The Alkaloids of Papaveraceous Plants: Lv. A New Alkaloid, Eschscholtzidine, and Its Structure

Abstract

A very small amount of a new alkaloid, eschscholtzidine, present in E. californica, was s11on.n to be eschscholtzine in lvhich a methylenedioxy group is replaced by two methoxyls.The present authors have recorded the isolatioll of a number of alltaloids from Eschscholtzia californica Cham.(1). The fraction which yielded eschscholtzine has now yielded a nev-base, escl~scholtzidine, which so far has not been crystallized either free or in the form of salts. I t was ultimately purified by means of column chromatography, and its purity checked by the thin-layer technique (R, 0.51 on silica gel with cyclohexanechloroform-diethylamine (7: 2: 1 ) ) .T h a t this allcaloid was related t o eschscholtzine (2) was suspected because of its chemical behavior and its source. The nuclear magnetic resonance spectrum confirlned this close relation, and in fact indicated the structure shown by I.("Tz-oh~e OhIe Its nuclear nlagiletic resonance spectrum was superposable on that of eschscholtzine, except that 1101~ t~v o methoxyls (T 6.18 (31-1) and 6.27 (3EI)) and a methylenedioxy group (T 4.23 (21-1)) were evident. I-Ience it appeared t o have structure I. This was readily confirmed by first delnethylenating the alltaloid t o the corresponding dihydroxy base followed by methylation with diazomethane. The product was identical with a specimen of argenlonine lcindly supplied by Dr. T. 0. Soine. EXPERIMENTALThe final mother liquors, from \vhich no further alkaloids could be crystallized either a s free bases or as salts (hydrochloride, nitrate, and hydrobromide) (from 270 kg of E. californica), were combined, dissolved in dilute hydrochloric acid, and filtered. The solutior~ was then extracted with several portions of chloroform. The alltaloids were regenerated from the fraction that was extracted with chloroform, dissolved in ether, and dried with potassium hydroxide.The solution was then passed through a long colun~n of alumina (250 g, p1-I 8.15, activity 0.98) and eluted with dry cther. The first fraction colored on exposure to air and was discarded. The large middle fraction was again passed through a second column, and its middle fraction proved to be chromatographically pure; yield 3 g. For analysis a portion was distilled a t 180' and 1 nlm.

The Pavine and Isopavine Alkaloids

“…Journal ofNatural Products [Vol. 46,No. 3 It is important to note that the data quoted below are as cited in the original literature.…”

A Caryachnine N-Methosalt From Cryptocarya chinensis and PMR Spectral Characteristics of Some Quaternary Pavine Alkaloids

“…MS-902 instrument with a direct inlet system. 296 nm; cd (MeOH): [S]297 -39,400, [8]279 +82,000, +]233 -380,400; pmr (CDsOD): 3.30 (s, NMe2), 3.92 (s, OMe), 5.95 (AB q, J=1 Hz, OC#20), 6.60 (s, 2 ), 6.82 and 6.95 (2s, 1 Ar# each), (0 30 -20): 6.61, 6.65, 6.86 and 6.98 (4s, 1 Ar# each). This compound was identified by conversion to ( -)-caryachine methiodide (6) and a direct comparison of the latter with synthetic ( = )-caryachine methiodide (6a).…”

“…So far, three tertiary pavine alkaloids have been isolated from this species, namely, crychine (1), (+)-O-methylcaryachine (2a), and ( -jcaryachine (3), which also exists in racemic form (3a). Crychine is identical to eschscholtzine isolated from Eschscholtzia californica (4, 5), and (+)-0-methylcaryachine is the optical antipode of (-)-eschscholtzidine (2) from the same source (6). Two alternate structures, 2-hydroxy-3-methoxy-8,9-methylenedioxy-Armethylpavinane (3) and 3-hydroxy-2-methoxy-8,9-methylenedioxy-A7-methylpavinane (4), have been proposed for caryachine (2).…”

“…-dimethyl group appeared at 3.30 as a singlet. An iodide salt (6) was prepared from the perchlorate salt (5), and the mass spectrum of this iodide salt reflected the distinctive characteristics of the A7,A7-dimethylpavinane skeleton. As illustrated in scheme 1, the major mode of fragmentation represents the result from thermolysis of the parent salt (6) giving the tertiary molecular ion (11) at m/e 325 and the methyl iodide ion (12) at m/e 142.…”

“…The base peak (13) at m/e 188 and the major ion (14) at m/e 190 correspond to each half of the A7,AT-dimethylpavinane skeleton. The above data can be accommodated by two alternative structures, caryachine methiodide (6) or isocaryachine methiodide (7). Racemic forms of both compounds (6a and 7a) were then synthesized from (±)-caryachine (3a) and (±)-isocaryachine (4a) obtained from our previous work (7,11).…”