ALKALOIDS OF Lunasia amara BLANCO
Dec. 5, 1959
tives appear to have a lower anesthetic efficiency (ratio of potency to toxicity) than the higher alkoxy derivatives. 2. Effect of varying the N-substituted group R' : (a) branched chain groups were less potent and toxic than straight chain groups; (b) heterocyclic and aromatic amino groups had a lower anesthetic efficiency than the alkyl amino groups. Compounds 38, 40 and 41 proved to be more potent topically and less toxic than cocaine hydrochloride while compounds 13, 27, 29, 31, 32, 34, 3.5, 36, 40 and 41 were more potent on nerve block and infiltration anesthesia than procaine hydrochloride. The toxicity of this group ranged from equal to eight times as toxic as procaine hydrochloride. Several of these compounds when tried clinically in dental procedures were found to be as effective as procaine hydrochloride. The clinical evaluation is being continued and will be published elsewhere. Experimental T h e 0- and $-anisole and phenetoles were obtained from commercial sources. T h e P-bromophenyl propyl ether and the m- arid p-bromophenyl butyl and isoamyl ethers were prepared b y alkylating t h e bromophenol with the appropriate alkyl halide, with a method similar t o t h a t described for alkylating nitrophenols .6 1-p-Ethoxyphenyl-3-chloropropanol-2.-The Grignard reagent prepared from 42 g. (1.8 moles) of magnesium and ( 0 ) "Organic Syntheseq," Coli. Vol. 111, John Wiley and Sons, Inc., Kew Y o r k , h'. Y., 1955, p. 140.
[ C O S T R I R U T I O S FROM THE
6209
300 g. (1.5 moles) of p-bromophenetole in 850 ml. of dry ether was treated with 280 g. (3 moles) of freshly distilled epichlorohydrin in one liter of dry ether with stirring. T h e mixture was refluxed for one hour after addition of t h e epichlorohydrin and allowed t o stand overnight. T o the mixt u r e was added dropwise 150 ml. of water and then 850 ml. of a 2070 sulfuric acid solution with stirring. T h e ether solution was separated, dried over anhydrous sodium sulfate and distilled over a water-bath to remove the ether. T h e residue was distilled under high vacuum and the fraction boiling 108-108" at 35 p yielded 185 g . (587,) of a colorless liquid, %*OD 1.5369, d20 1.157, molecular refraction 57.94 (calcd. 57.43). 1-p-Ethoxyphenyl-3-n-propylaminopropanol-2 Hydrochloride.-A mixture of 25 g. (0.12 mole) of l-p-ethoxyphenyl-2chloropropanol-2, 40 g. (0.7 mole) of n-propylamine and 50 ml. of isopropyl alcohol was refluxed for 24 hours. T h e alcohol and excess amine were removed by evaporation on a steam-bath and the residue dissolved in 100 ml. of 2 N hydrochloric acid. T h e 3olution was extracted with three 50ml. portions of ether t o remove the unreacted chloropropanol and then made alkaline with 25 ml. of concentrated ammonium hydrouide solution, and extracted twice with 100-ml. portions of ether. T h e ether solution was dried over anhydrous sodium sulfate and t h e ether removed by distillation on a water-bath. T h e residue was distilled under high vacuum and the fraction at 125-127" at 30 was dissolved in 50 ml. of isopropyl alcohol and acidified with anhydrous hydrochloric acid t o yield on recrystallization from isopropyl alcohol 19 g. (60%) of the anesthetic salt, m.p. 151-153O, as white crystals.
Acknowledgment.-11-e are indebted to Richard Sriubas for assistance in the analyses and to llichael Fisher for assistance in the pharmacological testing of these compounds. BROOKLYX 7. S.Y.
LABORATORY O F CHEMISTRY OF NATURAL PRODUCTS, NATIONAL HEARTISSTITUTE, NATIOXAL INSTITUTES O F HEALTH,u. PUBLIC HEALTH SERVICE]
s.
Alkaloids of Lunasia umara Blanco.
Isolation Studies
BY SIDNEY GOODWIN, A. F. SMITH,A. A. VELASQUEZAND E. C. HORNING RECEIVEDAPRIL 2, 1959 The isolation and characterization of fourteen leaf alkaloids of Lunasia nmara Blanco are described.
