3 , Noticeable quantities of hydrogen chloride gas were evolved during the photolysis reaction. A gradual darkening of the solution occurs during the course of the reaction. Photolysis of hexane alone produces the same color change but requires longer periods of photolysis. Removal of the hexane from the heptachlor reaction solution leaves a light brown viscous liquid. Hexane apparently undergoes a photolytic free radical reaction to form a brown polymeric material. Photolysis of Heptachlor in Acetone Photolysis of heptachlor in acetone was carried out by using the same procedure and equipment as that for the photolysis of heptachlor in hexane, excepting that a 350 ml reactor vessel was used. A l g sample of heptachlor was dissolved in 350 ml of acetone and photolyzed for 7 hours. At the end of this time period gas chromatographic analysis of the areaction'mixture by using a 6' X 1/8", 5% DC 11 on Gas-Chrom Q column showed only a single product and a small amount of unreacted heptachlor. Removal of the acetone resulted in the formation of a crystalline ‘material on the walls of the flask. Vacuum sublimation of these crystals followed by purification by using a 5% DC 11 column at 140°gave crystals which were found to be identical to the cage compound obtained from the photolysis of heptachlor in hexane. ‘Purification of the Cage Compound Isolation of the cage compound was first achieved by using column 'chromatography in an unsucceszul attempt to separate the two photo- dechlorination compounds. A column, 3/4" in diameter, was filled to a depth of 8" with an alumina-hexane slurry. Activity I chromatographic grade alumina was used. A l 3 sample of the photolysis mixture was l4 placed on the column by using a medicine drOpper. Passage of the photolysis mixture into the column was followed by 100 ml of hexane. Next 100 ml of 1% CHC13 in hexane and then 100 ml of 5% CHCl3 in hexane were passed through the column. Samples, 10 ml in volume, were collected from the eluted solvents. The photodechlofination products were found in fractions 5 to 17. The cage compound was obtained as a crystalline material in fractions 25 to 35. The crystalline material was redissolved in acetone and chromatographed at 140. on a 6' X 1/8", 5% DC 11 on 60/80 mesh Gas-Chrom Q column. A pure white needlelike crystalline material was obtained from the fraction collector. It melted in the range 118-119.. The nmr spectrum gave a multiplet at 5.45T (1H) and a multiplet at 6.6T (4H). No infrared absorptions can be attributed to C=C stretching frequencies (1580 cm'l) or to =C-H stretching frequencies (3090 and 705 cm'l). The mass spectral deter- mination of the cage compound gave peaks m/e 369, 335, and 298. No indication of higher masses was evident, ruling out the formation of a dimeric product. Analysis: Calculated for ClOH5C16: C, 32.17; H, 1.35; C1, 66.47 Found: C, 32.42; H, 1.42; C1, 66.16. Purification of the Photodechlorination Compounds Samples were purified by first injecting the mixture into a 4' X 1/8" . , . 5% Carbowax 20M on 60/80 mesh Gas-Chrom Q column at 180' and collecting the two fractions using the fraction collector. Samples were further ‘purified by injection into a 6' X 1/8", 5% DC 11 on 60/80 mesh Gas-Chrom Q column at 160'. Since the photOproducts differ only by the interchange of protons and chlorines in the 5 and 6 positions, it was not possible to assign a 15 definite structure to either of the compounds. They are referred to here as peak I and peak II, the order of their elution from the carbowax column.' Peak I The compound from peak I is a white crystalline solid which only slowly crystallizes from the liquid obtained from the fraction collector. The infrared Spectrum is in agreement with the structure preposed, having the same general features as heptachlor itself. In contrast to the cage compound, absorptions are present at 1580 cm'1 (C=C stretch) and 3090 and 705 cm“1 (=C-H). Additional proof of the presence of a double bond is ' the decolorization of dilute KMn04 and Br2 in CC14. The nmr spectrum of I shows 6 protons, multiplets at 6.50 (1H), 6.07 (1H), 5.427'(1H), and singlets at 4.25 (2H), and 4.20‘r(lH). The singlet at 4.20"which falls partially under the larger singlet at 4.257, corresponds to the proton substituted in the photodechlorination. It is shifted downfield by two viscinal chlorine atoms. Analysis: Calculated for C10H6016: C, 35.44; H, 1.79; Cl, 62.77. Found C, 35.17; H, 1.85; C1 by difference 62.98. Peak II ‘ The second photodechlorination compound has properties similar to _ those of the first photodechlorination compOund. It is a white crystale. line solid melting