Tropane Alkaloids G. Fodor and R. Dharanipragada" Department of Chemistry West Virginia University Morganto wn WV 26506-6045 USA Reviewing the literature published between July 1985 and December 1986 (Continuing the coverage of literature in Natural Product Reports 1986 Vol. 3 p. 181 ) 1 Occurrence and Structure of New Alkaloids 2 The Chemistry of Tropanes 3 The Synthesis of Homotropanes including Anatoxin-a 4 Pharmacology 4.1 Atropine and its Derivatives 4.2 Cocaine 4.3 Scopolamine 4.4 Miscellaneous 5 Analysis 6 References 1 Occurrence and Structure of New Alkaloids A limited number of new tropane alkaloids have recently been isolated by Evans er al. from members of the Erythroxylaceae.'V2 The root-bark of Eryrhroxylum hypericifolium which is indigenous to Mauritius and to Reunion contains relatively the highest amounts (1.63 %) of the major alkaloid.The chemical analysis was based on mass spectroscopy;3 the prominent ions were of m/z 124 and in the nor-derivatives of m/z 110 similar to other tropanol esters. In all natural alkaloids in which there are substituents at C-6 or at C-7 these groups appear to be exo. Detailed n.m.r. analysis provided the characteristics of a tropan-3a-yl ester in the major product. Mass spectroscopy indicated that the esterifying acid is either 3- or 4-hydroxy- phenylacetic acid; hydrolysis confirmed the presence of the former. Therefore the base is tropan-3myl 3-(3-hydroxy- phenylacetate) (la). Such a combination had not been found in previously isolated natural tropane bases.The second major base was characterized as the 3-phenylacetate of (+)-tropane-3,6-diol (2a) ; the absolute con- figuration of the (-)-diol had earlier been determined by ~orrelation.~ The (+)-and the (-)-bisphenylacetate (2b) were prepared from the diols and the (-)-form proved to be identical with the product that was obtained from the natural product. Tropan-3ol-yl 3-phenylacetate (1 b) was the third alkaloid of E. hypericifolium. It was already known as an alkaloid from Erythroxylum dekir~dtii.~ A fourth crystalline alkaloid C,,H,,- NO, gave a crystalline picrate and was identified as tropane- 3a 6p-diyl 3-phenylacetate 6-acetate (2c). Evidence was pro- vided for its biogenesis from (+)-(3R,6R)-tropane-3a76p-diol.a hybrid of two species of Duboisia shows a twelve-times greater change for hyoscyamine than for hyoscine.' There is a correlation between alkaloid composition and atropine esterase activity in callus and in differentiated tissues of D. myoporoides.' It was found that the scopolamine and hyoscyamine contents of the five top leaves of Duboisia myoporoides are representative. 2 The Chemistry of Tropanes During a search for neuroleptic agents 3-cyanotropane was treated with 4-fluorophenylmagnesium bromide9 to give 4- fluorophenyl tropan-3P-yl ketone (4) which proved instead to have depressant activity on the central nervous system. Catalytic reduction of 6-phenyltrop-6-ene gave 6a-phenyltropane where- as lithium aluminium hydride attacked on the bridgehead to give 5-methy lamino-3-phenylcyclohept-1-ene.lo 6-Aryltropanols in which alkoxyaryl groups are probably P-oriented have been prepared.After N-demethylation (the method by which this was achieved is not specified) 6- phenylnortropanol was alkylated with P-benzoylethyl p-cyanoethyl