On the constitution of the bitter principle

011dersle11oorl ./ovnwl of l'ell'ri11111-_1; Sr·ip111·(' a11rl cl11i11111l /11d11sfr,1;, l'o/11111e 10, .\'11111/Je1· :!, A11ri/, JD3S.

Print0cl in th,• l'nion of South .-\fri<.:a by the Go1·prn111ent Printer, Pretoria.

On the Cons ti tu ti on o f

" Geigerin " I. The Degradat ion Acids.

the Bitter P rinciple Isola ti on of V a rious

Hy H. l ^L DE v\' AAL. Sl·c·ti 011 0 F p h il f'llla('(llOg_\' a !Hl Toxicolog,\·' OJl(lers1 epoort.

(l{P:t<l :it OnrlPrstepoort on Sth SPpl1·mher. l 1J07.)

IxTno ll l 'C'T 1 o:---.

Ac·co111>1i'\(: to thP prnpe1tip,;

or

the· hiitPl' p1in1·i1ilp UPig'l'l'in and thP iiclin• p1i11l'iple YPl'll!PPl'il' a1·id of th1· ·· Y1•J'Jlll'P!'lios ·· (Uei.r;eri11 11s11e1·n, Fl:in-.), clc·snlliP<1 hy RP111i11g·to11 :rnrl HoPL (l~Hfi) ;1rnl Hi.ming·ton, Hol'ls :11111 Ste.\·n (l!rlfi), lhl'sl' s11hsl;1nl'e;; \\'(J\lld ;1ppenr to be l·losl'ly 1c·l:d1•rl 11·it h rpg·:inl lr1 t hl·ir cherni(':1l sh-lid lll'l'S. J ll

s11mrn:ni;1,i11g thc· n·s1dt;; .tlrc-•:uly oldai11Pd, thc•se ;rnlhrll'S suggt>st part·

fornrnhl' for Ch·igerin (1 ), Yern1Perif' :1('i1l (:!) ;ind its clilactonc VerrnPerin (:~)a,; follo11·s, giYi11g :in indication of f'11p pos,;iblP inYOhP- ment of 0111· :dorn of oxygen in a kdo-Pnol b utorne1ism:

I -

COOR

1 -

^C'OOH

~

^{- OH}

I- OH

L= o

or

or

395

r - ^co

~ - 6

l - OH ~

^{= 0}

⁺

^{H to ring.}

I -

C'OOH

I

I -

('OOH

I -

^{OH .}

l -

OH:::;:::::::: = 0

+

^H to ring.

THE CO.'\SlTITTl<JS (JI' THE JJJTTLH PHJ.'\('l l'LE " Cl·:l(;J-:J! I K "

Tlwse ,;ul>s1:1n<·t•s hC'i11g i11 :ill i>rol>:1bility dosp]y n•l::dt>d to 011e :rnuthe1., rnnstitutional "·01-k 11·:1s begun on th!-' !'11en1i(':ll ('Onstitutio11

"f tJ1p hittt>r pri11ciple UeigL•ri11. Should 1he strnd uit" of the lattPr

be t·lu!'idail'd, then ;;irniLH rnPt ltocls oi· eu11stit 11ho11:il in\Tstigatio11

\\·he11 npplit•d to \"('J'nll•t•ril' :1<·id rn· Yl'rmt•t•rii1. rnig·lit he PX]H't·1l'd to lt•:1<l ~lll'l'('Ssfull.1· 1o tht• d t•;1ri11g 11p of their s11'11d t1res :1lso.

~llt>a1111·hilP ii 111:1.1· IH' poi11t1·d 0111 tl1:1t the hilfrr pri111·ipk,;. althm1gh

Yer.v i11fpn•sli11g sul1jl:'l't.s fo1· i11,·e,dig;1tion lw,·<· p10Yl'd to be most rlifti!'u!t frn111 thp co11;;titutio11nl .strnd11r:1! j)()int of 1·iew. Thus Jlt•th (HJ:lti) dl'snibi11g ;1 Jp11· sl'ores of l>iHt·1· prin(·ipks :dn·;1d.1 isolatl'd i'rOlll diffen•uf pJ:i11fs. p;;]Wl'ialh 1he fornilit•,; he11ti;1!1;11·e;H'.

<'ornposiLlP :ind L:1hi:ilP:1e poi1ils 01il tl1:d up till lht>11 1101 ;1 sing·lt·

hitll'I' priur·iple's strnd ure h:1d lil'e11 fnll1· Pl11r·id:1te1l.

1 n this adide 11·e 11·i,;h to Jpr·onl tlw first n°,;ults :1ln·:Hh oht;1i1wd on the l'Onst itut iou of Ueig·l'ri11 :incl to clesl'l'ilH' Yarious <l;·g·rndatio11 produf'ls oht:1i11t·rl li.1· o:;irbtion t11· othen1·isP. '!'hes!' ]1;11·e been 1·e1'.1·

enc·ou1-;1g·ing-. TTntil 11101·e sh11 I i11g- rn;1tl'ri:1l has hmn·1·pr been pn•- Jl<il'•·d ;11Hl 1111til hntht•r l't'.;11lts h::iYe hl'l'il obbi11t><l. \YP do 11ot 11·i.;h (o l'llter iuto n cle1:1iled llisnissinn of its possible strudural formula at this stag'l'.

THE Al'l'Ll(',\TJOX ()lo' Tll E "I ,LG.IL TEST .\S .\ ~I ETllOIJ FOR lJETEl"l'IC\l;

.\CE'nLl>EHYllE IS !.h:1c1·:1n:-; OXID..\.TIOS E\:PEllDIE!\"TS.

AL·r·onli11g to ~Ien·r !HJ:ll. p. -1-1()) a "hnr:1d <•risli<· i1iten.sl' l·olo11rntio11 is ohb i11eil \\'hP11 lo solutio11 . .; of kPto11es or ;1ldt>h:nll'S prdt'r:il>l.1· i11 11·atPr fol.;o akohol or ethpr) ()-rJ to I L'-c" of ;1 fn•shl.\·

pn·pan·d ()-:! tr1 ()-.-> P<-'J' c·e111. st1<li11m 11ilrnprt1c'sicl<' sol11lion is :1dd<·cl foll()\\'(;'(l h.1· :ilk:1li11ifil':tlio11 \1·ith ('()Jl('('llh:il<:d rnt:1ssi11rn l1,1·clrnxirle (D 1 · l+).

l.11 the aliphatic· ;;c•ries thi . .; re:1dio11 i,; :il11·;1Ys po:-;i! iYL• 11·h1·11 t ht•

group ;1i't::il'hed t·o the ke!o11ir· or :ilrlf'hnlil' r:11lid(• (in <t- posit·io11) consists of (';nhon :rntl l1ydrogt•11 rrnl,v. r\ldehyd1· or kd n11c gToups rliredly bou11rl to :1 ring· or i1H·l11dr·cl i11 a ring· strnd u1·c· Lio not giYC' the readio11, 11Pitht·r do ortho-al<leh.nli<· :ll'irls.

