Ahy
`
`a
`
`HO
`
`11
`
`2
`
`2325
`
`HO
`11R T
`17 UK
`Fi3C754cCIH31H
`
`Ii
`
`R2
`
`HV
`
`H HO
`
`OAc
`
`OCOPhH H
`
`IOCOCCC6H5
`
`1 R = H
`
`Ac R2 =
`
`I
`
`I
`
`OH NHCOC6H5
`
`3 R = R =H R2= <101H
`
`5 R = W = COCH2I R2= OH
`6 R =R1= Ac it2 = OH
`= Ac R2=0
`7 R
`8 R = H Ri= Ac R2 = 0
`
`PhCON
`
`Ph
`
`R0 TCOOMe
`
`2 R = H
`4 R = OC
`
`3
`
`OH
`
`12
`
`from 1 could
`The formation of 2 photochemically
`in terms of a concerted 2a
`be thought of
`r2a
`the formation of 3 An al
`reaction however
`such a mechanism
`cycloaddition
`does not account
`for
`ternative pathway which can account
`for the production
`of both 2 and 3 is an electrocyclic ringopening reaction
`that breaks the C6C7 bond of 1 to give the open chain
`cation 12
`Such a process is directly comparable to
`observed
`that
`of
`the
`upon the photoisomerization
`to the bicyclo310
`isoelectronic cyclohexa13dienes
`hexenes 1116 While the direct
`isomerization of 12 to
`give 2 is possible in view of the constant
`ratio of 2 to
`is attractive to con
`3 observed
`in these reactions
`sider that a cation resembling 11 might be formed either
`or thermally from 12 and that
`photochemically
`this
`gives the observed products 2 and 3
`
`it
`
`15 A trans ring juncture would result
`from the alternative 02s +
`r21 cycloaddition reaction
`16 J Meinwald and P H Mazzocchi J Amer Chem Soc 88 2850
`1966
`17 Holder of National Research Council of Canada Scholarship
`K E Hine17 R F Childs
`Department of Chemistry McMaster University
`Hamilton Ontario Canada
`Received January 20 1971
`
`Plant Antitumor Agents VI
`The Isolation and
`Structure of Taxol a Novel Antileukemic and
`Antitumor Agent from Taxus brevifolia2
`
`Sir
`We wish to report on the structure of a novel com
`pound named taxol 1 isolated from the stem bark of
`the western yew Taxus brevifolia34
`Taxol has potent
`0 Previous paper in this series M C Wani J A Kepler J B
`Thompson M E Wall and S G Levine Chem Commun 404 1970
`2 This investigation was conducted
`under Contract No SA 43 ph
`4322 Cancer Chemotherapy National Service Center National Cancer
`Institutes of Health XRay investigations were
`Institute National
`carried out at Duke University and were supported by a Duke Endow
`ment Grant
`3 A preliminary report dealing only with the isolation of 1 was
`presented by M E Wall and M C Wani at
`the 153rd National Meet
`ing of the American Chemical Society Miami Beach Fla 1967 Paper
`No M006
`4 Taxol has been isolated from several other species of the Taxus
`genus including T Cuspidata and T baccata We thank Dr Robert
`
`inhibitory properties and is
`and tumor
`antileukemic
`the first compound possessing the taxane6 ring which has
`been demonstrated to have such activity
`The alcohol extract of the stem bark was concentrated
`and partitioned between water and chloroform Guided
`by assay in 9KB and various leukemia systems three
`the residue from the
`successive chromatographies of
`chloroform extract on Florisil Sephadex LH20 and
`from aqueous
`followed
`by crystallization
`silica gel
`gave taxol 1 as needles7
`yield 002
`methanol
`M1 at mle 853 calcd for C471 161N014 853 mp 213
`216° dec 20D 4n Me0H Xmax Me0H 227