groups etc. to produce compounds (5). The new compounds proved to be weak opiate antagonists." A great variety of new N-alkyl-norscopolamines have been synthesized by demethylation of scopolamine followed by re-alkylatiorl with 26 different groups. The new derivatives were anti-cholinergically active. Among the quaternary salts N-ethyl- norscopolaminium methobromide is particularly active as a bronchospasmolytic. l2 In the search for new membrane-active compounds that resemble histrionicotoxin several 1 -substituted alkyl- alkenyl- ""??IC(O)CH Ph RO-MeNFiR ( 1 1 o ; R= C(0)CH2C6HLOH -3 (2)a; R=H b ; R=C(0)CH2Ph b ; R=C(O)CH,Ph c; R=C(O)Me A phenylacetic ester of tropane-3,6,7-triol was discovered as a minor component.Finally the structure of nortropan-3a-yl 3-phenylacetate (3) was ascribed to another minor alkaloid based on mass-spectral data since the fragment of m/z 119 suggested that phenylacetic acid is present rather than toluic acid. In summary the new alkaloids that were obtained by Evans and co-workers1*2 were already known as far as the alkamine component is concerned but the esterifying acids are new and represent distinctive features of certain species.Furthermore the combination of acetic phenylacetic and 3-hydroxyphenylacetic acids is unique. The seasonal variation6 of the content of tropane alkaloids in * Present address Department of Chemistry University of California Los Angeles CA 90024. 67 (3) R"P Ar +OR2 ( 5 ) Ar H Ph ,L -MeOC6HLefC. R' = Me ,[CH2],C(0)Ph ,[CH2I2CN [CH2I2Ph efc. R 2:H or Me NATURAL PRODUCT REPORTS 1988 .CH,OMe CHO b; R C(0)Me +-Ph3P-CHCH2C SCH R RN fi -Po-MeNpocJoH (12) II Ph 0" (13) and alkenynyl-tropanols have been synthesized.l3 The key intermediates were 1-methoxymethyltropan-3~-ol (7a) and 1-fonnyltropan-3P-yl acetate (8) which were obtained by the Robinson reaction from 2,5-dimethoxy-2-methoxymethyltetra-hydrofuran (6) followed by demethylation reduction and VNpf R selective oxidation of the primary alcohol group.The structural variation was achieved by using the Wittig reaction to produce (9) and (1 1) and by hydrogenating (9) to yield (10). A new method of entry into the tropane field,14 starting with pyrroles and the oxyallyl cation in the presence of di-iron nonacarbonyl (as a catalyst) has now been described in detail and in a more general context by N0~0ri.l~ Trop-6-en-3-one (12) was converted into trop-6-en-3a-01,~~ esterified with (9-0-acetyltropoyl chloride and the double-bond was then reduced (by catalytic hydrogenation) to give hyoscyamine (1 3) after Me,+ ,H partial hydrolysis. l5 Trop-6-en-3a-yl tropate was epoxidized Me N earlier17 to hyoscine.2,4-Diamino-5-(N-arylnortropan-3-yl)pyrimidines(14)have &cO; been synthesized as novel inhibitors of dihydrofolate re-0- ductase.l8 A computer-assisted analysis of the three-C02H dimensional structures of the binary complexes of the dihydro- folate reductase of Escherichiu coli with methotrexate and with other compounds led to the design of compounds (14) which are potent inhibitors of E. coli. The nortropanones have been prepared by the Robinson synthesis ; methoxyanilines were used as the amine components. Knoevenagel condensation of the N-arylnortropanones with ethyl cyanoacetate afforded Me\ Me the olefins and their subsequent hydrogenation gave