ThP colours prndu!'ed 1·:n.1· from ornng·e-n·11. red to nolt>t-n•d.

\1·hil'h on fi1<' ;1drlit·ion of org·:111i(· aeids ch~rnge from recl t·n i11tlig·o- hlue or from YiolPt hlne to h111e-gTeen P.g.

The solid ^{( l-} or $-Geig·eri11 i;; uni ::i ketone. nor riot's it sJio,1·

:1ldc•hyclic m· ketonil' prnperties i 11 n ne1iiT::il solutio11 (it iR presu111ahl_1·

orPsen( in the enol-form) but in clilut-e l1nlrnC'h loric· aricl solution it reads ns n ketone. 'rl1e J,pgal test· is. tlwrefore 11pg-;1tiY« with G<-'igf'rin. T'iThen Geigerin is dissoh·ecl in :1 ]() per r·ent. h:nlrnl'hlmir

396

I-T. L. JJE \\"A.H.

acid ;;olutiou (ketonic-±onn), coole<l do"·u and then neutralized ,,·ith Hi per cent. potn,,sium hydroxitle the immediate application of the Legal test yields a negative rewlt. This shows ei(her (1) that the enolic form is again obtained on neutralization or (2) that although Ueigerin may still he p1e,;e11t in the ketoni<; form, that the carbonyl- group i" tlirectly coutaiuecl rn a ring· structure or i.rnrne<l ia tely attached to it.

Iu the oxitbtio11 processfa; deseribcd belo,,- (see experimental part) ;icetalclehyde is Yery frequently formed as a byproduct tlnring the oxidation. L nder certain cin·urnstauce:> !he acetaldehyde is most

probahl_,~ liberated from a pre-cm·,;or funned thuing- the oxidation aml can tlrns ouly be deteded after aciclificatiou. Un<ler other condition:> (ether extradions of aC'id mediums or a<·i<l oxidations) aeetaldel1yde aceompanies the main oxidation protlud formed as a sticky oily rnaterial. \Yhen the latter is washerl away with pure ether (mtly Merck's aiHl Scheri11g-Kahlbaum's absolute ether has been 11sed in the,;e extractions), the :icdnldehycle may be ea;;ily all<l very con ve11ier1tly detected by means of the Legal test. The ethereal solution ur a \vatery or even an absolute alcoholic ,;olution (,,·hen acetadehycle is present) \rill immediately give a positive test with the Legal reagent, the watery phase turning intense orange-red. Tht> usual identification tests e.g. its pungent odour, its 2-4 diuitro- phenylh_vdrazone derivative with Brady's reagent ancl other tests will confirm its prnsence. Blank experiments with pure ether, absolute alcohol or water will g-i.ve only the "blank " greenish-yellow r-olourn ti on.

'l'hP following diagrn.m will demonstrate the conve11ience of the Legal test for cletecti ng- the acetalll ehvcle also formed during the isolation of the various oxidation products (compare tht• experimental part) :