`nm e 29800 273 1700 1ux3°1 33003500 OH NH
`1730 ester 1710 ketone 1650 amide cm The
`characteristic chemical shifts of 1 are shown in Table 1
`Because of
`the extremely limited quantity of taxol
`and its evident complexity attempts were made
`to
`prepare derivatives suitable for Xray analysis Al
`E Perdue New Crops Research Branch Plant
`ville Md for obtaining the plant material
`5 Taxol shows confirmed activity for description of bioassay pro
`cedures and leukemia and tumor systems cf Cancer Chem Rept 25
`1 1962 in L1210 P388 and P1534 leukemias being highly active
`two systems is also highly active as an inhibitor of WM256
`in the latter
`in 9KB assay
`and shows considerable cytotoxicity
`carcinosarcoma
`ED5o = 55 X 105
`Less pure concentrates containing taxol were also
`active in Sarcoma 180 and Lewis lung tumors
`6 B Lythgoe K Nakanishi
`and S Uyeo Proc Chem Soc 301
`1964
`7 All
`communication
`compounds
`have
`reported
`characterized spectrally ir uv nmr and analytically elemental
`mass spectrum
`8 Spectral assignments are based on the nmr spectra of
`9 M C Woods K Nakanishi
`and N S Bhacca Tetrahedron 22
`243 1966
`10 I W Harrison R M Scrowston and B Lythgoe J Chem Soc
`C 1933 1966
`11 D P Della Casa de Marcano and T G Halsall Chem Commun
`1382 1970
`
`Inudstry Station Belts
`
`in this
`
`been
`and
`
`taxane
`
`derivatives reported in the literature91
`
`Communications to the Editor
`
`Abraxis EX2021
`Actavis LLC v Abraxis Bioscience LLC
`1PR201701101 1PR201701103 1PR201701104
`
`

`

`Compound
`BaccatinV6
`
`8
`
`2326
`
`Table 1 Nmr Data 6 Units J Values in Hertz
`
`Position
`
`1
`
`C17 CH3
`C19 CH3
`C20 CH3
`C18 CH3
`C4 OAc
`C10 OAc
`C3 H
`C16 2 H
`
`114s
`122s
`167 s
`220s
`180s
`236s
`380 d J = 6
`424s
`
`104s
`110s
`162 s
`199s
`
`402 d J = 6
`438s
`
`120s
`126 s
`166 s
`218s
`208s
`228s
`396 d J = 6
`416 d J = 6
`436 d
`J = 6
`496 broad d
`J = 10
`571 d J = 6
`
`C5 H
`
`C2 H
`C13 H
`
`C10 H
`
`a
`
`492 d J = 10 499m
`568 d J = 6
`574 d J = 6
`620 broad t
`618 broad t
`J = 8
`646 s
`628 s
`683 s
`t = triplet m = multiplet q =
`S = singlet d = doublet
`b Reference 11
`In baccatinV 13a acetate
`quartet
`
`though a number of crystalline halogenated compounds
`were obtained none had properties suitable for Xray
`to a mild
`Taxol was
`therefore subjected
`analysis
`base catalyzed methanolysis at 0° yielding a nitrogen
`containing ahydroxy methyl ester 2 C17Hi7N04
`a
`tetraol 3 C291136010 and methyl acetate not isolated
`eq 1
`C471 151N04 + 2CH3OH
`C171117N04 + C291133010 + CH3CO2013 1
`
`1
`
`2
`
`needles
`
`Ci7Hi7N04 combustion method mass spec
`
`The methyl ester 2 crystallized from chloroform as
`trum pile 2811061 Ci7H13NO3 M 18 = 2811051
`a23D 496° Me0H X Me0H
`mp 183185°
`ester CO 1660 amide CO 1600 aromatic CC
`217 nm e 17700 v=3 3515 3455 OH NH 1730
`cm1 nmr 100 MHz CDC13 TMS 5 326 s 1 OH
`374 s 3 ester Me 456 d J = 2 Hz 1 C2 568
`q J = 2 10 Hz 1 C3 692 d J = 10 Hz 1 NH
`722776 m 10 aromatic X Ray analysis was
`performed on the pbromobenzoate 4 C24H20BrN05
`
`C231 1360i0 combustion method mass spectrum mle
`
`mp 161163° which crystallized
`in the monoclinic
`system space group C2 with cell dimensions a
