Palladium-mediated approach to dibenzo[b,e][1,4]diazepines and benzopyrido-analogues. An efficient synthesis of tarpane

Palladium-Catalyzed Benzodiazepines Synthesis

This review is focused on palladium-catalyzed reactions as efficient strategies aimed at the synthesis of different classes of benzodiazepines. Several reaction typologies are reported including hydroamination, amination, C–H arylation, N-arylation, and the Buchwald–Hartwig reaction, depending on the different substrates identified as halogenated starting materials (activated substrates) or unactivated unsaturated systems, which then exploit Pd(0)- or Pd(II)-catalytic species. In particular, the use of the domino reactions, as intra- or intermolecular processes, are reported as an efficient and eco-compatible tool to obtain differently functionalized benzodiazepines. Different domino reaction typologies are the carboamination, aminoarylation, aminoacethoxylation, aminohalogenation, and aminoazidation.

One-Pot Synthesis of Seven-Membered Heterocyclic Derivatives of Diazepines Involving Copper-Catalyzed Rearrangement Cascade Allyl-Amination

A novel and efficient method has been proposed for the synthesis of 1,4-benzodiazepine-5-ones from o-nitrobenzoic N-allylamides by using molybdenyl acetylacetonate and copper(II) trifluoromethanesulfonate as catalysts in the presence of triphenylphosphine. This synthesis process involves nitrene formation, C-H bond insertion, C═C bond rearrangement, and C-N bond formation cascade reactions via copper- and molybdenum-catalyzed mediation. The method features a wide substrate scope and a moderate to high yield (up to 90%), exhibiting the possibility for practical applications.

Direct Reductive Cyclocondensation of the Nitro Group with the Amido Group: Key Role of the Iminophosphorane Intermediate in the Synthesis of 1,4-Dibenzodiazepine Derivatives

A class of dialkylamino-substituted dibenzodiazepines and their hetero analogues was synthesized by the intramolecular aza-Wittig condensation of the amido group with iminophosphoranes. The one-pot, two-step procedure includes reductive synthesis of the intermediate iminophosphoranes from the corresponding nitroamides and tributylphosphine.

A catalytic route to dibenzodiazepines involving Buchwald–Hartwig coupling: reaction scope and mechanistic consideration

We report a new synthetic method for the synthesis of a family of dibenzodiazepines (DBDAs), employing Pd-catalyzed C–N coupling of o-bromoaldimine, with o-bromoaniline as the key step.

MoO2Cl2(DMF)2 catalyzed microwave assisted reductive cyclisation of nitroaromatics into dibenzodiazepines

Microwave induced, MoO₂Cl₂(DMF)₂ catalyzed synthesis of novel dibenzodiazepine scaffolds with potential biocidal activity.

11-(4-Meth-oxy-phen-yl)-3,3-dimethyl-2,3,4,5,10,11-hexa-hydro-1H-dibenzo[b,e][1,4]diazepin-1-one monohydrate

In the title compound, C(22)H(24)N(2)O(2)·H(2)O, the co-crystallized water mol-ecule inter-acts with the N and O atoms of the mol-ecule through O(w)-H⋯N, O(w)-H⋯O(meth-yl) and N-H⋯O(w) hydrogen-bonding inter-actions. These hydrogen bonds, along with the inter-molecular N-H⋯O=C hydrogen-bonding inter-actions, connect the mol-ecules into a three-dimensional network. The dihedral angle between the two aromatic rings is 65.46 (10)°.

Solvent-free, microwave-assisted N-arylation of indolines by using low palladium catalyst loadings

Indoline-based compounds are abundant in nature, and the indoline skeleton is an often-encountered scaffold in a range of biologically active alkaloids, pharmaceutically active compounds, and functional molecules (e.g., sensitizers for solar cells). The wide range of uses warrants further interest in the structural modification of this class of compounds. A series of substituted N-aryl indolines is prepared by a solvent-free, palladium-catalyzed procedure. The procedure requires only low loadings of catalyst, uses microwave irradiation, and starts from commercially available substrates. The method proceeds in good yields and in short reaction times with aryl bromides, chlorides, and iodides, also on 2-substituted indolines. The combination of solvent-free methods with microwave heating will further increase in importance in the search for more environmentally acceptable synthesis methods.