alkaline KMn0₄ Geigerin- - ----~

oxidation

H₂S0₄

Precursor --~ Acetaldehyde

+

^HCl

An Acid

I I

HCl

I l

~~~~~~~~~~-

Aceteldehydc lVIonocarboxyli

+

c acid

(C₁₀H₁₄0_{4 )}

HN0₃

~

I Acetaldehyde Oxalic

+

acid

Alkaline KMn04

oxidation

Geigerin - ----~ monocarboxylic-dilactonic acid (C₁-,H₁₈06 )

oxidation

+

Acetaldehyde 397

THE COCISTITCTION OF THE BITTER PRINCIPLE ' ' GEIGElUN '' .

.Neither of the degraclation aeicls, C10H1104 (lvI.P. ~01°) and C,,-,II,806 • H20 (:lU.l'. 280°) give the Legal test; thus in solution the application of the Leg·al test \Yill quiekly aff:inn the preseuee or absence of acetaldehycle.

ExPEJi urnNTAL.

lmproi:erl Ueiyer1:n E.i:lracllun.

About Iii Kilogram of dried grnund · · Y errneerbos · · was ex traded ^m the following way :

3·6 Kg. dried material ^\YaS extracted "·ith ethl'r ⁱ¹¹ <I laige

~oxhlet-t,vpe appmatus for :3 \\·orhug day;; (i.e. about 22 hours). Tbf'

ether

""IH

^{theu (lrawn oft, a1uotmling} to :1bout 8 litrf's in Yolnme.

The e!her ,;olu!io11 \\·as the11 diYiclecl iuto two elpial poiiious alld ea('h p:irt ,;hakPn ,,·ith about 5 litrf'o; of 1 per cent. h~·dnwhlorie acid (in 5 or li p01tio1rn), i.e. a total volurne of 10 litres. Through thi,;

solution air \vas then clr:nnt for :3 to 4 ho1u,; when ihe solution has n greeui~h-.\·ell()\\. tint \\·ith a pleasant ether-free fruit)· smell. The solution wa,; then shnkeu \1·ith a little chareoal, filtt>recl n11cl no1\·

shnk(rn \Yith 8 lb. of ('hlorofonn (in s11eressiYe pm·tions). Tlie c·hlornfor111 soi 11tio11 \\·as theu 1\·ashecl \\ ith a one per cl'nt. socliurn n11·b011ate soh1tion, hec·orni11g· nearly ('olourle,;s, <rncl ag<1i.11 11·:1sht•cl with cl i si.illecl \\'a tel'.

'l'he d1loroform solution was lhen d1·iecl oYer soclinm sulph:dc>, c:oncentrated at l'ecluf'eU pres,;ure lo about· C>OO c.c. of dilorofonn and left to en1pm·:1le in front of a fan. Aftf'r 2 to 3 cln>·s tlie resulting

!'nstalline resiclue ll'as boiled out "·ith 100 to 400 c.f'. of distillecl w:1ter aitcl filterer] into open clishes. Crystallization illlllle(liately set i.n on cooling and after ren ystalli,.;atiou from \1·ate1· a yield (on tlw average) of ] ·5 grn. of Geigerin was obt-ained, i.e. 0·40 g·ui. per 1 Kgrn. dri eel plau t rna lerial.

O.ridatio11 of Gei.r;eri11 1ritl1 .Y il1·i1· A.l'l«l to ¹¹ 111n1101·11 rf,n.ry1 i1·- dilarto11ir 11rid (C,,-,H180" · H"O).

'l\rn diftere11t methods both yielcling goocl recnilb, nn' clecoribf'll he lcrn· : --·

(a) l gm. Geigerin and 50 C.l'. nihil' a('id (1:1) were reftuxe(l for 12 hour,;, cluring "·hi('h time nitl'Ogen pProxicle fumrs were eYolvecl finally yielding a pale yellow solution. On cooling it "\'\'as cliluted with (listi.llecl \\'at.er and then thoroughly shaken 3 times >vith rhloroform, the chloroform solution '"ashed once "·ith >Yater, dried over exsiceated soclium sulphate and then evaporated in front of a fau at room temperaturf'. Crystals separated practicallv innne·

cliately. After the solution had been evaporated to ch>ness, the eryRtals \rere wn,;he(l with ether ancl ,,·ere obtained as f'Olourless hexag'onal prisms with a melting'-point, crude, of aho11t 250° and iu a yield of 0 · 26 gm.

The ether >Yashings eYaporated at room temperature left aeetaldehyde.

'l'he orig·ina 1 solution was again shaken 3 ti mes "-ith l'hlorofor111 nnd after the same treatment yielded another ,')() mg'm. of the new pro(lud, thus increasing the yield to about 000 mgrn. The material

11. L. DB \\"AAL

was twice iecrystalli,;e(l hom water. The (;l'ystals turned opaque '' at 105°; ahoYe 240° hexagonal prisms shot out \1·hich melted sharply at 280* (corr.) "·ithout decomposition.

The surne oxiclatiou procluct can be obtaiued by the oxidation of Geigeri11 ". i th ui tric acid ( 1 : 3 and l : 2), coucen tra ted nitric acid (D = ] ·J) and :urning nitric acid. 'l'he follo\\·iug method is espe- cially recommended: -

(b) 111troduce iuto an open pyrex <lish (capacity abcrnt 00 c.c.) l ·0 µ:m. Geigerin and coYer the subsiance witJ1 about 20 c.c. of con- ct'ntiateci nitri!' aci<l (D~l·-!) nnd warm on a boiling waterhath.

'l'he !'rystnls easily tlis8oh e. The oxidation is continue<l for about one day (S honrs). Continue the ~t<ldition of coucentrnted nitric acid no\\· arnl then all(l fiuallv allow to rnn!'entrate to about 10 c.c. Allow to cool do1n1 ( n.1·,;ta ls. freq uenil.1· sepnratiug imrnedintely) dilute with water to ah011l 100 ('.!'. a1t<l leaYe to stand in a11 ice-chest over- nig·ht. Henystallised from 11·ater 400 rngrn. of th(~ pme oxidation acid is obh1inetl ("JI.P. 280- see Fig. l ) (a hyprodnci of !he oxidatiou i:-; acetalclt>h~yde).

Fig. 1.- ..\cid obtained by the nitric Hf'id oxidation of Geigerin. m.p. 280°; x2:3.

I'ropettirs.-The sub~tance-

\1)