A number of chemical and pharmacological studies of Lunasia alkaloids have been recorded since the initial observations of Lewinl and Boorsma,' but the structures of these compounds have been unknown until recently. Both leaves and bark of trees of this genus of the Rutaceae contain "water-soluble'' alkaloids which are quaternary salts, and the organic bases include representatives of five classes of compounds. The following sections summarize what is known about the occurrence and structure of each of the alkaloids, and the Experimental section contains data relating to the isolation and characterization of the leaf bases of Lunasia amara Blanco of Philippine origin. 1Trith one exception (lunamaridine), all of the previously known bases have been found, together with a number of new ones. Table I contains formulas, melting points and yields of the leaf bases. 2-Arylquinolines.-An earlier report2 described the isolation, structural identification and synthesis (1) I,. Lewin, "1,ehrhuch der Toxikologie." 2nd Ed., Urban a n d Schwarzenberg, Vienna and Leipzig, 1897, p. 271; W . G. Hoorsma, Birll. l i t s t . Bel, Biiilunzovg. 6 , 1.5 (1900). (2) S. Goodwin, A. P . Smith and 73. C. IIorning. THISJ O U R N A L , 79, 2239 (1957)
TABLE I Name
Formula
hT.p., OC.
CisHi30S
66-07
Yield,=
yo
I
4-Methoxy-2-phenylquinoline I1 4-Methoxy-2-(3',4'methylenedioxyphenyl)-quinoline 111 7-Methoxy-1-methyl2-phenyl-4-quinolone IV Lunamarine V Kokusagine VI Skimrnianine VI1 Lunacrine VI11 Lunine IX Hydroxylunacrine X Hydroxylunine XI1 Lunacridine XI11 Hydroxylunacridine XIV Hydroxylunidine Lunacrinol Lunolone a
0.01
CI7H130~hT116-1 17
,002
C17HiaozS 198-200 Ci8Hi504N 245-247 Ci3He04N 195-197 CllH1304N 179-180 cit3H1908X 117-118 C ~ G H I ~ O I228-229 N C I ~ H I Q O ~201-203 N Cl6H17O51\- 228-230 C17H2301N $5-86 C17H23OuK 100-102 C I ~ I I ? ~ O G121-125 N CloHigOiN 187-188 , , . . . . . 100-103
,002 ,004 ,0003 ,0001 ,1 ,004 ,002 ,001
... ,003 ,001 ,0005 ,001
These yields are for pure material and are apprnximate.
SIDNEY GOODWIN, A. F. SMITH, A. 4. VELASQUEZ AND E. C. HORNING
6210
of 4-methoxy-2-phenylquinoline (I). One of the new substances isolated during this study was found to have the formula C L ~ H ~ ~ and O ~ Nthe , change in the ultraviolet absorption spectrum after acidification (a bathochromic shift) was similar to that observed for I. The behavior of the hydrochloride during a melting point determination
Vol. 81
tion spectra, suggested that these compounds were kokusagine (V) and skimmianine (VI). The tentative identification in both cases was confirmed by comparison with authentic specimens.