2-Methyl-N-p-tolyl-benzamide: a second monoclinic polymorph

The title compound, C₁₅H₁₅NO, (I), is a polymorph of the structure (II) reported by Gowda et al. [Acta Cryst. (2008), E64, o1494]. Compound (II) crystalllizes in the space group C2/c (Z = 8), whereas the title compound occurs in space group P2₁/c (Z = 4). The two mol­ecular structures differ slightly in the relative orientations of their central amide group with respect to the benzoyl ring [dihedral angles of 55.99 (7) for (I) and 59.96 (11)° for (II)] and in the inclination of the benzoyl and aniline rings [88.67 (8) for (I) and 81.44 (5)° for (II)]. In the crystal structure of (I), mol­ecules are linked by N—H⋯O hydrogen bonds, forming C(4) chains, which are augmented by weak C—H⋯O inter­actions. The structure is further stabilized by C—H⋯π contacts involving both of the aromatic rings.

4-Chloro-N-cyclo-hexyl-benzamide

In the title compound, C₁₃H₁₆ClNO, the cyclo­hexyl ring adopts a chair conformation, with puckering parameters Q = 0.576 (3) Å, θ = 0.1 (3) and ϕ = 8 (15)°. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link mol­ecules into one-dimensional chains propagating in [010].

4-Chloro-N-m-tolylbenzamide

In the title compound, C₁₄H₁₂ClNO, the dihedral angle between the two aromatic rings is 11.29 (15)°. The crystal packing is stabilized by N—H⋯O hydrogen bonds linking the mol­ecules into chains running along the c axis.

Heterocycles [h]-fused onto 4-oxoquinoline-3-carboxylic acid, part VIII [1]. Convenient synthesis and antimicrobial properties of substituted hexahydro[1,4]diazepino[2,3-h]quinoline-9-carboxylic acid and its tetrahydroquino[7,8-b]benzodiazepine analog

[1,4]Diazepino[2,3-h]quinolone carboxylic acid 3 and its benzo-homolog tetrahydroquino[7,8-b]benzodiazepine-3-carboxylic acid 5 were prepared via PPAcatalyzed thermal lactamization of the respective 8-amino-7-substituted-1,4-dihydroquinoline-3-carboxylic acid derivatives 8, 10. The latter compounds were obtained by reduction of their 8-nitro-7-substituted-1,4-dihydroquinoline-3-carboxylic acid precursors 7, 9 which, in turn, were prepared by reaction of 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-1,4-dihydroquinoline-3-carboxylic acid (6) with each of beta-alanine and anthranilic acid. All intermediates and target compounds were characterized using elemental analysis, NMR, IR and MS spectral data. The prepared targets and the intermediates have shown interesting antibacterial activity mainly against Gram positive strains. In particular, compound 8 showed good activity against S. aureus (MIC = 0.39 microg/mL) and B. subtilis (MIC = 0.78 microg/mL). Compounds 5a and 9 have also displayed good antifungal activity against C. albicans (MIC = 1.56 microg/mL and 0.78 microg/mL, respectively). None of the compounds tested showed any anticancer activity against solid breast cancer cell line MCF-7 cells or a human breast adenocarcinoma cell line.

N-Butyl-4-chloro-benzamide

In the title benzamide derivative, C(11)H(14)ClNO, the chloro-benzene and butyl-amine groups are each planar, with mean deviations from the planes of 0.013 and 0.030 Å, respectively, and a dihedral angle of 2.54 (9)° between the two planes. In the crystal structure, N-H⋯O hydrogen bonds link mol-ecules in rows along a. Short inter-molecular Cl⋯Cl inter-actions [3.4225 (5) Å] link these rows into sheets in the ac plane. Additional weak C-H⋯O and C-H⋯π inter-actions generate a three-dimensional network.