is rasil~· soluble in ammonia, alkalis and dilute sodium carbonate solution- is therefore an aci<l- aucl may be 1·ec0Yered on the addition of (lilute acids;

(2) <lissoheK slowly with011t colour in concentrated sulphuric acid but is practically insoluble in (lilnte mineral acids;

(3) is insoh1ble in beuzene, e!·her and petroleum ether;

(4) is sparingly solnhle in chloroform and ethyl acetate; (5) is solnble in 'rnter, methyl alcohol aucl ethyl alcohol; (6) is readily soluble in acetone:

(7) does not react with Brady's reagent:

(8) rloes not µ:ive a Legal te;;t;

(9) gives no colour with dilute or concentrated hydrochloric acid.

*Kofler micromelting point appo;ratus.

TUE COKST.lTUTIOK 01·' THE l!TTTEH PlUNClPLE " GEIGEJUN " .

.11 £era-analysis.*

(1) Drierl at room temperature in high vac. over P205•

(11) 5·208 mgm.: 10·9GO rngn1. C02 ; 3·0GO mgm. H 20.

found C=57·41; H =Ci·58.

Cale. C=57·G8; H =G·46.

C1JI1/\ · H20 (312. 31)

(b) 0·2Ul mg1n. iu 0·756 mgni. Camphor: 6 =G·7 i.e. rnol. 11·eight=310 (calc<L :l]2·31).

(2) D1·iet1 at 110° C. in highnc.

(a) 5·J24 mgm.; ll ·945 mgm. C02 ; 2·920 mgm. H20.

(/1) 4 · :"d9 mgm. ; 10 · 2:rn mgrn. C0_2; 2 <jiJ() rngm. Il₂0.

fouml (a) C~~G1·22; H =G·l4.

(/1) C = GJ · 49 ; H = 6 · 29.

Cale. C=Gl·22; H =fi·l7.

CJ5H180G.

Jlir1·0-titrotio11.- 1G·G rngm. d tlw aeicl (lissoh ed in about 10 r-.r-. ''"uter required O·n0 «.«. O·l X XaOil, i.e. assumrng one

- COUH the molecular weight is 299.

Rotation.- vVeight ,=59 ·8 rngm.

Yolurne=l·)·O c.c. abs. ak.

8

+

1·45°.

Therefore

[ ex. J

^:.,]9)5

⁺

^{1·45 2 x x 5100 ·98 x 15}

+

181 ·85° . .II ethyl-ester.

To a wluti.ou of 00 rngm. of ihe above oxidatio11 acid dissolved ill about G t·o 7 c.c. of ncetone, an ethereal solution of diazornetlrnne '"a" slo,Yly a<lclerl (i«e-r·ooli11g) mitil a sliµ:ht exce,;s of <1iazomethm1e

"·as noticPahle. The solution

""is

^{then left to s}tanrl oYeruight \vell- stoppere<L It was then allowed to evaporate and the crystalline r<'sid ue ( ueerlles gr011 ping in aggregn tes) ""' s renystallized frou 1

dilute methyl nlcohol. A.Her 1·ecrysialli1rntio11, wasltecl ~Yith !J() per

«ent. aleobol arul then with ether, the colo11rles;; six-si<led prismatic uee<lles rnt>lterl i'1ia1ply 11·itho11t rlt>cornposition :ii 190-191° (C'orr.) . . lf ir· ro-a n11 l ygis.

4·974 mgm.: 11 ·T~o 1.ug'm. CO": 2·970 mgni. H"O; 0·010 mgm. res.

fomlll Cc~ G2 · 2cJ; H = G · 70.

Cal«. C=62·5n; H =fi·54.

C1,H1,0.1COOCH3 :

(C11•H,11

0,J

* All micro-analysis by Dr. Ing. A. 8chocllcr, Berlin.

H. T.. DE \L\AL.

=

Fig. 2.- ::\fethyl ester of rnonoc:arboxylic dilactonic acid m.p. lQ0-191°; x50.

JJrese11ee of T,ar·lo11e uu11111i11.r;s in the "11e1c " acid, in.Ji. 280°.

02 · (J mg-. of the acic1 was c1issohecl in i he cold in 5 c.c. of 9() per cent. alcoholic· pota~,;iurn hydroxide (F ~ 0 · 097) and aftei: fiye minuies the wlution hack iitratec1 \\·ith 0 · l X hydrochloric acid.

G c.c·. Alcoh. KOH (1<'~0·091). =4·8;) c.c. of O·l K KOH.

Bae!; tit.ration requirecl .. 2·!:l0 c.c·. of O·l N HCl.

Therefore r1iffereuce -Cl ·9:-) c.c. () · 1 K KOH. Ko'' 31 ·23 (rnol. 1d. =:~12-:l) mgr. acid req.: 1 c.r. ll·l :N" KOH

for one - COOH.

Therefore 32·0 rngr. aeid req<l.: 1 ·024 c:.c·. 0·] N KOH for one - COOI-I.

1.e. theory for .2 r·arboxyles =2·0,-> l'.C'. O·l ~KOH.

founrl = l ·90 c>.c. 0 1 X KOH.

To ihe abow sol11tio11 4·85 r·.c. O·l K alcoholic potassium hnlroxic1f' was again ac1<led anr1 ihe solution left for i) hours a( :17°

C.

Bad titration required Therefore difference

3·90 c-.c. O·l X I-ICl.

~0·90 c.c. 0·1 N KOH.

Theory for OJ)!' -

roon

^{= 1 . 02 LC. 0.] ~ KOH.}

Again 4·85 c.c. of: O· l X alcoholic potass. hydroxide \\·as added and the solution left for anoiher 5 hours at 37°.

THE CO:\STlTLJTIOX OF TIIb llITTElt l'ltIKClPLE " GEIGElffK ".

Back titration rec1uired 4·80 c.e. U· l X HCl.

Therefore no siguific·ant diffe1 cnce.

'l'he:;e figures indicate that after 5 mi11utes one lactone grnup is saponified to a carboxylic group and afte1·

o

hours a second lacto11e group is saponified to a secoml <'arboxylic group. Finally. ~·e thus haYe a tribasic acid (the original acid being monocal'boxyl1c) which was again proYed by the reladoniz:ition.

Rela.cto11iwtio11 of the Trirarlw.rylic Acid.

Continui11g "·ith the aboYe solntio11 containing the tricarlioxylic acid, experiments were conducted to determine whet.her any of the carboxyle groups could relactonise.

5 e.e. 0·1 X HCl 1rns arlderl a11rl the solution lefi. for 20 hours at 37° C;

Back titration required 'l'herefore difference Theory for 2 lactones ...

2 80

=2·20

= 2·l)rj

<'.C.

c.c.

C'.C.

O·l

x

E.OH.

0·1 :\ HCl.

O· l :\ HCl.

After the aclclition of another 2·0 c.<:. O·l H('l ancl lenYing the solution for G hours at 37°, it was back titrated and the had: titration requirec] exactly 2 c.c. of O·l ~KOH; therefore no change.