the N N tropan-3a-yl cyanoacetates. Reduction with lithium in liquid ammonia led to the exo 3P-stereoisomers.Ultimately con- densation with guanidine resulted in the formation of the 3-(5-pyrimidyl)tropanes. The amide group in the diamino- dihydropyrimidinones was eliminated in the usual way by phosphoryl chloride followed by reductive dehalogenation. NATURAL PRODUCT REPORTS 1988-G. FODOR AND R. DHARANIPRAGADA OH (18) (19) (20)a; R=H (17) b; R-Me BUt0,C I tBu 0,C I C H Ph 0P Bu'0,C U CH,Ph (22) (23)a; R=H ( 21 1 b; R = CH2Ph f-- -Me + H02C* Me I 0 0 CH2Ph CH Ph (26) a; R = CH2Ph (25) (2Ll b;R=H c; R = C02But 0 Me (27) Scheme 1 The synthesis of an intermediate in the synthesis of cocaine N-methylpyrrolidine-2,5-diaceticacid (1 6) has been accomplished in four steps.19 N-Methylpyrrole and acetylene- dicarboxylic acid gave a Diels-Alder adduct N-methyl-7- azabicyclo[2.2.1 ]hep ta- 2,5-diene-2,3-dicarboxylicacid which upon catalytic hydrogenation under pressure gave a di-carboxylic acid (15).The cleavage of the C-C bond in the dimethyl ester of (1 5)between the carboxyl groups was achieved at -78 "C with sodium in liquid ammonia; the product was (16). 3 The Synthesis of Homotropanes including Anatoxin-a Pseudopelletierine oxime by analogy with tropinone oxime,20 is chiral and was recently resolved by Razdan and Sharma.21 The phenomenon was predicted by Shriner in 1943 and named 'geometrical enantiomerism' by Lyle and Lyle22 in 1959 when they resolved cis- 1-methyl-2,6-diphenylpiperidin-4-one oxime.We reported in these Reports (Nat. Prod. Rep. 1985 2 pp. 222-225) the total synthesis of (+)-and of (-)-anatoxin-a. A recent short and efficient route23 to anatoxin-a starts with cis-cyclo-octane- 1,5-diol which upon oxidation and con-densation gives the bicyclic hemiketal aminal (1 7). Pyridine hydrobromide and bromine at 115 "Cresulted in reorganization of the aminal to the homotropan-2-one (18) presumably via bromination and cyclization of 5-methylaminocyclo-octanone. The homotropanone gave the intermediate24 @-unsaturated nitrile (19). Finally deprotonation (with LiNPrL) and trapping (with oxygen) of the delocalized anion followed by hydrolysis afforded N-methylanatoxin-a (20b) which had previously been converted into anatoxin-a (20a).Synthetic and conformational studies have been performed on anatoxin-a by Rapoport and co-w~rkers.~~ The thiolactam (2 l) which is readily available from D-pyroglutamic acid was alkylated with the trifiate of a protected ketohexanoate followed by sulphur contraction to yield the vinylogous carbamate (22) as shown in Scheme 1. Ammonium formate then gives the secondary amine (23a) from (22) in one step. The cis-N-benzyl isomer (24) was cyclized to (26a) via the iminium ion (25). The N-deprotected and re-protected bicyclic homo- tropanyl methyl ketone (26c) was then converted into the homotropenyl methyl ketone (27) by trimethylsilylation (to form the enol ether) and oxidation with lead(@ acetate; (27) was then deacylated to (20a). Extensive conformational analysis of anatoxin-a proved that the seven-membered ring adopts a twist-chair conformation.NOE experiments revealed that the acetyl side-chain is almost freely rotating while crystal-packing forces in the solid state force the enone into a single conformation. NATURAL