Mass Spectra of Some Furoquinoline Alkaloids

Abstract

The mass spectra of six furoquinoline alkaloids have been recorded and mechanisms have been proposed for their fragmentation upon electron impact. Strong metastable peaks, present in all spectra, have aided in the interpretation of the fragmentation of these alkaloids. The three alkaloids with a methoxyl group in the 8-position of the quinoline ring may be differentiated from the other three by the presence of relatively intense peaks a t M-1 and M-29.In this investigation we wish to report upon the fragmentation of some furoquinoline alkaloids upon electron impact. The alkaloids which we have examined include dictamnine I and several of its derivatives containing methoxy and methylenedioxy substituents in the benzenoid ring. They are represented in the general formula shown below.The spectra of furan and some of its derivatives have been studied (1, 2) but very little has been reported on the spectra of quinoline and its derivatives (3). No studies t o our knowledge have been reported on the furoquinoline system itself. Oxygenated benzene systems have, however, been investigated in detail (2, 4, 5) and since all of these alkaloids with the exception of dictamnine carry oxygenated substituents in the benzene ring one might expect t o observe fragmentation processes akin to those of the oxygenated benzenes.T h e spectra of the six alkaloids are shown in Fig. 1. All show a n intense molecular ion peak a s one would expect of this aromatic system. I n each case they also exhibit a peak a t M-15 owing to the loss of a methyl group characteristic of the presence of methoxyl substituents. Of structural interest is the fact t h a t the three alkaloids with a n 8-methoxyl substituent show strong peaks a t M-1 and M-29. This behavior is also characteristic of 8-methoxy quinolines which we have measured in this laboratory. I t seems very likely, therefore, t h a t an 8-methoxyl substituent will give this characteristic pattern in all furoquinoline alkaloids.I n attempting t o rationalize the fragmentation of these alkaloids we have first examined the spectrum of dictamnine, the simplest member of the group, and have then examined the spectra of the other alkaloids t o ascertain if they undergo similar fragmentation processes.

Escherichia coli strains isolated from pigs with edema disease produce a variant of Shiga-like toxin II

“…Histological studies of pigs inoculated with EDP [15] (herein designated SLT-II variant) and mice or rabbits inoculated with Shiga toxin [16,17] suggest that these toxins may cause vascular lesions in animals. Furthermore, it has been postulated that the neurological signs observed in pigs with ED and mice or rabbits inoculated with Shiga toxin are secondary effects of alterations in the vasculature of the central nervous system rather than the result of the direct action of EDP or Shiga toxin on nerve cells [5,16,17].…”

A New Lanostane Triterpene from Skimmia laureola

“…lycopersici (tomato) [5]. A number of coumarins, e. g. isogospherol (2) [6], heraclenol (3) [7], (+)-7-methoxy-6-(2 R-methoxy-3 -hydroxy-3 -methyl butyl)coumarin (4) [1], 5,8-dimethoxy coumarin-2H-1-benzopyran-2-one (5) [8], 7-methoxy-6-[2 -oxo-3 -methyl butyl]coumarin (6) [9] and (+)-ulopterol (7) [10,11], were isolated, in addition to various quinoline alkaloids, e. g. 4-methoxy-1-methyl-3-(2 S-acetoxy-3 -ene butyl)-2-quinolone (8) [12], 4-methoxy-1-methyl-3-(2 S-acetoxy-3 -hydroxy butyl)-2-quinolone (9) [12], 3-hydroxy-2,2,6-trimethyl-3,4,5,6-tetrahydro-2H-pyrano[3,2-c]quinoline-5-one (10) [13], 4-methoxy-1-methyl-3-(2 -oxo-3 -methyl butyl)-2-quinolone (11) [15], 4-methoxy-1-methyl-3-(2 S-hydroxy-3 -ene butyl)-2-quinolone (12) [12], methyl isoplatydesmine (13) [2], ribalinin (14) [14] and dictamnine (15) [15 -18].…”

Synthetic oligodeoxyribonucleotide probes to detect verocytotoxin-producing Escherichia coli in diseased pigs

“…We have recently shown that SLT-I and SLT-II of E. coli O157 : H7 strains are not active in piglets: they were not able to induce fluid transudation nor did they cause mucosal lesions [20]. In contrast lesions were demonstrated with SLT-IIp [21]. 2.…”