'l'hns 2 of the 3 carboxyl groups were relacto11ized after 20 hours.

D11plic11te Sapo11i:ficatio11 and Re-lacto11izatw11.

32 · 0 mgT. of tlw d iladon ic-monoca rboxylic aci tl (111.P. 280°) 1rns clissohPrl iu {) c.c. of O·l X alcoholic KOH at roo111 ternpP1ntme and back titrated 1Yith O· l X HCl after seven minute~.

Back titration required 2 · 80 c.c. 0·1 K HCl.

rl'lterefor~ cliff ere nee= 2 · 20 c .c. 0 · 1 X KOH.

After another hour (i.e. onf' hour and s:"Yf'll miJJutes) a back titration of Fi c.c. X alroholic: KOH 1Yith O· l K HCl gaYe a cliffereuc:e of 0 80 c-.c. 0·1 N KOH.

rrhe1 efore tohl cliffcerf'nce ~·~ 0 · 00 c.c. 0 · l N KOH.

'1¹heory £01 3--COOII=3·1)7 ('.c. O·l KE.OH.

Aft.er 18 honrs the total cliffereuce \1-as raised io 3·10 e.c. O·l K KOH, i.e. a practically complete sapcmifif'ation of the monohasic- clilactonic acicl was acrmnpli:,hPd after ()/ minutes to a trihasic-acicl.

Simi larh relactoniza tion of the ahoYe soktion follows : --- ·

A Her 30 minutes clifff'reuee After 2 hour,,; difference After i hours difference .. . After 24 hours difference .. . 'l'heory for 2 lactone-grnup~

~0·80

= l

·an

=1 ·60

= 1 . 8()

=2 00

<'.C. 0.]

x

l'..(;. 0· l

x

c.c. O·l K c.r:. 0·1 ~ c .('. O·l

x

took plare as

HCl.

HCI.

HCl.

HC'l.

HCl.

II. L. DE WAAL.

Summarising these re;mlts we haYe for the monornrboxylic- dilactonic-acicl (:!\LP. :280°) an empirical formula of C15H1800·H20 constituted as follo" s: -

I -

^COOR

I

\- CO

~ - 6

I 1- co I I L- o I -

COOR

1- co

I I +

aqueous KOH

~ - 0 - -- - --+C₁₂H₁₇

I -co I I L- o I-

COOR

I- co I I

~-0

/ -co

l - 6

+

^{alcoholic KOH}

- - - --+C12H17 (within 5 minutes) at room temperature

I -

^COOH

1 - ^co

r

^COOCH~

1 - ^co

I I

1 - 0

1- co

l - 6 r

^COOK

J - 10

- 0

I- co

l-

⁰

r -

^COOK

I -

COOK

~

^{- OH}

1 I - 1°

L - o I -

COOK

I I I

~-0 ¹

- - COOK

+

alcoholic KOH _

- - -~C12^H1 ^~ - COOl'-

I 1°

(approx. 5 hours) at 37°

I L- o

and the relactonization

I -

^COOR

I I -

^COOR

~

I

- COOR

I

I-OH

I L-

^OH

-L HC!

--'---- --+

^C12H17

(l-2 hours) at 37°

403

1 - 0H

L -

^OH

r -

^COOR

1 -

^COOR

1

-

^OH

- co

L - o I

THE COKSTlTU'l'IOK 01' TIU~ DITTEil PJUKCTPLE " GEIGElUN ".

r -

^COOR

1 -

^COOR

1-

^COOR

1-0H

l-

^OH

(-COOR

1- ^co

+

HCl

I I

-i>-C12H1, ·H20 ~ - 0 (approx. 20 hourn) at 37° ^J

J - CO

I I l-

⁰

(Same as I above).

Considering the easP with "·hich one carboxyl group is relacto11ised in the presence of 0 · l N hydrol'hloric acid, it is interest-

ing to (;ompare this phe11omenon "·ith that of Verrneeric acid (o;ee

Rimi11gt011, Roets and Steyn, pp. Cil7-G18). In the latter at:id onP t:arboxyl grnup similarly lactonises much more readily than the second (e.g. in the presence of the hyclrochloric acid of the Brady's reagent ^11· hen the 2 · 4-dini tropheny lhyclrazoue of V ermee ric aci<l is prepared). A possible structural explanatio11 for this phenomenon is cliscussecl further below.

An attempt to prnpare a sernicarbazone from this new acicl was negative. 50 rngm. acid "·as dissolved in 3c.c. absolute alcohol and to this a solution of GO 111g1n. sernicarbazide-hydrochloride and GO mgrn. sodium acetate in 0·5 c.c. "·ater "·a;.; added. The mixttue \Yas refluxed for 8 honrn. The original acid of :Jl.P. 280° \\·as regainecl q ua11titatiYely.

An acety lation attempt proYecl also the a hsence of free hyclroxyl groups. GO mgru. aci<l dissohed in I c.c. of pyriclin \\·as left to staucl for seyeral days '"ith 0 · 2 c.c. of acetic anhydride. The original acid of }LP. 280° ^\Yas again reconred.

These negative experiments for a carbony 1- or hydroxyl raclicle are in harmony \Yith the saponificaiion and relnctonization findings above. The nature of the aci<l- a monolrnsic-dilactonic acicl- accounts for the functions of all its six oxygen atoms. As this acicl results from the oxidation of Geigerin (Ci;,H2n04 ), of which the function of the fourth oxygen atom (s<~e page :39f)) is still unknown, it may prove very vahrnhle for determining the fun('tion of that fourth oxygen atom. Also hy comparing the two formulae of Geigerin ( C "H2110₁) an<l of the monof'arhoxy lic-dilactonic-acicl (Ci,H₁₈0r,) we find that the nitric acid oxidation led to a gain of t\YO ox~cg·en :itorns nccompanied hy a loss of two hyclrog·en atom:-;

onlv. A revie\Y of the liternhire showed that this ncid j,, still n11l;no11·n, and further experiments as regards its structure will haYe to he performe(l.

Meanwhile \\·e could explain such an oxidation l1S follows:

11. L. IJE \Ll.-\1 ..

The fad tl1:d· Geigt·l'in, 11·hi!'l1 i:; a 1110110-l:idonc :rn(l 1Yhi('h 1,;

in rwicl medium mono-b•im1il', c;111 hl' oxilli:;ed 11·ith nitric acid to a diladu1tit·-111011"ha.;i(' :11·id t hu:<

