HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 3, No. 4, 1975
Published online:
■ Mass Spectra of 3,4-Dihydro-4-imino-3-methylpyrimidines, Their Methylamino-isomers, and Related Systems
Desmond J. Brown* and Kazuharu Ienaga
*John Curtin School of Medical Research, Canberra City 2601, Australia
Abstract
Those 3,4-dihydro-4-imino-3-methylpyrimidines and related systems, which undergo rapid Dimroth rearrangement in solution, have mass spectra indistinguishable from their methylaminoisomers. Similar imines, which do not rearrange easily, have their own fragmentation patterns. 4-Methylamino, methoxy, methylthio, and hydroxymethyl derivatives of pyrimidine and quinazoline, as well as the corresponding 6-substituted purines, have a common fragmentation pathway, hitherto unrecognized.
Published online:
■ Reactions of Pyridine N-Oxide with Enamines of N-Substituted 4-Piperidones in the Presence of an Acylating Agent
Michio Nakanishi, Masahiro Yatabe, and Masatomo Hamana*
*Faculty of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
Abstract
Pyridine N-oxide reacts with enamines of N-benzoyl-, N-ethoxycarbonyl- and N-acetyl-4-piperidones in the presence of benzoyl chloride to give N-substituted 3-(2-pyridy1)-4-piperidones in fair or good yields. Enamine of N-methyl- or N-benzyl-4-piperidone resists this reaction.
Published online:
■ Reaction of 2-Substituted 6-Methyl-4H-1,3-oxazin-4-one Derivatives with Enamine
Tetsuzo Kato,* Yutaka Yamamoto, and Masatsugu Kondo
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Reaction of 1-(1-cyclopenten-1-yl)pyrrolidine (IIa) with 6-methyl-2-phenyl-4H-1,3-oxazin-4-one (Ia), 2-ethoxy-2,6-dimethyl-3,4-dihydro-2H-1,3-oxazin-4-one (Ib), and 2-benzyl-2-ethoxy-6-methyl-3,4-dihydro-2H- 1,3-oxazin-4-one (Ic) gave rise to 4-acetyl-3-hydroxy-1-phenyl-6,7-dihydro-5H-2-pyrindine (IIIa), 4-acetyl-3-hydroxy-1-methyl-6,7-dihydro-5H-2-pyrindine (IIIb), and 4-acetyl-1-benzyl-3-hydroxy-6,7-dihydro-4H-2-pyrindine (IIIc), respectively.
Similar reaction of 1-(1-cyclohexen-1-yl)pyrrolidine (IIb) with Ia afforded 4-acetyl-3-hydroxy-1-phenyl-5,6,7,8-tetrahydroisoquinoline (IV).
Published online:
■ The Origin of the Methylenoxy Bridge in Some Isoquinoline Alkaloids
Maurice Shamma* and Jerome L. Moniot
*Department of Chemistry, The Pennsylvania State University, York Campus, P1031 Edgecomb Avenue, York, Pennsylvania 17403, U.S.A.
Abstract
The isolation of nantenine methochloride (1) from T. polygamum points to an oxonium ion being involved in the biogenesis of the methylenoxy bridge of thalphenine (3). Oxonium ions are also implicated in the formation of insularine (7), cissampareine (9), and reponduline (12).
Published online:
■ Structural Elucidation of Two New Spirobenzylisoquinoline Alkaloids, Yenhusomine and Yenhusomidine
Sheng-Teh Lu,* Tsann-Long Su, Tetsuji Kametani, and Masataka Ihara
*School of Pharmacy, Kaohsiung Medical College, 100 Shih Chuen 1st Rd., Kaohsiung 80708, Taiwan, R.O.C.
Abstract
Yenhusomine and yenhusomidine, isolated from Corydalis ochotensis Turcz. (Papaveraceae) together with protopine, ochotensimine, and adlumidine, were assigned structures (3) and (4), respectively.
Published online:
■ Synthesis of N-Demethylfagaronine
Ichiya Ninomiya,* Takeaki Naito, and Hisashi Ishii
*Kobe Women’s College of Pharmacy, Motoyamakita, Higashinad, kobe, Hyogo658, Japan
Abstract
N-Demethylfagaronine (II) was synthesized by the route including the enamide photocyclization.
Published online:
■ Synthesis of the 1,2,3,4-Tetrahydroisoquinolines and Related Compounds by Phenolic Cyclisation
Tetsuji Kametani,* Keiichiro Fukumoto, Kazuo Kigasawa, Mineharu Hiiragi, and Haruhide Ishimaru
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
The new synthetic reaction of the 1-monosubstituted and 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines from 3-hydroxyphenethylamines and carbonyl compounds without an acidlc catalyst is described.
Published online:
■ The Formation of Alkaloids in Mammalian Tissues
Arnold Brossi*
*The Department of Chemistry Research, Hoffman-La Roghe Inc., Nutley, New Jersey 07110, U.S.A.
Abstract
Condensation of the amino acids L-dopa and L-tryptophan with acetaldehyde, a major metabolite of ethanol, may take place in mammalian systems. The following review summarizes the present knowledge on this interesting subject and includes the synthesis of a variety of substances which might be formed during such interactions.