PRODUCT REPORTS 1988 -ii,iii 0 ____) -QH Q+ I I OH I 0 (28) (29) OH h Reagents i PhH reflux; ii MnO, CH,Cl,; iii m-ClC H CO,H CH,Cl,; iv HO[CH,],OH TsOH PhH reflux; v MsCl Et,N CH,Cl,; vi NiCl, LiAlH, THF at -78 "C; vii AcC1 then H,6; & TsOH Me,CO Scheme 2 8u*O2C 4 Br 8 I P HQH -Br Br Br Br Br (35) (361 (37) (38) v vi 1 Reagents i PhHgCBr,; ii NaBH,CN NH,OAc MeCH(OH)Me 3A molecular sieves; iii TsOH then AgOTs MeCN; iv HBr hv then Et,N MeCN at 70"C then di-t-butyl dicarbonate CH,Cl,; v MeC(O)N(Me)OMe ButLi THF ; vi F,CCO,H CH,Cl Scheme 3 An independent synthesis of anatoxin-a is based on Tufa- riello's nitrone approach (Scheme 2).26 1-Pyrroline 1-oxide (28) gave upon cycloaddition with hexa-3,5-dien-2-01(29) a bicyclic adduct (30).This was oxidized to a second monocyclic nitrone (3 1). A second ring-closure afforded a cyclo-adduct (32) which then through a series of operations [via (33) and (34)] gave racemic anatoxin-a (20a). Another new strategy has been developedz7 for the synthesis of racemic anatoxin-a (Scheme 3). An aminobicyclo-octane intermediate (36) (as a mixture of stereoisomers) was prepared by reductive amination of a dibromobicyclo-octanone (35) and was converted (by a disrotatory electrocyclic cleavage -transannular cyclization) into the bromocyclo-octenylamine (37).This was converted into (38) which was allowed to react with N-methoxy-N-methyl- acetamide in the presence of t-butyl-lithium and then hydrolysed to give anatoxin-a (20a). A conformational study of homotropan-3-one and of homotropane itself has been carried out; both lH and 13C n.m.r. spectroscopy and measurements of dipole moments were used.28 The results pointed to a chair conformation of the homopiperidine ring (39) as expected. The 'H n.m.r. data and the dipole moments were similar to those that were reported for tropanes twenty years ago? 4 Pharmacology 4.1 Atropine and its Derivatives Tropine 3,5-dichlorobenzoate was synthesized and its effects on the flare response to intradermal injection of 5-hydroxy- tryptamine were examined.30 The effects of a series of atropine derivatives (analogues) some being substituted by an oxygen function and some having acetic or benzoic acid as the esterifying component instead of tropic acid and of nortropines and N-oxides were studied in the specific binding of 3H-labelled quinuclidinyl benzilate to muscarinic receptors in rat brain.31 The use of tropan-3-yl3,4,5-trichloro-and alkoxy-benzoates for the successful treatment of migraine has been patented.32 The formation of solid compounds (1 :1 ratio) between atropine scopolamine and other tropane derivatives with Bromocresol Green at pH 2.9 has been observed.33 The binding occurred NATURAL PRODUCT REPORTS 1988-G.FODOR AND R. DHARANIPRAGADA Me help understanding of the mode of action of anaesthetics. The +/ Br -microvascular effects of anisodamine were studied in the spinotrapezius muscle of a rat that was under alfathesin anesthesia ;anisodamine increased the arteriolar diameter and the velocity of cell AOW? (39) (LO)R= (S1-tropoyl 5 Analysis Atropine sulphate has been potentiometrically titrated with sodium tetraphenylborate ;ion-selective electrodes were used to detect the end-p~int.