Apparicine

C.gHajNj (MW 264) Apparicine (66) (Pericalline) 188-190 -176.5 XI, XVI calcarea, cerifera, citrifolia, coffeoides, dichotoma, divaricata, eusepala, heterophylla, heyneana, humblotii, orientalis, pachysiphon, sessilifolia, siphilitica... 

Almost all of the signals in the CMR spectrum could be superimposed on those of vobasinol (314) and apparicine (66). Diagnostically useful differences were found in the shift of C-3 of 314 and in the shift and multiplicity of C-22 of apparicine (downfield doublet, 112.2—>123.0 ppm). 

Predictably, vobparicine originates from attack of the strongly nucleophilic C-22 of 66 on C-3 of 314. In fact, when a mixture of vobasinol and excess apparicine was refluxed for 2 hr in 1.5% methanolic HC1 under nitrogen, vobparicine was formed, identical in all respects with the natural product. Vobparicine was considered to be a genuine alkaloid because the conditions for its synthesis were not achieved during isolation procedure. 

The related alkaloids ervaticine (15) and apparicine (16a) have been isolated from the leaves of Ervatamia coronaria (85H(23)2975) and from the wood of Vallesia antillana (77MI249), respectively. The latter exhibits high antibacterial activity. Subsequently, 16(S)-hydroxy-16,22-dihydroapparicine (16b) was isolated from the leaves of T. dichotoma (84JNP835). 

Apomorphine 169, 170 Aporphine alkaloids 151, 152 Apparicine 16, 147 Arborine 105, 106 Arctigenin 39 Aren tin 41, 47 Arecaidine 86... 

The first extractions of Strempeliopsis strempelioides K. Schum. (Family Apo-cynaceae), from Cuba, reveal that it is rich in alkaloids. The leaves and stem bark contain, amongst others, (+)-tubotaiwine and (+)-condylocarpine, and the stem bark also contains (-)-apparicine.80 Apparicine (pericalline) also occurs, together with O-acetylvallesamine, 19,20-dihydrocondylocarpine, and eleven other alkaloids, in the wood and stem bark of Ervatamia heyneana (Wall.) T. Cooke,81 and... 

In the proton n.m.r. spectrum of apparicine (164), spin-lattice relaxation times and selected steady-state and transient n.O.e. enhancements have been studied.82 In... 

Among compounds related to uleine that have been isolated from A. dasycarpon are X-noruleine (CCLVII-B), dasycarpidone (CCLVII-A), the corresponding alcohol, dasycarpidol, X-nordasycarpidone, and 1,1 -dihydro-l -hydroxyuleine. Dasycarpidone may be obtained from uleine by ozonolysis, or from dasycarpidol by oxidation with chromium trioxide in pyridine. l,l -Dihydro-l -hydroxyuleine has been synthesized from uleine by hydroboration (143b). Apparicine, an alkaloid of novel skeleton present in A. dasycarpon and several other species, has been shown to have the structure CCLVII-U (37). 

This alkaloid has been identified as apparicine [CCLVII-U p. 473 (37)]. 

Mass spectrometry aided also in the structure determination of apparicine (223),110 vallesamine (224),111 and o-acetylvallesamine.111 The spectrum of uleine (225)112 aided in the identification of naturally occurring derivatives thereof.113... 

As the azocinoindole 40 constitutes the tricyclic substructure of the indole alkaloid apparicine , we attempted to improve the cyclization yield. Satisfactorily, the regioselectivity was completely switched to the 8-endo mode when the alkene acceptor was substituted at the internal position by a bromine atom. Thus, cyclization of selenoester 43 led to the desired target 40 as the only reaction product in 75% yield. Clearly, the bromine atom not only sterically prevented the competitive 1-exo attack, but also benefited the cyclization by activation of the double bond. It should be noted that similar halogen-controlled 8-endo cyclizations are known in the literature, but involving amidyl-type radicals <06OL2647>. 

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