Domingo Dominguez

Synthesis of fused rings at a pivotal nitrogen: tandem Heck reactions of N-vinyl-2-iodobenzamides

Abstract A short two-step synthesis of the tetracyclic nitrogen heterocycles 2 (isoindoloneindole, isoindoloneisoquinoline and isoindolone[3]benzazepine) is presented. Condensation of the corresponding o- bromoarylamine with acetaldehyde followed by acylation with o- iodobenzoyl chloride affords the key dihalo N -vinylbenzamides 1 , which are then cyclized by a tandem Heck reaction.

Synthesis of the benzo[b]fluorene core of the kinamycins by cycloaromatization of non-conjugated benzotriynes

Abstract Non-conjugated benzotriynes 2 undergo a novel radical cycloaromatization to provide the benzo[ b ]fluorene core of the kinamycins. The overall process involves a thermal intramolecular cyclization to the non-benzenoid biradicals 4 followed by radical cyclization and hydrogen abstraction.

A new rearrangement of cyclic allenes via 1,2-dehydro[10]annulenes: formation of benzo[c]fluorenones

Abstract A new rearrangement of cyclic allenes giving benzo[ c ]fluorenones was observed when studying intramolecular dehydro Diels–Alder reactions of silyl-substituted alkynes with arenynes (aryldiacetylenes).

[1]Benzopyrano[2,3,4-i,j]isoquinolines: a new, versatile route from 1-bromoxanthones

Abstract [1]Benzopyrano[2,3,4- i , j ]isoquinolines were synthesized from a bromoxanthone by assembly of the isoquinoline ring in three steps: vinylation, hydroamination and ring-closing reduction of the xanthone carbonyl.

Synthesis of a (2)benzazepine analogue of clavizepine

Abstract The synthesis of N -tosylbenzopyran[2]benzazepinone 2 using a simple protocol for assembly of an azepine ring on the xanthene skeleton is described. Formation of the Cue5f8C bond between C9 of the xanthen-9-ol 7 and the β-C of N -tosyl aminoacetaldehyde dimethyl acetal leads to 10 , which upon treatment with formaldehyde undergoes ring closure.

Chapter 4 Dibenzazonine Alkaloids

Publisher Summary This chapter describes the occurrence and classification, structure determination, synthesis, biosynthesis, pharmacological properties, and related alkaloids: dibenzazecines. Dibenzazonines are found in plants of the families Menispermaceae, Leguminosae, Fumariaceae, and Papaveraceae, and only eight naturally occurring dibenzazonines are known. Shamma and Moniot classified dibenzazonines into two groups: type A, which comprises the fully oxygenated bases, and type B, which includes alkaloids that have undergone a net deoxygenation with respect to their biogenetic precursors. The first group is represented by erybidine (1) and crassifolazonine (2), which both have substitutes at C-2 and C-3 but differ in the oxygenation pattern of ring C. Alkaloids of type B are more numerous and include the unusually tetrasubstituted protostephanine (3) and the trisubstituted laurifonine (4), laurifine (5), laurifinine (6), neodihydrothebaine (7), and bractazonine (8). Dibenzazonines have been synthesized by three general approaches: (A) construction of the azonine ring from an appropriately substituted biphenyl derivative, (B) formation of the aryl–aryl bond, and (C) by rearrangement of various types of alkaloids. The alkaloid protostephanine exerts a moderately strong and persistent hypotensive effect. Most of the other compounds show some central nervous activity.