~' Anisodamine-selective electrodes were upon the tetraphenylborate or dipicrylamine salt in c1-analogy with the previous reference on atropine.47 Accordingly other alkaloids interfered with the determination.Atropine and scopolamine were determined in Belladonna tincture by using separation by t.1.c. on Siluf0'01.~~ Atropine sulphate has been MeNfloR HO OC(0)CPh,OH determined in lumitropine tablets by colorimetry with Bromo- cresol Green.50 Contamination of automatic injectors by A (Ll) R = (S)-tropoyl ( 12 1 material within the cartridge has been in~estigated.~~ formulation that contained atropine sulphate was found to be lethal to mice. The toxic material originated from zinc henolic hydroxyl group Of the dye and the lone comnounds that were nresegk,7iq,,&gm .m.Qng$>.m$la 1c__--ectrdns of The rropane-nitrogen giving :ocqpairs IGs quan-irties of atropine ic cornmerciai -preparations havc been difficult to understand how quaternary tropanium salts can determined by high-performance liquid chromatography in form such complexes.The visible ultraviolet and infrared injections in eye drops and in emulsions,52 or by h.p.1.c. with spectra of the complexes were Tropan-3a-yl 1H-fluorescence detection.53 Biological evaluation of injections of indole-3-carboxylate was studied for its antiarrhythmic and atropine sulphate was used -in comparison to analytical-electrophysiological effects as an antagonist of 5-hydroxy- chemical determination^^^ (cf. ref. 47). The stability of atropine tryptamine.34 and hyoscyamine in syrups as a function of pH has been The tropic acid residue in atropine was replaced by 4- studied;55 40% of the samples lost their activity above pH 7. morpholyl- and 4-piperazinyl-alkanoic acids and the central Studies on PVC atropine-selective electrodes have been ac-cholinolytic effect of these esters was investigated concerning ~omplished.~~ A photometric method has been elaborated for neuronal electric activity in rabbits.35 the determination of atropine and scopolamine in Belludonna extract^,^' based on t.1.c.of the extracts on silica gel. A novel t.1.c. technique was applied to differentiate cocaine from 4.2 Cocaine amphetamines and other stimulants of the central nervous A review (with 126 references) has appeared on the neuro- Ultramicrotitrimetric determination of alkaloids in chemical and physiological effects of cocaine related to the Datura flowers has been carried out by titration with 0.05N behavioural and learning mechanism^.^^ Cocaine was known to perchloric acid of the chloroform-methanol extracts.59 A induce teratogenesis and the mechanism has now been shown method for single-reagent polarization fluoroimmunoassay of to involve inhibition of the uptake of norepinephrine and benzoylecgonine which is the major metabolite of cocaine in placental vasoconstriction.37 urine has been worked out.60 Anisodamine has been studied by The effect of three different routes of administration of Raman spectroscopy in its interaction with phospholipid cocaine to rhesus monkeys was studied in order to learn about membranes.61 Trospium chloride is N-spirobutano-3a-benzil-the discriminative stimulus properties of cocaine and d-oyloxynortropanium chloride (42) which is metabolized to amphetamine.38 the spirotropanol in human plasma and urine.Its determination has been achieved62 by fluorometry after derivatization of the alcoholic hydroxyl group with benzoxaprofen chloride and 4.3 Scopolamine separation by h.p.1.c. The bioavailability of the quaternary Migraine headaches are being treated with transdermal compound trospium chloride has been determined as 2.9% in scop01amine.