OCH,
The occurrence of these furoquinolines in a plant of the Rutaceae is not surprising. They were not detected in earlier studies, but their occurrence (formation of a quinolone) was also similar to that along with quinolines and quinolones in this inobserved for I. Synthetic studies, to be su:n- stance suggests that some of the compountls oi marized later, resulted in the identification of this unknown structure remaining from 0ui.w work substance as 4-methoxy-2-(3',4'-methyIenedioxy- may be qui2iolines or quinolones. For example, phenyl)-quinoline (11). orixine' ( C I ~ H ~ I - - ~ ~may O ~ be N ) a quinolone similar Cusparine, galipine and other quinolines have to lunacridine, and kokusagoline7 (Cl,HI3OjK)may been found in plants of the Rutaceae (Cusparia sp.), be a 3-aryl-4quinolone. Both of these compounds but this is the first occurrence of 2-arylquinolines occur in 0r1'mn. japonica along with skinimianine and kokusagine. noted for a natural source. 2-Aryl-4-quinolones.-The isolation, structural Dihydrofuro-4-quinolones.-The major alkaloid identification and synthesis of 7-methoxy- l-mcthyl- of Lzuzasia sp. is lunacrine. This compound has 2-phenyl-4-quinolone (111) has been described by been found in every previous investigationS Johnstone, Price and This quinolone was and it is now known to have the structure VII.g.10 found in the bark of L.quercz;folia (Warb.) Lau- The assignnient of position of the S-methoxyl group terb. and K. Schum collected in northern Australia. is based on both ultraviolet spectra comparisons9,11 =Inother alkaloid, One of the leaf alkaloids of I=. nnznra was found to arid on the n.m.r. have physical properties corresponding to this occurring in lower yield, corresponded to the substance, and identity was established by direct lunine described by I3o0rsma.~~This substaiice, comparison with an authentic sample provided by m . p . 228-.22!3", was the sainc as a substancc isoDr. J. R. Price. Another leaf alkaloid, C18HI5O4N, lated3 from L.perc$olin. T h e rnipirical formula m.p. 245-247", seemed also froin its properties to was found to be C16Hli04N. The analytical data fall into this structural class. This compound is indicated that one methylimiiio group was present the lunamarine of earlier ~ o r k e r sand , ~ synthetic but no inethosyl groups. Th-e n.m.r. spectrum studies (to be reported later) have established its indicated that the ring system and the side chain structure as IV. It is of interest to note that the structure were the same as that in lunacrine relationship between TI1 and IV is the same as (VII), that a methylcnedioxy group was present and that the aromatic substituents were placed as that found for I and 11. represented in VTIT.'a The long wazvc Icngth maximum in the ultraviolet absorption spcctruin
8
$2qp-0 CHaO
-4lthough these substituted 4-quinolones are a relatively recent addition to alkaloid structures, they may occur more often than their late discovery would indicate.j The quitiolone I11 has also been found as a bark component of Cnsl'miroa edulis,6a Mexican tree of the Rutaceae. Furoqtlino1ines.-Two optically inactive alkaloids, present in trace aniounts, gave ultraviolet absorption spectra that resenibled those of known naturally occurring furoquinolines. The analytical data and melting points, together with the absorp(3) IE. R. J o h n s t m e , J . R . Price a n d A . R . Todd, A u s f . J . C h ~ ; m .11, , R E (19.58): J . R. Trice. "Prof:ress in t h e Chemistry of Organic S a c u r a l Products," E d . L. Zechmeister, Vo!. 13, 1R;G. p. X02. (4) F A . Steldt a n d K . K . Chen. J A w 7 Piiniiu. A s s o c . , S c i . E d , , 32, 107 (1943). ( 5 ) Lunamdridine, C1aFI>aOaS, m.p. 209-21 O o , isolated by enrlier workers' m a y well be a 2-phenvl-l-qiiinr,Il,ne. F u r t h e r work must await reisr,lation o f t h e mntrri:d. (6) I;. Sondheimer a n d A. Rleisels, .I. O r $ . C h m r . , 23, 712 (!95X)