c,.H,.o {

c o co

^I

I ⁰

0 ^HN03

>

^C12H11

co

0 0 ^I

COOH,

,.;ee111,.; to :support the 1ie11· th:11 thP foul'ih oxygp11 :110111 in liPige1in i.-;

no( d hPl'-UOlllld lll' l',l't']jt', Jiut 1110~( JikPh 1Jl·e~e1tl i11 a ii.1·\lrnxyJ- grn11p, 11·hich 1«1111101 be <1l't'tyl:ited (.;iP1ic hi11tlr;11H·t•). \\-e t'ould tlw11 1•xplaill ;;ncl1 an oxidutio11 liy po~1ulaii11g n 111et'ha11i.;n1 .;illlilar t" !hat frequently pn1·01111terPd i11 (\ip ";1rnphor group (11'1·1J1·11e.;). ,-\,.; <111 an l'Xa111ple the oxiclatio11 .111:1.1· lw eit1•d of 1-:1111phor lt.1· 11itril' :1('id 1hrnugh 1·arnphol'i1· :11·id 1o c:1111ph:rni1· ;1t'id (Bl'e1h). 111 :Ill :1nalog·o11.;

lll:11111er the oxitl:dio11 of (;l'igPri11 l'Ould he· fon11111:t1t-'tl :1' follo11·,:

- CO I - 0

=0

- OH

Geigerin.

as a Ses~uiterflene.

/ HNO ,

R COOH -

0 - - - --...::,.,.. R :OOH

- co

- 0

I

Dilactonic-monocarboxylic acid.

Tn 1 he L1Hc·r m·i1l ll1e l:ic·tone group (outsicll') rna,v ht> easily . .;aponific·cl (.;;1rne ns in hl'if':Pl'i11 11·hp1·p it giYl'.; lieiµ:cric :1l'id) a111l the ne1v-fonlled lac!one g-roup (inside) mn.1· hP 111ol'P diflicultl,\·

405

THE CONSTlTUTlOK OF THE HITTER PlUKCTPLE " GEIGE!UK " .

saponified, i.e. as \Ye haYe found, may be the lactone group which is only saponifiecl after stamliug for 2-1 hours (at least) \Tith alcoholic potassium h.nhoxicle at 37°C.

Other faets which seem to coincide with a sesquiterpene structure for Geigerin are (I) the formation of naphthalene on clistillation with zinc dust ((;ompare Himingtou and l{oets p. 497) and (2) the forma- tion (under l)roper conditions) of a C10H1404 acid, "·hen Ueigerin is oxidised "·ith alkaline permanganate solution. \Ye have aga111 been able to confirm the formation of this acid (compare Himingtou and Hoets, p .. )02) and its properties seem to point to a terpene-acid e.g. C'amphanic aci(l (\\·hich h(mever "till nwaits identification) .

.Tndgiug from the properties of the m011ocadJox:-·lic--cliladonil"

acid OLP. 280°), it appe;irs to be a very stable compound as the following experiment will nlso serve to exemplify.

'l'o 60 mgni. of the acid clissohed in 10 r.c. glal"inl aC'etic acid was added 2 c.c. concentrated sulplHuic aci1l uud the mixture \\·armed on a boiling 1rnterbath (ni·tical tube) for 2 to 3 cla:;·i:;. The acetic af'icl \H1S distille<l oil under reduf'ed press111·p to a Yery small Yolurne.

The dark brnvrn solution 1rns diluted "·ith a little "·ater and when put into the ice-chest the original acicl again crystallised out quantitatiYely. A ft er recrystallization it had }LP. 280°

Permrmyanate O.rydatio11 of the Ji 01wrrubn.r!Jlir-dilacto11ir acirl to o.1:alir aod.

100 mgm. of the aboYe acid (M. P. 280°) and 1 gm. sodium c:arbonate ''"ere dissolved in 5 c.c. of distilled \Yater nncl 25 c.c. of a 3 per cent. pobssium permanganate solution slowly atlclecL 'rhe solution 1rns kPpt gently boiling unfler a " ~ormal-SC'hliff ., refiu:s:

concleusor for :2 hours. After having coole(l do"-n, the manganese clioxi(le of the C'ompletely rlec:olourecl solntion was filtered off.

The still alkaline solution \Yas thoroughly shaken with pure ether. On eYaporation the ether left a Yery ,;mall amorphous resic111e,

\\·hich on aeiclific·ation \Yith dilute h1·clrochlori(· acicl yielclecl acetaldeh.vcle (2, -! dinitropheuyl-h)-drazoU:e tle1in1tiw "-ith Brad:;r"R reagent of }f. "P. lG0-161 ^a11 d other i<len tifi(:ation tests).

The ahoYe solution was then al"idifiecl "·ith HCl and again thoroughly shakc>n "·itb ethPr. On the eYfll>Oratiou of the ether a crystalline s11 lista11 c·e (shining plates) deposi tecl, "-hi ch darkened at 60-80°, ancl rnelte<l 1Yith suhlimation alHl 11111C"h eYolution of gas at about 1'10°. The C'lTstals 1Yere clissolved in a little cold water and the sol11tio11 left to ~vaporatc> on a 1rnich-glass. They darkened at 70-80°, sublimation oC'r;urre<l from 155° upvrnrds ai1 d with gas- evolution the crvstals rneltPd at 16'1°. The substance clissohed \\·ith ::;trong effPrYeser\ce in dilute sotliurn rnrhonaJe solution and "·as founcl to be identical with the degradation acid obtained by the perman- ganate oxiclation of Geigerin (see below) nml both again identical

\\·ith oxalic nf'id.

H. L. DE \\'c\A L.

De.IJradatinn of Ueigerin to Oxalic Acid.

To l · ,-J gm. Geigerin clissohecl i 11 16() c.L of \Yater "·as added 00 <'.<·. of <l 10 per cen!. sodium ('3rbonate solutiou. The flask,

<·01nai11i11g this soh1tiou, \\·as fiited ,,·ith ^{;1 ··} :i"tll·m:il-Sclilift .. rdiux co11<lcnsor, Urn lop end of whieh again ('arrie<l :1 ,, l'lornral-Srhliff "

dropping 1'111111el. 'l'l1rough tbe dropping funnel 180 c.C'. of a 2·0 per t·<·nt. pohlssiurn permanganate ,.;oluiion ,,·;1s droppC'd in, ,,·hile the fiask \\·as held on a liniling 1Y:ti<,rl>at·h for hrn l1011rs. Boiling

