39654-52-9

-

As part of our continuing efforts toward more fully understanding the structure-activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels-Alder cyc

An eight-step synthesis of 11,12-didehydrodibenzo[ a,e]cycloocten-5(6H)-one (10) was developed. The structure of 10 was assigned by spectroscopic means and confirmed by X-ray analysis of its 2,4-dinitrophenylhydrazone derivative. Reaction of the triple bond of 10 with dicarbonyl(h5-cyclopentadienyl)cobalt or dicarbonyl(η5-pentamethylcyclopentadienyl)cobalt gave the corresponding metal-stabilized cyclobutadiene complexes. Georg Thieme Verlag Stuttgart.

The synthesis of a series of novel tricyclic p-quinone methides (p-QMs) from 5-(p-alkyloxyaryl)-10,11-dihydrodibenzo[a,d]cyclohepten-5-ol and related substrates in moderate-to-good yields is reported. The reaction is proposed to proceed under mild acidic conditions by O-dealkylation of the p-alkoxy group on the p-position of the pendant 5-aryl ring on the B-ring of the tricyclic system.The effect of different alkyl groups on the oxygen atom, as well as substituent groups on the phenyl ring flanking the O-alkyl group has also been investigated The mechanism of the reaction is discussed in terms of the relatively high intermediate cation stabilities, the possible intermediacy of a hemiketal, as well as conformational effects. Various modifications to the central seven-membered B-ring to introduce more rigidity to the tricyclic system have been made and the scope of the reaction further elaborated. Furthermore, the single crystal structure of dienone 14 has been determined and the p-quinone methide shown to be non-planar, which would account for the relative conformational rigidity of these systems and their ability to accommodate the planar cyclohexa-2,5-dienone moiety and thus explain the stability of these systems relative to their 5- and six-membered B-ring counterparts. These compounds may be useful for the synthesis of novel dyes or compounds which may exhibit photochromic and thermochromic properties. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).

BABAR-Phos is a very stable polycyclic phosphirane which is easily synthesized in few steps from dibenzosuberenone. BABAR-Phos is remarkably stable and is not oxygenated with O2 nor does it react with sulfur in boiling toluene. BABAR-Phos can be used as a ligand in homogenous catalysis. Substituents at the carbon of the PC2 heterocycle can be introduced and asymmetric BABAR-Phos were prepared. The coordination chemistry of rhodium complexes containing these as ligands was investigated.

The 5H-dibenzocyclohepten-5-ols (1a-e) undergo sequential intramolecular and conventional Ritter reactions with acetonitrile to afford the cyclohepten-11-yl>acetamides (6a-e).Typical yields for these one-flask conversions are 52-64percent, except for the reaction of (1a) where production of the dimeric substance (4a) is favoured.Alcohol (1a) can provide either type of product in good yield, depending on the conditions employed, when reacted with benzonitrile.The molecular skeleton present in the adducts (6) has been confirmed by determination of the crystal structure of (6c) , a 9.188(3), b 14.632(5), c 16.563(9) Angstroem, α 115.64(9), β 90.92(2), γ 96.29(2) deg, Z 4, R 0.043>.

Sterically hindered 5,11-dicarbo analogues of clozapine were prepared as potential chiral antipsychotic agents, with the possibility that for a particular analogue the antispychotic activity of clozapine may reside in one enantiomer of the analogue wherea