`2291 b = 518 c = 1966 A i3 = 9980° and Z = 4
`The structure was solved by the heavy atom method and
`the molecular parameters anisotropic Br
`isotropic
`C N and 0 were refined by full matrix least squares
`1772 ob
`calculations to the present R of 0125 over
`served reflections
`The tetraol 3 crystallized from methanol as needles
`5262188 C29143400 M 18 = 5262203 mp 245247°
`cD 4205° Me0H XMe0H 227 nme 14700
`cm1 nmr
`KBr
`lima 16801720 ester and ketone
`could not be obtained for lack of solubility in CDC13
`or DMSOd6 XRay analysis was performed on the
`bisiodoacetate 5 C33H3801212 mp 202203°
`dec
`nmr 100 Mz CDC13 TMS 5 372 s 2 C7 iodo
`acetate CH 382 s 2 C10 iodoacetate CH 620
`12 G Zemplen A Gerecs and Hadacsy Ber 69 1827 1936
`13 The absolute configurations of 4 and 5 were established using the
`anomalous scattering of the halogen atoms and they are as represented
`Full details of the Xray analysis will be reported elsewhere
`
`Journal of the American Chemical Society I 939 I May 5 1971
`
`s 1 H C10 The bisiodoacetate 5 crystallized in
`the orthorhombic system space group P212121 with
`cell dimensions a = 967 b = 1534 c = 2369 A and
`Z = 4 The structure solution was by the heavy atom
`method all nonhydrogen atoms being located in two
`Positional and thermal
`successive Fourier syntheses
`isotropic C and 0 were
`parameters anisotropic I
`refined by full matrix least squares calculations and the
`present R is 0142 for 2305 observed reflections
`is interesting to note that Halsall and coworkers
`It
`have also recently reported the isolation of the diter
`penoid baccatinV a naturally occurring oxetan similar
`
`for
`
`functions of 1 on the tetraol 3 Taxol could
`
`indicate that
`
`to the tetraol 3 differing only in the configuration of
`the hydroxyl group at C7 The reported chemical
`are reproduced in Table I
`shifts of baccatinV
`comparison with those of taxol
`Assuming that no rearrangement of 1 occurs under
`the mild methanolysis conditions the final structure
`of taxol requires the placement of the two hydrolyzed
`ester
`not be oxidized by carefully washed neutral
`to litmus
`and activated manganese
`dioxide 1516 indicating
`that
`the two esters were located at
`10
`the allylic positions
`The chemical shifts of protons at C10 and
`and 13
`C13 cf Table I were also in accord with this ob
`servation Oxidation of 1 with activated manganese
`conditions pH of
`dioxide under mild basic
`the
`yielded com
`suspension was 8 in acetone
`aqueous
`pound 8 mp 210212
`The molecular composition
`mass spectrum mle 5842266 C31H36011 = 5842257
`it was formed by the loss of
`of 8 suggested
`the
`that
`nitrogen containing ahydroxy ester function and oxida
`Several in
`tion of the liberated allylic hydroxyl group
`the hydrolyzed
`lines indicate that
`ester
`dependent
`function was at C13 The ultraviolet Xmax Me0H
`272 nm e 4800 and infrared spectra
`vmax CHC13
`1680 cm1 of 8 are in complete accord with this struc
`the alternative Li 910dioxo for
`ture and rule out
`the nmr spectrum of 8 cf
`mulation Secondly
`Table I clearly shows the presence of a singlet due to
`the C10 proton at 3 646 as required by formulation 8
`the methyl ester 2 is
`Bioassay data 17