\\'<'Is then "onti1111ed on a "·ire gauze for a11otl1l'r hour, during 1\·hic:h t inw anut IH•r 70 <·.f·. of the 2 .. -> iw1· ('e11i. potas;;irnn pern1a11g;1naie solution ,,·as drnpped in- in :111 th1·reforp '?:)() 1·.c. of 2··-J per ('e11t.

K~I11( l, ~ol utio11. At thi,; stag·1· dl'<«>lou ri,,;atio11 was Yer.1· ,,;lo\\' aud the oxid:1tion \\·as interrupted after :it hours.

\\'h<'11 cool lhe ,.;olutio11 "·a;; filh·reo and the faintly .'·p[lo,,· dear solulion 1·xtra1·h•<l '' ith pure ether in a bulihle-Pxtrador for 7'.2 hmm;. (Esf'ept for a little :icetaldeh,vde 11othi11g els(' coul<l hn isolated from th1' foint residue obtained ;1fter the eYaporalio11 of the ether).

The ,;olidion \\':1:> then aC'iclifi1!11 \\·ith hnhochlori(' acid and again extrnded i11 ;1 huhhle-extrn1·lllr ,,·ith p.ure d her for ,;<·Yeral d:1y,; until 1·0111plPi<• rxhc1ustio11.

A Her :2.J: illlur,; extrad io11, t·hl' etlH•r e;.;lral'i un 1·,·aporntio11 1leposited about Fill i11g111. of d!'gra1lation aC'ill. After ;1notlwr .24 hour..;, a11olher !-:() 111g·111. "·ere oliL1i111•fl. Aftt'r one ,,·eek'.' 1·011ti11ued l'Xh:ll'i ion 110 111ore .of thl' (legr;irhl ion a1·id could he ohlaine11 aIJ<l the toL1l ·'·iel1l amm111te<l to :1lio11t -J.00 rngm.

011 i hr eY;1porat ion of the,;e ('t her t,xtrads n ystals ~eparatPd

,,·hi('h po;;,..;rssed the follo\\-ing propl'rtie;;:

(1) Soluhll' "-ithout colour in tlilute or l'nncr11tratecl HCl.

(2) Soh1hle wiihoul C'olour i11 eoncl•ntrated H"SO ...

(:3) Soluhle without ('Olour in 1lilute or 1·once11tratP<l :XH,OIT. (.f) 11 <li..;.~oh-es \Yith strnng· efferY<"StP11<·e 111 2.1, per f'euL

( i))

(G )

(7)

sotli11111 cnhonate ~olutio11.

:Xo n·actio11 \Yit 11 Br:1dy ·s n•ngcnt.

\'er.'· rP:1clil,· ,;oluble in ,,·aler.

l•:nsily sol11Lle i11 ali..;olul<· aleohnl, :dcohol :11111 ac:<·lic al'icl.

1lil ulP alrnl1ol, 111t•th,vl

(8) SolulilP i11 Pthyl nt·PLr\e, (H) J>raclic·alh i11,;ll[uhl1· 111

('arho11 te.lracblori<l<'.

l'lher, aceillne ;111d tol11e11('.

hl·11z1·11e, pdroleurn P!'lwr

(lfl) Soluhle i11 al'dic anhY<lride and rliox;r 11.

l<'rorn a rnixtun• of :wetone an1l f'arhon tdracltloriilP f·olourlec;s shi11i11g· pL1te..; nystalliserl, "-hirh turned op;iqtte (lo~c; of ,,·at1·r) c1t Ii) to 80°, s11lili111ation shirted :it ]cl.()O 8nrl the n~-sbls then JIJ(,lted

;\ t ]8()0.

Jj lCl'U-(lll(ll.IJ·'ls:

+·8-HI mg. dried at room 1ernpe1ature in li.Y. lost 2·(i28 mg. lll

weigh!.

2·72:) i11g·. d1ietl a( room !ern1,ernt11rl' 111 11.Y. lost l ·:Jl3 mg:. lll

\H•ig\\(.

\I! 2 212 111 g· Ill . 2 · UYll Ill g-n I. (_'(),; IJ·.·1,'\ll 111µ:111. 11

,< ) .

\2) (I 2117 111µ,··111. Ill ^·) 1-t.'-\ 111 µ·1n. (\1111plior D.

:n

^{I, l.f'.}

mol. \\'(•ig·ht = <),].

( : ~ ) 11·F1+ n1g·111. Ill + 22Y ^111g·1Jl. ( ':1 Ill p '"']' D. 2(i !J, 1.t'.

111 (}I. \\'(' i g· h (

sn.

\-'ou11cl:

c

^{- 2.-,. 11 lll' I' l'Pll 1 . ; I}

^r

^{' ) . %} per cent.; ^{Jll ()} l.

\\ it t. KU and !:FJ.

('21-1₂( )1: <·<1kubtt>d: C= 2li·(i7 per t·e11t.; Il =2·22 pPr Gl'llt.

rnol. \1·h1.= llll.

The <lllal_\·sis ;11111 1llP properti('s proY1·1l ( h:d !li1· 11eg1:1d~d ion aGicl obtaine<l aboYe \Y:t~ icle11tical "·ith ox:tlic :1r-id. Sirnibrly thl'

<ll'g-rarbhon :1r·i1l olit ainecl h1· (he pof:bsit1m perm;111g·:111afr oxidai ion of the mono1·:1rl1oxYlic 1liLwto11ic· :1eid (see Jl. l+) \\:JS irlentie:1l with oxali1· nc:irl in nil iespeds. Again these hn1 cleg-radation acirls ween·

fully identic:1l beh\·een e:1r-h uthl'r (no ml'lting· poiut depres,;ions eh-.).

:lU1·11111fs lo t!eu11ule Geluerin 1clt!t 1·0111·e11twtet7 s11lph11l'IC 11cld.

Aliou( 211() lllglll. of Oeig·e1in \1:1s dissoh!•tl i11 about 10 c.l'.

co11<·l·11fr;tl1•d sulpl1ul'i(' a<·i,l. Tl)(• solnt ion \\';1.-; g1·til \5' \\'<1l'llle'1 lo ahou( ¹)11° <tlld the l1-•111011-\·ello1\· . .;0]11tio11 \1·as lhl'll slo1y]y run into JOO c:.1·. of \l·ah·r 11t1<kl' G!;11!inuo11s stirnng so th<1t th<· i.;"lnJH'ra!un•

1Ji.l JJOt Tise (JYer S()O (' (C"on1p;11·e l'feiffer and !lP \Ltal (J!J:h). The pa IP Yl'llm\· .--ohti ion \\·:1s il1e11 .•'11:1 ken "ith l'tl1er <incl 011 eYaporation of the C'tlw1· :1 hig· crop of colourless n.1·,;L1llinP C"oh1rnns sep:1n1tecl. Thl' -;ulht:111ce proYe!l io lie non-ph1·11o!i .. , 11011-acidic· aud was easil.'· itlentifie1l <ts f:l-GPig·erin (!·ornpan· Hi111i11gto11 :1rnl HoPh p:tgl' 48!1).

Un l'l'\ll':1ti11g !he :1btll'e <'Xp1·rin1e11t \1·i1h ]grn. of Geigerin <lll!l 4fl ('.('. of (·on1·1•11tr:1tecl sulplrn1·ic· aei(l i1111 into ;1bm1t 400 c.c. of

\Yater (t1'11l}Wra111r<' 10-.'-\0°(') :rn l'i hc•n•al l'Xi 1'<1ct of thP sol11i ion ga\'1~

n n1i.dt11·t• of ^IL- a1Hl (:l-Ueig·"1·i11 only. Hep1'<1h·d e:dr<1din11 \\·ith r-hlornforn1 g·;t\'!' thl' s.111w 1·c.;11lh.

('0J1('l'lltr;1it•1l sulpl:11l'il' :H·id is lb1•1efore i111·;1p:1lile of iiP('Olll-

