Cularine, Cancentrine, and Quettamine Alkaloids

Abstract

The cularines are isoquinoline alkaloids with a tetracyclic nucleus incorporating a central dihydrooxepine or oxepine system. Most cularines have been found among plants of the Fumariaceae, where they are formed by intramolecular oxidative coupling of 7,8,3',4'-tetraoxygenated tetrahydrobenzylisoquinolines.Lately, however, the cularine base gouregine (31) has been isolated from a member of the Annonaceae, and its biogenesis probably proceeds by oxidation of an aporphine precursor (54). Even more recently, the cularines linaresine (36) and dihydrolinaresine (37) have been encountered in a barberry bush (Berberidaceae), and their biogenetic origin may possibly derive from initial oxidation of a protoberberinium salt (70).Over the years, different numbering systems for the cularines have been used, but the more systematic one is given below and is based on analogy with the numbering system for the benzylisoquinolines.Cularine alkaloids obtained from the Fumariaceae are generally strongly dextrorotatory. (+)-Cularine (7) itselfwas assigned the S configuration at C-1 based on chemical (15) as well as X-ray evidence ( 3 1, 32).Cularine and aporphine alkaloids exhibit an interesting parallelism. Oxocularines (e.g., 20) are found in nature and should be compared with the numerous oxoaporphines known. The 4-hydroxylated cularines limousamine (14) and 4-hydroxysarcocapnine (27) have their counterparts among the 4-hydroxylated aporphines. Additionally, a 3,4-dioxocularine such as yagonine (39) is the analog of the 4,5-dioxoaporphines pontevedrine and cepharadione-B. The aptly named aristoyagonine (4) bears a distinct structural analogy to the aristolactams. Finally, quaternary N-methocularines may undergo Hofmann p-elimination to afford secocularines (e.g., 42) as a counterpart to the formation of P-dimethylaminoethylphenanthrenes from aporphines.Cancentrine-type alkaloids are dimers involving a cularine unit linked to a morphinan unit through a spiro-bridge. They were found in a Dicentra species, and they have been included in the present listing. The numbering system is as indicated below.Whereas classical-type cularine alkaloids of the Fumariaceae are biogenetically derived from intramolecular oxidative coupling of tetraoxygenated tetrahydrobenzylisoquinoline precursors, the quettamines are obtained from in vivo intramolecular

Synthesis of Biaryl Ethers by the Copper-Catalyzed Chan–Evans–Lam Etherification from Benzylic Amine Boronate Esters

“…The Chan–Evans–Lam etherification of ortho -borylated benzylic amines was recognized as a valuable synthetic reaction based on the prevalence of biaryl ethers, with a benzylic amine in the ortho position, in biologically active compounds. − For example, tetrandrine, a bisbenzylisoquinoline alkaloid with extensive bioactivity is a cyclic diaryl ether with built-in benzylic amines (Figure ). Although this class of ethers has been accessed by the Ullman reaction or by nucleophilic aromatic substitution, the Chan–Evans–Lam etherification − was envisioned to have significant advantages over these methods including the ability to selectively incorporate the boronate ester into a readily available amine, and the orthogonal reactivity of the boronate ester to any other halides present in the arene.…”

Composition Alcaloëdique de Corydalis claviculata

“…Les structures de la(+)-réticuline (0,02 g) (17), la(+)-juziphine (0,02 g) ( 18), la léonticine (0,01 g) (6,7), la(-)-glaziovine(0,02g)(19), la(+>isoboldine(0,11 g) (20), la(+ )-stylopine(3,6g)(21), la(-)cheilanthifoline (0,13 g) ( 21), l'oxy-8 coptisine (0,01 g) ( 22), la protopine (8,9 g) ( 23), la dihydrosanguinarine(0,01 g) (24), la( -)-pallidine (0,01 g) (25), lacrassifolazonine (0,52 g) ( 26), la viguine(0,01 g) (15), la (+ )-cularine (16,4 g) (27), la(+)-cularidine (20,1 g) ( 25), (27), la(+)-cularicine [5] (0,02 g) ( 27), et la (+ )-enneaphylline (0,01 g) (28,29) ont été déterminées en comparant leurs valeurs spectrales avec celles données par la bibliographie.…”

Base Promoted Intramolecular O‐arylation For The Synthesis of Dibenzo[b,f]oxepinones Toward Dihydroartocarpol D

“…Dibenzo[ b , f ]oxepins are significant framework present in many biologically activity natural products such as the artocarpols, [1] bauhinoxepins, [2] and cularines [3] (Figure 1). Besides, a large number of synthetic dibenzo[ b , f ]oxepins and analogues have been proved to be excellent therapeutic agents.…”