`inactive and the tetraol 3 only 0001th as active
`
`as
`taxol
`that
`the activity
`is interesting to speculate
`of taxol may to some extent be due to the easily cleaved
`function at C13 which may be
`allylic ahydroxy ester
`capable of acting as a leaving group under physio
`logical conditions
`
`It
`
`We wish to thank Drs S G
`Acknowledgments
`and J A
`Levine North Carolina State University
`Kepler for helpful discussions and Mr J B Thompson
`and Mrs L W Ambrosio for expert
`technical as
`sistance We wish also to thank Dr David Rosenthal
`and Mr Fred Williams of the Research Triangle Center
`for Mass Spectrometry for mass spectral data Their
`work was supported by the Biotechnology Resources
`
`14 This is a reasonable assumption in view of the fact
`that
`the
`methanolysis of taxinine gives dideacetyltaxinine which gives taxinine
`upon reacetylation cf M Kurono Y Nakadaira S Onuma K
`Sasaki and K Nakanishi Tetrahedron Lett 2153 1963
`15 I M Goldman J Org Chem 34 1979 1969
`the same conditions the 710diacetate 6 C331140012 mp
`16 Under
`225227° obtained from 3 was smoothly oxidized to the corresponding
`conjugated ketone 7 C331138032 mp 236238
`17 The cytotoxicities of 1 2 and 3 have been determined and have
`ED5o values 55 X 105 10 X 105 and 22 X 105 respectively
`
`

`

`2327
`
`Closs method Irradiation of
`la 500 mg in 500
`ml of cyclohexane 0003 M at 2537 nm for relatively
`short periods 34 hr in a preparative photochemical
`reactor while simultaneously
`sparging with a slow
`stream of argon provided 230 mg 46 7o of 2a mp
`17759°
`mp 176178° which may be isolated
`by elution chromatography on alumina
`For convenience
`the mechanism for the rearrange
`ment of la is formulated as a diradical process as out
`lined below
`
`C51153CCCC6H5
`
`la
`
`C6F15 3c =CC6H5
`3a
`
`C6H5
`
`C6H52C=CC6H
`
`3b
`
`hv
`
`hv
`
`C6H5A7C6H5
`
`C6H5
`
`C6H5
`
`2a
`
`C6H5
`
`C6115
`
`C6H5
`
`4
`
`5
`
`The formation of 2a indicates that
`the intermediate
`perhaps 3b formed by rearrangement of a diradicallike
`intermediate such as 3a cyclizes
`in a
`in part
`at
`least
`process analogous to the photochemical
`rearrangement
`and
`of propenes to cyclopropanes23
`Alternatively
`in a con
`perhaps more likely the reaction proceeds
`certed manner
`to form when the
`Additional photoproducts
`begin
`irradiation time is extended as evidenced by the appear
`ance of nmr signals at 7 494 and 467 CDC13 char
`the benzyl protons of 4 and 5 respec
`acteristic of
`An nmr study of the variation in product
`tively54b
`time under standard
`function of
`composition
`as a
`irradiation conditions in benzene proved instructive
`The quantitative
`data summarized in Table I were
`
`2a
`
`25
`46
`
`70
`
`4
`
`42
`
`35
`Trace
`
`5
`
`19
`
`9
`Trace
`
`Time
`hr
`
`24
`
`4 1
`
`Table I
`
`LICLG1111111cll
`
`UL51lL111
`
`01011 en
`
`in high conversion 80 upon
`
`unit
`
`in
`
`Luc
`for 2a centered at 7 230 CDC13 in addition to the
`singlets for the benzyl protons of 4 and 5 Although
`these data confirm that
`the photolysis of la in cyclo
`hexane proceeds
`7 a The preparative irradiations
`in a Rayonet
`were conducted
`RPR 208 Reactor The Southern New England Ultraviolet Co Middle