po~i 1q .. ~· (Jt>igt·rl11.

,\n ;!li1'111pt t11 o.,idisl' -l.'111 111g111. (jeig·l·l'i11 dis.sol\'l·d in :il>nut '!() , ... 11;i!t·1· :111d \II 1·.(·. !JG per .. e11I. :tl('()lrnl 1\i!h ~- r·.('. of :30 pel' 1·<•111. liydrng·t'll p1·rnxidP :rnd n·H11:-;i11g· ilie rnixtm·!' fol' (i hour . .;

Ltiled. 1-rn·h;111.~·etl Cf<·igcrin \1·:1s n'CO\l'red q11a11lit:1liYl'l.\·.

20(! rngm. (~eigeri11 \\'<b dis,nh-ed i11 aliout :!II 1·.1·. gbcicil ac·di ..

:l('irl; 2 (·.1·. of ~,8 per ('Pili .~ulplrnTil' :1cid \\·:1~ :Hlr1t-cl <111<1 ihe wlidio11 hc,ah•!l 011 ;1 hoiling '"'1te1·h:1th 11111ler a 1·efl11:-; C"0111!1·ns"1· for 1 ho11r~.

+OS

II. J .. JJE \\".\.~L.

The ac.;etic a('id 11-a" theu <listilled of-t at rt'ducecl preHsUrt' leaving a final nJlume of ahout 3 c.c. (<hrk brn1Yn lit1uid). Then -l:O c.c.

11 :iter w:1H stirred in yielcliug an oily precipitate which in the courst, of a fortnig·ht sl01dy <olwugetl into :1 ('olourless group of cryst::tls, 1d1ich after recrystalli"'ation from water was found to bc- a mixture of a- and /)-Ueig·eri IL

::lffempts fo prPpllr!' 111·/d llllllde., of (;Cl!JCl/n ^ii/Id fl1e ))fOllO-

("((/"b1u·yli1·-rfilarfo11/1" 11r·1rl (Jl.P. 280°).

Hansen (1931) Lles<·rihl't> the preµ:naho11 of ALintolic acid arnir1<·

ho111 tlw bitt.er pri111·iple .ALinto-lactnne by nwans of c.;o]d sattn:1te1l al<-ol10lit·-:1rnrno11ia Holutio1b. Si111iLn atten1plH to obtain ihe :1cid am iclt• ol' thc l:ictone Gt'L'"t'1i11 prnYed 11t•o-:d in• :lH tlw follo11·i1w l:'XfH='li lllt'llb 11-iJl ilJ u:fraft=' ~ - , r . r

(J)

(2)

To 1() rngm. of Ue·igel'in l , ... ol' <·old H:tt111:l10<l 1110tll\l- nl<-oboli<· amrnouia 1YaH :ulderl :11Hl the .Holution :1llc)\1:e<l to stand for Oil<) 11<·ek at morn 1en1pPr:1tun'. Ulll·h::inp:ed Ueigeri11 of :\I. P. 189-190° 1Yas reCOY<'red (cump:ire Ahder- haldeu, rn:Jli) \Yhcre Al:rnto-acetarnide c1ysl:1llised out after standing· for :! houfo).

To 10 mg. of Geigerin ] c.('. of ('Old s;tlur:ite<l eihd- ::ilcoholic.; ammonia 1rns ;1cldec1 and the ,;olution, 11.'~ll 8topperetl, allo11ecl to st:rncl for 7 days. Lndrnnged o-

Geig0rin of :\I.I'.

rnn°c

\\as then quantitatiYely recovered.

(These experinlPntR 1yi_l] l>P n•pe:1te<l with Geig·eric ~1ci.fl).

(:l) To 10 ^1ug. of tlw m0110carbox>-lic-dilactonic aeid (seep. :398) 1 c.r. of cold :;aturated metln-1-al<-oholic arnmonia 11·a:;

a<lded ,rnd the solution :1llo11·e'cl to shrncl for one 11·eek.

1..:-nchrrng·etl :1cicl of ~I.P. :!S0°C 11as ;1g·nin i.sobie<l.

(J) A similnr Px1wrirneni :tH 111 (1) 11·iih d hd-akol10li<·

ammoma g«1Ye the sarne 11egahn• H'sulls.

l. Based 011 the results alre:llh: obt:1iue1l on the ('on,;iitut ion uf tlH· liiilPr prin<·iple Geigeri11 (Ge11;~'1111 11spem. llan·.) :1 p1eli1ni11:1n·

1liHl·ussiou ::tH to ib strudure is put fon1·anl iu this p:qwr. A rnore

<lt·iail<'Cl dis('ussiou :tH to the constitutio1i:; of Geip:E'riu :ind thl' :tl'lin•

pl'inciph• Yenneeric :t('id i,.; resern(l fo1 a bh•r <l:tte.

2. Kitric a(:i.d oxidation of !ieig·erin yiel<ls "" ;1cifl C, ... H"O" · H,( ^l together 11·ith :1cetalcleh>·<le.

:J. 'l'he c,51-IIROr;. H,O OI.P. :!S0°C') ;1cifl iH ^:l mono-c·arhoxylic- dilaetoni(' acid, fhuH ihP functious of :111 six oxygen atoms :1re knmn1.

011 saponification \Yith alcoholic pota~sium hyclrnxi<le :1 triba~ic :1l'itl

re~ults which m:lY :q:~'ai n 1w n•ladonizPd to the <libnoni<·-111011oh:1Hic acirl. It has[ ex

l ~' =

+ 181·8:)^0. is n·ry

~b l1l e

^lrnt c:rn he nxirliHe1l

11·ith alknline potas,;ium perrn:111g·:rn:1te io o:-.:ali(' :ll·i<l.

THE COXSTl1TTI01'\ OF nm ^lllTTEll PUINCIPLE " GEl(;ERlN ".

4. O:s:alic acid is also a dired oxidation product of Geigerin with potassium permanganate. H i,; interesting to note that quite <1

number of hitter principles e.g. Abnto-ladone, Artemi;;ill ancl Pikroglobularin (Abclerhalden, 1936) ali:>o yield oxalic acid when oxidiser] ''"ith potassium perrnaugauate. A nitric ucid oxidation of Pocl<•phyllotoxi11 (Abderhalclen, 1936, p. 1Ci2) also led to oxalic ac·i<l.

:J. 'l'lH'~e c·onstitutional result,.; ma>· best he s1mm1arise<l as follows:

alcoh. KOH

-.A~o/ ^c,.H,.O. ~.P. 280°C~.) ^{kf1 HCI Tri basic acid}

/.MnO.

^{Acetaldehyde. 110,}

Geigerin KMnO, An acid ~ Oxalic acid

+

precursor +

j

Acetaldehyde

-} H,so,

C10H"O' (M.P. 201°C.)

+ acetafdehyde

G. Basing on the infonnation ⁶⁰ for obtained the Yie"· ^1s expres,;ecl, that the fourth oxygen atom of Geigerin mny be con:-;ti- tu tecl i 11 a h.\·<lroxy 1-group (in ,.,tearl of et her-boun cl or c-.n· lic) an cl that Geigerin might belong to tlw sesquiterpe11e das,; of substances.

AcExo 11·LEDGE:\1EXT.

In condnsion I "·i-h to thnnk Dr. Himinµ;ton oi thi,.; dep;ntment for his kind interest iu thi,; research.

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