CH1 VI1
\
qh-h y'
0"-
0
'-0
CH,
VII r
of VI11 was shifted bathochroniically 011 aciclification; this is contrary t o the effect noted for lunacrine. The direction of the shift evidently depends on the nature and extent of alkoxy1 substitution, and this effect has been confirmed in other work. Two additional akaloids were found to bc rtlated to lunacrine and lunine. Both of these m i terials were present in small quantity, a ~ t it l was SOC.J n j o n . 51, 7 0 i ( 1 9 n l ) . , "The Plmit .\lk:ilui
Experimental
Dec. 5, 1059
ALKALOIDSOF Lunasia amara BLANCO
6213
Hydroxylunidine (XIV) was eluted after XI11 with benzene-ethyl acetate ( 2 : 3 ) . T h e Labat test was positive. Crystallization from ethyl acetate-cyclohexane afforded is, 124-1250, [01123588 + 2 i . v [a~231:,6 +74.3" (c 0.820); infrared spectrum: A, 6.09s, (i.lAs, Anal. Calcd for C16H1704S.HC10A: C , 49.li6; 13, 4.68, 6.27s, 9.41s, 9.54111, 1 0 . 6 4 ~1.1; ultraviolet spcctrunl: A,, S ,3.61. Found: C, 49.47; H, 4.72; N, 3.62. 228, sh237, ~11260,267, 318 ant1 sh330 ITIM (4.43, 4.36, 4.33, 4.37, 3.94 and 3.83, resp.); A m i n 249 and 279 m p (log E 4.12 Lunamarine (IV), the least soluble of the series, can be and 3.53, resp.); no change on acidification. purified by crystallization from a varietj o f solvents. The Anal. Calcd. for C17H210fiS: C , 60.88; H, 6.31; N, analytical sample was crystallized from niethj lene chloride ciq colorless crJstals, m . p . 245-247' [a]25,sQ -0.7' (c 0.110 g . 4.18; OCHs, 9.25; ( N ) C H s , 4.48. Found: C , 61.37, 61.39; 13, 6.22, 6.45; N, 4.17; OCHa, 9.68; ( S ) C H a , 5.63. in chloroform). Lunamarine gave a positive Labat test; infrared: 6.15s, 6.24s, 6.39r11, 9.37m, 9.661~1,1 0 . 7 2 ~p ; Hydroxylunine X.-The fraction containing this alkaloid ultraviolet spectruni: A, 228, 246, 250, 259, 317 and sh32i was eluted with 5% ethanol in chloroform. Trituration of mp (log e 4.50, 4.48, 1.48, 4.51, 4.28 and 4.27,resp.); A,, the residue with benzene afforded a tan solid corresponding t o 239, 248, 2j5 and 287 mp (log t 4.46, 4 48, 4.44 and 3 . 5 3 , about 30y0of the fraction. The benzene solution was treated resp.). separately to yield lunacrinol and hydroxylunacrine. T h e Anal. Calcd for CISHISOI?;: C , 69.89; H, 4.89; S, solid material was purified by chromatography on silicic 4.53; OCH3, 10.03; (K)CHa, 1.86.F c N I ~C~,:69.79;H , acid; the product was eluted n-ith 5y0 methanol in chloroform. Crystallization from benzcne gave a sample with in .p. 3.00;N, 4.52; OCH,, 9.90;( S ) C H z , 4.74. 228-230", [ 0 1 ] ~ ~ j g g-5.9', [ a ]26436 - 13.8' (c 0.276); infrared Lunolone, isolated only from chromatogram B, was eluted spectrum: 6.98111, 6.22w, 6.44vs, 6.91s, 9.39m, 9.52111, immediately after I1 n ith ethyl acetate-benzene ( 5 :95). 10.64wp; ultraviolet spectrum: A, 220, 246, sh268, 320 and 330 mp; Ami, 224, 282 and 326 mp. I n 1 .Vh>-drochloric T h e crystalline solid which formed in the oily red residue was acid: A, separated by trituration with ether-pentane. Lunolone 223, 260 and 340 m p ; A m i n 233 and 277 nip. crystallized from ethyl acetate-pentane a$ colorless prisms, Anal. Calcd. for C16H~i05S: C, 63.36; €1, 5.65; N, m.p. 100-103°, [ o ~ ] ~ ~ j +20.6' g g and / ~ ~ ] * ~ , 3 f i 54.7' (c, 4.62; ( N ) C H 3 ,4.96. Found: C , 63.48; H , 5.66; S , 4.33; 0.996); infrared spectrum: 6.14s, 6.21m, 6.32 p ; ultravio- ( N ) C H 3 ,4.62; OCHI, none. sh233, 240, 258, 287, and 296 and 322let spectrum: A, Hydroxylunacrine (IX).-The benzene solution (from the 333 mp (log t 4.34, 4.36, 4.37, 3.86, 3.86 and 3.60, resp.); preceding experiment) was carried through an acid extracA,, 247, 278, 291 and 311 mp (log t 4.26, 3.80, 3.84 and tion procedure t o eliminate neutral material ( a small 3.54, resp.); unchanged on acidification. quantity of brown t a r resulted). T h e alkaloid fraction was Hydroxylunacridine (XIII) .