at 51-52.. The nmr spectrum for compound II is similar to that obtained for compound I except for slight changes in the field positions. Three multiplets appear centered at 5.5 (Th), 6.09 (1H), and 6.5‘T(1H). Singlets are found at 4.30 (2H) and 4.20‘r(lH). The infrared ISpectrum of II is identical to that obtained from I except for slight changes in the intensity of several of the absorptions. The.mass Spectra 16 of the compounds gave peaks m/e 335, 298, and 264. No indication of any fragments corresponding to heptachlor or to a dimer was found. Analysis: Caltulated for C10H6016: C, 35.44; H, 1.79; Cl, 62.77. Found: c, 35.61; H, 1.90: CI, 62.64. Dechlorination by Metal Reduction A 100 ml, 3 neck, round bottom flask was fitted with a 50 m1 drOpping funnel, gas inlet valve, and a reflux condenser with drying tube. A magnetic stirring bar was placed in the flask.» A 3 g quantity of lithium metal chips and 25 ml of tetrahydrofuran were placed in the flask and nitrogen gas was paSsed through the flask. A solution of 10 g of tertiary butyl alcohol, 25 ml of tetrahydrofuran, and 2.7 (~.008 m) of purified photolysis mixture was slowly introduced into the reaction flask. An exothermic reaction began after 10 minutes. -The flask was cooled by 4.1mmersion in an ice bath to keep the rate of reaction under control. After 15 minutes the reaction subsided and the mixture was allowed to reflux gently for 30 minutes without external heating. Heat was then applied by using a heating mantle. Gentle refluxing was continued for 1.5 hours to maintain refluxing. The heat source was removed, the mix- ture cooled, and the excess lithium chips were removed. The mixture was poured over cracked ice. The ice was removed and the aqueous solution ‘was extracted with two 25 ml portions of ether. The combined etherial “extracts were dried over MgSO4 and the solvent removedlunder vacuum to “yield 0.2 g of residue. Gas chromatographic analysis showed this to be. 65% dicyc10pentadiene. Fraction collection gave a sample with an infrared spectrum identical to that of commercial dicyclopentadiene. Thus skeletal rearrangements were ruled out. SUMMARY Photolysis of heptachlor in ultraviolet light produced three products. In the absence of a triplet sensitizer and using a protonic solvent, photodechlorination of the vinyl chlorines in the 5 or 6. position was observed. The photodechlorination products were identified as 1,4,5,7,8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (VI) and 1,4,6,7,8,8-hexachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (VII). Small amounts of the cage compound 2,3,4,4,5,6,lO-heptachloropentacyclo- [5.3.0.02’10”.0"']decane (V), formed by 4Hcycloaddition, was also obtained. In the presence of a triplet sensitizing protonic solvent only the cage compound (V) was formed. No evidence of dimer formation or changes in the carbon chain was found. 17 18 uoflnoouoom mo souuooom moumuwaH 059 .H ouswfim OONH coma oomN comm q. ‘P u a u d d 1 d .. o; H To mg .. To .7 To HONVHUOSSV l9 .uooooum aOHuonuoHnoououoam umufim mnu mo Esuuoomm monoumaH mms .N madman .EU 00¢ com com oooa OONH coma comm 00mm " i i .. i n n u 0 n a .r i i .. o; . h... To 4. m.o .. m.o .. «.0 HONVHHOSHV 20 .wosomsou GoaumawnoHnoovouoam voooom onu wo.s=uuooom monoumsH 65H .m snowflm .50 cos coo oom oooH ‘ I ‘ d ‘ OONH coma d d d comm comm .- 'P uni. ‘- .. o.H h.o a. m.o _ . . To 1 . . .. N.o o.o 21 .oooooUMwowkorJo.o.m.mgoHomomuaooouoHnomuoonnoH.o.m.¢.¢.n.~ mo souuooom consumaH onfi .s ouowfim comm T coo .coo coo oooH coNH coma comm 1 d d J u #- .— .1- ob - p c J -F e To It NCO c.c HDNVHHOSHV 22 2mm oH .oaoo :« acaaomuomm mo sapwooom M22 059 .m ouowwm c n d m o m . 1 u - d a a J {H _ as}? 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Now. an. cam. now. ncH. sou. omH. and. +sHos=oHu ++msonmoflo .+eaonmoHo +sHosmoHu +maommoHo +oaonmoHo +msommoHu +oaommoflo +hfloamoao SOH uaoemoum com com mmm HH vaDOQEOU coaumoauoHnoooouosm sow com mmm H ocsomsoo coauocwuoasoooOoonm com mmm com cooooeoo owmo . oousom one xmom ucoumm .esuuooam mom: onu ca osmom uoouom Ou monomeoo axoom HoEOmH mo auaoaouoH may ..H oases REFERENCES CITED W. R. Young and W. A. Rawlings, J. Econ. Entomol., 51, 11 (1958). R. B. Woodward and R. Hoffman, J. Am. Chem. Soc., E1) 395 (1965). G. D. Schenk and R. Steinmetz, Chem. Ber., 26, 52C (1963). C. W. Bird, R. C. Cookson, and E. Crundwell, J. Chem. Soc. 4809 (1961). C. M. Anderson, J. B. Bremner, I. W. McCay, and R. W. Warrener, Tet. Letters, 19, 1255 (1968). J. H. Beynon, Mass Spectrometry and Its Application to Organic Chemistry, Elsevier Publishing Co., New York, 1960, p 289. "'TITI'IIIIIIIIMInjlflfiifllfilES