~~ A theoretical description of transdermal drug men from urinary extraction data.63 delivery has been developed. The levels of scopolamine in plasma have been predicted by using this theoretical Cimetropium bromide [N-cyclopropylmethylscopolaminium 6 References bromide (40)] has been studied as to its antimuscarinic properties ;41 in vitro cimetropium ion displaces [N-methyl-1 M.S. Al-Said W. C. Evans and R. J. Grout Phytochemistry 3H]scopolamine that is bound to muscarinic receptors in 1986 25 851. peripheral organs. Cimetropium bromide is as potent as 2 M. S. Al-Said W. C. Evans and R. J. Grout J.Chem. Soc. Perkin Trans. I 1986 957. atropine in inhibiting acetylcholine-induced intestinal spasms 3 E. Blossey H. Budzikiewicz M. Ohashi G. Fodor and C. in cats.42 Djerassi Tetrahedron 1964 20 585. The influence of ipratropium bromide (N-isopropylscopol- 4 G. Fodor and F. Soti J. Chem. SOC. 1965 6830. aminium bromide) on the frequency of beating of ciliary hairs 5 M. A. I. A1 Yahya W. C. Evans and R. J. Grout J. Chem. Soc. in human nasal mucosa has been in~estigated.~~ Perkin Trans. 1 1979 2130. 6 T. Ikenaga K. Hama S.Takemoto and H. Ohashi Nettai Nogyo 1985 29 229 (Chem. Abstr. 1986 104 106317). 4.4 Miscellaneous 7 Y. Kitamura H. Miura and M. Sugii Chem. Pharm. Bull. 1985 has been 33 5445. Anisodamine (41) i.e. 6P-hydroxyhyo~cyamine,~~ studied by e.s.r. It increases the fluidity of 8 T. Ikenaga S. Takemoto and H. Ohashi Nettai Nogyo 1985,29 231. dipalmitoyl phosphatidic acid liposomes. In a different 9 J. A. Fontenla A. Eirin and J. M. Calleja Arch. Farmacol. freeze-fracture electron microscopy was used to study the Toxicol. 1984 10 151. effect of anisodamine on the formation of lipidic particles in egg 10 G. H. Dewar R. T. Parfitt and L. Sheh J. Chem. Res. (9,1985 phosphatidylethanolamine liposomes. All of this is supposed to 1. NPR 5 11 G. H. Dewar R.T. Parfitt and L. Sheh Eur. J. Med. Chem.- Chim. Ther. 1985 20 228. 12 R.Banholzer and K. H. Pook Arzneim.-Forsch. 1985 35 217. 13 R.Dharanipragada and G. Fodor J. Chem. SOC. Perkin Trans. I 1986 545. 14 Reviewed by G. Fodor in ‘The Alkaloids’ ed. M. F.LGrundon (Specialist Periodical Reports) The Chemical Society London 1976 Vol. 6 p. 65. 15 R. Noyori and Y. Hayakawa Tetrahedron 1985 41 5879. 16 G. Fodor J. Toth 1. Koczor P. Dob6 and I. Vincze Chem. Ind. (London) 1956 764; J. Chem. SOC. 1959 3461. 17 G. Fodor Magy. Tud. Akad. Kem. Tud. Oszt. Kozl. 1963 20 338 (Chem. Abstr. 1964 60,573b). 18 H. Maag R. Locher J. J. Daly and I. Kompis Helv. Chim. Acta 1986 69 887. 19 A. P. Krapcho and J. A. Vivelo J. Chem. SOC. Chem. Commun.1985 233. 20 H. Singh and B. Razdan Indian J. Chem. 1968 569. 21 B. Razdan and A. K. Sharma Curr. Sci. 1984 53 1183. 22 R. E. Lyle and G. G. Lyle J. Org. Chem. 1959 24 1679. 23 J. R. Wiseman and S. Y. Lee J. Org. Chem. 1986 51 2485. 24 P. S. Watt and R. R. Wroble J. Org. Chem. 1976 41 2939. 25 A. Koskinen and H. Rapoport J. Med. Chem. 1985 28 1301. 26 J. F. Tufariello H. Merckler K. Pushpananda and A. Senaratne Tetrahedron 1985 41 3447. 