`town Conn with 8 RUL 2537nm lamps b an RPR100
`equipped with 16 8W 2537nm lamps c an RPR100 unit fitted with
`16 8W 3100 or 3500nm lamps
`8 R B Woodward and R Hoffmann Angew Chem Int Ed Engl
`8 781 1969
`9 a All nmr spectra were recorded on a Varian A60 instrument
`the solvent indicated with tetramethylsilane as an internal standard b
`new compounds gave satisfactory combustion andor mass spec
`tral analyses c mass spectral data were obtained on a PerkinElmer
`Hitachi RMU6 spectrometer
`
`all
`
`Communications to the Editor
`
`of Research Resources National
`Branch Division
`Institutes of Health under Grant No PR 330
`M C Wani H L Taylor Monroe E Wall
`Chemistry and Life Sciences Laboratory
`Research Triangle Institute
`Research Triangle Park North Carolina
`27709
`P Coggon A T McPhail
`Paul M Gross Chemical Laboratory
`Duke University Durham North Carolina
`Received February 16 1971
`
`27706
`
`Photocyclization of ArylSubstituted Acetylenes
`Application of Dir methane like
`Rearrangements
`to Arylcyclopropene Syntheses
`
`Sir
`
`In a continuation of previous studies on the photo
`and related
`cyclization of arylsubstituted propenes2
`such
`as 3alkoxy
`functionalized
`propenyl
`systems
`substituted propenes3 we have investigated the photo
`chemistry of several aryl substituted acetylenes with
`the intent of developing a convenient
`route to cyclo
`systems which in
`functionalized
`propenes
`including
`turn might serve as precursors
`for cyclopropenium
`Our continuing
`in the photo
`derivatives4
`interest
`chemistry of cyclopropenesd provided an additional
`incentive for this study
`
`C6H5C CCC6H52R
`la R
`C6H5
`b R = OCH3
`
`C6H5
`
`C6115
`
`C6H5
`2a R = C6H5
`b R
`c R = 0C2H5
`d R =
`
`la was
`by
`Tetraphenylpropyne
`a
`synthesized
`procedupe which is a modification of the Wieland and
`1 A preliminary report of this work was presented at
`the 160th
`National Meeting of the American Chemical Society Chicago Ill Sept
`19702 G W Griffin A F Marcantonio H Kristinsson R C Petter
`son and C S Irving Tetrahedron Lett 2951 1965
`3 J J Brophy and G W Griffin ibid 493 1970
`4 Recently J W Wilson and K L Huhtanen Chem Commun 454
`1968 described
`rearrangement of methyl 333
`the photochemical
`i
`iv
`triphenylpropyne
`to the
`carboxylate
`indenophenanthrene
`The diradical species ii was proposed as a possible intermediate leading
`to the indene iii which in turn undergoes
`subsequent
`dehydrocyclization
`to iv A similar diradical species has been postulated by us as an inter
`and photochemical55
`mediate in the therma15
`rearrangement of tetra
`phenylcyclopropene 2a to triphenylindene 4
`
`C6H5 3CC
`
`CCOMe
`
`hv
`
`C6H52CC=CCO2Me
`
`c6115
`
`1 1
`
`C6H5
`
`C6H5
`
`Me02C
`
`iv
`
`COMe
`
`lit
`
`H
`5 a M A Battiste B Halton and R H Grubbs Chem Com
`mun 907 1967 b R H Grubbs MS Thesis University of Florida
`1965 c H Kristinsson and G W Griffin J Amer Chem Soc 88
`1579 1966 d H Kristinsson Tetrahedron
`Lett 2343 1966 e
`A S Monahan J D Freilich and J J Fong ibid 1865 1970 f
`H Diirr Justus Liebigs Ann Chem 723 102 1969
`6 a A W Herriot PhD Thesis University of Florida 1967
`b H Wieland and H Closs Justus Liebigs Ann Chem 470 201 1929
`
`