-In t h e course of t h e developplaced in aqueous solution at pH 5 , and the mixture was exment of chroniatogram B, a :ellow-brown color extended tracted with ether. The combined ether solutions were reover the entire column; ethyl acetate (1007,) was applied t o served for the isolation of lunacrinol. T h e aqueous solution the column, and the colored material was rapidly swept off. taken to pH 12 and extracted with ethyl acetate and A single fraction (1.3 1.) was taken. T h e residue was a was with chloroform. T h e organic solutions ( p H 12 extraction) brown gum (20.08 g . ) from which.crystalline m a t e r i d could yielded a solid t h a t was recrystallized several times from not be obtained. Neutral impurities were not present in a n y ethyl acetate; m.p. 201-203"; this gave variable analytical quantity, since 18.57 g. of material was recovered (as a red d a t a , and low and variable negative rotation values, but a gum) after extraction of an ethyl acetate-ether solution of the residue with 2 A7 hydrochloric acid, followed by basifica- satisfactory perchlorate was obtained. The infrared ( 6 p region) and ultraviolet spectra were identical with those of tion and extraction mith chloroform. A portion of the gum lunacrine. was converted t o a crystalline picrate; after cr! stallization hydroperchlorate was recrystallized from acetone this was shown to be identical with lunacrine fromHydroxylunacrine methanol-ether t o yield colorless rods, m.p. 216-218' picrate. Subsequent chromatography on aluminum oxide dec., [ 0 1 ] ~ % g g --14.6', [ a ] * * m , -23.2' ( c 0.881); infrared afforded lunacrine, 111, XIII and XIV; the total 4-quinospectrum: 2.81m, 6.03s, 6.20s, 6.50s, 6.69s p ( S u j o l ) . lones amounted t o 41YGand the total carbostyrils amounted Anal. Calcd. for ClsHls04n'.HC104:C , 49.30; H , 5.17; to 5470. -4ttempts t o verify t h e implication t h a t carbostyril S , 3.59. Found: C, 48.99; H, 5.42; N, 3.62. derivatives should not have been extracted with acid (while quinolinium derivatives would be), have not been carried Lunacrino1.-The ether extract (preceding experiment) o u t ; further investigation is anticipated. was examined; a new product mas present which was puriOn chromatography of the gum, hgdroxylunacridine wa? fied by several recrystallizations from ethyl acetate. An eluted with benzene-ethyl acetate 13:2 ) ; the product crys- analytical sample was obtained as colorless prisms, m.p. 187tallized in t h e residue only after very long standing. The 188", [ a ] 2 4 B -5.4", ~ [ 0 1 I z 4 4 3 6 -11.0' ( c 1.03); infrared specLabat test was negative (reddish color). Recrystallization t r u m : 6.1lvw, 6.21m, 6.26m, 6.38nis, 6.43vs, 6.68s; ultrafrom ethyl acetate-cyclohexane afforded colorless needles, 243, sh300, 321, sh329-333 mp; A,,:, violet spectrum: A,, m.p. 100-102", [ o ( ] ~ ~+31.5' ~s~ a n d [ c ~ +84.2" ] ~ ~ (~L ~ 275 ~ mp. In 1 N hydrochloric acid: A,, 255,305, sh325 nip; 0.990); infrared spectrum: A, 6.13s, 6.21m, 6.33s, 9.32s, Ami, 273 m p . I n 1 N potassium hydroxide (SOT0 aqueous 10.57w p ; ultraviolet spectrum: A,, 239, 257, 284, 293, 250, 289, 300, sh320 mp. ethanol) after 24 hours: A,, 332 and sh345 mp (log e4.39,4.39,3.93,3.90,3.55 and 3.41, Anal. Calcd. for ClfiH~sOIN:C . 66.42; H , 6.62; 0 , resp.); A,, 224, 246, 275, 291 and 310 mp (log €4.32, 4.32, 22.12; N , 4.84; 0CH3, 10.73; (Ii)CH;,, 5.20; H*, 0.35. 3.88, 3.898 and 3 37, resp.); no change on acidification. Found: C, 66.29; H , 6.57; 0, 22.7; S, 4.91; OCH,, Anal. Calcd. for C I ~ H L Y O ; SC: , 63.53; H, 7.21; S, 9.36; (N)CH3,5.9; ( C ) C H n ,4.6; H*, 0.52 (reactinti a t 95"). 4.36. Found: C , 63.67,63.84; H , 6.84, 7.03; K, 4.29. BETHESDA 14,MD.
Lunine Hydroperchlorate.-Lunine was converted t o this salt in methanol-ether. The analytical sample, m.p. 232236", crystallized froin tlir same iolveiit pair a i long, colorIC\\ needles.
+