27 R. L. Danheiser J. M. Morin Jr. and E. J. Salaski J.Am. Chem. SOC.,1985 107 8066. 28 P. Scheiber and K. Nador Liebigs Ann. Chem. 1985 913. 29 R. J. Bishop G. Fodor A. R. Katritzky L. E. Sutton and F. J. Swinbourne J. Chem. SOC. C 1966 74. Ref. 28 erroneously gave 1976 as the year of this publication.30 J. M. Orwin and J. R. Fozard Eur. J. Clin. Pharmacol. 1986,30 209. 31 X.-Y. Niu and Z.-H. Ren Yaoxue Xuebao 1984 19 326 (Chem. Abstr. 1985 103 47831). 32 J. R. Fozard and M. W. Gittos. U.S. Patent 4563455 (1981) (Chem. Abstr. 1986 105 54608). 33 A. Hernandez and J. Thomas Cienc. Ind. Farm. 1985 4 284 (Chem. Abstr. 1986 104 193019). 34 F. M. Williams A. L. Rothaul K. A. Kane and J. R. Parratt J. Cardiovasc. Pharmacol. 1985 7 550. 35 S. N. Kozhechkin and L. M. Kostochka Byull Eksp. Biol. Med. 1985 100 468 (Chem. Abstr. 1986 104 28389). 36 S. Castellani and E. H. Ellinwood Psychopharmacology (Amster- dam) 1985 2 442. 37 M. P. Mahalik R. F. Gautieri and D. E. Marin Jr. Res. Com- mun. Subst. Abuse 1984 5 279. 38 R. de la Garza and C.E. Johanson Pharmacol. Biochem. Behav. 1986 24 765. NATURAL PRODUCT REPORTS. 1988 39 M. N. Innes U.S. Patent 4532244 (Chem. Abstr. 1985 103 129 097). 40 R. H. Guy and J. Hadgraft J. Controlled Release 1985 1 177. 41 A. Schiavone G. B. Schiavi L. de Conti R. Micheletti A. Sagrada R. Hammer and A. Giachetti Arzneim.-Forsch. 1985 35 796. 42 A. Sagrada A. Schiavone L. Cervo and A. Giachetti Boll. Chim. Farm. 1986 125 75. 43 G. Akkoclu and N. Konietzko Atemwegs-Lungenkrankh. 1985 11 527. 44 A. Romeike Naturwissenschaften 1962 49 281 ; G. Fodor I. Koczor and G. Janzso Arch. Pharm. (Weinheim Ger.) 1962 295 91. 45 F. Hwang J.-W. Chen B.-C. Chao and Z.-F. Wang Bopuxue Zazhi 1984 1 481 (Chem. Abstr. 1986 104 200023).46 R. J. Xiu F. A. DeLano and B. W. Zweifach Adv. Chin. Med. Muter. Res. Int. Symp. 1984 1985 545 (Chem. Abstr. 1986 104 161 942). 47 M. E. Carrera A. Momberg and E. Cifuentes Bol. SOC. Chil. Quim. 1984 29 333. 48 L. Shen Y. Zhang and R.-Q. Yu Yaoxue Xuebao 1985 20 151 (Chem. Abstr. 1985 103 27363). 49 M. S. Grishina V. V. Dyukova L. L. Kovalenko and D. M. Popov Farmatsiya (Moscow) 1986 35 24 (Chem. Abstr. 1986 104 230558). 50 X. Wang Yaoxue Tongbao 1984 19 261 (Chem. Abstr. 1985 103 59394). 51 R. 1. Ellin A. Kaminskis P. Zvirblis W. E. Sultan M. B. Shutz and R. Matthews J. Pharm. Sci. 1985 74 788. 52 A. Better0 and P. Bolletin Ann. Chim. (Rome) 1985 75 351. 53 U. R. Cieri J. Assoc. Ofl.Anal. Chem. 1985 68 1042. 54 I. Shukrallah and A.Kandil J. Drug. Res. 1984 15 37. 55 H.-X. Lin H. Liu and G.-L. Shen Yaowu Fenxi Zazhi 1985 5 150 (Chem. Abstr. 1986 104 39816). 56 C. Kahn-Borenstein J. Pharm. Belg. 1986 41 5. 57 I. A Petrishek A. V. Gaevskii M. Ya. Lovkova A. B. Golovkin and N. 1. Grinkevich Khim.-Farm. Zh. 1986 20 710 (Chem. Abstr. 1986 105 102688). 58 J. M. Bonicamp and L. Pryor J. Tenn. Acad. Sci. 1986 61 9. 59 L.-S. Xu and A.-K. Liu Yaowu Fenxi Zazhi 1985 5 240 (Chem. Abstr. 1986 104 10685). 60 D. L. Colbert D. S. Smith J. Landon and A. M. Sidki Ann. Clin. Biochem. 1986 23 37. 61 Y. Sun and S. Wang Kexue Tongbao (Foreign Lung. Ed.) 1986 31 413 (Chem. Abstr. 1986 105 25333). 62 G. Schladitz-Keil H. Spahn and E. Mutschler J. Chromatogr. 1985 345 99. 63 G. Schladitz-Keil H. Spahn and E. Mutschler Arzneim.-Forsch. 1986 36,984.